constraint.c

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/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): 2007, Joshua Leung, major recode
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include <stdio.h> 
#include <stddef.h>
#include <string.h>
#include <math.h>
#include <float.h>

#include "MEM_guardedalloc.h"

#include "BLI_blenlib.h"
#include "BLI_math.h"
#include "BLI_editVert.h"
#include "BLI_kdopbvh.h"
#include "BLI_utildefines.h"

#include "DNA_armature_types.h"
#include "DNA_camera_types.h"
#include "DNA_constraint_types.h"
#include "DNA_modifier_types.h"
#include "DNA_object_types.h"
#include "DNA_action_types.h"
#include "DNA_curve_types.h"
#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"

#include "DNA_lattice_types.h"
#include "DNA_scene_types.h"
#include "DNA_text_types.h"
#include "DNA_tracking_types.h"
#include "DNA_movieclip_types.h"


#include "BKE_action.h"
#include "BKE_anim.h" /* for the curve calculation part */
#include "BKE_armature.h"
#include "BKE_blender.h"
#include "BKE_bvhutils.h"
#include "BKE_camera.h"
#include "BKE_constraint.h"
#include "BKE_displist.h"
#include "BKE_deform.h"
#include "BKE_DerivedMesh.h"    /* for geometry targets */
#include "BKE_cdderivedmesh.h" /* for geometry targets */
#include "BKE_object.h"
#include "BKE_ipo.h"
#include "BKE_global.h"
#include "BKE_library.h"
#include "BKE_idprop.h"
#include "BKE_shrinkwrap.h"
#include "BKE_mesh.h"
#include "BKE_tracking.h"
#include "BKE_movieclip.h"

#ifdef WITH_PYTHON
#include "BPY_extern.h"
#endif

#ifndef M_PI
#define M_PI        3.14159265358979323846
#endif



/* ************************ Constraints - General Utilities *************************** */
/* These functions here don't act on any specific constraints, and are therefore should/will
 * not require any of the special function-pointers afforded by the relevant constraint 
 * type-info structs.
 */

/* -------------- Naming -------------- */

/* Find the first available, non-duplicate name for a given constraint */
void unique_constraint_name (bConstraint *con, ListBase *list)
{
    BLI_uniquename(list, con, "Const", '.', offsetof(bConstraint, name), sizeof(con->name));
}

/* ----------------- Evaluation Loop Preparation --------------- */

/* package an object/bone for use in constraint evaluation */
/* This function MEM_calloc's a bConstraintOb struct, that will need to be freed after evaluation */
bConstraintOb *constraints_make_evalob (Scene *scene, Object *ob, void *subdata, short datatype)
{
    bConstraintOb *cob;
    
    /* create regardless of whether we have any data! */
    cob= MEM_callocN(sizeof(bConstraintOb), "bConstraintOb");
    
    /* for system time, part of deglobalization, code nicer later with local time (ton) */
    cob->scene= scene;
    
    /* based on type of available data */
    switch (datatype) {
        case CONSTRAINT_OBTYPE_OBJECT:
        {
            /* disregard subdata... calloc should set other values right */
            if (ob) {
                cob->ob = ob;
                cob->type = datatype;
                cob->rotOrder = EULER_ORDER_DEFAULT; // TODO: when objects have rotation order too, use that
                copy_m4_m4(cob->matrix, ob->obmat);
            }
            else
                unit_m4(cob->matrix);
            
            copy_m4_m4(cob->startmat, cob->matrix);
        }
            break;
        case CONSTRAINT_OBTYPE_BONE:
        {
            /* only set if we have valid bone, otherwise default */
            if (ob && subdata) {
                cob->ob = ob;
                cob->pchan = (bPoseChannel *)subdata;
                cob->type = datatype;
                
                if (cob->pchan->rotmode > 0) {
                    /* should be some type of Euler order */
                    cob->rotOrder= cob->pchan->rotmode; 
                }
                else {
                    /* Quats, so eulers should just use default order */
                    cob->rotOrder= EULER_ORDER_DEFAULT;
                }
                
                /* matrix in world-space */
                mult_m4_m4m4(cob->matrix, ob->obmat, cob->pchan->pose_mat);
            }
            else
                unit_m4(cob->matrix);
                
            copy_m4_m4(cob->startmat, cob->matrix);
        }
            break;
            
        default: /* other types not yet handled */
            unit_m4(cob->matrix);
            unit_m4(cob->startmat);
            break;
    }
    
    return cob;
}

/* cleanup after constraint evaluation */
void constraints_clear_evalob (bConstraintOb *cob)
{
    float delta[4][4], imat[4][4];
    
    /* prevent crashes */
    if (cob == NULL) 
        return;
    
    /* calculate delta of constraints evaluation */
    invert_m4_m4(imat, cob->startmat);
    mult_m4_m4m4(delta, cob->matrix, imat);
    
    /* copy matrices back to source */
    switch (cob->type) {
        case CONSTRAINT_OBTYPE_OBJECT:
        {
            /* cob->ob might not exist! */
            if (cob->ob) {
                /* copy new ob-matrix back to owner */
                copy_m4_m4(cob->ob->obmat, cob->matrix);
                
                /* copy inverse of delta back to owner */
                invert_m4_m4(cob->ob->constinv, delta);
            }
        }
            break;
        case CONSTRAINT_OBTYPE_BONE:
        {
            /* cob->ob or cob->pchan might not exist */
            if (cob->ob && cob->pchan) {
                /* copy new pose-matrix back to owner */
                mult_m4_m4m4(cob->pchan->pose_mat, cob->ob->imat, cob->matrix);
                
                /* copy inverse of delta back to owner */
                invert_m4_m4(cob->pchan->constinv, delta);
            }
        }
            break;
    }
    
    /* free tempolary struct */
    MEM_freeN(cob);
}

/* -------------- Space-Conversion API -------------- */

/* This function is responsible for the correct transformations/conversions 
 * of a matrix from one space to another for constraint evaluation.
 * For now, this is only implemented for Objects and PoseChannels.
 */
void constraint_mat_convertspace (Object *ob, bPoseChannel *pchan, float mat[][4], short from, short to)
{
    float tempmat[4][4];
    float diff_mat[4][4];
    float imat[4][4];
    
    /* prevent crashes in these unlikely events  */
    if (ob==NULL || mat==NULL) return;
    /* optimise trick - check if need to do anything */
    if (from == to) return;
    
    /* are we dealing with pose-channels or objects */
    if (pchan) {
        /* pose channels */
        switch (from) {
            case CONSTRAINT_SPACE_WORLD: /* ---------- FROM WORLDSPACE ---------- */
            {
                /* world to pose */
                invert_m4_m4(imat, ob->obmat);
                copy_m4_m4(tempmat, mat);
                mult_m4_m4m4(mat, imat, tempmat);
                
                /* use pose-space as stepping stone for other spaces... */
                if (ELEM(to, CONSTRAINT_SPACE_LOCAL, CONSTRAINT_SPACE_PARLOCAL)) {
                    /* call self with slightly different values */
                    constraint_mat_convertspace(ob, pchan, mat, CONSTRAINT_SPACE_POSE, to);
                }
            }
                break;
            case CONSTRAINT_SPACE_POSE: /* ---------- FROM POSESPACE ---------- */
            {
                /* pose to world */
                if (to == CONSTRAINT_SPACE_WORLD) {
                    copy_m4_m4(tempmat, mat);
                    mult_m4_m4m4(mat, ob->obmat, tempmat);
                }
                /* pose to local */
                else if (to == CONSTRAINT_SPACE_LOCAL) {
                    if (pchan->bone) {
                        if (pchan->parent) {
                            float offs_bone[4][4];
                                
                            /* construct offs_bone the same way it is done in armature.c */
                            copy_m4_m3(offs_bone, pchan->bone->bone_mat);
                            copy_v3_v3(offs_bone[3], pchan->bone->head);
                            offs_bone[3][1]+= pchan->bone->parent->length;
                            
                            if (pchan->bone->flag & BONE_HINGE) {
                                /* pose_mat = par_pose-space_location * chan_mat */
                                float tmat[4][4];
                                
                                /* the rotation of the parent restposition */
                                copy_m4_m4(tmat, pchan->bone->parent->arm_mat);
                                
                                /* the location of actual parent transform */
                                copy_v3_v3(tmat[3], offs_bone[3]);
                                offs_bone[3][0]= offs_bone[3][1]= offs_bone[3][2]= 0.0f;
                                mul_m4_v3(pchan->parent->pose_mat, tmat[3]);
                                
                                mult_m4_m4m4(diff_mat, tmat, offs_bone);
                                invert_m4_m4(imat, diff_mat);
                            }
                            else {
                                /* pose_mat = par_pose_mat * bone_mat * chan_mat */
                                mult_m4_m4m4(diff_mat, pchan->parent->pose_mat, offs_bone);
                                invert_m4_m4(imat, diff_mat);
                            }
                        }
                        else {
                            /* pose_mat = chan_mat * arm_mat */
                            invert_m4_m4(imat, pchan->bone->arm_mat);
                        }
                        
                        copy_m4_m4(tempmat, mat);
                        mult_m4_m4m4(mat, imat, tempmat);
                    }
                }
                /* pose to local with parent */
                else if (to == CONSTRAINT_SPACE_PARLOCAL) {
                    if (pchan->bone) {
                        invert_m4_m4(imat, pchan->bone->arm_mat);
                        copy_m4_m4(tempmat, mat);
                        mult_m4_m4m4(mat, imat, tempmat);
                    }
                }
            }
                break;
            case CONSTRAINT_SPACE_LOCAL: /* ------------ FROM LOCALSPACE --------- */
            {
                /* local to pose - do inverse procedure that was done for pose to local */
                if (pchan->bone) {
                    /* we need the posespace_matrix = local_matrix + (parent_posespace_matrix + restpos) */                     
                    if (pchan->parent) {
                        float offs_bone[4][4];
                        
                        /* construct offs_bone the same way it is done in armature.c */
                        copy_m4_m3(offs_bone, pchan->bone->bone_mat);
                        copy_v3_v3(offs_bone[3], pchan->bone->head);
                        offs_bone[3][1]+= pchan->bone->parent->length;
                        
                        if (pchan->bone->flag & BONE_HINGE) {
                            /* pose_mat = par_pose-space_location * chan_mat */
                            float tmat[4][4];
                            
                            /* the rotation of the parent restposition */
                            copy_m4_m4(tmat, pchan->bone->parent->arm_mat);
                            
                            /* the location of actual parent transform */
                            copy_v3_v3(tmat[3], offs_bone[3]);
                            zero_v3(offs_bone[3]);
                            mul_m4_v3(pchan->parent->pose_mat, tmat[3]);
                            
                            mult_m4_m4m4(diff_mat, tmat, offs_bone);
                            copy_m4_m4(tempmat, mat);
                            mult_m4_m4m4(mat, diff_mat, tempmat);
                        }
                        else {
                            /* pose_mat = par_pose_mat * bone_mat * chan_mat */
                            mult_m4_m4m4(diff_mat, pchan->parent->pose_mat, offs_bone);
                            copy_m4_m4(tempmat, mat);
                            mult_m4_m4m4(mat, diff_mat, tempmat);
                        }
                    }
                    else {
                        copy_m4_m4(diff_mat, pchan->bone->arm_mat);
                        
                        copy_m4_m4(tempmat, mat);
                        mult_m4_m4m4(mat, diff_mat, tempmat);
                    }
                }
                
                /* use pose-space as stepping stone for other spaces */
                if (ELEM(to, CONSTRAINT_SPACE_WORLD, CONSTRAINT_SPACE_PARLOCAL)) {
                    /* call self with slightly different values */
                    constraint_mat_convertspace(ob, pchan, mat, CONSTRAINT_SPACE_POSE, to);
                }               
            }
                break;
            case CONSTRAINT_SPACE_PARLOCAL: /* -------------- FROM LOCAL WITH PARENT ---------- */
            {
                /* local + parent to pose */
                if (pchan->bone) {                  
                    copy_m4_m4(diff_mat, pchan->bone->arm_mat);
                    copy_m4_m4(tempmat, mat);
                    mult_m4_m4m4(mat, tempmat, diff_mat);
                }
                
                /* use pose-space as stepping stone for other spaces */
                if (ELEM(to, CONSTRAINT_SPACE_WORLD, CONSTRAINT_SPACE_LOCAL)) {
                    /* call self with slightly different values */
                    constraint_mat_convertspace(ob, pchan, mat, CONSTRAINT_SPACE_POSE, to);
                }
            }
                break;
        }
    }
    else {
        /* objects */
        if (from==CONSTRAINT_SPACE_WORLD && to==CONSTRAINT_SPACE_LOCAL) {
            /* check if object has a parent */
            if (ob->parent) {
                /* 'subtract' parent's effects from owner */
                mult_m4_m4m4(diff_mat, ob->parent->obmat, ob->parentinv);
                invert_m4_m4(imat, diff_mat);
                copy_m4_m4(tempmat, mat);
                mult_m4_m4m4(mat, imat, tempmat);
            }
            else {
                /* Local space in this case will have to be defined as local to the owner's 
                 * transform-property-rotated axes. So subtract this rotation component.
                 */
                object_to_mat4(ob, diff_mat);
                normalize_m4(diff_mat);
                zero_v3(diff_mat[3]);
                
                invert_m4_m4(imat, diff_mat);
                copy_m4_m4(tempmat, mat);
                mult_m4_m4m4(mat, imat, tempmat);
            }
        }
        else if (from==CONSTRAINT_SPACE_LOCAL && to==CONSTRAINT_SPACE_WORLD) {
            /* check that object has a parent - otherwise this won't work */
            if (ob->parent) {
                /* 'add' parent's effect back to owner */
                copy_m4_m4(tempmat, mat);
                mult_m4_m4m4(diff_mat, ob->parent->obmat, ob->parentinv);
                mult_m4_m4m4(mat, diff_mat, tempmat);
            }
            else {
                /* Local space in this case will have to be defined as local to the owner's 
                 * transform-property-rotated axes. So add back this rotation component.
                 */
                object_to_mat4(ob, diff_mat);
                normalize_m4(diff_mat);
                zero_v3(diff_mat[3]);
                
                copy_m4_m4(tempmat, mat);
                mult_m4_m4m4(mat, diff_mat, tempmat);
            }
        }
    }
}

/* ------------ General Target Matrix Tools ---------- */

/* function that sets the given matrix based on given vertex group in mesh */
static void contarget_get_mesh_mat (Object *ob, const char *substring, float mat[][4])
{
    DerivedMesh *dm = NULL;
    Mesh *me= ob->data;
    EditMesh *em = BKE_mesh_get_editmesh(me);
    float vec[3] = {0.0f, 0.0f, 0.0f};
    float normal[3] = {0.0f, 0.0f, 0.0f}, plane[3];
    float imat[3][3], tmat[3][3];
    const int defgroup= defgroup_name_index(ob, substring);
    short freeDM = 0;
    
    /* initialize target matrix using target matrix */
    copy_m4_m4(mat, ob->obmat);
    
    /* get index of vertex group */
    if (defgroup == -1) return;

    /* get DerivedMesh */
    if (em) {
        /* target is in editmode, so get a special derived mesh */
        dm = CDDM_from_editmesh(em, ob->data);
        freeDM= 1;
    }
    else {
        /* when not in EditMode, use the 'final' derived mesh, depsgraph
         * ensures we build with CD_MDEFORMVERT layer 
         */
        dm = (DerivedMesh *)ob->derivedFinal;
    }
    
    /* only continue if there's a valid DerivedMesh */
    if (dm) {
        MDeformVert *dvert = dm->getVertDataArray(dm, CD_MDEFORMVERT);
        int numVerts = dm->getNumVerts(dm);
        int i, count = 0;
        float co[3], nor[3];
        
        /* check that dvert is a valid pointers (just in case) */
        if (dvert) {
            MDeformVert *dv= dvert;
            /* get the average of all verts with that are in the vertex-group */
            for (i = 0; i < numVerts; i++, dv++) {
                MDeformWeight *dw= defvert_find_index(dv, defgroup);
                if (dw && dw->weight != 0.0f) {
                    dm->getVertCo(dm, i, co);
                    dm->getVertNo(dm, i, nor);
                    add_v3_v3(vec, co);
                    add_v3_v3(normal, nor);
                    count++;
                    
                }
            }

            /* calculate averages of normal and coordinates */
            if (count > 0) {
                mul_v3_fl(vec, 1.0f / count);
                mul_v3_fl(normal, 1.0f / count);
            }
            
            
            /* derive the rotation from the average normal: 
             *      - code taken from transform_manipulator.c, 
             *          calc_manipulator_stats, V3D_MANIP_NORMAL case
             */
            /*  we need the transpose of the inverse for a normal... */
            copy_m3_m4(imat, ob->obmat);
            
            invert_m3_m3(tmat, imat);
            transpose_m3(tmat);
            mul_m3_v3(tmat, normal);
            
            normalize_v3(normal);
            copy_v3_v3(plane, tmat[1]);
            
            copy_v3_v3(tmat[2], normal);
            cross_v3_v3v3(tmat[0], normal, plane);
            cross_v3_v3v3(tmat[1], tmat[2], tmat[0]);
            
            copy_m4_m3(mat, tmat);
            normalize_m4(mat);
            
            
            /* apply the average coordinate as the new location */
            mul_v3_m4v3(mat[3], ob->obmat, vec);
        }
    }
    
    /* free temporary DerivedMesh created (in EditMode case) */
    if (dm && freeDM)
        dm->release(dm);
    if (em)
        BKE_mesh_end_editmesh(me, em);
}

/* function that sets the given matrix based on given vertex group in lattice */
static void contarget_get_lattice_mat (Object *ob, const char *substring, float mat[][4])
{
    Lattice *lt= (Lattice *)ob->data;
    
    DispList *dl = find_displist(&ob->disp, DL_VERTS);
    float *co = dl?dl->verts:NULL;
    BPoint *bp = lt->def;
    
    MDeformVert *dv = lt->dvert;
    int tot_verts= lt->pntsu*lt->pntsv*lt->pntsw;
    float vec[3]= {0.0f, 0.0f, 0.0f}, tvec[3];
    int grouped=0;
    int i, n;
    const int defgroup= defgroup_name_index(ob, substring);
    
    /* initialize target matrix using target matrix */
    copy_m4_m4(mat, ob->obmat);

    /* get index of vertex group */
    if (defgroup == -1) return;
    if (dv == NULL) return;
    
    /* 1. Loop through control-points checking if in nominated vertex-group.
     * 2. If it is, add it to vec to find the average point.
     */
    for (i=0; i < tot_verts; i++, dv++) {
        for (n= 0; n < dv->totweight; n++) {
            MDeformWeight *dw= defvert_find_index(dv, defgroup);
            if (dw && dw->weight > 0.0f) {
                /* copy coordinates of point to temporary vector, then add to find average */
                memcpy(tvec, co ? co : bp->vec, 3 * sizeof(float));

                add_v3_v3(vec, tvec);
                grouped++;
            }
        }
        
        /* advance pointer to coordinate data */
        if (co) co += 3;
        else    bp++;
    }
    
    /* find average location, then multiply by ob->obmat to find world-space location */
    if (grouped)
        mul_v3_fl(vec, 1.0f / grouped);
    mul_v3_m4v3(tvec, ob->obmat, vec);
    
    /* copy new location to matrix */
    copy_v3_v3(mat[3], tvec);
}

/* generic function to get the appropriate matrix for most target cases */
/* The cases where the target can be object data have not been implemented */
static void constraint_target_to_mat4 (Object *ob, const char *substring, float mat[][4], short from, short to, float headtail)
{
    /*  Case OBJECT */
    if (!strlen(substring)) {
        copy_m4_m4(mat, ob->obmat);
        constraint_mat_convertspace(ob, NULL, mat, from, to);
    }
    /*  Case VERTEXGROUP */
    /* Current method just takes the average location of all the points in the
     * VertexGroup, and uses that as the location value of the targets. Where 
     * possible, the orientation will also be calculated, by calculating an
     * 'average' vertex normal, and deriving the rotaation from that.
     *
     * NOTE: EditMode is not currently supported, and will most likely remain that
     *      way as constraints can only really affect things on object/bone level.
     */
    else if (ob->type == OB_MESH) {
        contarget_get_mesh_mat(ob, substring, mat);
        constraint_mat_convertspace(ob, NULL, mat, from, to);
    }
    else if (ob->type == OB_LATTICE) {
        contarget_get_lattice_mat(ob, substring, mat);
        constraint_mat_convertspace(ob, NULL, mat, from, to);
    }
    /*  Case BONE */
    else {
        bPoseChannel *pchan;
        
        pchan = get_pose_channel(ob->pose, substring);
        if (pchan) {
            /* Multiply the PoseSpace accumulation/final matrix for this
             * PoseChannel by the Armature Object's Matrix to get a worldspace
             * matrix.
             */
            if (headtail < 0.000001f) {
                /* skip length interpolation if set to head */
                mult_m4_m4m4(mat, ob->obmat, pchan->pose_mat);
            }
            else {
                float tempmat[4][4], loc[3];
                
                /* interpolate along length of bone */
                interp_v3_v3v3(loc, pchan->pose_head, pchan->pose_tail, headtail);  
                
                /* use interpolated distance for subtarget */
                copy_m4_m4(tempmat, pchan->pose_mat);   
                copy_v3_v3(tempmat[3], loc);
                
                mult_m4_m4m4(mat, ob->obmat, tempmat);
            }
        } 
        else
            copy_m4_m4(mat, ob->obmat);
            
        /* convert matrix space as required */
        constraint_mat_convertspace(ob, pchan, mat, from, to);
    }
}

/* ************************* Specific Constraints ***************************** */
/* Each constraint defines a set of functions, which will be called at the appropriate
 * times. In addition to this, each constraint should have a type-info struct, where
 * its functions are attached for use. 
 */
 
/* Template for type-info data:
 *  - make a copy of this when creating new constraints, and just change the functions
 *    pointed to as necessary
 *  - although the naming of functions doesn't matter, it would help for code
 *    readability, to follow the same naming convention as is presented here
 *  - any functions that a constraint doesn't need to define, don't define
 *    for such cases, just use NULL 
 *  - these should be defined after all the functions have been defined, so that
 *    forward-definitions/prototypes don't need to be used!
 *  - keep this copy #if-def'd so that future constraints can get based off this
 */
#if 0
static bConstraintTypeInfo CTI_CONSTRNAME = {
    CONSTRAINT_TYPE_CONSTRNAME, /* type */
    sizeof(bConstrNameConstraint), /* size */
    "ConstrName", /* name */
    "bConstrNameConstraint", /* struct name */
    constrname_free, /* free data */
    constrname_relink, /* relink data */
    constrname_id_looper, /* id looper */
    constrname_copy, /* copy data */
    constrname_new_data, /* new data */
    constrname_get_tars, /* get constraint targets */
    constrname_flush_tars, /* flush constraint targets */
    constrname_get_tarmat, /* get target matrix */
    constrname_evaluate /* evaluate */
};
#endif

/* This function should be used for the get_target_matrix member of all 
 * constraints that are not picky about what happens to their target matrix.
 */
static void default_get_tarmat (bConstraint *con, bConstraintOb *UNUSED(cob), bConstraintTarget *ct, float UNUSED(ctime))
{
    if (VALID_CONS_TARGET(ct))
        constraint_target_to_mat4(ct->tar, ct->subtarget, ct->matrix, CONSTRAINT_SPACE_WORLD, ct->space, con->headtail);
    else if (ct)
        unit_m4(ct->matrix);
}

/* This following macro should be used for all standard single-target *_get_tars functions 
 * to save typing and reduce maintainance woes.
 * (Hopefully all compilers will be happy with the lines with just a space on them. Those are
 *  really just to help this code easier to read)
 */
// TODO: cope with getting rotation order...
#define SINGLETARGET_GET_TARS(con, datatar, datasubtarget, ct, list) \
    { \
        ct= MEM_callocN(sizeof(bConstraintTarget), "tempConstraintTarget"); \
         \
        ct->tar= datatar; \
        BLI_strncpy(ct->subtarget, datasubtarget, sizeof(ct->subtarget)); \
        ct->space= con->tarspace; \
        ct->flag= CONSTRAINT_TAR_TEMP; \
         \
        if (ct->tar) { \
            if ((ct->tar->type==OB_ARMATURE) && (ct->subtarget[0])) { \
                bPoseChannel *pchan= get_pose_channel(ct->tar->pose, ct->subtarget); \
                ct->type = CONSTRAINT_OBTYPE_BONE; \
                ct->rotOrder= (pchan) ? (pchan->rotmode) : EULER_ORDER_DEFAULT; \
            }\
            else if (OB_TYPE_SUPPORT_VGROUP(ct->tar->type) && (ct->subtarget[0])) { \
                ct->type = CONSTRAINT_OBTYPE_VERT; \
                ct->rotOrder = EULER_ORDER_DEFAULT; \
            } \
            else {\
                ct->type = CONSTRAINT_OBTYPE_OBJECT; \
                ct->rotOrder= ct->tar->rotmode; \
            } \
        } \
         \
        BLI_addtail(list, ct); \
    }
    
/* This following macro should be used for all standard single-target *_get_tars functions 
 * to save typing and reduce maintainance woes. It does not do the subtarget related operations
 * (Hopefully all compilers will be happy with the lines with just a space on them. Those are
 *  really just to help this code easier to read)
 */
// TODO: cope with getting rotation order...
#define SINGLETARGETNS_GET_TARS(con, datatar, ct, list) \
    { \
        ct= MEM_callocN(sizeof(bConstraintTarget), "tempConstraintTarget"); \
         \
        ct->tar= datatar; \
        ct->space= con->tarspace; \
        ct->flag= CONSTRAINT_TAR_TEMP; \
         \
        if (ct->tar) ct->type = CONSTRAINT_OBTYPE_OBJECT; \
         \
        BLI_addtail(list, ct); \
    }

/* This following macro should be used for all standard single-target *_flush_tars functions
 * to save typing and reduce maintainance woes.
 * Note: the pointer to ct will be changed to point to the next in the list (as it gets removed)
 * (Hopefully all compilers will be happy with the lines with just a space on them. Those are
 *  really just to help this code easier to read)
 */
#define SINGLETARGET_FLUSH_TARS(con, datatar, datasubtarget, ct, list, nocopy) \
    { \
        if (ct) { \
            bConstraintTarget *ctn = ct->next; \
            if (nocopy == 0) { \
                datatar= ct->tar; \
                BLI_strncpy(datasubtarget, ct->subtarget, sizeof(datasubtarget)); \
                con->tarspace= (char)ct->space; \
            } \
             \
            BLI_freelinkN(list, ct); \
            ct= ctn; \
        } \
    }
    
/* This following macro should be used for all standard single-target *_flush_tars functions
 * to save typing and reduce maintainance woes. It does not do the subtarget related operations.
 * Note: the pointer to ct will be changed to point to the next in the list (as it gets removed)
 * (Hopefully all compilers will be happy with the lines with just a space on them. Those are
 *  really just to help this code easier to read)
 */
#define SINGLETARGETNS_FLUSH_TARS(con, datatar, ct, list, nocopy) \
    { \
        if (ct) { \
            bConstraintTarget *ctn = ct->next; \
            if (nocopy == 0) { \
                datatar= ct->tar; \
                con->tarspace= (char)ct->space; \
            } \
             \
            BLI_freelinkN(list, ct); \
            ct= ctn; \
        } \
    }
 
/* --------- ChildOf Constraint ------------ */

static void childof_new_data (void *cdata)
{
    bChildOfConstraint *data= (bChildOfConstraint *)cdata;
    
    data->flag = (CHILDOF_LOCX | CHILDOF_LOCY | CHILDOF_LOCZ |
                    CHILDOF_ROTX |CHILDOF_ROTY | CHILDOF_ROTZ |
                    CHILDOF_SIZEX | CHILDOF_SIZEY | CHILDOF_SIZEZ);
    unit_m4(data->invmat);
}

static void childof_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bChildOfConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->tar, userdata);
}

static int childof_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bChildOfConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* standard target-getting macro for single-target constraints */
        SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void childof_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bChildOfConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
    }
}

static void childof_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
    bChildOfConstraint *data= con->data;
    bConstraintTarget *ct= targets->first;

    /* only evaluate if there is a target */
    if (VALID_CONS_TARGET(ct)) {
        float parmat[4][4];
        
        /* simple matrix parenting */
        if(data->flag == CHILDOF_ALL) {
            
            /* multiply target (parent matrix) by offset (parent inverse) to get 
             * the effect of the parent that will be exherted on the owner
             */
            mult_m4_m4m4(parmat, ct->matrix, data->invmat);
            
            /* now multiply the parent matrix by the owner matrix to get the 
             * the effect of this constraint (i.e.  owner is 'parented' to parent)
             */
            mult_m4_m4m4(cob->matrix, parmat, cob->matrix);
        }
        else {
            float invmat[4][4], tempmat[4][4];
            float loc[3], eul[3], size[3];
            float loco[3], eulo[3], sizo[3];
            
            /* get offset (parent-inverse) matrix */
            copy_m4_m4(invmat, data->invmat);
            
            /* extract components of both matrices */
            copy_v3_v3(loc, ct->matrix[3]);
            mat4_to_eulO(eul, ct->rotOrder, ct->matrix);
            mat4_to_size(size, ct->matrix);
            
            copy_v3_v3(loco, invmat[3]);
            mat4_to_eulO(eulo, cob->rotOrder, invmat);
            mat4_to_size(sizo, invmat);
            
            /* disable channels not enabled */
            if (!(data->flag & CHILDOF_LOCX)) loc[0]= loco[0]= 0.0f;
            if (!(data->flag & CHILDOF_LOCY)) loc[1]= loco[1]= 0.0f;
            if (!(data->flag & CHILDOF_LOCZ)) loc[2]= loco[2]= 0.0f;
            if (!(data->flag & CHILDOF_ROTX)) eul[0]= eulo[0]= 0.0f;
            if (!(data->flag & CHILDOF_ROTY)) eul[1]= eulo[1]= 0.0f;
            if (!(data->flag & CHILDOF_ROTZ)) eul[2]= eulo[2]= 0.0f;
            if (!(data->flag & CHILDOF_SIZEX)) size[0]= sizo[0]= 1.0f;
            if (!(data->flag & CHILDOF_SIZEY)) size[1]= sizo[1]= 1.0f;
            if (!(data->flag & CHILDOF_SIZEZ)) size[2]= sizo[2]= 1.0f;
            
            /* make new target mat and offset mat */
            loc_eulO_size_to_mat4(ct->matrix, loc, eul, size, ct->rotOrder);
            loc_eulO_size_to_mat4(invmat, loco, eulo, sizo, cob->rotOrder);
            
            /* multiply target (parent matrix) by offset (parent inverse) to get 
             * the effect of the parent that will be exherted on the owner
             */
            mult_m4_m4m4(parmat, ct->matrix, invmat);
            
            /* now multiply the parent matrix by the owner matrix to get the 
             * the effect of this constraint (i.e.  owner is 'parented' to parent)
             */
            copy_m4_m4(tempmat, cob->matrix);
            mult_m4_m4m4(cob->matrix, parmat, tempmat);

            /* without this, changes to scale and rotation can change location
             * of a parentless bone or a disconnected bone. Even though its set
             * to zero above. */
            if (!(data->flag & CHILDOF_LOCX)) cob->matrix[3][0]= tempmat[3][0];
            if (!(data->flag & CHILDOF_LOCY)) cob->matrix[3][1]= tempmat[3][1];
            if (!(data->flag & CHILDOF_LOCZ)) cob->matrix[3][2]= tempmat[3][2]; 
        }
    }
}

/* XXX note, con->flag should be CONSTRAINT_SPACEONCE for bone-childof, patched in readfile.c */
static bConstraintTypeInfo CTI_CHILDOF = {
    CONSTRAINT_TYPE_CHILDOF, /* type */
    sizeof(bChildOfConstraint), /* size */
    "ChildOf", /* name */
    "bChildOfConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    childof_id_looper, /* id looper */
    NULL, /* copy data */
    childof_new_data, /* new data */
    childof_get_tars, /* get constraint targets */
    childof_flush_tars, /* flush constraint targets */
    default_get_tarmat, /* get a target matrix */
    childof_evaluate /* evaluate */
};

/* -------- TrackTo Constraint ------- */

static void trackto_new_data (void *cdata)
{
    bTrackToConstraint *data= (bTrackToConstraint *)cdata;
    
    data->reserved1 = TRACK_Y;
    data->reserved2 = UP_Z;
}   

static void trackto_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bTrackToConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->tar, userdata);
}

static int trackto_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bTrackToConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* standard target-getting macro for single-target constraints */
        SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void trackto_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bTrackToConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
    }
}


static int basis_cross (int n, int m)
{
    switch (n-m) {
        case 1: 
        case -2:
            return 1;
            
        case -1: 
        case 2:
            return -1;
            
        default:
            return 0;
    }
}

static void vectomat (float *vec, float *target_up, short axis, short upflag, short flags, float m[][3])
{
    float n[3];
    float u[3]; /* vector specifying the up axis */
    float proj[3];
    float right[3];
    float neg = -1;
    int right_index;

    if (normalize_v3_v3(n, vec) == 0.0f) {
        n[0] = 0.0f;
        n[1] = 0.0f;
        n[2] = 1.0f;
    }
    if (axis > 2) axis -= 3;
    else negate_v3(n);

    /* n specifies the transformation of the track axis */
    if (flags & TARGET_Z_UP) { 
        /* target Z axis is the global up axis */
        copy_v3_v3(u, target_up);
    }
    else { 
        /* world Z axis is the global up axis */
        u[0] = 0;
        u[1] = 0;
        u[2] = 1;
    }

    /* project the up vector onto the plane specified by n */
    project_v3_v3v3(proj, u, n); /* first u onto n... */
    sub_v3_v3v3(proj, u, proj); /* then onto the plane */
    /* proj specifies the transformation of the up axis */

    if (normalize_v3(proj) == 0.0f) { /* degenerate projection */
        proj[0] = 0.0f;
        proj[1] = 1.0f;
        proj[2] = 0.0f;
    }

    /* Normalized cross product of n and proj specifies transformation of the right axis */
    cross_v3_v3v3(right, proj, n);
    normalize_v3(right);

    if (axis != upflag) {
        right_index = 3 - axis - upflag;
        neg = (float)basis_cross(axis, upflag);
        
        /* account for up direction, track direction */
        m[right_index][0] = neg * right[0];
        m[right_index][1] = neg * right[1];
        m[right_index][2] = neg * right[2];
        
        copy_v3_v3(m[upflag], proj);
        
        copy_v3_v3(m[axis], n);
    }
    /* identity matrix - don't do anything if the two axes are the same */
    else {
        unit_m3(m);
    }
}


static void trackto_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
    bTrackToConstraint *data= con->data;
    bConstraintTarget *ct= targets->first;
    
    if (VALID_CONS_TARGET(ct)) {
        float size[3], vec[3];
        float totmat[3][3];
        float tmat[4][4];
        
        /* Get size property, since ob->size is only the object's own relative size, not its global one */
        mat4_to_size(size, cob->matrix);
        
        /* Clear the object's rotation */   
        cob->matrix[0][0]=size[0];
        cob->matrix[0][1]=0;
        cob->matrix[0][2]=0;
        cob->matrix[1][0]=0;
        cob->matrix[1][1]=size[1];
        cob->matrix[1][2]=0;
        cob->matrix[2][0]=0;
        cob->matrix[2][1]=0;
        cob->matrix[2][2]=size[2];
        
        /* targetmat[2] instead of ownermat[2] is passed to vectomat
         * for backwards compatibility it seems... (Aligorith)
         */
        sub_v3_v3v3(vec, cob->matrix[3], ct->matrix[3]);
        vectomat(vec, ct->matrix[2], 
                (short)data->reserved1, (short)data->reserved2, 
                data->flags, totmat);
        
        copy_m4_m4(tmat, cob->matrix);
        mul_m4_m3m4(cob->matrix, totmat, tmat);
    }
}

static bConstraintTypeInfo CTI_TRACKTO = {
    CONSTRAINT_TYPE_TRACKTO, /* type */
    sizeof(bTrackToConstraint), /* size */
    "TrackTo", /* name */
    "bTrackToConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    trackto_id_looper, /* id looper */
    NULL, /* copy data */
    trackto_new_data, /* new data */
    trackto_get_tars, /* get constraint targets */
    trackto_flush_tars, /* flush constraint targets */
    default_get_tarmat, /* get target matrix */
    trackto_evaluate /* evaluate */
};

/* --------- Inverse-Kinemetics --------- */

static void kinematic_new_data (void *cdata)
{
    bKinematicConstraint *data= (bKinematicConstraint *)cdata;
    
    data->weight= 1.0f;
    data->orientweight= 1.0f;
    data->iterations = 500;
    data->dist= 1.0f;
    data->flag= CONSTRAINT_IK_TIP|CONSTRAINT_IK_STRETCH|CONSTRAINT_IK_POS;
}

static void kinematic_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bKinematicConstraint *data= con->data;
    
    /* chain target */
    func(con, (ID**)&data->tar, userdata);
    
    /* poletarget */
    func(con, (ID**)&data->poletar, userdata);
}

static int kinematic_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bKinematicConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* standard target-getting macro for single-target constraints is used twice here */
        SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
        SINGLETARGET_GET_TARS(con, data->poletar, data->polesubtarget, ct, list)
        
        return 2;
    }
    
    return 0;
}

static void kinematic_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bKinematicConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
        SINGLETARGET_FLUSH_TARS(con, data->poletar, data->polesubtarget, ct, list, nocopy)
    }
}

static void kinematic_get_tarmat (bConstraint *con, bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
    bKinematicConstraint *data= con->data;
    
    if (VALID_CONS_TARGET(ct)) 
        constraint_target_to_mat4(ct->tar, ct->subtarget, ct->matrix, CONSTRAINT_SPACE_WORLD, ct->space, con->headtail);
    else if (ct) {
        if (data->flag & CONSTRAINT_IK_AUTO) {
            Object *ob= cob->ob;
            
            if (ob == NULL) {
                unit_m4(ct->matrix);
            }
            else {
                float vec[3];
                /* move grabtarget into world space */
                mul_v3_m4v3(vec, ob->obmat, data->grabtarget);
                copy_m4_m4(ct->matrix, ob->obmat);
                copy_v3_v3(ct->matrix[3], vec);
            }
        }
        else
            unit_m4(ct->matrix);
    }
}

static bConstraintTypeInfo CTI_KINEMATIC = {
    CONSTRAINT_TYPE_KINEMATIC, /* type */
    sizeof(bKinematicConstraint), /* size */
    "IK", /* name */
    "bKinematicConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    kinematic_id_looper, /* id looper */
    NULL, /* copy data */
    kinematic_new_data, /* new data */
    kinematic_get_tars, /* get constraint targets */
    kinematic_flush_tars, /* flush constraint targets */
    kinematic_get_tarmat, /* get target matrix */
    NULL /* evaluate - solved as separate loop */
};

/* -------- Follow-Path Constraint ---------- */

static void followpath_new_data (void *cdata)
{
    bFollowPathConstraint *data= (bFollowPathConstraint *)cdata;
    
    data->trackflag = TRACK_Y;
    data->upflag = UP_Z;
    data->offset = 0;
    data->followflag = 0;
}

static void followpath_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bFollowPathConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->tar, userdata);
}

static int followpath_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bFollowPathConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* standard target-getting macro for single-target constraints without subtargets */
        SINGLETARGETNS_GET_TARS(con, data->tar, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void followpath_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bFollowPathConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGETNS_FLUSH_TARS(con, data->tar, ct, list, nocopy)
    }
}

static void followpath_get_tarmat (bConstraint *con, bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
    bFollowPathConstraint *data= con->data;
    
    if (VALID_CONS_TARGET(ct)) {
        Curve *cu= ct->tar->data;
        float vec[4], dir[3], radius;
        float totmat[4][4]= MAT4_UNITY;
        float curvetime;

        unit_m4(ct->matrix);

        /* note: when creating constraints that follow path, the curve gets the CU_PATH set now,
         *      currently for paths to work it needs to go through the bevlist/displist system (ton) 
         */
        
        /* only happens on reload file, but violates depsgraph still... fix! */
        if (cu->path==NULL || cu->path->data==NULL)
            makeDispListCurveTypes(cob->scene, ct->tar, 0);
        
        if (cu->path && cu->path->data) {
            float quat[4];
            if ((data->followflag & FOLLOWPATH_STATIC) == 0) {
                /* animated position along curve depending on time */
                Nurb *nu = cu->nurb.first;
                curvetime= cu->ctime - data->offset;
                
                /* ctime is now a proper var setting of Curve which gets set by Animato like any other var that's animated,
                 * but this will only work if it actually is animated... 
                 *
                 * we divide the curvetime calculated in the previous step by the length of the path, to get a time
                 * factor, which then gets clamped to lie within 0.0 - 1.0 range
                 */
                curvetime /= cu->pathlen;

                if (nu && nu->flagu & CU_NURB_CYCLIC) {
                    /* If the curve is cyclic, enable looping around if the time is
                     * outside the bounds 0..1 */
                    if ((curvetime < 0.0f) || (curvetime > 1.0f)) {
                        curvetime -= floor(curvetime);
                    }
                }
                else {
                    /* The curve is not cyclic, so clamp to the begin/end points. */
                    CLAMP(curvetime, 0.0f, 1.0f);
                }
            }
            else {
                /* fixed position along curve */
                curvetime= data->offset_fac;
            }
            
            if ( where_on_path(ct->tar, curvetime, vec, dir, (data->followflag & FOLLOWPATH_FOLLOW) ? quat : NULL, &radius, NULL) ) { /* quat_pt is quat or NULL*/
                if (data->followflag & FOLLOWPATH_FOLLOW) {
#if 0
                    float x1, q[4];
                    vec_to_quat(quat, dir, (short)data->trackflag, (short)data->upflag);
                    
                    normalize_v3(dir);
                    q[0]= (float)cos(0.5*vec[3]);
                    x1= (float)sin(0.5*vec[3]);
                    q[1]= -x1*dir[0];
                    q[2]= -x1*dir[1];
                    q[3]= -x1*dir[2];
                    mul_qt_qtqt(quat, q, quat);
#else
                    quat_apply_track(quat, data->trackflag, data->upflag);
#endif

                    quat_to_mat4(totmat, quat);
                }

                if (data->followflag & FOLLOWPATH_RADIUS) {
                    float tmat[4][4], rmat[4][4];
                    scale_m4_fl(tmat, radius);
                    mult_m4_m4m4(rmat, tmat, totmat);
                    copy_m4_m4(totmat, rmat);
                }
                
                copy_v3_v3(totmat[3], vec);
                
                mul_serie_m4(ct->matrix, ct->tar->obmat, totmat, NULL, NULL, NULL, NULL, NULL, NULL);
            }
        }
    }
    else if (ct)
        unit_m4(ct->matrix);
}

static void followpath_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
    bConstraintTarget *ct= targets->first;
    
    /* only evaluate if there is a target */
    if (VALID_CONS_TARGET(ct)) {
        float obmat[4][4];
        float size[3];
        bFollowPathConstraint *data= con->data;
        
        /* get Object transform (loc/rot/size) to determine transformation from path */
        // TODO: this used to be local at one point, but is probably more useful as-is
        copy_m4_m4(obmat, cob->matrix);
        
        /* get scaling of object before applying constraint */
        mat4_to_size(size, cob->matrix);
        
        /* apply targetmat - containing location on path, and rotation */
        mul_serie_m4(cob->matrix, ct->matrix, obmat, NULL, NULL, NULL, NULL, NULL, NULL);
        
        /* un-apply scaling caused by path */
        if ((data->followflag & FOLLOWPATH_RADIUS)==0) { /* XXX - assume that scale correction means that radius will have some scale error in it - Campbell */
            float obsize[3];
            
            mat4_to_size( obsize,cob->matrix);
            if (obsize[0])
                mul_v3_fl(cob->matrix[0], size[0] / obsize[0]);
            if (obsize[1])
                mul_v3_fl(cob->matrix[1], size[1] / obsize[1]);
            if (obsize[2])
                mul_v3_fl(cob->matrix[2], size[2] / obsize[2]);
        }
    }
}

static bConstraintTypeInfo CTI_FOLLOWPATH = {
    CONSTRAINT_TYPE_FOLLOWPATH, /* type */
    sizeof(bFollowPathConstraint), /* size */
    "Follow Path", /* name */
    "bFollowPathConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    followpath_id_looper, /* id looper */
    NULL, /* copy data */
    followpath_new_data, /* new data */
    followpath_get_tars, /* get constraint targets */
    followpath_flush_tars, /* flush constraint targets */
    followpath_get_tarmat, /* get target matrix */
    followpath_evaluate /* evaluate */
};

/* --------- Limit Location --------- */


static void loclimit_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *UNUSED(targets))
{
    bLocLimitConstraint *data = con->data;
    
    if (data->flag & LIMIT_XMIN) {
        if (cob->matrix[3][0] < data->xmin)
            cob->matrix[3][0] = data->xmin;
    }
    if (data->flag & LIMIT_XMAX) {
        if (cob->matrix[3][0] > data->xmax)
            cob->matrix[3][0] = data->xmax;
    }
    if (data->flag & LIMIT_YMIN) {
        if (cob->matrix[3][1] < data->ymin)
            cob->matrix[3][1] = data->ymin;
    }
    if (data->flag & LIMIT_YMAX) {
        if (cob->matrix[3][1] > data->ymax)
            cob->matrix[3][1] = data->ymax;
    }
    if (data->flag & LIMIT_ZMIN) {
        if (cob->matrix[3][2] < data->zmin) 
            cob->matrix[3][2] = data->zmin;
    }
    if (data->flag & LIMIT_ZMAX) {
        if (cob->matrix[3][2] > data->zmax)
            cob->matrix[3][2] = data->zmax;
    }
}

static bConstraintTypeInfo CTI_LOCLIMIT = {
    CONSTRAINT_TYPE_LOCLIMIT, /* type */
    sizeof(bLocLimitConstraint), /* size */
    "Limit Location", /* name */
    "bLocLimitConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    NULL, /* id looper */
    NULL, /* copy data */
    NULL, /* new data */
    NULL, /* get constraint targets */
    NULL, /* flush constraint targets */
    NULL, /* get target matrix */
    loclimit_evaluate /* evaluate */
};

/* -------- Limit Rotation --------- */

static void rotlimit_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *UNUSED(targets))
{
    bRotLimitConstraint *data = con->data;
    float loc[3];
    float eul[3];
    float size[3];
    
    copy_v3_v3(loc, cob->matrix[3]);
    mat4_to_size(size, cob->matrix);

    mat4_to_eulO(eul, cob->rotOrder, cob->matrix);

    /* constraint data uses radians internally */
    
    /* limiting of euler values... */
    if (data->flag & LIMIT_XROT) {
        if (eul[0] < data->xmin) 
            eul[0] = data->xmin;
            
        if (eul[0] > data->xmax)
            eul[0] = data->xmax;
    }
    if (data->flag & LIMIT_YROT) {
        if (eul[1] < data->ymin)
            eul[1] = data->ymin;
            
        if (eul[1] > data->ymax)
            eul[1] = data->ymax;
    }
    if (data->flag & LIMIT_ZROT) {
        if (eul[2] < data->zmin)
            eul[2] = data->zmin;
            
        if (eul[2] > data->zmax)
            eul[2] = data->zmax;
    }
        
    loc_eulO_size_to_mat4(cob->matrix, loc, eul, size, cob->rotOrder);
}

static bConstraintTypeInfo CTI_ROTLIMIT = {
    CONSTRAINT_TYPE_ROTLIMIT, /* type */
    sizeof(bRotLimitConstraint), /* size */
    "Limit Rotation", /* name */
    "bRotLimitConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    NULL, /* id looper */
    NULL, /* copy data */
    NULL, /* new data */
    NULL, /* get constraint targets */
    NULL, /* flush constraint targets */
    NULL, /* get target matrix */
    rotlimit_evaluate /* evaluate */
};

/* --------- Limit Scaling --------- */


static void sizelimit_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *UNUSED(targets))
{
    bSizeLimitConstraint *data = con->data;
    float obsize[3], size[3];
    
    mat4_to_size( size,cob->matrix);
    mat4_to_size( obsize,cob->matrix);
    
    if (data->flag & LIMIT_XMIN) {
        if (size[0] < data->xmin) 
            size[0] = data->xmin;   
    }
    if (data->flag & LIMIT_XMAX) {
        if (size[0] > data->xmax) 
            size[0] = data->xmax;
    }
    if (data->flag & LIMIT_YMIN) {
        if (size[1] < data->ymin) 
            size[1] = data->ymin;   
    }
    if (data->flag & LIMIT_YMAX) {
        if (size[1] > data->ymax) 
            size[1] = data->ymax;
    }
    if (data->flag & LIMIT_ZMIN) {
        if (size[2] < data->zmin) 
            size[2] = data->zmin;   
    }
    if (data->flag & LIMIT_ZMAX) {
        if (size[2] > data->zmax) 
            size[2] = data->zmax;
    }
    
    if (obsize[0]) 
        mul_v3_fl(cob->matrix[0], size[0]/obsize[0]);
    if (obsize[1]) 
        mul_v3_fl(cob->matrix[1], size[1]/obsize[1]);
    if (obsize[2]) 
        mul_v3_fl(cob->matrix[2], size[2]/obsize[2]);
}

static bConstraintTypeInfo CTI_SIZELIMIT = {
    CONSTRAINT_TYPE_SIZELIMIT, /* type */
    sizeof(bSizeLimitConstraint), /* size */
    "Limit Scaling", /* name */
    "bSizeLimitConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    NULL, /* id looper */
    NULL, /* copy data */
    NULL, /* new data */
    NULL, /* get constraint targets */
    NULL, /* flush constraint targets */
    NULL, /* get target matrix */
    sizelimit_evaluate /* evaluate */
};

/* ----------- Copy Location ------------- */

static void loclike_new_data (void *cdata)
{
    bLocateLikeConstraint *data= (bLocateLikeConstraint *)cdata;
    
    data->flag = LOCLIKE_X|LOCLIKE_Y|LOCLIKE_Z;
}

static void loclike_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bLocateLikeConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->tar, userdata);
}

static int loclike_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bLocateLikeConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* standard target-getting macro for single-target constraints */
        SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void loclike_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bLocateLikeConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
    }
}

static void loclike_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
    bLocateLikeConstraint *data= con->data;
    bConstraintTarget *ct= targets->first;
    
    if (VALID_CONS_TARGET(ct)) {
        float offset[3] = {0.0f, 0.0f, 0.0f};
        
        if (data->flag & LOCLIKE_OFFSET)
            copy_v3_v3(offset, cob->matrix[3]);
            
        if (data->flag & LOCLIKE_X) {
            cob->matrix[3][0] = ct->matrix[3][0];
            
            if (data->flag & LOCLIKE_X_INVERT) cob->matrix[3][0] *= -1;
            cob->matrix[3][0] += offset[0];
        }
        if (data->flag & LOCLIKE_Y) {
            cob->matrix[3][1] = ct->matrix[3][1];
            
            if (data->flag & LOCLIKE_Y_INVERT) cob->matrix[3][1] *= -1;
            cob->matrix[3][1] += offset[1];
        }
        if (data->flag & LOCLIKE_Z) {
            cob->matrix[3][2] = ct->matrix[3][2];
            
            if (data->flag & LOCLIKE_Z_INVERT) cob->matrix[3][2] *= -1;
            cob->matrix[3][2] += offset[2];
        }
    }
}

static bConstraintTypeInfo CTI_LOCLIKE = {
    CONSTRAINT_TYPE_LOCLIKE, /* type */
    sizeof(bLocateLikeConstraint), /* size */
    "Copy Location", /* name */
    "bLocateLikeConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    loclike_id_looper, /* id looper */
    NULL, /* copy data */
    loclike_new_data, /* new data */
    loclike_get_tars, /* get constraint targets */
    loclike_flush_tars, /* flush constraint targets */
    default_get_tarmat, /* get target matrix */
    loclike_evaluate /* evaluate */
};

/* ----------- Copy Rotation ------------- */

static void rotlike_new_data (void *cdata)
{
    bRotateLikeConstraint *data= (bRotateLikeConstraint *)cdata;
    
    data->flag = ROTLIKE_X|ROTLIKE_Y|ROTLIKE_Z;
}

static void rotlike_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bChildOfConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->tar, userdata);
}

static int rotlike_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bRotateLikeConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* standard target-getting macro for single-target constraints */
        SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void rotlike_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bRotateLikeConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
    }
}

static void rotlike_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
    bRotateLikeConstraint *data= con->data;
    bConstraintTarget *ct= targets->first;
    
    if (VALID_CONS_TARGET(ct)) {
        float   loc[3];
        float   eul[3], obeul[3];
        float   size[3];
        
        copy_v3_v3(loc, cob->matrix[3]);
        mat4_to_size(size, cob->matrix);
        
        /* to allow compatible rotations, must get both rotations in the order of the owner... */
        mat4_to_eulO(obeul, cob->rotOrder, cob->matrix);
        /* we must get compatible eulers from the beginning because some of them can be modified below (see bug #21875) */
        mat4_to_compatible_eulO(eul, obeul, cob->rotOrder, ct->matrix);
        
        if ((data->flag & ROTLIKE_X)==0)
            eul[0] = obeul[0];
        else {
            if (data->flag & ROTLIKE_OFFSET)
                rotate_eulO(eul, cob->rotOrder, 'X', obeul[0]);
            
            if (data->flag & ROTLIKE_X_INVERT)
                eul[0] *= -1;
        }
        
        if ((data->flag & ROTLIKE_Y)==0)
            eul[1] = obeul[1];
        else {
            if (data->flag & ROTLIKE_OFFSET)
                rotate_eulO(eul, cob->rotOrder, 'Y', obeul[1]);
            
            if (data->flag & ROTLIKE_Y_INVERT)
                eul[1] *= -1;
        }
        
        if ((data->flag & ROTLIKE_Z)==0)
            eul[2] = obeul[2];
        else {
            if (data->flag & ROTLIKE_OFFSET)
                rotate_eulO(eul, cob->rotOrder, 'Z', obeul[2]);
            
            if (data->flag & ROTLIKE_Z_INVERT)
                eul[2] *= -1;
        }
        
        /* good to make eulers compatible again, since we don't know how much they were changed above */
        compatible_eul(eul, obeul);
        loc_eulO_size_to_mat4(cob->matrix, loc, eul, size, cob->rotOrder);
    }
}

static bConstraintTypeInfo CTI_ROTLIKE = {
    CONSTRAINT_TYPE_ROTLIKE, /* type */
    sizeof(bRotateLikeConstraint), /* size */
    "Copy Rotation", /* name */
    "bRotateLikeConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    rotlike_id_looper, /* id looper */
    NULL, /* copy data */
    rotlike_new_data, /* new data */
    rotlike_get_tars, /* get constraint targets */
    rotlike_flush_tars, /* flush constraint targets */
    default_get_tarmat, /* get target matrix */
    rotlike_evaluate /* evaluate */
};

/* ---------- Copy Scaling ---------- */

static void sizelike_new_data (void *cdata)
{
    bSizeLikeConstraint *data= (bSizeLikeConstraint *)cdata;
    
    data->flag = SIZELIKE_X|SIZELIKE_Y|SIZELIKE_Z;
}

static void sizelike_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bSizeLikeConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->tar, userdata);
}

static int sizelike_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bSizeLikeConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* standard target-getting macro for single-target constraints */
        SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void sizelike_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bSizeLikeConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
    }
}

static void sizelike_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
    bSizeLikeConstraint *data= con->data;
    bConstraintTarget *ct= targets->first;
    
    if (VALID_CONS_TARGET(ct)) {
        float obsize[3], size[3];
        
        mat4_to_size(size, ct->matrix);
        mat4_to_size(obsize, cob->matrix);
        
        if ((data->flag & SIZELIKE_X) && (obsize[0] != 0)) {
            if (data->flag & SIZELIKE_OFFSET) {
                size[0] += (obsize[0] - 1.0f);
                mul_v3_fl(cob->matrix[0], size[0] / obsize[0]);
            }
            else
                mul_v3_fl(cob->matrix[0], size[0] / obsize[0]);
        }
        if ((data->flag & SIZELIKE_Y) && (obsize[1] != 0)) {
            if (data->flag & SIZELIKE_OFFSET) {
                size[1] += (obsize[1] - 1.0f);
                mul_v3_fl(cob->matrix[1], size[1] / obsize[1]);
            }
            else
                mul_v3_fl(cob->matrix[1], size[1] / obsize[1]);
        }
        if ((data->flag & SIZELIKE_Z) && (obsize[2] != 0)) {
            if (data->flag & SIZELIKE_OFFSET) {
                size[2] += (obsize[2] - 1.0f);
                mul_v3_fl(cob->matrix[2], size[2] / obsize[2]);
            }
            else
                mul_v3_fl(cob->matrix[2], size[2] / obsize[2]);
        }
    }
}

static bConstraintTypeInfo CTI_SIZELIKE = {
    CONSTRAINT_TYPE_SIZELIKE, /* type */
    sizeof(bSizeLikeConstraint), /* size */
    "Copy Scale", /* name */
    "bSizeLikeConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    sizelike_id_looper, /* id looper */
    NULL, /* copy data */
    sizelike_new_data, /* new data */
    sizelike_get_tars, /* get constraint targets */
    sizelike_flush_tars, /* flush constraint targets */
    default_get_tarmat, /* get target matrix */
    sizelike_evaluate /* evaluate */
};

/* ----------- Copy Transforms ------------- */

static void translike_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bTransLikeConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->tar, userdata);
}

static int translike_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bTransLikeConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* standard target-getting macro for single-target constraints */
        SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void translike_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bTransLikeConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
    }
}

static void translike_evaluate (bConstraint *UNUSED(con), bConstraintOb *cob, ListBase *targets)
{
    bConstraintTarget *ct= targets->first;
    
    if (VALID_CONS_TARGET(ct)) {
        /* just copy the entire transform matrix of the target */
        copy_m4_m4(cob->matrix, ct->matrix);
    }
}

static bConstraintTypeInfo CTI_TRANSLIKE = {
    CONSTRAINT_TYPE_TRANSLIKE, /* type */
    sizeof(bTransLikeConstraint), /* size */
    "Copy Transforms", /* name */
    "bTransLikeConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    translike_id_looper, /* id looper */
    NULL, /* copy data */
    NULL, /* new data */
    translike_get_tars, /* get constraint targets */
    translike_flush_tars, /* flush constraint targets */
    default_get_tarmat, /* get target matrix */
    translike_evaluate /* evaluate */
};

/* ---------- Maintain Volume ---------- */

static void samevolume_new_data (void *cdata)
{
    bSameVolumeConstraint *data= (bSameVolumeConstraint *)cdata;

    data->flag = SAMEVOL_Y;
    data->volume = 1.0f;
}

static void samevolume_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *UNUSED(targets))
{
    bSameVolumeConstraint *data= con->data;

    float volume = data->volume;
    float fac = 1.0f;
    float obsize[3];

    mat4_to_size(obsize, cob->matrix);
    
    /* calculate normalising scale factor for non-essential values */
    if (obsize[data->flag] != 0) 
        fac = sqrtf(volume / obsize[data->flag]) / obsize[data->flag];
    
    /* apply scaling factor to the channels not being kept */
    switch (data->flag) {
        case SAMEVOL_X:
            mul_v3_fl(cob->matrix[1], fac);
            mul_v3_fl(cob->matrix[2], fac);
            break;
        case SAMEVOL_Y:
            mul_v3_fl(cob->matrix[0], fac);
            mul_v3_fl(cob->matrix[2], fac);
            break;
        case SAMEVOL_Z:
            mul_v3_fl(cob->matrix[0], fac);
            mul_v3_fl(cob->matrix[1], fac);
            break;
    }
}

static bConstraintTypeInfo CTI_SAMEVOL = {
    CONSTRAINT_TYPE_SAMEVOL, /* type */
    sizeof(bSameVolumeConstraint), /* size */
    "Maintain Volume", /* name */
    "bSameVolumeConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    NULL, /* id looper */
    NULL, /* copy data */
    samevolume_new_data, /* new data */
    NULL, /* get constraint targets */
    NULL, /* flush constraint targets */
    NULL, /* get target matrix */
    samevolume_evaluate /* evaluate */
};

/* ----------- Python Constraint -------------- */

static void pycon_free (bConstraint *con)
{
    bPythonConstraint *data= con->data;
    
    /* id-properties */
    IDP_FreeProperty(data->prop);
    MEM_freeN(data->prop);
    
    /* multiple targets */
    BLI_freelistN(&data->targets);
}   

static void pycon_relink (bConstraint *con)
{
    bPythonConstraint *data= con->data;
    
    ID_NEW(data->text);
}

static void pycon_copy (bConstraint *con, bConstraint *srccon)
{
    bPythonConstraint *pycon = (bPythonConstraint *)con->data;
    bPythonConstraint *opycon = (bPythonConstraint *)srccon->data;
    
    pycon->prop = IDP_CopyProperty(opycon->prop);
    BLI_duplicatelist(&pycon->targets, &opycon->targets);
}

static void pycon_new_data (void *cdata)
{
    bPythonConstraint *data= (bPythonConstraint *)cdata;
    
    /* everything should be set correctly by calloc, except for the prop->type constant.*/
    data->prop = MEM_callocN(sizeof(IDProperty), "PyConstraintProps");
    data->prop->type = IDP_GROUP;
}

static int pycon_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bPythonConstraint *data= con->data;
        
        list->first = data->targets.first;
        list->last = data->targets.last;
        
        return data->tarnum;
    }
    
    return 0;
}

static void pycon_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bPythonConstraint *data= con->data;
    bConstraintTarget *ct;
    
    /* targets */
    for (ct= data->targets.first; ct; ct= ct->next)
        func(con, (ID**)&ct->tar, userdata);
        
    /* script */
    func(con, (ID**)&data->text, userdata);
}

/* Whether this approach is maintained remains to be seen (aligorith) */
static void pycon_get_tarmat (bConstraint *con, bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
#ifdef WITH_PYTHON
    bPythonConstraint *data= con->data;
#endif

    if (VALID_CONS_TARGET(ct)) {
        /* special exception for curves - depsgraph issues */
        if (ct->tar->type == OB_CURVE) {
            Curve *cu= ct->tar->data;
            
            /* this check is to make sure curve objects get updated on file load correctly.*/
            if (cu->path==NULL || cu->path->data==NULL) /* only happens on reload file, but violates depsgraph still... fix! */
                makeDispListCurveTypes(cob->scene, ct->tar, 0);             
        }
        
        /* firstly calculate the matrix the normal way, then let the py-function override
         * this matrix if it needs to do so
         */
        constraint_target_to_mat4(ct->tar, ct->subtarget, ct->matrix, CONSTRAINT_SPACE_WORLD, ct->space, con->headtail);
        
        /* only execute target calculation if allowed */
#ifdef WITH_PYTHON
        if (G.f & G_SCRIPT_AUTOEXEC)
            BPY_pyconstraint_target(data, ct);
#endif
    }
    else if (ct)
        unit_m4(ct->matrix);
}

static void pycon_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
#ifndef WITH_PYTHON
    (void)con; (void)cob; (void)targets; /* unused */
    return;
#else
    bPythonConstraint *data= con->data;
    
    /* only evaluate in python if we're allowed to do so */
    if ((G.f & G_SCRIPT_AUTOEXEC)==0)  return;
    
/* currently removed, until I this can be re-implemented for multiple targets */
#if 0
    /* Firstly, run the 'driver' function which has direct access to the objects involved 
     * Technically, this is potentially dangerous as users may abuse this and cause dependency-problems,
     * but it also allows certain 'clever' rigging hacks to work.
     */
    BPY_pyconstraint_driver(data, cob, targets);
#endif
    
    /* Now, run the actual 'constraint' function, which should only access the matrices */
    BPY_pyconstraint_exec(data, cob, targets);
#endif /* WITH_PYTHON */
}

static bConstraintTypeInfo CTI_PYTHON = {
    CONSTRAINT_TYPE_PYTHON, /* type */
    sizeof(bPythonConstraint), /* size */
    "Script", /* name */
    "bPythonConstraint", /* struct name */
    pycon_free, /* free data */
    pycon_relink, /* relink data */
    pycon_id_looper, /* id looper */
    pycon_copy, /* copy data */
    pycon_new_data, /* new data */
    pycon_get_tars, /* get constraint targets */
    NULL, /* flush constraint targets */
    pycon_get_tarmat, /* get target matrix */
    pycon_evaluate /* evaluate */
};

/* -------- Action Constraint ----------- */

static void actcon_relink (bConstraint *con)
{
    bActionConstraint *data= con->data;
    ID_NEW(data->act);
}

static void actcon_new_data (void *cdata)
{
    bActionConstraint *data= (bActionConstraint *)cdata;
    
    /* set type to 20 (Loc X), as 0 is Rot X for backwards compatibility */
    data->type = 20;
}

static void actcon_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bActionConstraint *data= con->data;
    
    /* target */
    func(con, (ID**)&data->tar, userdata);
    
    /* action */
    func(con, (ID**)&data->act, userdata);
}

static int actcon_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bActionConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* standard target-getting macro for single-target constraints */
        SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void actcon_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bActionConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
    }
}

static void actcon_get_tarmat (bConstraint *con, bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
    bActionConstraint *data = con->data;
    
    if (VALID_CONS_TARGET(ct)) {
        float tempmat[4][4], vec[3];
        float s, t;
        short axis;
        
        /* initialise return matrix */
        unit_m4(ct->matrix);
        
        /* get the transform matrix of the target */
        constraint_target_to_mat4(ct->tar, ct->subtarget, tempmat, CONSTRAINT_SPACE_WORLD, ct->space, con->headtail);
        
        /* determine where in transform range target is */
        /* data->type is mapped as follows for backwards compatibility:
         *  00,01,02    - rotation (it used to be like this)
         *  10,11,12    - scaling
         *  20,21,22    - location
         */
        if (data->type < 10) {
            /* extract rotation (is in whatever space target should be in) */
            mat4_to_eul(vec, tempmat);
            mul_v3_fl(vec, RAD2DEGF(1.0f)); /* rad -> deg */
            axis= data->type;
        }
        else if (data->type < 20) {
            /* extract scaling (is in whatever space target should be in) */
            mat4_to_size(vec, tempmat);
            axis= data->type - 10;
        }
        else {
            /* extract location */
            copy_v3_v3(vec, tempmat[3]);
            axis= data->type - 20;
        }
        
        /* Target defines the animation */
        s = (vec[axis]-data->min) / (data->max-data->min);
        CLAMP(s, 0, 1);
        t = (s * (data->end-data->start)) + data->start;
        
        if (G.f & G_DEBUG)
            printf("do Action Constraint %s - Ob %s Pchan %s \n", con->name, cob->ob->id.name+2, (cob->pchan)?cob->pchan->name:NULL);
        
        /* Get the appropriate information from the action */
        if (cob->type == CONSTRAINT_OBTYPE_BONE) {
            Object workob;
            bPose *pose;
            bPoseChannel *pchan, *tchan;
            
            /* make a temporary pose and evaluate using that */
            pose = MEM_callocN(sizeof(bPose), "pose");
            
            /* make a copy of the bone of interest in the temp pose before evaluating action, so that it can get set 
             *  - we need to manually copy over a few settings, including rotation order, otherwise this fails
             */
            pchan = cob->pchan;
            
            tchan= verify_pose_channel(pose, pchan->name);
            tchan->rotmode= pchan->rotmode;
            
            /* evaluate action using workob (it will only set the PoseChannel in question) */
            what_does_obaction(cob->ob, &workob, pose, data->act, pchan->name, t);
            
            /* convert animation to matrices for use here */
            pchan_calc_mat(tchan);
            copy_m4_m4(ct->matrix, tchan->chan_mat);
            
            /* Clean up */
            free_pose(pose);
        }
        else if (cob->type == CONSTRAINT_OBTYPE_OBJECT) {
            Object workob;
            
            /* evaluate using workob */
            // FIXME: we don't have any consistent standards on limiting effects on object...
            what_does_obaction(cob->ob, &workob, NULL, data->act, NULL, t);
            object_to_mat4(&workob, ct->matrix);
        }
        else {
            /* behaviour undefined... */
            puts("Error: unknown owner type for Action Constraint");
        }
    }
}

static void actcon_evaluate (bConstraint *UNUSED(con), bConstraintOb *cob, ListBase *targets)
{
    bConstraintTarget *ct= targets->first;
    
    if (VALID_CONS_TARGET(ct)) {
        float temp[4][4];
        
        /* Nice and simple... we just need to multiply the matrices, as the get_target_matrix
         * function has already taken care of everything else.
         */
        copy_m4_m4(temp, cob->matrix);
        mult_m4_m4m4(cob->matrix, temp, ct->matrix);
    }
}

static bConstraintTypeInfo CTI_ACTION = {
    CONSTRAINT_TYPE_ACTION, /* type */
    sizeof(bActionConstraint), /* size */
    "Action", /* name */
    "bActionConstraint", /* struct name */
    NULL, /* free data */
    actcon_relink, /* relink data */
    actcon_id_looper, /* id looper */
    NULL, /* copy data */
    actcon_new_data, /* new data */
    actcon_get_tars, /* get constraint targets */
    actcon_flush_tars, /* flush constraint targets */
    actcon_get_tarmat, /* get target matrix */
    actcon_evaluate /* evaluate */
};

/* --------- Locked Track ---------- */

static void locktrack_new_data (void *cdata)
{
    bLockTrackConstraint *data= (bLockTrackConstraint *)cdata;
    
    data->trackflag = TRACK_Y;
    data->lockflag = LOCK_Z;
}   

static void locktrack_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bLockTrackConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->tar, userdata);
}

static int locktrack_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bLockTrackConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void locktrack_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bLockTrackConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
    }
}

static void locktrack_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
    bLockTrackConstraint *data= con->data;
    bConstraintTarget *ct= targets->first;
    
    if (VALID_CONS_TARGET(ct)) {
        float vec[3],vec2[3];
        float totmat[3][3];
        float tmpmat[3][3];
        float invmat[3][3];
        float tmat[4][4];
        float mdet;
        
        /* Vector object -> target */
        sub_v3_v3v3(vec, ct->matrix[3], cob->matrix[3]);
        switch (data->lockflag){
        case LOCK_X: /* LOCK X */
        {
            switch (data->trackflag) {
                case TRACK_Y: /* LOCK X TRACK Y */
                {
                    /* Projection of Vector on the plane */
                    project_v3_v3v3(vec2, vec, cob->matrix[0]);
                    sub_v3_v3v3(totmat[1], vec, vec2);
                    normalize_v3(totmat[1]);
                    
                    /* the x axis is fixed */
                    normalize_v3_v3(totmat[0], cob->matrix[0]);
                    
                    /* the z axis gets mapped onto a third orthogonal vector */
                    cross_v3_v3v3(totmat[2], totmat[0], totmat[1]);
                }
                    break;
                case TRACK_Z: /* LOCK X TRACK Z */
                {
                    /* Projection of Vector on the plane */
                    project_v3_v3v3(vec2, vec, cob->matrix[0]);
                    sub_v3_v3v3(totmat[2], vec, vec2);
                    normalize_v3(totmat[2]);
                    
                    /* the x axis is fixed */
                    normalize_v3_v3(totmat[0], cob->matrix[0]);
                    
                    /* the z axis gets mapped onto a third orthogonal vector */
                    cross_v3_v3v3(totmat[1], totmat[2], totmat[0]);
                }
                    break;
                case TRACK_nY: /* LOCK X TRACK -Y */
                {
                    /* Projection of Vector on the plane */
                    project_v3_v3v3(vec2, vec, cob->matrix[0]);
                    sub_v3_v3v3(totmat[1], vec, vec2);
                    normalize_v3(totmat[1]);
                    negate_v3(totmat[1]);
                    
                    /* the x axis is fixed */
                    normalize_v3_v3(totmat[0], cob->matrix[0]);
                    
                    /* the z axis gets mapped onto a third orthogonal vector */
                    cross_v3_v3v3(totmat[2], totmat[0], totmat[1]);
                }
                    break;
                case TRACK_nZ: /* LOCK X TRACK -Z */
                {
                    /* Projection of Vector on the plane */
                    project_v3_v3v3(vec2, vec, cob->matrix[0]);
                    sub_v3_v3v3(totmat[2], vec, vec2);
                    normalize_v3(totmat[2]);
                    negate_v3(totmat[2]);
                        
                    /* the x axis is fixed */
                    normalize_v3_v3(totmat[0], cob->matrix[0]);
                        
                    /* the z axis gets mapped onto a third orthogonal vector */
                    cross_v3_v3v3(totmat[1], totmat[2], totmat[0]);
                }
                    break;
                default:
                {
                    unit_m3(totmat);
                }
                    break;
            }
        }
            break;
        case LOCK_Y: /* LOCK Y */
        {
            switch (data->trackflag) {
                case TRACK_X: /* LOCK Y TRACK X */
                {
                    /* Projection of Vector on the plane */
                    project_v3_v3v3(vec2, vec, cob->matrix[1]);
                    sub_v3_v3v3(totmat[0], vec, vec2);
                    normalize_v3(totmat[0]);
                    
                    /* the y axis is fixed */
                    normalize_v3_v3(totmat[1], cob->matrix[1]);

                    /* the z axis gets mapped onto a third orthogonal vector */
                    cross_v3_v3v3(totmat[2], totmat[0], totmat[1]);
                }
                    break;
                case TRACK_Z: /* LOCK Y TRACK Z */
                {
                    /* Projection of Vector on the plane */
                    project_v3_v3v3(vec2, vec, cob->matrix[1]);
                    sub_v3_v3v3(totmat[2], vec, vec2);
                    normalize_v3(totmat[2]);
                    
                    /* the y axis is fixed */
                    normalize_v3_v3(totmat[1], cob->matrix[1]);
                    
                    /* the z axis gets mapped onto a third orthogonal vector */
                    cross_v3_v3v3(totmat[0], totmat[1], totmat[2]);
                }
                    break;
                case TRACK_nX: /* LOCK Y TRACK -X */
                {
                    /* Projection of Vector on the plane */
                    project_v3_v3v3(vec2, vec, cob->matrix[1]);
                    sub_v3_v3v3(totmat[0], vec, vec2);
                    normalize_v3(totmat[0]);
                    negate_v3(totmat[0]);
                    
                    /* the y axis is fixed */
                    normalize_v3_v3(totmat[1], cob->matrix[1]);
                    
                    /* the z axis gets mapped onto a third orthogonal vector */
                    cross_v3_v3v3(totmat[2], totmat[0], totmat[1]);
                }
                    break;
                case TRACK_nZ: /* LOCK Y TRACK -Z */
                {
                    /* Projection of Vector on the plane */
                    project_v3_v3v3(vec2, vec, cob->matrix[1]);
                    sub_v3_v3v3(totmat[2], vec, vec2);
                    normalize_v3(totmat[2]);
                    negate_v3(totmat[2]);
                    
                    /* the y axis is fixed */
                    normalize_v3_v3(totmat[1], cob->matrix[1]);
                    
                    /* the z axis gets mapped onto a third orthogonal vector */
                    cross_v3_v3v3(totmat[0], totmat[1], totmat[2]);
                }
                    break;
                default:
                {
                    unit_m3(totmat);
                }
                    break;
            }
        }
            break;
        case LOCK_Z: /* LOCK Z */
        {
            switch (data->trackflag) {
                case TRACK_X: /* LOCK Z TRACK X */
                {
                    /* Projection of Vector on the plane */
                    project_v3_v3v3(vec2, vec, cob->matrix[2]);
                    sub_v3_v3v3(totmat[0], vec, vec2);
                    normalize_v3(totmat[0]);
                    
                    /* the z axis is fixed */
                    normalize_v3_v3(totmat[2], cob->matrix[2]);
                    
                    /* the x axis gets mapped onto a third orthogonal vector */
                    cross_v3_v3v3(totmat[1], totmat[2], totmat[0]);
                }
                    break;
                case TRACK_Y: /* LOCK Z TRACK Y */
                {
                    /* Projection of Vector on the plane */
                    project_v3_v3v3(vec2, vec, cob->matrix[2]);
                    sub_v3_v3v3(totmat[1], vec, vec2);
                    normalize_v3(totmat[1]);
                    
                    /* the z axis is fixed */
                    normalize_v3_v3(totmat[2], cob->matrix[2]);
                        
                    /* the x axis gets mapped onto a third orthogonal vector */
                    cross_v3_v3v3(totmat[0], totmat[1], totmat[2]);
                }
                    break;
                case TRACK_nX: /* LOCK Z TRACK -X */
                {
                    /* Projection of Vector on the plane */
                    project_v3_v3v3(vec2, vec, cob->matrix[2]);
                    sub_v3_v3v3(totmat[0], vec, vec2);
                    normalize_v3(totmat[0]);
                    negate_v3(totmat[0]);
                    
                    /* the z axis is fixed */
                    normalize_v3_v3(totmat[2], cob->matrix[2]);
                    
                    /* the x axis gets mapped onto a third orthogonal vector */
                    cross_v3_v3v3(totmat[1], totmat[2], totmat[0]);
                }
                    break;
                case TRACK_nY: /* LOCK Z TRACK -Y */
                {
                    /* Projection of Vector on the plane */
                    project_v3_v3v3(vec2, vec, cob->matrix[2]);
                    sub_v3_v3v3(totmat[1], vec, vec2);
                    normalize_v3(totmat[1]);
                    negate_v3(totmat[1]);
                    
                    /* the z axis is fixed */
                    normalize_v3_v3(totmat[2], cob->matrix[2]);
                        
                    /* the x axis gets mapped onto a third orthogonal vector */
                    cross_v3_v3v3(totmat[0], totmat[1], totmat[2]);
                }
                    break;
                default:
                {
                    unit_m3(totmat);
                }
                    break;
            }
        }
            break;
        default:
        {
            unit_m3(totmat);
        }
            break;
        }
        /* Block to keep matrix heading */
        copy_m3_m4(tmpmat, cob->matrix);
        normalize_m3(tmpmat);
        invert_m3_m3(invmat, tmpmat);
        mul_m3_m3m3(tmpmat, totmat, invmat);
        totmat[0][0] = tmpmat[0][0];totmat[0][1] = tmpmat[0][1];totmat[0][2] = tmpmat[0][2];
        totmat[1][0] = tmpmat[1][0];totmat[1][1] = tmpmat[1][1];totmat[1][2] = tmpmat[1][2];
        totmat[2][0] = tmpmat[2][0];totmat[2][1] = tmpmat[2][1];totmat[2][2] = tmpmat[2][2];
        
        copy_m4_m4(tmat, cob->matrix);
        
        mdet = determinant_m3(  totmat[0][0],totmat[0][1],totmat[0][2],
                        totmat[1][0],totmat[1][1],totmat[1][2],
                        totmat[2][0],totmat[2][1],totmat[2][2]);
        if (mdet==0) {
            unit_m3(totmat);
        }
        
        /* apply out transformaton to the object */
        mul_m4_m3m4(cob->matrix, totmat, tmat);
    }
}

static bConstraintTypeInfo CTI_LOCKTRACK = {
    CONSTRAINT_TYPE_LOCKTRACK, /* type */
    sizeof(bLockTrackConstraint), /* size */
    "Locked Track", /* name */
    "bLockTrackConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    locktrack_id_looper, /* id looper */
    NULL, /* copy data */
    locktrack_new_data, /* new data */
    locktrack_get_tars, /* get constraint targets */
    locktrack_flush_tars, /* flush constraint targets */
    default_get_tarmat, /* get target matrix */
    locktrack_evaluate /* evaluate */
};

/* ---------- Limit Distance Constraint ----------- */

static void distlimit_new_data (void *cdata)
{
    bDistLimitConstraint *data= (bDistLimitConstraint *)cdata;
    
    data->dist= 0.0f;
}

static void distlimit_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bDistLimitConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->tar, userdata);
}

static int distlimit_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bDistLimitConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* standard target-getting macro for single-target constraints */
        SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void distlimit_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bDistLimitConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
    }
}

static void distlimit_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
    bDistLimitConstraint *data= con->data;
    bConstraintTarget *ct= targets->first;
    
    /* only evaluate if there is a target */
    if (VALID_CONS_TARGET(ct)) {
        float dvec[3], dist=0.0f, sfac=1.0f;
        short clamp_surf= 0;
        
        /* calculate our current distance from the target */
        dist= len_v3v3(cob->matrix[3], ct->matrix[3]);
        
        /* set distance (flag is only set when user demands it) */
        if (data->dist == 0)
            data->dist= dist;
        
        /* check if we're which way to clamp from, and calculate interpolation factor (if needed) */
        if (data->mode == LIMITDIST_OUTSIDE) {
            /* if inside, then move to surface */
            if (dist <= data->dist) {
                clamp_surf= 1;
                if (dist != 0.0f) sfac= data->dist / dist;
            }
            /* if soft-distance is enabled, start fading once owner is dist+softdist from the target */
            else if (data->flag & LIMITDIST_USESOFT) {
                if (dist <= (data->dist + data->soft)) {
                    
                }
            }
        }
        else if (data->mode == LIMITDIST_INSIDE) {
            /* if outside, then move to surface */
            if (dist >= data->dist) {
                clamp_surf= 1;
                if (dist != 0.0f) sfac= data->dist / dist;
            }
            /* if soft-distance is enabled, start fading once owner is dist-soft from the target */
            else if (data->flag & LIMITDIST_USESOFT) {
                // FIXME: there's a problem with "jumping" when this kicks in
                if (dist >= (data->dist - data->soft)) {
                    sfac = (float)( data->soft*(1.0f - expf(-(dist - data->dist)/data->soft)) + data->dist );
                    if (dist != 0.0f) sfac /= dist;
                    
                    clamp_surf= 1;
                }
            }
        }
        else {
            if (IS_EQF(dist, data->dist)==0) {
                clamp_surf= 1;
                if (dist != 0.0f) sfac= data->dist / dist;
            }
        }
        
        /* clamp to 'surface' (i.e. move owner so that dist == data->dist) */
        if (clamp_surf) {
            /* simply interpolate along line formed by target -> owner */
            interp_v3_v3v3(dvec, ct->matrix[3], cob->matrix[3], sfac);
            
            /* copy new vector onto owner */
            copy_v3_v3(cob->matrix[3], dvec);
        }
    }
}

static bConstraintTypeInfo CTI_DISTLIMIT = {
    CONSTRAINT_TYPE_DISTLIMIT, /* type */
    sizeof(bDistLimitConstraint), /* size */
    "Limit Distance", /* name */
    "bDistLimitConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    distlimit_id_looper, /* id looper */
    NULL, /* copy data */
    distlimit_new_data, /* new data */
    distlimit_get_tars, /* get constraint targets */
    distlimit_flush_tars, /* flush constraint targets */
    default_get_tarmat, /* get a target matrix */
    distlimit_evaluate /* evaluate */
};

/* ---------- Stretch To ------------ */

static void stretchto_new_data (void *cdata)
{
    bStretchToConstraint *data= (bStretchToConstraint *)cdata;
    
    data->volmode = 0;
    data->plane = 0;
    data->orglength = 0.0; 
    data->bulge = 1.0;
}

static void stretchto_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bStretchToConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->tar, userdata);
}

static int stretchto_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bStretchToConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* standard target-getting macro for single-target constraints */
        SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void stretchto_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bStretchToConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
    }
}

static void stretchto_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
    bStretchToConstraint *data= con->data;
    bConstraintTarget *ct= targets->first;
    
    /* only evaluate if there is a target */
    if (VALID_CONS_TARGET(ct)) {
        float size[3], scale[3], vec[3], xx[3], zz[3], orth[3];
        float totmat[3][3];
        float tmat[4][4];
        float dist;
        
        /* store scaling before destroying obmat */
        mat4_to_size(size, cob->matrix);
        
        /* store X orientation before destroying obmat */
        normalize_v3_v3(xx, cob->matrix[0]);
        
        /* store Z orientation before destroying obmat */
        normalize_v3_v3(zz, cob->matrix[2]);
        
        sub_v3_v3v3(vec, cob->matrix[3], ct->matrix[3]);
        vec[0] /= size[0];
        vec[1] /= size[1];
        vec[2] /= size[2];
        
        dist = normalize_v3(vec);
        //dist = len_v3v3( ob->obmat[3], targetmat[3]);
        
        /* data->orglength==0 occurs on first run, and after 'R' button is clicked */
        if (data->orglength == 0)  
            data->orglength = dist;
        if (data->bulge == 0) 
            data->bulge = 1.0;
        
        scale[1] = dist/data->orglength;
        switch (data->volmode) {
        /* volume preserving scaling */
        case VOLUME_XZ :
            scale[0] = 1.0f - (float)sqrt(data->bulge) + (float)sqrt(data->bulge*(data->orglength/dist));
            scale[2] = scale[0];
            break;
        case VOLUME_X:
            scale[0] = 1.0f + data->bulge * (data->orglength /dist - 1);
            scale[2] = 1.0;
            break;
        case VOLUME_Z:
            scale[0] = 1.0;
            scale[2] = 1.0f + data->bulge * (data->orglength /dist - 1);
            break;
            /* don't care for volume */
        case NO_VOLUME:
            scale[0] = 1.0;
            scale[2] = 1.0;
            break;
        default: /* should not happen, but in case*/
            return;    
        } /* switch (data->volmode) */

        /* Clear the object's rotation and scale */
        cob->matrix[0][0]=size[0]*scale[0];
        cob->matrix[0][1]=0;
        cob->matrix[0][2]=0;
        cob->matrix[1][0]=0;
        cob->matrix[1][1]=size[1]*scale[1];
        cob->matrix[1][2]=0;
        cob->matrix[2][0]=0;
        cob->matrix[2][1]=0;
        cob->matrix[2][2]=size[2]*scale[2];
        
        sub_v3_v3v3(vec, cob->matrix[3], ct->matrix[3]);
        normalize_v3(vec);
        
        /* new Y aligns  object target connection*/
        negate_v3_v3(totmat[1], vec);
        switch (data->plane) {
        case PLANE_X:
            /* build new Z vector */
            /* othogonal to "new Y" "old X! plane */
            cross_v3_v3v3(orth, vec, xx);
            normalize_v3(orth);
            
            /* new Z*/
            copy_v3_v3(totmat[2], orth);
            
            /* we decided to keep X plane*/
            cross_v3_v3v3(xx, orth, vec);
            normalize_v3_v3(totmat[0], xx);
            break;
        case PLANE_Z:
            /* build new X vector */
            /* othogonal to "new Y" "old Z! plane */
            cross_v3_v3v3(orth, vec, zz);
            normalize_v3(orth);
            
            /* new X */
            negate_v3_v3(totmat[0], orth);
            
            /* we decided to keep Z */
            cross_v3_v3v3(zz, orth, vec);
            normalize_v3_v3(totmat[2], zz);
            break;
        } /* switch (data->plane) */
        
        copy_m4_m4(tmat, cob->matrix);
        mul_m4_m3m4(cob->matrix, totmat, tmat);
    }
}

static bConstraintTypeInfo CTI_STRETCHTO = {
    CONSTRAINT_TYPE_STRETCHTO, /* type */
    sizeof(bStretchToConstraint), /* size */
    "Stretch To", /* name */
    "bStretchToConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    stretchto_id_looper, /* id looper */
    NULL, /* copy data */
    stretchto_new_data, /* new data */
    stretchto_get_tars, /* get constraint targets */
    stretchto_flush_tars, /* flush constraint targets */
    default_get_tarmat, /* get target matrix */
    stretchto_evaluate /* evaluate */
};

/* ---------- Floor ------------ */

static void minmax_new_data (void *cdata)
{
    bMinMaxConstraint *data= (bMinMaxConstraint *)cdata;
    
    data->minmaxflag = TRACK_Z;
    data->offset = 0.0f;
    data->cache[0] = data->cache[1] = data->cache[2] = 0.0f;
    data->flag = 0;
}

static void minmax_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bMinMaxConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->tar, userdata);
}

static int minmax_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bMinMaxConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* standard target-getting macro for single-target constraints */
        SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void minmax_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bMinMaxConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
    }
}

static void minmax_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
    bMinMaxConstraint *data= con->data;
    bConstraintTarget *ct= targets->first;
    
    /* only evaluate if there is a target */
    if (VALID_CONS_TARGET(ct)) {
        float obmat[4][4], imat[4][4], tarmat[4][4], tmat[4][4];
        float val1, val2;
        int index;
        
        copy_m4_m4(obmat, cob->matrix);
        copy_m4_m4(tarmat, ct->matrix);
        
        if (data->flag & MINMAX_USEROT) {
            /* take rotation of target into account by doing the transaction in target's localspace */
            invert_m4_m4(imat, tarmat);
            mult_m4_m4m4(tmat, imat, obmat);
            copy_m4_m4(obmat, tmat);
            unit_m4(tarmat);
        }
        
        switch (data->minmaxflag) {
        case TRACK_Z:
            val1 = tarmat[3][2];
            val2 = obmat[3][2]-data->offset;
            index = 2;
            break;
        case TRACK_Y:
            val1 = tarmat[3][1];
            val2 = obmat[3][1]-data->offset;
            index = 1;
            break;
        case TRACK_X:
            val1 = tarmat[3][0];
            val2 = obmat[3][0]-data->offset;
            index = 0;
            break;
        case TRACK_nZ:
            val2 = tarmat[3][2];
            val1 = obmat[3][2]-data->offset;
            index = 2;
            break;
        case TRACK_nY:
            val2 = tarmat[3][1];
            val1 = obmat[3][1]-data->offset;
            index = 1;
            break;
        case TRACK_nX:
            val2 = tarmat[3][0];
            val1 = obmat[3][0]-data->offset;
            index = 0;
            break;
        default:
            return;
        }
        
        if (val1 > val2) {
            obmat[3][index] = tarmat[3][index] + data->offset;
            if (data->flag & MINMAX_STICKY) {
                if (data->flag & MINMAX_STUCK) {
                    copy_v3_v3(obmat[3], data->cache);
                } 
                else {
                    copy_v3_v3(data->cache, obmat[3]);
                    data->flag |= MINMAX_STUCK;
                }
            }
            if (data->flag & MINMAX_USEROT) {
                /* get out of localspace */
                mult_m4_m4m4(tmat, ct->matrix, obmat);
                copy_m4_m4(cob->matrix, tmat);
            } 
            else {          
                copy_v3_v3(cob->matrix[3], obmat[3]);
            }
        } 
        else {
            data->flag &= ~MINMAX_STUCK;
        }
    }
}

static bConstraintTypeInfo CTI_MINMAX = {
    CONSTRAINT_TYPE_MINMAX, /* type */
    sizeof(bMinMaxConstraint), /* size */
    "Floor", /* name */
    "bMinMaxConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    minmax_id_looper, /* id looper */
    NULL, /* copy data */
    minmax_new_data, /* new data */
    minmax_get_tars, /* get constraint targets */
    minmax_flush_tars, /* flush constraint targets */
    default_get_tarmat, /* get target matrix */
    minmax_evaluate /* evaluate */
};

/* ------- RigidBody Joint ---------- */

static void rbj_new_data (void *cdata)
{
    bRigidBodyJointConstraint *data= (bRigidBodyJointConstraint *)cdata;
    
    // removed code which set target of this constraint  
    data->type=1;
}

static void rbj_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bRigidBodyJointConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->tar, userdata);
    func(con, (ID**)&data->child, userdata);
}

static int rbj_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bRigidBodyJointConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* standard target-getting macro for single-target constraints without subtargets */
        SINGLETARGETNS_GET_TARS(con, data->tar, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void rbj_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bRigidBodyJointConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGETNS_FLUSH_TARS(con, data->tar, ct, list, nocopy)
    }
}

static bConstraintTypeInfo CTI_RIGIDBODYJOINT = {
    CONSTRAINT_TYPE_RIGIDBODYJOINT, /* type */
    sizeof(bRigidBodyJointConstraint), /* size */
    "Rigid Body Joint", /* name */
    "bRigidBodyJointConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    rbj_id_looper, /* id looper */
    NULL, /* copy data */
    rbj_new_data, /* new data */
    rbj_get_tars, /* get constraint targets */
    rbj_flush_tars, /* flush constraint targets */
    default_get_tarmat, /* get target matrix */
    NULL /* evaluate - this is not solved here... is just an interface for game-engine */
};

/* -------- Clamp To ---------- */

static void clampto_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bClampToConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->tar, userdata);
}

static int clampto_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bClampToConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* standard target-getting macro for single-target constraints without subtargets */
        SINGLETARGETNS_GET_TARS(con, data->tar, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void clampto_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bClampToConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGETNS_FLUSH_TARS(con, data->tar, ct, list, nocopy)
    }
}

static void clampto_get_tarmat (bConstraint *UNUSED(con), bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
    if (VALID_CONS_TARGET(ct)) {
        Curve *cu= ct->tar->data;
        
        /* note: when creating constraints that follow path, the curve gets the CU_PATH set now,
         *      currently for paths to work it needs to go through the bevlist/displist system (ton) 
         */
        
        /* only happens on reload file, but violates depsgraph still... fix! */
        if (cu->path==NULL || cu->path->data==NULL)
            makeDispListCurveTypes(cob->scene, ct->tar, 0);
    }
    
    /* technically, this isn't really needed for evaluation, but we don't know what else
     * might end up calling this...
     */
    if (ct)
        unit_m4(ct->matrix);
}

static void clampto_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
    bClampToConstraint *data= con->data;
    bConstraintTarget *ct= targets->first;
    
    /* only evaluate if there is a target and it is a curve */
    if (VALID_CONS_TARGET(ct) && (ct->tar->type == OB_CURVE)) {
        Curve *cu= data->tar->data;
        float obmat[4][4], ownLoc[3];
        float curveMin[3], curveMax[3];
        float targetMatrix[4][4]= MAT4_UNITY;
        
        copy_m4_m4(obmat, cob->matrix);
        copy_v3_v3(ownLoc, obmat[3]);
        
        INIT_MINMAX(curveMin, curveMax)
        minmax_object(ct->tar, curveMin, curveMax);
        
        /* get targetmatrix */
        if (cu->path && cu->path->data) {
            float vec[4], dir[3], totmat[4][4];
            float curvetime;
            short clamp_axis;
            
            /* find best position on curve */
            /* 1. determine which axis to sample on? */
            if (data->flag == CLAMPTO_AUTO) {
                float size[3];
                sub_v3_v3v3(size, curveMax, curveMin);
                
                /* find axis along which the bounding box has the greatest
                 * extent. Otherwise, default to the x-axis, as that is quite
                 * frequently used.
                 */
                if ((size[2]>size[0]) && (size[2]>size[1]))
                    clamp_axis= CLAMPTO_Z - 1;
                else if ((size[1]>size[0]) && (size[1]>size[2]))
                    clamp_axis= CLAMPTO_Y - 1;
                else
                    clamp_axis = CLAMPTO_X - 1;
            }
            else 
                clamp_axis= data->flag - 1;
                
            /* 2. determine position relative to curve on a 0-1 scale based on bounding box */
            if (data->flag2 & CLAMPTO_CYCLIC) {
                /* cyclic, so offset within relative bounding box is used */
                float len= (curveMax[clamp_axis] - curveMin[clamp_axis]);
                float offset;
                
                /* check to make sure len is not so close to zero that it'll cause errors */
                if (IS_EQ(len, 0) == 0) {
                    /* find bounding-box range where target is located */
                    if (ownLoc[clamp_axis] < curveMin[clamp_axis]) {
                        /* bounding-box range is before */
                        offset= curveMin[clamp_axis];
                        
                        while (ownLoc[clamp_axis] < offset)
                            offset -= len;
                        
                        /* now, we calculate as per normal, except using offset instead of curveMin[clamp_axis] */
                        curvetime = (ownLoc[clamp_axis] - offset) / (len);
                    }
                    else if (ownLoc[clamp_axis] > curveMax[clamp_axis]) {
                        /* bounding-box range is after */
                        offset= curveMax[clamp_axis];
                        
                        while (ownLoc[clamp_axis] > offset) {
                            if ((offset + len) > ownLoc[clamp_axis])
                                break;
                            else
                                offset += len;
                        }
                        
                        /* now, we calculate as per normal, except using offset instead of curveMax[clamp_axis] */
                        curvetime = (ownLoc[clamp_axis] - offset) / (len);
                    }
                    else {
                        /* as the location falls within bounds, just calculate */
                        curvetime = (ownLoc[clamp_axis] - curveMin[clamp_axis]) / (len);
                    }
                }
                else {
                    /* as length is close to zero, curvetime by default should be 0 (i.e. the start) */
                    curvetime= 0.0f;
                }
            }
            else {
                /* no cyclic, so position is clamped to within the bounding box */
                if (ownLoc[clamp_axis] <= curveMin[clamp_axis])
                    curvetime = 0.0f;
                else if (ownLoc[clamp_axis] >= curveMax[clamp_axis])
                    curvetime = 1.0f;
                else if ( IS_EQ((curveMax[clamp_axis] - curveMin[clamp_axis]), 0) == 0 )
                    curvetime = (ownLoc[clamp_axis] - curveMin[clamp_axis]) / (curveMax[clamp_axis] - curveMin[clamp_axis]);
                else 
                    curvetime = 0.0f;
            }
            
            /* 3. position on curve */
            if (where_on_path(ct->tar, curvetime, vec, dir, NULL, NULL, NULL) ) {
                unit_m4(totmat);
                copy_v3_v3(totmat[3], vec);
                
                mul_serie_m4(targetMatrix, ct->tar->obmat, totmat, NULL, NULL, NULL, NULL, NULL, NULL);
            }
        }
        
        /* obtain final object position */
        copy_v3_v3(cob->matrix[3], targetMatrix[3]);
    }
}

static bConstraintTypeInfo CTI_CLAMPTO = {
    CONSTRAINT_TYPE_CLAMPTO, /* type */
    sizeof(bClampToConstraint), /* size */
    "Clamp To", /* name */
    "bClampToConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    clampto_id_looper, /* id looper */
    NULL, /* copy data */
    NULL, /* new data */
    clampto_get_tars, /* get constraint targets */
    clampto_flush_tars, /* flush constraint targets */
    clampto_get_tarmat, /* get target matrix */
    clampto_evaluate /* evaluate */
};

/* ---------- Transform Constraint ----------- */

static void transform_new_data (void *cdata)
{
    bTransformConstraint *data= (bTransformConstraint *)cdata;
    
    data->map[0]= 0;
    data->map[1]= 1;
    data->map[2]= 2;
}

static void transform_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bTransformConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->tar, userdata);
}

static int transform_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bTransformConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* standard target-getting macro for single-target constraints */
        SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void transform_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bTransformConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
    }
}

static void transform_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
    bTransformConstraint *data= con->data;
    bConstraintTarget *ct= targets->first;
    
    /* only evaluate if there is a target */
    if (VALID_CONS_TARGET(ct)) {
        float loc[3], eul[3], size[3];
        float dvec[3], sval[3];
        int i;
        
        /* obtain target effect */
        switch (data->from) {
            case 2: /* scale */
                mat4_to_size( dvec,ct->matrix);
                break;
            case 1: /* rotation (convert to degrees first) */
                mat4_to_eulO(dvec, cob->rotOrder, ct->matrix);
                mul_v3_fl(dvec, RAD2DEGF(1.0f)); /* rad -> deg */
                break;
            default: /* location */
                copy_v3_v3(dvec, ct->matrix[3]);
                break;
        }
        
        /* extract components of owner's matrix */
        copy_v3_v3(loc, cob->matrix[3]);
        mat4_to_eulO(eul, cob->rotOrder, cob->matrix);
        mat4_to_size(size, cob->matrix);    
        
        /* determine where in range current transforms lie */
        if (data->expo) {
            for (i=0; i<3; i++) {
                if (data->from_max[i] - data->from_min[i])
                    sval[i]= (dvec[i] - data->from_min[i]) / (data->from_max[i] - data->from_min[i]);
                else
                    sval[i]= 0.0f;
            }
        }
        else {
            /* clamp transforms out of range */
            for (i=0; i<3; i++) {
                CLAMP(dvec[i], data->from_min[i], data->from_max[i]);
                if (data->from_max[i] - data->from_min[i])
                    sval[i]= (dvec[i] - data->from_min[i]) / (data->from_max[i] - data->from_min[i]);
                else
                    sval[i]= 0.0f;
            }
        }
        
        
        /* apply transforms */
        switch (data->to) {
            case 2: /* scaling */
                for (i=0; i<3; i++)
                    size[i]= data->to_min[i] + (sval[(int)data->map[i]] * (data->to_max[i] - data->to_min[i])); 
                break;
            case 1: /* rotation */
                for (i=0; i<3; i++) {
                    float tmin, tmax;
                    
                    tmin= data->to_min[i];
                    tmax= data->to_max[i];
                    
                    /* all values here should be in degrees */
                    eul[i]= tmin + (sval[(int)data->map[i]] * (tmax - tmin)); 
                    
                    /* now convert final value back to radians */
                    eul[i] = DEG2RADF(eul[i]);
                }
                break;
            default: /* location */
                /* get new location */
                for (i=0; i<3; i++)
                    loc[i]= (data->to_min[i] + (sval[(int)data->map[i]] * (data->to_max[i] - data->to_min[i])));
                
                /* add original location back on (so that it can still be moved) */
                add_v3_v3v3(loc, cob->matrix[3], loc);
                break;
        }
        
        /* apply to matrix */
        loc_eulO_size_to_mat4(cob->matrix, loc, eul, size, cob->rotOrder);
    }
}

static bConstraintTypeInfo CTI_TRANSFORM = {
    CONSTRAINT_TYPE_TRANSFORM, /* type */
    sizeof(bTransformConstraint), /* size */
    "Transform", /* name */
    "bTransformConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    transform_id_looper, /* id looper */
    NULL, /* copy data */
    transform_new_data, /* new data */
    transform_get_tars, /* get constraint targets */
    transform_flush_tars, /* flush constraint targets */
    default_get_tarmat, /* get a target matrix */
    transform_evaluate /* evaluate */
};

/* ---------- Shrinkwrap Constraint ----------- */

static void shrinkwrap_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bShrinkwrapConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->target, userdata);
}

static int shrinkwrap_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bShrinkwrapConstraint *data = con->data;
        bConstraintTarget *ct;
        
        SINGLETARGETNS_GET_TARS(con, data->target, ct, list)
        
        return 1;
    }
    
    return 0;
}


static void shrinkwrap_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bShrinkwrapConstraint *data = con->data;
        bConstraintTarget *ct= list->first;
        
        SINGLETARGETNS_FLUSH_TARS(con, data->target, ct, list, nocopy)
    }
}


static void shrinkwrap_get_tarmat (bConstraint *con, bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
    bShrinkwrapConstraint *scon = (bShrinkwrapConstraint *) con->data;
    
    if( VALID_CONS_TARGET(ct) && (ct->tar->type == OB_MESH) )
    {
        int fail = FALSE;
        float co[3] = {0.0f, 0.0f, 0.0f};
        float no[3] = {0.0f, 0.0f, 0.0f};
        float dist;
        
        SpaceTransform transform;
        DerivedMesh *target = object_get_derived_final(ct->tar);
        BVHTreeRayHit hit;
        BVHTreeNearest nearest;
        
        BVHTreeFromMesh treeData= {NULL};
        
        nearest.index = -1;
        nearest.dist = FLT_MAX;
        
        hit.index = -1;
        hit.dist = 100000.0f;  //TODO should use FLT_MAX.. but normal projection doenst yet supports it
        
        unit_m4(ct->matrix);
        
        if(target != NULL)
        {
            space_transform_from_matrixs(&transform, cob->matrix, ct->tar->obmat);
            
            switch(scon->shrinkType)
            {
                case MOD_SHRINKWRAP_NEAREST_SURFACE:
                case MOD_SHRINKWRAP_NEAREST_VERTEX:
                    
                    if(scon->shrinkType == MOD_SHRINKWRAP_NEAREST_VERTEX)
                        bvhtree_from_mesh_verts(&treeData, target, 0.0, 2, 6);
                    else
                        bvhtree_from_mesh_faces(&treeData, target, 0.0, 2, 6);
                    
                    if(treeData.tree == NULL)
                    {
                        fail = TRUE;
                        break;
                    }
                    
                    space_transform_apply(&transform, co);
                    
                    BLI_bvhtree_find_nearest(treeData.tree, co, &nearest, treeData.nearest_callback, &treeData);
                    
                    dist = len_v3v3(co, nearest.co);
                    if(dist != 0.0f) {
                        interp_v3_v3v3(co, co, nearest.co, (dist - scon->dist)/dist);   /* linear interpolation */
                    }
                    space_transform_invert(&transform, co);
                break;
                
                case MOD_SHRINKWRAP_PROJECT:
                    if(scon->projAxis & MOD_SHRINKWRAP_PROJECT_OVER_X_AXIS) no[0] = 1.0f;
                    if(scon->projAxis & MOD_SHRINKWRAP_PROJECT_OVER_Y_AXIS) no[1] = 1.0f;
                    if(scon->projAxis & MOD_SHRINKWRAP_PROJECT_OVER_Z_AXIS) no[2] = 1.0f;
                    
                    if(INPR(no,no) < FLT_EPSILON)
                    {
                        fail = TRUE;
                        break;
                    }
                    
                    normalize_v3(no);
                    
                    
                    bvhtree_from_mesh_faces(&treeData, target, scon->dist, 4, 6);
                    if(treeData.tree == NULL)
                    {
                        fail = TRUE;
                        break;
                    }
                    
                    if(normal_projection_project_vertex(0, co, no, &transform, treeData.tree, &hit, treeData.raycast_callback, &treeData) == FALSE)
                    {
                        fail = TRUE;
                        break;
                    }
                    copy_v3_v3(co, hit.co);
                break;
            }
            
            free_bvhtree_from_mesh(&treeData);
            
            target->release(target);
            
            if(fail == TRUE)
            {
                /* Don't move the point */
                co[0] = co[1] = co[2] = 0.0f;
            }
            
            /* co is in local object coordinates, change it to global and update target position */
            mul_m4_v3(cob->matrix, co);
            copy_v3_v3(ct->matrix[3], co);
        }
    }
}

static void shrinkwrap_evaluate (bConstraint *UNUSED(con), bConstraintOb *cob, ListBase *targets)
{
    bConstraintTarget *ct= targets->first;
    
    /* only evaluate if there is a target */
    if (VALID_CONS_TARGET(ct))
    {
        copy_v3_v3(cob->matrix[3], ct->matrix[3]);
    }
}

static bConstraintTypeInfo CTI_SHRINKWRAP = {
    CONSTRAINT_TYPE_SHRINKWRAP, /* type */
    sizeof(bShrinkwrapConstraint), /* size */
    "Shrinkwrap", /* name */
    "bShrinkwrapConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    shrinkwrap_id_looper, /* id looper */
    NULL, /* copy data */
    NULL, /* new data */
    shrinkwrap_get_tars, /* get constraint targets */
    shrinkwrap_flush_tars, /* flush constraint targets */
    shrinkwrap_get_tarmat, /* get a target matrix */
    shrinkwrap_evaluate /* evaluate */
};

/* --------- Damped Track ---------- */

static void damptrack_new_data (void *cdata)
{
    bDampTrackConstraint *data= (bDampTrackConstraint *)cdata;
    
    data->trackflag = TRACK_Y;
}   

static void damptrack_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bDampTrackConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->tar, userdata);
}

static int damptrack_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bDampTrackConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void damptrack_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bDampTrackConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
    }
}

/* array of direction vectors for the tracking flags */
static const float track_dir_vecs[6][3] = {
    {+1,0,0}, {0,+1,0}, {0,0,+1},       /* TRACK_X,  TRACK_Y,  TRACK_Z */
    {-1,0,0}, {0,-1,0}, {0,0,-1}        /* TRACK_NX, TRACK_NY, TRACK_NZ */
};

static void damptrack_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
    bDampTrackConstraint *data= con->data;
    bConstraintTarget *ct= targets->first;
    
    if (VALID_CONS_TARGET(ct)) {
        float obvec[3], tarvec[3], obloc[3];
        float raxis[3], rangle;
        float rmat[3][3], tmat[4][4];
        
        /* find the (unit) direction that the axis we're interested in currently points 
         *  - mul_mat3_m4_v3() only takes the 3x3 (rotation+scaling) components of the 4x4 matrix 
         *  - the normalisation step at the end should take care of any unwanted scaling
         *    left over in the 3x3 matrix we used
         */
        copy_v3_v3(obvec, track_dir_vecs[data->trackflag]);
        mul_mat3_m4_v3(cob->matrix, obvec);
        
        if (normalize_v3(obvec) == 0.0f) {
            /* exceptional case - just use the track vector as appropriate */
            copy_v3_v3(obvec, track_dir_vecs[data->trackflag]);
        }
        
        /* find the (unit) direction vector going from the owner to the target */
        copy_v3_v3(obloc, cob->matrix[3]);
        sub_v3_v3v3(tarvec, ct->matrix[3], obloc);
        
        if (normalize_v3(tarvec) == 0.0f) {
            /* the target is sitting on the owner, so just make them use the same direction vectors */
            // FIXME: or would it be better to use the pure direction vector?
            copy_v3_v3(tarvec, obvec);
            //copy_v3_v3(tarvec, track_dir_vecs[data->trackflag]);
        }
        
        /* determine the axis-angle rotation, which represents the smallest possible rotation
         * between the two rotation vectors (i.e. the 'damping' referred to in the name)
         *  - we take this to be the rotation around the normal axis/vector to the plane defined
         *    by the current and destination vectors, which will 'map' the current axis to the 
         *    destination vector
         *  - the min/max wrappers around (obvec . tarvec) result (stored temporarily in rangle)
         *    are used to ensure that the smallest angle is chosen
         */
        cross_v3_v3v3(raxis, obvec, tarvec);
        
        rangle= dot_v3v3(obvec, tarvec);
        rangle= acos( MAX2(-1.0f, MIN2(1.0f, rangle)) );
        
        /* construct rotation matrix from the axis-angle rotation found above 
         *  - this call takes care to make sure that the axis provided is a unit vector first
         */
        axis_angle_to_mat3(rmat, raxis, rangle);
        
        /* rotate the owner in the way defined by this rotation matrix, then reapply the location since
         * we may have destroyed that in the process of multiplying the matrix
         */
        unit_m4(tmat);
        mul_m4_m3m4(tmat, rmat, cob->matrix); // m1, m3, m2
        
        copy_m4_m4(cob->matrix, tmat);
        copy_v3_v3(cob->matrix[3], obloc);
    }
}

static bConstraintTypeInfo CTI_DAMPTRACK = {
    CONSTRAINT_TYPE_DAMPTRACK, /* type */
    sizeof(bDampTrackConstraint), /* size */
    "Damped Track", /* name */
    "bDampTrackConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    damptrack_id_looper, /* id looper */
    NULL, /* copy data */
    damptrack_new_data, /* new data */
    damptrack_get_tars, /* get constraint targets */
    damptrack_flush_tars, /* flush constraint targets */
    default_get_tarmat, /* get target matrix */
    damptrack_evaluate /* evaluate */
};

/* ----------- Spline IK ------------ */

static void splineik_free (bConstraint *con)
{
    bSplineIKConstraint *data= con->data;
    
    /* binding array */
    if (data->points)
        MEM_freeN(data->points);
}   

static void splineik_copy (bConstraint *con, bConstraint *srccon)
{
    bSplineIKConstraint *src= srccon->data;
    bSplineIKConstraint *dst= con->data;
    
    /* copy the binding array */
    dst->points= MEM_dupallocN(src->points);
}

static void splineik_new_data (void *cdata)
{
    bSplineIKConstraint *data= (bSplineIKConstraint *)cdata;

    data->chainlen= 1;
}

static void splineik_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bSplineIKConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->tar, userdata);
}

static int splineik_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bSplineIKConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* standard target-getting macro for single-target constraints without subtargets */
        SINGLETARGETNS_GET_TARS(con, data->tar, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void splineik_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bSplineIKConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGETNS_FLUSH_TARS(con, data->tar, ct, list, nocopy)
    }
}

static void splineik_get_tarmat (bConstraint *UNUSED(con), bConstraintOb *cob, bConstraintTarget *ct, float UNUSED(ctime))
{
    if (VALID_CONS_TARGET(ct)) {
        Curve *cu= ct->tar->data;
        
        /* note: when creating constraints that follow path, the curve gets the CU_PATH set now,
         *      currently for paths to work it needs to go through the bevlist/displist system (ton) 
         */
        
        /* only happens on reload file, but violates depsgraph still... fix! */
        if (cu->path==NULL || cu->path->data==NULL)
            makeDispListCurveTypes(cob->scene, ct->tar, 0);
    }
    
    /* technically, this isn't really needed for evaluation, but we don't know what else
     * might end up calling this...
     */
    if (ct)
        unit_m4(ct->matrix);
}

static bConstraintTypeInfo CTI_SPLINEIK = {
    CONSTRAINT_TYPE_SPLINEIK, /* type */
    sizeof(bSplineIKConstraint), /* size */
    "Spline IK", /* name */
    "bSplineIKConstraint", /* struct name */
    splineik_free, /* free data */
    NULL, /* relink data */
    splineik_id_looper, /* id looper */
    splineik_copy, /* copy data */
    splineik_new_data, /* new data */
    splineik_get_tars, /* get constraint targets */
    splineik_flush_tars, /* flush constraint targets */
    splineik_get_tarmat, /* get target matrix */
    NULL /* evaluate - solved as separate loop */
};

/* ----------- Pivot ------------- */

static void pivotcon_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bPivotConstraint *data= con->data;
    
    /* target only */
    func(con, (ID**)&data->tar, userdata);
}

static int pivotcon_get_tars (bConstraint *con, ListBase *list)
{
    if (con && list) {
        bPivotConstraint *data= con->data;
        bConstraintTarget *ct;
        
        /* standard target-getting macro for single-target constraints */
        SINGLETARGET_GET_TARS(con, data->tar, data->subtarget, ct, list)
        
        return 1;
    }
    
    return 0;
}

static void pivotcon_flush_tars (bConstraint *con, ListBase *list, short nocopy)
{
    if (con && list) {
        bPivotConstraint *data= con->data;
        bConstraintTarget *ct= list->first;
        
        /* the following macro is used for all standard single-target constraints */
        SINGLETARGET_FLUSH_TARS(con, data->tar, data->subtarget, ct, list, nocopy)
    }
}

static void pivotcon_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *targets)
{
    bPivotConstraint *data= con->data;
    bConstraintTarget *ct= targets->first;
    
    float pivot[3], vec[3];
    float rotMat[3][3];

    /* pivot correction */
    float axis[3], angle;
    
    /* firstly, check if pivoting should take place based on the current rotation */
    if (data->rotAxis != PIVOTCON_AXIS_NONE) {
        float rot[3];
        
        /* extract euler-rotation of target */
        mat4_to_eulO(rot, cob->rotOrder, cob->matrix);
        
        /* check which range might be violated */
        if (data->rotAxis < PIVOTCON_AXIS_X) {
            /* negative rotations (data->rotAxis = 0 -> 2) */
            if (rot[data->rotAxis] > 0.0f)
                return;
        }
        else {
            /* positive rotations (data->rotAxis = 3 -> 5 */
            if (rot[data->rotAxis - PIVOTCON_AXIS_X] < 0.0f)
                return;
        }
    }
    
    /* find the pivot-point to use  */
    if (VALID_CONS_TARGET(ct)) {
        /* apply offset to target location */
        add_v3_v3v3(pivot, ct->matrix[3], data->offset);
    }
    else {
        /* no targets to worry about... */
        if ((data->flag & PIVOTCON_FLAG_OFFSET_ABS) == 0) {
            /* offset is relative to owner */
            add_v3_v3v3(pivot, cob->matrix[3], data->offset);
        }
        else {
            /* directly use the 'offset' specified as an absolute position instead */
            copy_v3_v3(pivot, data->offset);
        }
    }
    
    /* get rotation matrix representing the rotation of the owner */
    // TODO: perhaps we might want to include scaling based on the pivot too?
    copy_m3_m4(rotMat, cob->matrix);
    normalize_m3(rotMat);


    /* correct the pivot by the rotation axis otherwise the pivot translates when it shouldnt */
    mat3_to_axis_angle(axis, &angle, rotMat);
    if(angle) {
        float dvec[3];
        sub_v3_v3v3(vec, pivot, cob->matrix[3]);
        project_v3_v3v3(dvec, vec, axis);
        sub_v3_v3(pivot, dvec);
    }

    /* perform the pivoting... */
        /* 1. take the vector from owner to the pivot */
    sub_v3_v3v3(vec, cob->matrix[3], pivot);
        /* 2. rotate this vector by the rotation of the object... */
    mul_m3_v3(rotMat, vec);
        /* 3. make the rotation in terms of the pivot now */
    add_v3_v3v3(cob->matrix[3], pivot, vec);
}


static bConstraintTypeInfo CTI_PIVOT = {
    CONSTRAINT_TYPE_PIVOT, /* type */
    sizeof(bPivotConstraint), /* size */
    "Pivot", /* name */
    "bPivotConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    pivotcon_id_looper, /* id looper */
    NULL, /* copy data */
    NULL, /* new data */ // XXX: might be needed to get 'normal' pivot behaviour...
    pivotcon_get_tars, /* get constraint targets */
    pivotcon_flush_tars, /* flush constraint targets */
    default_get_tarmat, /* get target matrix */
    pivotcon_evaluate /* evaluate */
};

/* ----------- Follow Track ------------- */

static void followtrack_new_data (void *cdata)
{
    bFollowTrackConstraint *data= (bFollowTrackConstraint *)cdata;
    
    data->clip= NULL;
    data->flag |= FOLLOWTRACK_ACTIVECLIP;
}

static void followtrack_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bFollowTrackConstraint *data= con->data;
    
    func(con, (ID**)&data->clip, userdata);
    func(con, (ID**)&data->camera, userdata);
    func(con, (ID**)&data->depth_ob, userdata);
}

static void followtrack_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *UNUSED(targets))
{
    Scene *scene= cob->scene;
    bFollowTrackConstraint *data= con->data;
    MovieClip *clip= data->clip;
    MovieTracking *tracking;
    MovieTrackingTrack *track;
    MovieTrackingObject *tracking_object;
    Object *camob= data->camera ? data->camera : scene->camera;

    if (data->flag & FOLLOWTRACK_ACTIVECLIP)
        clip= scene->clip;

    if (!clip || !data->track[0] || !camob)
        return;

    tracking= &clip->tracking;

    if(data->object[0])
        tracking_object= BKE_tracking_named_object(tracking, data->object);
    else
        tracking_object= BKE_tracking_get_camera_object(tracking);

    if(!tracking_object)
        return;

    track= BKE_tracking_named_track(tracking, tracking_object, data->track);

    if (!track)
        return;

    if (data->flag & FOLLOWTRACK_USE_3D_POSITION) {
        if (track->flag & TRACK_HAS_BUNDLE) {
            float obmat[4][4], mat[4][4];

            copy_m4_m4(obmat, cob->matrix);

            if((tracking_object->flag&TRACKING_OBJECT_CAMERA)==0) {
                float imat[4][4];

                copy_m4_m4(mat, camob->obmat);

                BKE_tracking_get_interpolated_camera(tracking, tracking_object, scene->r.cfra, imat);
                invert_m4(imat);

                mul_serie_m4(cob->matrix, obmat, mat, imat, NULL, NULL, NULL, NULL, NULL);
                translate_m4(cob->matrix, track->bundle_pos[0], track->bundle_pos[1], track->bundle_pos[2]);
            }
            else {
                BKE_get_tracking_mat(cob->scene, camob, mat);

                mult_m4_m4m4(cob->matrix, obmat, mat);
                translate_m4(cob->matrix, track->bundle_pos[0], track->bundle_pos[1], track->bundle_pos[2]);
            }
        }
    }
    else {
        MovieTrackingMarker *marker;
        float vec[3], disp[3], axis[3], mat[4][4];
        float aspect= (scene->r.xsch*scene->r.xasp) / (scene->r.ysch*scene->r.yasp);
        float len, d;

        where_is_object_mat(scene, camob, mat);

        /* camera axis */
        vec[0]= 0.0f;
        vec[1]= 0.0f;
        vec[2]= 1.0f;
        mul_v3_m4v3(axis, mat, vec);

        /* distance to projection plane */
        copy_v3_v3(vec, cob->matrix[3]);
        sub_v3_v3(vec, mat[3]);
        project_v3_v3v3(disp, vec, axis);

        len= len_v3(disp);

        if (len > FLT_EPSILON) {
            CameraParams params;
            float pos[2], rmat[4][4];

            marker= BKE_tracking_get_marker(track, scene->r.cfra);

            add_v2_v2v2(pos, marker->pos, track->offset);

            camera_params_init(&params);
            camera_params_from_object(&params, camob);

            if (params.is_ortho) {
                vec[0]= params.ortho_scale * (pos[0]-0.5f+params.shiftx);
                vec[1]= params.ortho_scale * (pos[1]-0.5f+params.shifty);
                vec[2]= -len;

                if (aspect > 1.0f) vec[1] /= aspect;
                else vec[0] *= aspect;

                mul_v3_m4v3(disp, camob->obmat, vec);

                copy_m4_m4(rmat, camob->obmat);
                zero_v3(rmat[3]);
                mult_m4_m4m4(cob->matrix, cob->matrix, rmat);

                copy_v3_v3(cob->matrix[3], disp);
            }
            else {
                d= (len*params.sensor_x) / (2.0f*params.lens);

                vec[0]= d*(2.0f*(pos[0]+params.shiftx)-1.0f);
                vec[1]= d*(2.0f*(pos[1]+params.shifty)-1.0f);
                vec[2]= -len;

                if (aspect > 1.0f) vec[1] /= aspect;
                else vec[0] *= aspect;

                mul_v3_m4v3(disp, camob->obmat, vec);

                /* apply camera rotation so Z-axis would be co-linear */
                copy_m4_m4(rmat, camob->obmat);
                zero_v3(rmat[3]);
                mult_m4_m4m4(cob->matrix, cob->matrix, rmat);

                copy_v3_v3(cob->matrix[3], disp);
            }

            if(data->depth_ob && data->depth_ob->derivedFinal) {
                Object *depth_ob= data->depth_ob;
                BVHTreeFromMesh treeData= NULL_BVHTreeFromMesh;
                BVHTreeRayHit hit;
                float ray_start[3], ray_end[3], ray_nor[3], imat[4][4];
                int result;

                invert_m4_m4(imat, depth_ob->obmat);

                mul_v3_m4v3(ray_start, imat, camob->obmat[3]);
                mul_v3_m4v3(ray_end, imat, cob->matrix[3]);

                sub_v3_v3v3(ray_nor, ray_end, ray_start);

                bvhtree_from_mesh_faces(&treeData, depth_ob->derivedFinal, 0.0f, 4, 6);

                hit.dist= FLT_MAX;
                hit.index= -1;

                result= BLI_bvhtree_ray_cast(treeData.tree, ray_start, ray_nor, 0.0f, &hit, treeData.raycast_callback, &treeData);

                if(result != -1) {
                    mul_v3_m4v3(cob->matrix[3], depth_ob->obmat, hit.co);
                }

                free_bvhtree_from_mesh(&treeData);
            }
        }
    }
}

static bConstraintTypeInfo CTI_FOLLOWTRACK = {
    CONSTRAINT_TYPE_FOLLOWTRACK, /* type */
    sizeof(bFollowTrackConstraint), /* size */
    "Follow Track", /* name */
    "bFollowTrackConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    followtrack_id_looper, /* id looper */
    NULL, /* copy data */
    followtrack_new_data, /* new data */
    NULL, /* get constraint targets */
    NULL, /* flush constraint targets */
    NULL, /* get target matrix */
    followtrack_evaluate /* evaluate */
};

/* ----------- Camre Solver ------------- */

static void camerasolver_new_data (void *cdata)
{
    bCameraSolverConstraint *data= (bCameraSolverConstraint *)cdata;
    
    data->clip = NULL;
    data->flag |= CAMERASOLVER_ACTIVECLIP;
}

static void camerasolver_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bCameraSolverConstraint *data= con->data;
    
    func(con, (ID**)&data->clip, userdata);
}

static void camerasolver_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *UNUSED(targets))
{
    Scene *scene= cob->scene;
    bCameraSolverConstraint *data= con->data;
    MovieClip *clip= data->clip;

    if (data->flag & CAMERASOLVER_ACTIVECLIP)
        clip= scene->clip;

    if (clip) {
        float mat[4][4], obmat[4][4];
        MovieTracking *tracking= &clip->tracking;
        MovieTrackingObject *object= BKE_tracking_get_camera_object(tracking);

        BKE_tracking_get_interpolated_camera(tracking, object, scene->r.cfra, mat);

        copy_m4_m4(obmat, cob->matrix);

        mult_m4_m4m4(cob->matrix, obmat, mat);
    }
}

static bConstraintTypeInfo CTI_CAMERASOLVER = {
    CONSTRAINT_TYPE_CAMERASOLVER, /* type */
    sizeof(bCameraSolverConstraint), /* size */
    "Camera Solver", /* name */
    "bCameraSolverConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    camerasolver_id_looper, /* id looper */
    NULL, /* copy data */
    camerasolver_new_data, /* new data */
    NULL, /* get constraint targets */
    NULL, /* flush constraint targets */
    NULL, /* get target matrix */
    camerasolver_evaluate /* evaluate */
};

/* ----------- Object Solver ------------- */

static void objectsolver_new_data (void *cdata)
{
    bObjectSolverConstraint *data= (bObjectSolverConstraint *)cdata;

    data->clip = NULL;
    data->flag |= OBJECTSOLVER_ACTIVECLIP;
    unit_m4(data->invmat);
}

static void objectsolver_id_looper (bConstraint *con, ConstraintIDFunc func, void *userdata)
{
    bObjectSolverConstraint *data= con->data;

    func(con, (ID**)&data->clip, userdata);
    func(con, (ID**)&data->camera, userdata);
}

static void objectsolver_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *UNUSED(targets))
{
    Scene *scene= cob->scene;
    bObjectSolverConstraint *data= con->data;
    MovieClip *clip= data->clip;
    Object *camob= data->camera ? data->camera : scene->camera;

    if (data->flag & OBJECTSOLVER_ACTIVECLIP)
        clip= scene->clip;

    if(!camob || !clip)
        return;

    if (clip) {
        MovieTracking *tracking= &clip->tracking;
        MovieTrackingObject *object;

        object= BKE_tracking_named_object(tracking, data->object);

        if(object) {
            float mat[4][4], obmat[4][4], imat[4][4], cammat[4][4], camimat[4][4], parmat[4][4];

            where_is_object_mat(scene, camob, cammat);

            BKE_tracking_get_interpolated_camera(tracking, object, scene->r.cfra, mat);

            invert_m4_m4(camimat, cammat);
            mult_m4_m4m4(parmat, cammat, data->invmat);

            copy_m4_m4(cammat, camob->obmat);
            copy_m4_m4(obmat, cob->matrix);

            invert_m4_m4(imat, mat);

            mul_serie_m4(cob->matrix, cammat, imat, camimat, parmat, obmat, NULL, NULL, NULL);
        }
    }
}

static bConstraintTypeInfo CTI_OBJECTSOLVER = {
    CONSTRAINT_TYPE_OBJECTSOLVER, /* type */
    sizeof(bObjectSolverConstraint), /* size */
    "Object Solver", /* name */
    "bObjectSolverConstraint", /* struct name */
    NULL, /* free data */
    NULL, /* relink data */
    objectsolver_id_looper, /* id looper */
    NULL, /* copy data */
    objectsolver_new_data, /* new data */
    NULL, /* get constraint targets */
    NULL, /* flush constraint targets */
    NULL, /* get target matrix */
    objectsolver_evaluate /* evaluate */
};

/* ************************* Constraints Type-Info *************************** */
/* All of the constraints api functions use bConstraintTypeInfo structs to carry out
 * and operations that involve constraint specific code.
 */

/* These globals only ever get directly accessed in this file */
static bConstraintTypeInfo *constraintsTypeInfo[NUM_CONSTRAINT_TYPES];
static short CTI_INIT= 1; /* when non-zero, the list needs to be updated */

/* This function only gets called when CTI_INIT is non-zero */
static void constraints_init_typeinfo (void)
{
    constraintsTypeInfo[0]=  NULL;                  /* 'Null' Constraint */
    constraintsTypeInfo[1]=  &CTI_CHILDOF;          /* ChildOf Constraint */
    constraintsTypeInfo[2]=  &CTI_TRACKTO;          /* TrackTo Constraint */
    constraintsTypeInfo[3]=  &CTI_KINEMATIC;        /* IK Constraint */
    constraintsTypeInfo[4]=  &CTI_FOLLOWPATH;       /* Follow-Path Constraint */
    constraintsTypeInfo[5]=  &CTI_ROTLIMIT;         /* Limit Rotation Constraint */
    constraintsTypeInfo[6]=  &CTI_LOCLIMIT;         /* Limit Location Constraint */
    constraintsTypeInfo[7]=  &CTI_SIZELIMIT;        /* Limit Scaling Constraint */
    constraintsTypeInfo[8]=  &CTI_ROTLIKE;          /* Copy Rotation Constraint */
    constraintsTypeInfo[9]=  &CTI_LOCLIKE;          /* Copy Location Constraint */
    constraintsTypeInfo[10]= &CTI_SIZELIKE;         /* Copy Scaling Constraint */
    constraintsTypeInfo[11]= &CTI_PYTHON;           /* Python/Script Constraint */
    constraintsTypeInfo[12]= &CTI_ACTION;           /* Action Constraint */
    constraintsTypeInfo[13]= &CTI_LOCKTRACK;        /* Locked-Track Constraint */
    constraintsTypeInfo[14]= &CTI_DISTLIMIT;        /* Limit Distance Constraint */
    constraintsTypeInfo[15]= &CTI_STRETCHTO;        /* StretchTo Constaint */ 
    constraintsTypeInfo[16]= &CTI_MINMAX;           /* Floor Constraint */
    constraintsTypeInfo[17]= &CTI_RIGIDBODYJOINT;   /* RigidBody Constraint */
    constraintsTypeInfo[18]= &CTI_CLAMPTO;          /* ClampTo Constraint */    
    constraintsTypeInfo[19]= &CTI_TRANSFORM;        /* Transformation Constraint */
    constraintsTypeInfo[20]= &CTI_SHRINKWRAP;       /* Shrinkwrap Constraint */
    constraintsTypeInfo[21]= &CTI_DAMPTRACK;        /* Damped TrackTo Constraint */
    constraintsTypeInfo[22]= &CTI_SPLINEIK;         /* Spline IK Constraint */
    constraintsTypeInfo[23]= &CTI_TRANSLIKE;        /* Copy Transforms Constraint */
    constraintsTypeInfo[24]= &CTI_SAMEVOL;          /* Maintain Volume Constraint */
    constraintsTypeInfo[25]= &CTI_PIVOT;            /* Pivot Constraint */
    constraintsTypeInfo[26]= &CTI_FOLLOWTRACK;      /* Follow Track Constraint */
    constraintsTypeInfo[27]= &CTI_CAMERASOLVER;     /* Camera Solver Constraint */
    constraintsTypeInfo[28]= &CTI_OBJECTSOLVER;     /* Object Solver Constraint */
}

/* This function should be used for getting the appropriate type-info when only
 * a constraint type is known
 */
bConstraintTypeInfo *get_constraint_typeinfo (int type)
{
    /* initialise the type-info list? */
    if (CTI_INIT) {
        constraints_init_typeinfo();
        CTI_INIT = 0;
    }
    
    /* only return for valid types */
    if ( (type >= CONSTRAINT_TYPE_NULL) && 
         (type < NUM_CONSTRAINT_TYPES ) ) 
    {
        /* there shouldn't be any segfaults here... */
        return constraintsTypeInfo[type];
    }
    else {
        printf("No valid constraint type-info data available. Type = %i \n", type);
    }
    
    return NULL;
} 
 
/* This function should always be used to get the appropriate type-info, as it
 * has checks which prevent segfaults in some weird cases.
 */
bConstraintTypeInfo *constraint_get_typeinfo (bConstraint *con)
{
    /* only return typeinfo for valid constraints */
    if (con)
        return get_constraint_typeinfo(con->type);
    else
        return NULL;
}

/* ************************* General Constraints API ************************** */
/* The functions here are called by various parts of Blender. Very few (should be none if possible)
 * constraint-specific code should occur here.
 */
 
/* ---------- Data Management ------- */

/* Free data of a specific constraint if it has any info.
 * be sure to run BIK_clear_data() when freeing an IK constraint,
 * unless DAG_scene_sort is called. */
void free_constraint_data (bConstraint *con)
{
    if (con->data) {
        bConstraintTypeInfo *cti= constraint_get_typeinfo(con);
        
        /* perform any special freeing constraint may have */
        if (cti && cti->free_data)
            cti->free_data(con);
        
        /* free constraint data now */
        MEM_freeN(con->data);
    }
}

/* Free all constraints from a constraint-stack */
void free_constraints (ListBase *list)
{
    bConstraint *con;
    
    /* Free constraint data and also any extra data */
    for (con= list->first; con; con= con->next)
        free_constraint_data(con);
    
    /* Free the whole list */
    BLI_freelistN(list);
}


/* Remove the specified constraint from the given constraint stack */
int remove_constraint (ListBase *list, bConstraint *con)
{
    if (con) {
        free_constraint_data(con);
        BLI_freelinkN(list, con);
        return 1;
    }
    else
        return 0;
}

/* Remove all the constraints of the specified type from the given constraint stack */
void remove_constraints_type (ListBase *list, short type, short last_only)
{
    bConstraint *con, *conp;
    
    if (list == NULL)
        return;
    
    /* remove from the end of the list to make it faster to find the last instance */
    for (con= list->last; con; con= conp) {
        conp= con->prev;
        
        if (con->type == type) {
            remove_constraint(list, con);
            if (last_only) 
                return;
        }
    }
}

/* ......... */

/* Creates a new constraint, initialises its data, and returns it */
static bConstraint *add_new_constraint_internal (const char *name, short type)
{
    bConstraint *con= MEM_callocN(sizeof(bConstraint), "Constraint");
    bConstraintTypeInfo *cti= get_constraint_typeinfo(type);
    const char *newName;

    /* Set up a generic constraint datablock */
    con->type = type;
    con->flag |= CONSTRAINT_EXPAND;
    con->enforce = 1.0f;

    /* Determine a basic name, and info */
    if (cti) {
        /* initialise constraint data */
        con->data = MEM_callocN(cti->size, cti->structName);
        
        /* only constraints that change any settings need this */
        if (cti->new_data)
            cti->new_data(con->data);
        
        /* if no name is provided, use the type of the constraint as the name */
        newName= (name && name[0]) ? name : cti->name;
    }
    else {
        /* if no name is provided, use the generic "Const" name */
        // NOTE: any constraint type that gets here really shouldn't get added...
        newName= (name && name[0]) ? name : "Const";
    }
    
    /* copy the name */
    BLI_strncpy(con->name, newName, sizeof(con->name));
    
    /* return the new constraint */
    return con;
}

/* if pchan is not NULL then assume we're adding a pose constraint */
static bConstraint *add_new_constraint (Object *ob, bPoseChannel *pchan, const char *name, short type)
{
    bConstraint *con;
    ListBase *list;
    
    /* add the constraint */
    con= add_new_constraint_internal(name, type);
    
    /* find the constraint stack - bone or object? */
    list = (pchan) ? (&pchan->constraints) : (&ob->constraints);
    
    if (list) {
        /* add new constraint to end of list of constraints before ensuring that it has a unique name
         * (otherwise unique-naming code will fail, since it assumes element exists in list)
         */
        BLI_addtail(list, con);
        unique_constraint_name(con, list);
        
        /* if the target list is a list on some PoseChannel belonging to a proxy-protected
         * Armature layer, we must tag newly added constraints with a flag which allows them
         * to persist after proxy syncing has been done
         */
        if (proxylocked_constraints_owner(ob, pchan))
            con->flag |= CONSTRAINT_PROXY_LOCAL;
        
        /* make this constraint the active one */
        constraints_set_active(list, con);
    }
    
    /* set type+owner specific immutable settings */
    // TODO: does action constraint need anything here - i.e. spaceonce?
    switch (type) {
        case CONSTRAINT_TYPE_CHILDOF:
        {
            /* if this constraint is being added to a posechannel, make sure
             * the constraint gets evaluated in pose-space */
            if (pchan) {
                con->ownspace = CONSTRAINT_SPACE_POSE;
                con->flag |= CONSTRAINT_SPACEONCE;
            }
        }
            break;
    }
    
    return con;
}

/* ......... */

/* Add new constraint for the given bone */
bConstraint *add_pose_constraint (Object *ob, bPoseChannel *pchan, const char *name, short type)
{
    if (pchan == NULL)
        return NULL;
    
    return add_new_constraint(ob, pchan, name, type);
}

/* Add new constraint for the given object */
bConstraint *add_ob_constraint(Object *ob, const char *name, short type)
{
    return add_new_constraint(ob, NULL, name, type);
}

/* ......... */

/* Reassign links that constraints have to other data (called during file loading?) */
void relink_constraints (ListBase *conlist)
{
    bConstraint *con;
    bConstraintTarget *ct;
    
    for (con= conlist->first; con; con= con->next) {
        bConstraintTypeInfo *cti= constraint_get_typeinfo(con);
        
        if (cti) {
            /* relink any targets */
            if (cti->get_constraint_targets) {
                ListBase targets = {NULL, NULL};
                
                cti->get_constraint_targets(con, &targets);
                for (ct= targets.first; ct; ct= ct->next) {
                    ID_NEW(ct->tar);
                }
                
                if (cti->flush_constraint_targets)
                    cti->flush_constraint_targets(con, &targets, 0);
            }
            
            /* relink any other special data */
            if (cti->relink_data)
                cti->relink_data(con);
        }
    }
}

/* Run the given callback on all ID-blocks in list of constraints */
void id_loop_constraints (ListBase *conlist, ConstraintIDFunc func, void *userdata)
{
    bConstraint *con;
    
    for (con= conlist->first; con; con= con->next) {
        bConstraintTypeInfo *cti= constraint_get_typeinfo(con);
        
        if (cti) {
            if (cti->id_looper)
                cti->id_looper(con, func, userdata);
        }
    }
}

/* ......... */

/* helper for copy_constraints(), to be used for making sure that ID's are valid */
static void con_extern_cb(bConstraint *UNUSED(con), ID **idpoin, void *UNUSED(userData))
{
    if (*idpoin && (*idpoin)->lib)
        id_lib_extern(*idpoin);
}

/* duplicate all of the constraints in a constraint stack */
void copy_constraints (ListBase *dst, const ListBase *src, int do_extern)
{
    bConstraint *con, *srccon;
    
    dst->first= dst->last= NULL;
    BLI_duplicatelist(dst, src);
    
    for (con=dst->first, srccon=src->first; con && srccon; srccon=srccon->next, con=con->next) {
        bConstraintTypeInfo *cti= constraint_get_typeinfo(con);
        
        /* make a new copy of the constraint's data */
        con->data = MEM_dupallocN(con->data);
        
        /* only do specific constraints if required */
        if (cti) {
            /* perform custom copying operations if needed */
            if (cti->copy_data)
                cti->copy_data(con, srccon);
            
            /* for proxies we dont want to make extern */
            if (do_extern) {
                /* go over used ID-links for this constraint to ensure that they are valid for proxies */
                if (cti->id_looper)
                    cti->id_looper(con, con_extern_cb, NULL);
            }
        }
    }
}

/* ......... */

bConstraint *constraints_findByName(ListBase *list, const char *name)
{
    return BLI_findstring(list, name, offsetof(bConstraint, name));
}

/* finds the 'active' constraint in a constraint stack */
bConstraint *constraints_get_active (ListBase *list)
{
    bConstraint *con;
    
    /* search for the first constraint with the 'active' flag set */
    if (list) {
        for (con= list->first; con; con= con->next) {
            if (con->flag & CONSTRAINT_ACTIVE)
                return con;
        }
    }
    
    /* no active constraint found */
    return NULL;
}

/* Set the given constraint as the active one (clearing all the others) */
void constraints_set_active (ListBase *list, bConstraint *con)
{
    bConstraint *c;
    
    if (list) {
        for (c= list->first; c; c= c->next) {
            if (c == con) 
                c->flag |= CONSTRAINT_ACTIVE;
            else 
                c->flag &= ~CONSTRAINT_ACTIVE;
        }
    }
}

/* -------- Constraints and Proxies ------- */

/* Rescue all constraints tagged as being CONSTRAINT_PROXY_LOCAL (i.e. added to bone that's proxy-synced in this file) */
void extract_proxylocal_constraints (ListBase *dst, ListBase *src)
{
    bConstraint *con, *next;
    
    /* for each tagged constraint, remove from src and move to dst */
    for (con= src->first; con; con= next) {
        next= con->next;
        
        /* check if tagged */
        if (con->flag & CONSTRAINT_PROXY_LOCAL) {
            BLI_remlink(src, con);
            BLI_addtail(dst, con);
        }
    }
}

/* Returns if the owner of the constraint is proxy-protected */
short proxylocked_constraints_owner (Object *ob, bPoseChannel *pchan)
{
    /* Currently, constraints can only be on object or bone level */
    if (ob && ob->proxy) {
        if (ob->pose && pchan) {
            bArmature *arm= ob->data;
            
            /* On bone-level, check if bone is on proxy-protected layer */
            if ((pchan->bone) && (pchan->bone->layer & arm->layer_protected))
                return 1;
        }
        else {
            /* FIXME: constraints on object-level are not handled well yet */
            return 1;
        }   
    }
    
    return 0;
}

/* -------- Target-Matrix Stuff ------- */

/* This function is a relic from the prior implementations of the constraints system, when all
 * constraints either had one or no targets. It used to be called during the main constraint solving
 * loop, but is now only used for the remaining cases for a few constraints. 
 *
 * None of the actual calculations of the matrices should be done here! Also, this function is
 * not to be used by any new constraints, particularly any that have multiple targets.
 */
void get_constraint_target_matrix (struct Scene *scene, bConstraint *con, int n, short ownertype, void *ownerdata, float mat[][4], float ctime)
{
    bConstraintTypeInfo *cti= constraint_get_typeinfo(con);
    ListBase targets = {NULL, NULL};
    bConstraintOb *cob;
    bConstraintTarget *ct;
    
    if (cti && cti->get_constraint_targets) {
        /* make 'constraint-ob' */
        cob= MEM_callocN(sizeof(bConstraintOb), "tempConstraintOb");
        cob->type= ownertype;
        cob->scene = scene;
        switch (ownertype) {
            case CONSTRAINT_OBTYPE_OBJECT: /* it is usually this case */
            {
                cob->ob= (Object *)ownerdata;
                cob->pchan= NULL;
                if (cob->ob) {
                    copy_m4_m4(cob->matrix, cob->ob->obmat);
                    copy_m4_m4(cob->startmat, cob->matrix);
                }
                else {
                    unit_m4(cob->matrix);
                    unit_m4(cob->startmat);
                }
            }   
                break;
            case CONSTRAINT_OBTYPE_BONE: /* this may occur in some cases */
            {
                cob->ob= NULL; /* this might not work at all :/ */
                cob->pchan= (bPoseChannel *)ownerdata;
                if (cob->pchan) {
                    copy_m4_m4(cob->matrix, cob->pchan->pose_mat);
                    copy_m4_m4(cob->startmat, cob->matrix);
                }
                else {
                    unit_m4(cob->matrix);
                    unit_m4(cob->startmat);
                }
            }
                break;
        }
        
        /* get targets - we only need the first one though (and there should only be one) */
        cti->get_constraint_targets(con, &targets);
        
        /* only calculate the target matrix on the first target */
        ct= (bConstraintTarget *)targets.first;
        while(ct && n-- > 0)
            ct= ct->next;

        if (ct) {
            if (cti->get_target_matrix)
                cti->get_target_matrix(con, cob, ct, ctime);
            copy_m4_m4(mat, ct->matrix);
        }
        
        /* free targets + 'constraint-ob' */
        if (cti->flush_constraint_targets)
            cti->flush_constraint_targets(con, &targets, 1);
        MEM_freeN(cob);
    }
    else {
        /* invalid constraint - perhaps... */
        unit_m4(mat);
    }
}

/* Get the list of targets required for solving a constraint */
void get_constraint_targets_for_solving (bConstraint *con, bConstraintOb *cob, ListBase *targets, float ctime)
{
    bConstraintTypeInfo *cti= constraint_get_typeinfo(con);
    
    if (cti && cti->get_constraint_targets) {
        bConstraintTarget *ct;
        
        /* get targets 
         *  - constraints should use ct->matrix, not directly accessing values
         *  - ct->matrix members have not yet been calculated here! 
         */
        cti->get_constraint_targets(con, targets);
        
        /* set matrices 
         *  - calculate if possible, otherwise just initialise as identity matrix 
         */
        if (cti->get_target_matrix) {
            for (ct= targets->first; ct; ct= ct->next) 
                cti->get_target_matrix(con, cob, ct, ctime);
        }
        else {
            for (ct= targets->first; ct; ct= ct->next)
                unit_m4(ct->matrix);
        }
    }
}
 
/* ---------- Evaluation ----------- */

/* This function is called whenever constraints need to be evaluated. Currently, all
 * constraints that can be evaluated are everytime this gets run.
 *
 * constraints_make_evalob and constraints_clear_evalob should be called before and 
 * after running this function, to sort out cob
 */
void solve_constraints (ListBase *conlist, bConstraintOb *cob, float ctime)
{
    bConstraint *con;
    float oldmat[4][4];
    float enf;

    /* check that there is a valid constraint object to evaluate */
    if (cob == NULL)
        return;
    
    /* loop over available constraints, solving and blending them */
    for (con= conlist->first; con; con= con->next) {
        bConstraintTypeInfo *cti= constraint_get_typeinfo(con);
        ListBase targets = {NULL, NULL};
        
        /* these we can skip completely (invalid constraints...) */
        if (cti == NULL) continue;
        if (con->flag & (CONSTRAINT_DISABLE|CONSTRAINT_OFF)) continue;
        /* these constraints can't be evaluated anyway */
        if (cti->evaluate_constraint == NULL) continue;
        /* influence == 0 should be ignored */
        if (con->enforce == 0.0f) continue;
        
        /* influence of constraint
         *  - value should have been set from animation data already
         */
        enf = con->enforce;
        
        /* make copy of worldspace matrix pre-constraint for use with blending later */
        copy_m4_m4(oldmat, cob->matrix);
        
        /* move owner matrix into right space */
        constraint_mat_convertspace(cob->ob, cob->pchan, cob->matrix, CONSTRAINT_SPACE_WORLD, con->ownspace);
        
        /* prepare targets for constraint solving */
        get_constraint_targets_for_solving(con, cob, &targets, ctime);
        
        /* Solve the constraint and put result in cob->matrix */
        cti->evaluate_constraint(con, cob, &targets);
        
        /* clear targets after use 
         *  - this should free temp targets but no data should be copied back
         *    as constraints may have done some nasty things to it...
         */
        if (cti->flush_constraint_targets) {
            cti->flush_constraint_targets(con, &targets, 1);
        }
        
        /* move owner back into worldspace for next constraint/other business */
        if ((con->flag & CONSTRAINT_SPACEONCE) == 0) 
            constraint_mat_convertspace(cob->ob, cob->pchan, cob->matrix, con->ownspace, CONSTRAINT_SPACE_WORLD);
            
        /* Interpolate the enforcement, to blend result of constraint into final owner transform 
         *  - all this happens in worldspace to prevent any weirdness creeping in ([#26014] and [#25725]),
         *    since some constraints may not convert the solution back to the input space before blending
         *    but all are guaranteed to end up in good "worldspace" result
         */
        /* Note: all kind of stuff here before (caused trouble), much easier to just interpolate, or did I miss something? -jahka */
        if (enf < 1.0f) {
            float solution[4][4];
            copy_m4_m4(solution, cob->matrix);
            blend_m4_m4m4(cob->matrix, oldmat, solution, enf);
        }
    }
}