armature.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.
 *
 * Contributor(s): Full recode, Ton Roosendaal, Crete 2005
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include <ctype.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <stdio.h>
#include <float.h>

#include "MEM_guardedalloc.h"

#include "BLI_bpath.h"
#include "BLI_math.h"
#include "BLI_blenlib.h"
#include "BLI_utildefines.h"

#include "DNA_anim_types.h"
#include "DNA_armature_types.h"
#include "DNA_constraint_types.h"
#include "DNA_mesh_types.h"
#include "DNA_lattice_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_nla_types.h"
#include "DNA_scene_types.h"
#include "DNA_object_types.h"

#include "BKE_animsys.h"
#include "BKE_armature.h"
#include "BKE_action.h"
#include "BKE_anim.h"
#include "BKE_constraint.h"
#include "BKE_curve.h"
#include "BKE_depsgraph.h"
#include "BKE_DerivedMesh.h"
#include "BKE_deform.h"
#include "BKE_displist.h"
#include "BKE_global.h"
#include "BKE_idprop.h"
#include "BKE_library.h"
#include "BKE_lattice.h"
#include "BKE_main.h"
#include "BKE_object.h"
#include "BKE_scene.h"

#include "BIK_api.h"
#include "BKE_sketch.h"

/*  **************** Generic Functions, data level *************** */

bArmature *add_armature(const char *name)
{
    bArmature *arm;
    
    arm= alloc_libblock (&G.main->armature, ID_AR, name);
    arm->deformflag = ARM_DEF_VGROUP|ARM_DEF_ENVELOPE;
    arm->flag = ARM_COL_CUSTOM; /* custom bone-group colors */
    arm->layer= 1;
    return arm;
}

bArmature *get_armature(Object *ob)
{
    if(ob->type==OB_ARMATURE)
        return (bArmature *)ob->data;
    return NULL;
}

void free_bonelist (ListBase *lb)
{
    Bone *bone;

    for(bone=lb->first; bone; bone=bone->next) {
        if(bone->prop) {
            IDP_FreeProperty(bone->prop);
            MEM_freeN(bone->prop);
        }
        free_bonelist(&bone->childbase);
    }
    
    BLI_freelistN(lb);
}

void free_armature(bArmature *arm)
{
    if (arm) {
        free_bonelist(&arm->bonebase);
        
        /* free editmode data */
        if (arm->edbo) {
            BLI_freelistN(arm->edbo);
            
            MEM_freeN(arm->edbo);
            arm->edbo= NULL;
        }

        /* free sketch */
        if (arm->sketch) {
            freeSketch(arm->sketch);
            arm->sketch = NULL;
        }
        
        /* free animation data */
        if (arm->adt) {
            BKE_free_animdata(&arm->id);
            arm->adt= NULL;
        }
    }
}

void make_local_armature(bArmature *arm)
{
    Main *bmain= G.main;
    int is_local= FALSE, is_lib= FALSE;
    Object *ob;

    if (arm->id.lib==NULL) return;
    if (arm->id.us==1) {
        id_clear_lib_data(bmain, &arm->id);
        return;
    }

    for(ob= bmain->object.first; ob && ELEM(0, is_lib, is_local); ob= ob->id.next) {
        if(ob->data == arm) {
            if(ob->id.lib) is_lib= TRUE;
            else is_local= TRUE;
        }
    }

    if(is_local && is_lib == FALSE) {
        id_clear_lib_data(bmain, &arm->id);
    }
    else if(is_local && is_lib) {
        bArmature *arm_new= copy_armature(arm);
        arm_new->id.us= 0;

        /* Remap paths of new ID using old library as base. */
        BKE_id_lib_local_paths(bmain, arm->id.lib, &arm_new->id);

        for(ob= bmain->object.first; ob; ob= ob->id.next) {
            if(ob->data == arm) {
                if(ob->id.lib==NULL) {
                    ob->data= arm_new;
                    arm_new->id.us++;
                    arm->id.us--;
                }
            }
        }
    }
}

static void copy_bonechildren (Bone* newBone, Bone* oldBone, Bone* actBone, Bone **newActBone)
{
    Bone    *curBone, *newChildBone;
    
    if(oldBone == actBone)
        *newActBone= newBone;

    if(oldBone->prop)
        newBone->prop= IDP_CopyProperty(oldBone->prop);

    /*  Copy this bone's list*/
    BLI_duplicatelist(&newBone->childbase, &oldBone->childbase);
    
    /*  For each child in the list, update it's children*/
    newChildBone=newBone->childbase.first;
    for (curBone=oldBone->childbase.first;curBone;curBone=curBone->next){
        newChildBone->parent=newBone;
        copy_bonechildren(newChildBone, curBone, actBone, newActBone);
        newChildBone=newChildBone->next;
    }
}

bArmature *copy_armature(bArmature *arm)
{
    bArmature *newArm;
    Bone        *oldBone, *newBone;
    Bone        *newActBone= NULL;
    
    newArm= copy_libblock(&arm->id);
    BLI_duplicatelist(&newArm->bonebase, &arm->bonebase);
    
    /*  Duplicate the childrens' lists*/
    newBone=newArm->bonebase.first;
    for (oldBone=arm->bonebase.first;oldBone;oldBone=oldBone->next){
        newBone->parent=NULL;
        copy_bonechildren (newBone, oldBone, arm->act_bone, &newActBone);
        newBone=newBone->next;
    };
    
    newArm->act_bone= newActBone;

    newArm->edbo= NULL;
    newArm->act_edbone= NULL;
    newArm->sketch= NULL;

    return newArm;
}

static Bone *get_named_bone_bonechildren (Bone *bone, const char *name)
{
    Bone *curBone, *rbone;
    
    if (!strcmp (bone->name, name))
        return bone;
    
    for (curBone=bone->childbase.first; curBone; curBone=curBone->next){
        rbone=get_named_bone_bonechildren (curBone, name);
        if (rbone)
            return rbone;
    }
    
    return NULL;
}


Bone *get_named_bone (bArmature *arm, const char *name)
/*
    Walk the list until the bone is found
 */
{
    Bone *bone=NULL, *curBone;
    
    if (!arm) return NULL;
    
    for (curBone=arm->bonebase.first; curBone; curBone=curBone->next){
        bone = get_named_bone_bonechildren (curBone, name);
        if (bone)
            return bone;
    }
    
    return bone;
}

/* Finds the best possible extension to the name on a particular axis. (For renaming, check for unique names afterwards)
 *  strip_number: removes number extensions  (TODO: not used)
 *  axis: the axis to name on
 *  head/tail: the head/tail co-ordinate of the bone on the specified axis
 */
int bone_autoside_name (char name[MAXBONENAME], int UNUSED(strip_number), short axis, float head, float tail)
{
    unsigned int len;
    char    basename[MAXBONENAME]= "";
    char    extension[5]= "";

    len= strlen(name);
    if (len == 0) return 0;
    BLI_strncpy(basename, name, sizeof(basename));
    
    /* Figure out extension to append: 
     *  - The extension to append is based upon the axis that we are working on.
     *  - If head happens to be on 0, then we must consider the tail position as well to decide
     *    which side the bone is on
     *      -> If tail is 0, then it's bone is considered to be on axis, so no extension should be added
     *      -> Otherwise, extension is added from perspective of object based on which side tail goes to
     *  - If head is non-zero, extension is added from perspective of object based on side head is on
     */
    if (axis == 2) {
        /* z-axis - vertical (top/bottom) */
        if (IS_EQ(head, 0)) {
            if (tail < 0)
                strcpy(extension, "Bot");
            else if (tail > 0)
                strcpy(extension, "Top");
        }
        else {
            if (head < 0)
                strcpy(extension, "Bot");
            else
                strcpy(extension, "Top");
        }
    }
    else if (axis == 1) {
        /* y-axis - depth (front/back) */
        if (IS_EQ(head, 0)) {
            if (tail < 0)
                strcpy(extension, "Fr");
            else if (tail > 0)
                strcpy(extension, "Bk");
        }
        else {
            if (head < 0)
                strcpy(extension, "Fr");
            else
                strcpy(extension, "Bk");
        }
    }
    else {
        /* x-axis - horizontal (left/right) */
        if (IS_EQ(head, 0)) {
            if (tail < 0)
                strcpy(extension, "R");
            else if (tail > 0)
                strcpy(extension, "L");
        }
        else {
            if (head < 0)
                strcpy(extension, "R");
            else if (head > 0)
                strcpy(extension, "L");
        }
    }

    /* Simple name truncation 
     *  - truncate if there is an extension and it wouldn't be able to fit
     *  - otherwise, just append to end
     */
    if (extension[0]) {
        int change = 1;
        
        while (change) { /* remove extensions */
            change = 0;
            if (len > 2 && basename[len-2]=='.') {
                if (basename[len-1]=='L' || basename[len-1] == 'R' ) { /* L R */
                    basename[len-2] = '\0';
                    len-=2;
                    change= 1;
                }
            } else if (len > 3 && basename[len-3]=='.') {
                if (    (basename[len-2]=='F' && basename[len-1] == 'r') || /* Fr */
                        (basename[len-2]=='B' && basename[len-1] == 'k')    /* Bk */
                ) {
                    basename[len-3] = '\0';
                    len-=3;
                    change= 1;
                }
            } else if (len > 4 && basename[len-4]=='.') {
                if (    (basename[len-3]=='T' && basename[len-2]=='o' && basename[len-1] == 'p') || /* Top */
                        (basename[len-3]=='B' && basename[len-2]=='o' && basename[len-1] == 't')    /* Bot */
                ) {
                    basename[len-4] = '\0';
                    len-=4;
                    change= 1;
                }
            }
        }

        if ((MAXBONENAME - len) < strlen(extension) + 1) { /* add 1 for the '.' */
            strncpy(name, basename, len-strlen(extension));
        }

        BLI_snprintf(name, MAXBONENAME, "%s.%s", basename, extension);

        return 1;
    }

    else {
        return 0;
    }
}

/* ************* B-Bone support ******************* */

#define MAX_BBONE_SUBDIV    32

/* data has MAX_BBONE_SUBDIV+1 interpolated points, will become desired amount with equal distances */
static void equalize_bezier(float *data, int desired)
{
    float *fp, totdist, ddist, dist, fac1, fac2;
    float pdist[MAX_BBONE_SUBDIV+1];
    float temp[MAX_BBONE_SUBDIV+1][4];
    int a, nr;
    
    pdist[0]= 0.0f;
    for(a=0, fp= data; a<MAX_BBONE_SUBDIV; a++, fp+=4) {
        copy_qt_qt(temp[a], fp);
        pdist[a+1]= pdist[a]+len_v3v3(fp, fp+4);
    }
    /* do last point */
    copy_qt_qt(temp[a], fp);
    totdist= pdist[a];
    
    /* go over distances and calculate new points */
    ddist= totdist/((float)desired);
    nr= 1;
    for(a=1, fp= data+4; a<desired; a++, fp+=4) {
        
        dist= ((float)a)*ddist;
        
        /* we're looking for location (distance) 'dist' in the array */
        while((dist>= pdist[nr]) && nr<MAX_BBONE_SUBDIV) {
            nr++;
        }
        
        fac1= pdist[nr]- pdist[nr-1];
        fac2= pdist[nr]-dist;
        fac1= fac2/fac1;
        fac2= 1.0f-fac1;
        
        fp[0]= fac1*temp[nr-1][0]+ fac2*temp[nr][0];
        fp[1]= fac1*temp[nr-1][1]+ fac2*temp[nr][1];
        fp[2]= fac1*temp[nr-1][2]+ fac2*temp[nr][2];
        fp[3]= fac1*temp[nr-1][3]+ fac2*temp[nr][3];
    }
    /* set last point, needed for orientation calculus */
    copy_qt_qt(fp, temp[MAX_BBONE_SUBDIV]);
}

/* returns pointer to static array, filled with desired amount of bone->segments elements */
/* this calculation is done  within unit bone space */
Mat4 *b_bone_spline_setup(bPoseChannel *pchan, int rest)
{
    static Mat4 bbone_array[MAX_BBONE_SUBDIV];
    static Mat4 bbone_rest_array[MAX_BBONE_SUBDIV];
    Mat4 *result_array= (rest)? bbone_rest_array: bbone_array;
    bPoseChannel *next, *prev;
    Bone *bone= pchan->bone;
    float h1[3], h2[3], scale[3], length, hlength1, hlength2, roll1=0.0f, roll2;
    float mat3[3][3], imat[4][4], posemat[4][4], scalemat[4][4], iscalemat[4][4];
    float data[MAX_BBONE_SUBDIV+1][4], *fp;
    int a, doscale= 0;

    length= bone->length;

    if(!rest) {
        /* check if we need to take non-uniform bone scaling into account */
        scale[0]= len_v3(pchan->pose_mat[0]);
        scale[1]= len_v3(pchan->pose_mat[1]);
        scale[2]= len_v3(pchan->pose_mat[2]);

        if(fabsf(scale[0] - scale[1]) > 1e-6f || fabsf(scale[1] - scale[2]) > 1e-6f) {
            unit_m4(scalemat);
            scalemat[0][0]= scale[0];
            scalemat[1][1]= scale[1];
            scalemat[2][2]= scale[2];
            invert_m4_m4(iscalemat, scalemat);

            length *= scale[1];
            doscale = 1;
        }
    }
    
    hlength1= bone->ease1*length*0.390464f;     // 0.5*sqrt(2)*kappa, the handle length for near-perfect circles
    hlength2= bone->ease2*length*0.390464f;
    
    /* evaluate next and prev bones */
    if(bone->flag & BONE_CONNECTED)
        prev= pchan->parent;
    else
        prev= NULL;
    
    next= pchan->child;
    
    /* find the handle points, since this is inside bone space, the 
        first point = (0,0,0)
        last point =  (0, length, 0) */
    
    if(rest) {
        invert_m4_m4(imat, pchan->bone->arm_mat);
    }
    else if(doscale) {
        copy_m4_m4(posemat, pchan->pose_mat);
        normalize_m4(posemat);
        invert_m4_m4(imat, posemat);
    }
    else
        invert_m4_m4(imat, pchan->pose_mat);
    
    if(prev) {
        float difmat[4][4], result[3][3], imat3[3][3];

        /* transform previous point inside this bone space */
        if(rest)
            copy_v3_v3(h1, prev->bone->arm_head);
        else
            copy_v3_v3(h1, prev->pose_head);
        mul_m4_v3(imat, h1);

        if(prev->bone->segments>1) {
            /* if previous bone is B-bone too, use average handle direction */
            h1[1]-= length;
            roll1= 0.0f;
        }

        normalize_v3(h1);
        mul_v3_fl(h1, -hlength1);

        if(prev->bone->segments==1) {
            /* find the previous roll to interpolate */
            if(rest)
                mult_m4_m4m4(difmat, imat, prev->bone->arm_mat);
            else
                mult_m4_m4m4(difmat, imat, prev->pose_mat);
            copy_m3_m4(result, difmat);             // the desired rotation at beginning of next bone
            
            vec_roll_to_mat3(h1, 0.0f, mat3);           // the result of vec_roll without roll
            
            invert_m3_m3(imat3, mat3);
            mul_m3_m3m3(mat3, result, imat3);           // the matrix transforming vec_roll to desired roll
            
            roll1= (float)atan2(mat3[2][0], mat3[2][2]);
        }
    }
    else {
        h1[0]= 0.0f; h1[1]= hlength1; h1[2]= 0.0f;
        roll1= 0.0f;
    }
    if(next) {
        float difmat[4][4], result[3][3], imat3[3][3];
        
        /* transform next point inside this bone space */
        if(rest)
            copy_v3_v3(h2, next->bone->arm_tail);
        else
            copy_v3_v3(h2, next->pose_tail);
        mul_m4_v3(imat, h2);
        /* if next bone is B-bone too, use average handle direction */
        if(next->bone->segments>1);
        else h2[1]-= length;
        normalize_v3(h2);
        
        /* find the next roll to interpolate as well */
        if(rest)
            mult_m4_m4m4(difmat, imat, next->bone->arm_mat);
        else
            mult_m4_m4m4(difmat, imat, next->pose_mat);
        copy_m3_m4(result, difmat);             // the desired rotation at beginning of next bone
        
        vec_roll_to_mat3(h2, 0.0f, mat3);           // the result of vec_roll without roll
        
        invert_m3_m3(imat3, mat3);
        mul_m3_m3m3(mat3, imat3, result);           // the matrix transforming vec_roll to desired roll
        
        roll2= (float)atan2(mat3[2][0], mat3[2][2]);
        
        /* and only now negate handle */
        mul_v3_fl(h2, -hlength2);
    }
    else {
        h2[0]= 0.0f; h2[1]= -hlength2; h2[2]= 0.0f;
        roll2= 0.0;
    }

    /* make curve */
    if(bone->segments > MAX_BBONE_SUBDIV)
        bone->segments= MAX_BBONE_SUBDIV;
    
    forward_diff_bezier(0.0, h1[0],     h2[0],          0.0,        data[0],    MAX_BBONE_SUBDIV, 4*sizeof(float));
    forward_diff_bezier(0.0, h1[1],     length + h2[1], length,     data[0]+1,  MAX_BBONE_SUBDIV, 4*sizeof(float));
    forward_diff_bezier(0.0, h1[2],     h2[2],          0.0,        data[0]+2,  MAX_BBONE_SUBDIV, 4*sizeof(float));
    forward_diff_bezier(roll1, roll1 + 0.390464f*(roll2-roll1), roll2 - 0.390464f*(roll2-roll1),    roll2,  data[0]+3,  MAX_BBONE_SUBDIV, 4*sizeof(float));
    
    equalize_bezier(data[0], bone->segments);   // note: does stride 4!
    
    /* make transformation matrices for the segments for drawing */
    for(a=0, fp= data[0]; a<bone->segments; a++, fp+=4) {
        sub_v3_v3v3(h1, fp+4, fp);
        vec_roll_to_mat3(h1, fp[3], mat3);      // fp[3] is roll

        copy_m4_m3(result_array[a].mat, mat3);
        copy_v3_v3(result_array[a].mat[3], fp);

        if(doscale) {
            /* correct for scaling when this matrix is used in scaled space */
            mul_serie_m4(result_array[a].mat, iscalemat, result_array[a].mat,
                scalemat, NULL, NULL, NULL, NULL, NULL);
        }
    }
    
    return result_array;
}

/* ************ Armature Deform ******************* */

typedef struct bPoseChanDeform {
    Mat4        *b_bone_mats;   
    DualQuat    *dual_quat;
    DualQuat    *b_bone_dual_quats;
} bPoseChanDeform;

static void pchan_b_bone_defmats(bPoseChannel *pchan, bPoseChanDeform *pdef_info, int use_quaternion)
{
    Bone *bone= pchan->bone;
    Mat4 *b_bone= b_bone_spline_setup(pchan, 0);
    Mat4 *b_bone_rest= b_bone_spline_setup(pchan, 1);
    Mat4 *b_bone_mats;
    DualQuat *b_bone_dual_quats= NULL;
    float tmat[4][4]= MAT4_UNITY;
    int a;
    
    /* allocate b_bone matrices and dual quats */
    b_bone_mats= MEM_mallocN((1+bone->segments)*sizeof(Mat4), "BBone defmats");
    pdef_info->b_bone_mats= b_bone_mats;

    if(use_quaternion) {
        b_bone_dual_quats= MEM_mallocN((bone->segments)*sizeof(DualQuat), "BBone dqs");
        pdef_info->b_bone_dual_quats= b_bone_dual_quats;
    }
    
    /* first matrix is the inverse arm_mat, to bring points in local bone space
       for finding out which segment it belongs to */
    invert_m4_m4(b_bone_mats[0].mat, bone->arm_mat);

    /* then we make the b_bone_mats:
        - first transform to local bone space
        - translate over the curve to the bbone mat space
        - transform with b_bone matrix
        - transform back into global space */

    for(a=0; a<bone->segments; a++) {
        invert_m4_m4(tmat, b_bone_rest[a].mat);

        mul_serie_m4(b_bone_mats[a+1].mat, pchan->chan_mat, bone->arm_mat,
            b_bone[a].mat, tmat, b_bone_mats[0].mat, NULL, NULL, NULL);

        if(use_quaternion)
            mat4_to_dquat( &b_bone_dual_quats[a],bone->arm_mat, b_bone_mats[a+1].mat);
    }
}

static void b_bone_deform(bPoseChanDeform *pdef_info, Bone *bone, float *co, DualQuat *dq, float defmat[][3])
{
    Mat4 *b_bone= pdef_info->b_bone_mats;
    float (*mat)[4]= b_bone[0].mat;
    float segment, y;
    int a;
    
    /* need to transform co back to bonespace, only need y */
    y= mat[0][1]*co[0] + mat[1][1]*co[1] + mat[2][1]*co[2] + mat[3][1];
    
    /* now calculate which of the b_bones are deforming this */
    segment= bone->length/((float)bone->segments);
    a= (int)(y/segment);
    
    /* note; by clamping it extends deform at endpoints, goes best with
       straight joints in restpos. */
    CLAMP(a, 0, bone->segments-1);

    if(dq) {
        copy_dq_dq(dq, &(pdef_info->b_bone_dual_quats)[a]);
    }
    else {
        mul_m4_v3(b_bone[a+1].mat, co);

        if(defmat)
            copy_m3_m4(defmat, b_bone[a+1].mat);
    }
}

/* using vec with dist to bone b1 - b2 */
float distfactor_to_bone (float vec[3], float b1[3], float b2[3], float rad1, float rad2, float rdist)
{
    float dist=0.0f; 
    float bdelta[3];
    float pdelta[3];
    float hsqr, a, l, rad;
    
    sub_v3_v3v3(bdelta, b2, b1);
    l = normalize_v3(bdelta);
    
    sub_v3_v3v3(pdelta, vec, b1);
    
    a = bdelta[0]*pdelta[0] + bdelta[1]*pdelta[1] + bdelta[2]*pdelta[2];
    hsqr = ((pdelta[0]*pdelta[0]) + (pdelta[1]*pdelta[1]) + (pdelta[2]*pdelta[2]));
    
    if (a < 0.0F){
        /* If we're past the end of the bone, do a spherical field attenuation thing */
        dist= ((b1[0]-vec[0])*(b1[0]-vec[0]) +(b1[1]-vec[1])*(b1[1]-vec[1]) +(b1[2]-vec[2])*(b1[2]-vec[2])) ;
        rad= rad1;
    }
    else if (a > l){
        /* If we're past the end of the bone, do a spherical field attenuation thing */
        dist= ((b2[0]-vec[0])*(b2[0]-vec[0]) +(b2[1]-vec[1])*(b2[1]-vec[1]) +(b2[2]-vec[2])*(b2[2]-vec[2])) ;
        rad= rad2;
    }
    else {
        dist= (hsqr - (a*a));
        
        if(l!=0.0f) {
            rad= a/l;
            rad= rad*rad2 + (1.0f-rad)*rad1;
        }
        else rad= rad1;
    }
    
    a= rad*rad;
    if(dist < a) 
        return 1.0f;
    else {
        l= rad+rdist;
        l*= l;
        if(rdist==0.0f || dist >= l) 
            return 0.0f;
        else {
            a= (float)sqrt(dist)-rad;
            return 1.0f-( a*a )/( rdist*rdist );
        }
    }
}

static void pchan_deform_mat_add(bPoseChannel *pchan, float weight, float bbonemat[][3], float mat[][3])
{
    float wmat[3][3];

    if(pchan->bone->segments>1)
        copy_m3_m3(wmat, bbonemat);
    else
        copy_m3_m4(wmat, pchan->chan_mat);

    mul_m3_fl(wmat, weight);
    add_m3_m3m3(mat, mat, wmat);
}

static float dist_bone_deform(bPoseChannel *pchan, bPoseChanDeform *pdef_info, float *vec, DualQuat *dq, float mat[][3], float *co)
{
    Bone *bone= pchan->bone;
    float fac, contrib=0.0;
    float cop[3], bbonemat[3][3];
    DualQuat bbonedq;

    if(bone==NULL) return 0.0f;
    
    copy_v3_v3(cop, co);

    fac= distfactor_to_bone(cop, bone->arm_head, bone->arm_tail, bone->rad_head, bone->rad_tail, bone->dist);
    
    if (fac > 0.0f) {
        
        fac*=bone->weight;
        contrib= fac;
        if(contrib > 0.0f) {
            if(vec) {
                if(bone->segments>1)
                    // applies on cop and bbonemat
                    b_bone_deform(pdef_info, bone, cop, NULL, (mat)?bbonemat:NULL);
                else
                    mul_m4_v3(pchan->chan_mat, cop);

                //  Make this a delta from the base position
                sub_v3_v3(cop, co);
                madd_v3_v3fl(vec, cop, fac);

                if(mat)
                    pchan_deform_mat_add(pchan, fac, bbonemat, mat);
            }
            else {
                if(bone->segments>1) {
                    b_bone_deform(pdef_info, bone, cop, &bbonedq, NULL);
                    add_weighted_dq_dq(dq, &bbonedq, fac);
                }
                else
                    add_weighted_dq_dq(dq, pdef_info->dual_quat, fac);
            }
        }
    }
    
    return contrib;
}

static void pchan_bone_deform(bPoseChannel *pchan, bPoseChanDeform *pdef_info, float weight, float *vec, DualQuat *dq, float mat[][3], float *co, float *contrib)
{
    float cop[3], bbonemat[3][3];
    DualQuat bbonedq;

    if (!weight)
        return;

    copy_v3_v3(cop, co);

    if(vec) {
        if(pchan->bone->segments>1)
            // applies on cop and bbonemat
            b_bone_deform(pdef_info, pchan->bone, cop, NULL, (mat)?bbonemat:NULL);
        else
            mul_m4_v3(pchan->chan_mat, cop);
        
        vec[0]+=(cop[0]-co[0])*weight;
        vec[1]+=(cop[1]-co[1])*weight;
        vec[2]+=(cop[2]-co[2])*weight;

        if(mat)
            pchan_deform_mat_add(pchan, weight, bbonemat, mat);
    }
    else {
        if(pchan->bone->segments>1) {
            b_bone_deform(pdef_info, pchan->bone, cop, &bbonedq, NULL);
            add_weighted_dq_dq(dq, &bbonedq, weight);
        }
        else
            add_weighted_dq_dq(dq, pdef_info->dual_quat, weight);
    }

    (*contrib)+=weight;
}

void armature_deform_verts(Object *armOb, Object *target, DerivedMesh *dm,
                           float (*vertexCos)[3], float (*defMats)[3][3],
                           int numVerts, int deformflag, 
                           float (*prevCos)[3], const char *defgrp_name)
{
    bPoseChanDeform *pdef_info_array;
    bPoseChanDeform *pdef_info= NULL;
    bArmature *arm= armOb->data;
    bPoseChannel *pchan, **defnrToPC = NULL;
    int *defnrToPCIndex= NULL;
    MDeformVert *dverts = NULL;
    bDeformGroup *dg;
    DualQuat *dualquats= NULL;
    float obinv[4][4], premat[4][4], postmat[4][4];
    const short use_envelope = deformflag & ARM_DEF_ENVELOPE;
    const short use_quaternion = deformflag & ARM_DEF_QUATERNION;
    const short invert_vgroup= deformflag & ARM_DEF_INVERT_VGROUP;
    int defbase_tot = 0;        /* safety for vertexgroup index overflow */
    int i, target_totvert = 0;  /* safety for vertexgroup overflow */
    int use_dverts = 0;
    int armature_def_nr;
    int totchan;

    if(arm->edbo) return;
    
    invert_m4_m4(obinv, target->obmat);
    copy_m4_m4(premat, target->obmat);
    mult_m4_m4m4(postmat, obinv, armOb->obmat);
    invert_m4_m4(premat, postmat);

    /* bone defmats are already in the channels, chan_mat */
    
    /* initialize B_bone matrices and dual quaternions */
    totchan= BLI_countlist(&armOb->pose->chanbase);

    if(use_quaternion) {
        dualquats= MEM_callocN(sizeof(DualQuat)*totchan, "dualquats");
    }
    
    pdef_info_array= MEM_callocN(sizeof(bPoseChanDeform)*totchan, "bPoseChanDeform");

    totchan= 0;
    pdef_info= pdef_info_array;
    for(pchan= armOb->pose->chanbase.first; pchan; pchan= pchan->next, pdef_info++) {
        if(!(pchan->bone->flag & BONE_NO_DEFORM)) {
            if(pchan->bone->segments > 1)
                pchan_b_bone_defmats(pchan, pdef_info, use_quaternion);

            if(use_quaternion) {
                pdef_info->dual_quat= &dualquats[totchan++];
                mat4_to_dquat( pdef_info->dual_quat,pchan->bone->arm_mat, pchan->chan_mat);
            }
        }
    }

    /* get the def_nr for the overall armature vertex group if present */
    armature_def_nr= defgroup_name_index(target, defgrp_name);
    
    if(ELEM(target->type, OB_MESH, OB_LATTICE)) {
        defbase_tot = BLI_countlist(&target->defbase);
        
        if(target->type==OB_MESH) {
            Mesh *me= target->data;
            dverts = me->dvert;
            if(dverts)
                target_totvert = me->totvert;
        }
        else {
            Lattice *lt= target->data;
            dverts = lt->dvert;
            if(dverts)
                target_totvert = lt->pntsu*lt->pntsv*lt->pntsw;
        }
    }
    
    /* get a vertex-deform-index to posechannel array */
    if(deformflag & ARM_DEF_VGROUP) {
        if(ELEM(target->type, OB_MESH, OB_LATTICE)) {
            /* if we have a DerivedMesh, only use dverts if it has them */
            if(dm)
                if(dm->getVertData(dm, 0, CD_MDEFORMVERT))
                    use_dverts = 1;
                else use_dverts = 0;
            else if(dverts) use_dverts = 1;

            if(use_dverts) {
                defnrToPC = MEM_callocN(sizeof(*defnrToPC) * defbase_tot, "defnrToBone");
                defnrToPCIndex = MEM_callocN(sizeof(*defnrToPCIndex) * defbase_tot, "defnrToIndex");
                for(i = 0, dg = target->defbase.first; dg;
                    i++, dg = dg->next) {
                    defnrToPC[i] = get_pose_channel(armOb->pose, dg->name);
                    /* exclude non-deforming bones */
                    if(defnrToPC[i]) {
                        if(defnrToPC[i]->bone->flag & BONE_NO_DEFORM) {
                            defnrToPC[i]= NULL;
                        }
                        else {
                            defnrToPCIndex[i]= BLI_findindex(&armOb->pose->chanbase, defnrToPC[i]);
                        }
                    }
                }
            }
        }
    }

    for(i = 0; i < numVerts; i++) {
        MDeformVert *dvert;
        DualQuat sumdq, *dq = NULL;
        float *co, dco[3];
        float sumvec[3], summat[3][3];
        float *vec = NULL, (*smat)[3] = NULL;
        float contrib = 0.0f;
        float armature_weight = 1.0f;   /* default to 1 if no overall def group */
        float prevco_weight = 1.0f;     /* weight for optional cached vertexcos */

        if(use_quaternion) {
            memset(&sumdq, 0, sizeof(DualQuat));
            dq= &sumdq;
        }
        else {
            sumvec[0] = sumvec[1] = sumvec[2] = 0.0f;
            vec= sumvec;

            if(defMats) {
                zero_m3(summat);
                smat = summat;
            }
        }

        if(use_dverts || armature_def_nr >= 0) {
            if(dm) dvert = dm->getVertData(dm, i, CD_MDEFORMVERT);
            else if(dverts && i < target_totvert) dvert = dverts + i;
            else dvert = NULL;
        } else
            dvert = NULL;

        if(armature_def_nr >= 0 && dvert) {
            armature_weight= defvert_find_weight(dvert, armature_def_nr);

            if(invert_vgroup) {
                armature_weight= 1.0f-armature_weight;
            }

            /* hackish: the blending factor can be used for blending with prevCos too */
            if(prevCos) {
                prevco_weight= armature_weight;
                armature_weight= 1.0f;
            }
        }

        /* check if there's any  point in calculating for this vert */
        if(armature_weight == 0.0f) continue;
        
        /* get the coord we work on */
        co= prevCos?prevCos[i]:vertexCos[i];
        
        /* Apply the object's matrix */
        mul_m4_v3(premat, co);
        
        if(use_dverts && dvert && dvert->totweight) { // use weight groups ?
            MDeformWeight *dw= dvert->dw;
            int deformed = 0;
            unsigned int j;
            
            for (j= dvert->totweight; j != 0; j--, dw++) {
                const int index = dw->def_nr;
                if(index < defbase_tot && (pchan= defnrToPC[index])) {
                    float weight = dw->weight;
                    Bone *bone= pchan->bone;
                    pdef_info= pdef_info_array + defnrToPCIndex[index];

                    deformed = 1;
                    
                    if(bone && bone->flag & BONE_MULT_VG_ENV) {
                        weight *= distfactor_to_bone(co, bone->arm_head,
                                                     bone->arm_tail,
                                                     bone->rad_head,
                                                     bone->rad_tail,
                                                     bone->dist);
                    }
                    pchan_bone_deform(pchan, pdef_info, weight, vec, dq, smat, co, &contrib);
                }
            }
            /* if there are vertexgroups but not groups with bones
             * (like for softbody groups)
             */
            if(deformed == 0 && use_envelope) {
                pdef_info= pdef_info_array;
                for(pchan= armOb->pose->chanbase.first; pchan;
                    pchan= pchan->next, pdef_info++) {
                    if(!(pchan->bone->flag & BONE_NO_DEFORM))
                        contrib += dist_bone_deform(pchan, pdef_info, vec, dq, smat, co);
                }
            }
        }
        else if(use_envelope) {
            pdef_info= pdef_info_array;
            for(pchan = armOb->pose->chanbase.first; pchan;
                pchan = pchan->next, pdef_info++) {
                if(!(pchan->bone->flag & BONE_NO_DEFORM))
                    contrib += dist_bone_deform(pchan, pdef_info, vec, dq, smat, co);
            }
        }

        /* actually should be EPSILON? weight values and contrib can be like 10e-39 small */
        if(contrib > 0.0001f) {
            if(use_quaternion) {
                normalize_dq(dq, contrib);

                if(armature_weight != 1.0f) {
                    copy_v3_v3(dco, co);
                    mul_v3m3_dq( dco, (defMats)? summat: NULL,dq);
                    sub_v3_v3(dco, co);
                    mul_v3_fl(dco, armature_weight);
                    add_v3_v3(co, dco);
                }
                else
                    mul_v3m3_dq( co, (defMats)? summat: NULL,dq);

                smat = summat;
            }
            else {
                mul_v3_fl(vec, armature_weight/contrib);
                add_v3_v3v3(co, vec, co);
            }

            if(defMats) {
                float pre[3][3], post[3][3], tmpmat[3][3];

                copy_m3_m4(pre, premat);
                copy_m3_m4(post, postmat);
                copy_m3_m3(tmpmat, defMats[i]);

                if(!use_quaternion) /* quaternion already is scale corrected */
                    mul_m3_fl(smat, armature_weight/contrib);

                mul_serie_m3(defMats[i], tmpmat, pre, smat, post,
                    NULL, NULL, NULL, NULL);
            }
        }
        
        /* always, check above code */
        mul_m4_v3(postmat, co);
        
        
        /* interpolate with previous modifier position using weight group */
        if(prevCos) {
            float mw= 1.0f - prevco_weight;
            vertexCos[i][0]= prevco_weight*vertexCos[i][0] + mw*co[0];
            vertexCos[i][1]= prevco_weight*vertexCos[i][1] + mw*co[1];
            vertexCos[i][2]= prevco_weight*vertexCos[i][2] + mw*co[2];
        }
    }

    if(dualquats) MEM_freeN(dualquats);
    if(defnrToPC) MEM_freeN(defnrToPC);
    if(defnrToPCIndex) MEM_freeN(defnrToPCIndex);

    /* free B_bone matrices */
    pdef_info= pdef_info_array;
    for(pchan = armOb->pose->chanbase.first; pchan; pchan = pchan->next, pdef_info++) {
        if(pdef_info->b_bone_mats) {
            MEM_freeN(pdef_info->b_bone_mats);
        }
        if(pdef_info->b_bone_dual_quats) {
            MEM_freeN(pdef_info->b_bone_dual_quats);
        }
    }

    MEM_freeN(pdef_info_array);
}

/* ************ END Armature Deform ******************* */

void get_objectspace_bone_matrix (struct Bone* bone, float M_accumulatedMatrix[][4], int UNUSED(root), int UNUSED(posed))
{
    copy_m4_m4(M_accumulatedMatrix, bone->arm_mat);
}

/* **************** Space to Space API ****************** */

/* Convert World-Space Matrix to Pose-Space Matrix */
void armature_mat_world_to_pose(Object *ob, float inmat[][4], float outmat[][4]) 
{
    float obmat[4][4];
    
    /* prevent crashes */
    if (ob==NULL) return;
    
    /* get inverse of (armature) object's matrix  */
    invert_m4_m4(obmat, ob->obmat);
    
    /* multiply given matrix by object's-inverse to find pose-space matrix */
    mult_m4_m4m4(outmat, inmat, obmat);
}

/* Convert Wolrd-Space Location to Pose-Space Location
 * NOTE: this cannot be used to convert to pose-space location of the supplied
 *      pose-channel into its local space (i.e. 'visual'-keyframing) 
 */
void armature_loc_world_to_pose(Object *ob, float *inloc, float *outloc) 
{
    float xLocMat[4][4]= MAT4_UNITY;
    float nLocMat[4][4];
    
    /* build matrix for location */
    copy_v3_v3(xLocMat[3], inloc);

    /* get bone-space cursor matrix and extract location */
    armature_mat_world_to_pose(ob, xLocMat, nLocMat);
    copy_v3_v3(outloc, nLocMat[3]);
}

/* Convert Pose-Space Matrix to Bone-Space Matrix 
 * NOTE: this cannot be used to convert to pose-space transforms of the supplied
 *      pose-channel into its local space (i.e. 'visual'-keyframing)
 */
void armature_mat_pose_to_bone(bPoseChannel *pchan, float inmat[][4], float outmat[][4])
{
    float pc_trans[4][4], inv_trans[4][4];
    float pc_posemat[4][4], inv_posemat[4][4];
    float pose_mat[4][4];

    /* paranoia: prevent crashes with no pose-channel supplied */
    if (pchan==NULL) return;

    /* default flag */
    if((pchan->bone->flag & BONE_NO_LOCAL_LOCATION)==0) {
        /* get the inverse matrix of the pchan's transforms */
        switch(pchan->rotmode) {
        case ROT_MODE_QUAT:
            loc_quat_size_to_mat4(pc_trans, pchan->loc, pchan->quat, pchan->size);
            break;
        case ROT_MODE_AXISANGLE:
            loc_axisangle_size_to_mat4(pc_trans, pchan->loc, pchan->rotAxis, pchan->rotAngle, pchan->size);
            break;
        default: /* euler */
            loc_eul_size_to_mat4(pc_trans, pchan->loc, pchan->eul, pchan->size);
        }

        copy_m4_m4(pose_mat, pchan->pose_mat);
    }
    else {
        /* local location, this is not default, different calculation
         * note: only tested for location with pose bone snapping.
         * If this is not useful in other cases the BONE_NO_LOCAL_LOCATION
         * case may have to be split into its own function. */
        unit_m4(pc_trans);
        copy_v3_v3(pc_trans[3], pchan->loc);

        /* use parents rotation/scale space + own absolute position */
        if(pchan->parent)   copy_m4_m4(pose_mat, pchan->parent->pose_mat);
        else                unit_m4(pose_mat);

        copy_v3_v3(pose_mat[3], pchan->pose_mat[3]);
    }


    invert_m4_m4(inv_trans, pc_trans);
    
    /* Remove the pchan's transforms from it's pose_mat.
     * This should leave behind the effects of restpose + 
     * parenting + constraints
     */
    mult_m4_m4m4(pc_posemat, pose_mat, inv_trans);
    
    /* get the inverse of the leftovers so that we can remove 
     * that component from the supplied matrix
     */
    invert_m4_m4(inv_posemat, pc_posemat);
    
    /* get the new matrix */
    mult_m4_m4m4(outmat, inv_posemat, inmat);
}

/* Convert Pose-Space Location to Bone-Space Location
 * NOTE: this cannot be used to convert to pose-space location of the supplied
 *      pose-channel into its local space (i.e. 'visual'-keyframing) 
 */
void armature_loc_pose_to_bone(bPoseChannel *pchan, float *inloc, float *outloc) 
{
    float xLocMat[4][4]= MAT4_UNITY;
    float nLocMat[4][4];
    
    /* build matrix for location */
    copy_v3_v3(xLocMat[3], inloc);

    /* get bone-space cursor matrix and extract location */
    armature_mat_pose_to_bone(pchan, xLocMat, nLocMat);
    copy_v3_v3(outloc, nLocMat[3]);
}

/* same as object_mat3_to_rot() */
void pchan_mat3_to_rot(bPoseChannel *pchan, float mat[][3], short use_compat)
{
    switch(pchan->rotmode) {
    case ROT_MODE_QUAT:
        mat3_to_quat(pchan->quat, mat);
        break;
    case ROT_MODE_AXISANGLE:
        mat3_to_axis_angle(pchan->rotAxis, &pchan->rotAngle, mat);
        break;
    default: /* euler */
        if(use_compat)  mat3_to_compatible_eulO(pchan->eul, pchan->eul, pchan->rotmode, mat);
        else            mat3_to_eulO(pchan->eul, pchan->rotmode, mat);
    }
}

/* Apply a 4x4 matrix to the pose bone,
 * similar to object_apply_mat4()
 */
void pchan_apply_mat4(bPoseChannel *pchan, float mat[][4], short use_compat)
{
    float rot[3][3];
    mat4_to_loc_rot_size(pchan->loc, rot, pchan->size, mat);
    pchan_mat3_to_rot(pchan, rot, use_compat);
}

/* Remove rest-position effects from pose-transform for obtaining
 * 'visual' transformation of pose-channel.
 * (used by the Visual-Keyframing stuff)
 */
void armature_mat_pose_to_delta(float delta_mat[][4], float pose_mat[][4], float arm_mat[][4])
{
    float imat[4][4];
    
    invert_m4_m4(imat, arm_mat);
    mult_m4_m4m4(delta_mat, imat, pose_mat);
}

/* **************** Rotation Mode Conversions ****************************** */
/* Used for Objects and Pose Channels, since both can have multiple rotation representations */

/* Called from RNA when rotation mode changes 
 *  - the result should be that the rotations given in the provided pointers have had conversions 
 *    applied (as appropriate), such that the rotation of the element hasn't 'visually' changed 
 */
void BKE_rotMode_change_values (float quat[4], float eul[3], float axis[3], float *angle, short oldMode, short newMode)
{
    /* check if any change - if so, need to convert data */
    if (newMode > 0) { /* to euler */
        if (oldMode == ROT_MODE_AXISANGLE) {
            /* axis-angle to euler */
            axis_angle_to_eulO( eul, newMode,axis, *angle);
        }
        else if (oldMode == ROT_MODE_QUAT) {
            /* quat to euler */
            normalize_qt(quat);
            quat_to_eulO( eul, newMode,quat);
        }
        /* else { no conversion needed } */
    }
    else if (newMode == ROT_MODE_QUAT) { /* to quat */
        if (oldMode == ROT_MODE_AXISANGLE) {
            /* axis angle to quat */
            axis_angle_to_quat(quat, axis, *angle);
        }
        else if (oldMode > 0) {
            /* euler to quat */
            eulO_to_quat( quat,eul, oldMode);
        }
        /* else { no conversion needed } */
    }
    else if (newMode == ROT_MODE_AXISANGLE) { /* to axis-angle */
        if (oldMode > 0) {
            /* euler to axis angle */
            eulO_to_axis_angle( axis, angle,eul, oldMode);
        }
        else if (oldMode == ROT_MODE_QUAT) {
            /* quat to axis angle */
            normalize_qt(quat);
            quat_to_axis_angle( axis, angle,quat);
        }
        
        /* when converting to axis-angle, we need a special exception for the case when there is no axis */
        if (IS_EQF(axis[0], axis[1]) && IS_EQF(axis[1], axis[2])) {
            /* for now, rotate around y-axis then (so that it simply becomes the roll) */
            axis[1]= 1.0f;
        }
    }
}

/* **************** The new & simple (but OK!) armature evaluation ********* */ 

/*  ****************** And how it works! ****************************************

  This is the bone transformation trick; they're hierarchical so each bone(b)
  is in the coord system of bone(b-1):

  arm_mat(b)= arm_mat(b-1) * yoffs(b-1) * d_root(b) * bone_mat(b) 
  
  -> yoffs is just the y axis translation in parent's coord system
  -> d_root is the translation of the bone root, also in parent's coord system

  pose_mat(b)= pose_mat(b-1) * yoffs(b-1) * d_root(b) * bone_mat(b) * chan_mat(b)

  we then - in init deform - store the deform in chan_mat, such that:

  pose_mat(b)= arm_mat(b) * chan_mat(b)
  
  *************************************************************************** */
/*  Computes vector and roll based on a rotation. "mat" must
     contain only a rotation, and no scaling. */ 
void mat3_to_vec_roll(float mat[][3], float *vec, float *roll) 
{
    if (vec)
        copy_v3_v3(vec, mat[1]);

    if (roll) {
        float vecmat[3][3], vecmatinv[3][3], rollmat[3][3];

        vec_roll_to_mat3(mat[1], 0.0f, vecmat);
        invert_m3_m3(vecmatinv, vecmat);
        mul_m3_m3m3(rollmat, vecmatinv, mat);

        *roll= (float)atan2(rollmat[2][0], rollmat[2][2]);
    }
}

/*  Calculates the rest matrix of a bone based
    On its vector and a roll around that vector */
void vec_roll_to_mat3(float *vec, float roll, float mat[][3])
{
    float   nor[3], axis[3], target[3]={0,1,0};
    float   theta;
    float   rMatrix[3][3], bMatrix[3][3];

    normalize_v3_v3(nor, vec);
    
    /*  Find Axis & Amount for bone matrix*/
    cross_v3_v3v3(axis,target,nor);

    /* was 0.0000000000001, caused bug [#23954], smaller values give unstable
     * roll when toggling editmode.
     *
     * was 0.00001, causes bug [#27675], with 0.00000495,
     * so a value inbetween these is needed.
     */
    if (dot_v3v3(axis,axis) > 0.000001f) {
        /* if nor is *not* a multiple of target ... */
        normalize_v3(axis);
        
        theta= angle_normalized_v3v3(target, nor);
        
        /*  Make Bone matrix*/
        vec_rot_to_mat3( bMatrix,axis, theta);
    }
    else {
        /* if nor is a multiple of target ... */
        float updown;
        
        /* point same direction, or opposite? */
        updown = ( dot_v3v3(target,nor) > 0 ) ? 1.0f : -1.0f;
        
        /* I think this should work ... */
        bMatrix[0][0]=updown; bMatrix[0][1]=0.0;    bMatrix[0][2]=0.0;
        bMatrix[1][0]=0.0;    bMatrix[1][1]=updown; bMatrix[1][2]=0.0;
        bMatrix[2][0]=0.0;    bMatrix[2][1]=0.0;    bMatrix[2][2]=1.0;
    }
    
    /*  Make Roll matrix*/
    vec_rot_to_mat3( rMatrix,nor, roll);
    
    /*  Combine and output result*/
    mul_m3_m3m3(mat, rMatrix, bMatrix);
}


/* recursive part, calculates restposition of entire tree of children */
/* used by exiting editmode too */
void where_is_armature_bone(Bone *bone, Bone *prevbone)
{
    float vec[3];
    
    /* Bone Space */
    sub_v3_v3v3(vec, bone->tail, bone->head);
    vec_roll_to_mat3(vec, bone->roll, bone->bone_mat);

    bone->length= len_v3v3(bone->head, bone->tail);
    
    /* this is called on old file reading too... */
    if(bone->xwidth==0.0f) {
        bone->xwidth= 0.1f;
        bone->zwidth= 0.1f;
        bone->segments= 1;
    }
    
    if(prevbone) {
        float offs_bone[4][4];  // yoffs(b-1) + root(b) + bonemat(b)
        
        /* bone transform itself */
        copy_m4_m3(offs_bone, bone->bone_mat);
                
        /* The bone's root offset (is in the parent's coordinate system) */
        copy_v3_v3(offs_bone[3], bone->head);

        /* Get the length translation of parent (length along y axis) */
        offs_bone[3][1]+= prevbone->length;
        
        /* Compose the matrix for this bone  */
        mult_m4_m4m4(bone->arm_mat, prevbone->arm_mat, offs_bone);
    }
    else {
        copy_m4_m3(bone->arm_mat, bone->bone_mat);
        copy_v3_v3(bone->arm_mat[3], bone->head);
    }
    
    /* and the kiddies */
    prevbone= bone;
    for(bone= bone->childbase.first; bone; bone= bone->next) {
        where_is_armature_bone(bone, prevbone);
    }
}

/* updates vectors and matrices on rest-position level, only needed 
   after editing armature itself, now only on reading file */
void where_is_armature (bArmature *arm)
{
    Bone *bone;
    
    /* hierarchical from root to children */
    for(bone= arm->bonebase.first; bone; bone= bone->next) {
        where_is_armature_bone(bone, NULL);
    }
}

/* if bone layer is protected, copy the data from from->pose
 * when used with linked libraries this copies from the linked pose into the local pose */
static void pose_proxy_synchronize(Object *ob, Object *from, int layer_protected)
{
    bPose *pose= ob->pose, *frompose= from->pose;
    bPoseChannel *pchan, *pchanp, pchanw;
    bConstraint *con;
    int error = 0;
    
    if (frompose==NULL) return;

    /* in some cases when rigs change, we cant synchronize
     * to avoid crashing check for possible errors here */
    for (pchan= pose->chanbase.first; pchan; pchan= pchan->next) {
        if (pchan->bone->layer & layer_protected) {
            if(get_pose_channel(frompose, pchan->name) == NULL) {
                printf("failed to sync proxy armature because '%s' is missing pose channel '%s'\n", from->id.name, pchan->name);
                error = 1;
            }
        }
    }

    if(error)
        return;
    
    /* clear all transformation values from library */
    rest_pose(frompose);
    
    /* copy over all of the proxy's bone groups */
        /* TODO for later - implement 'local' bone groups as for constraints
         *  Note: this isn't trivial, as bones reference groups by index not by pointer, 
         *       so syncing things correctly needs careful attention
         */
    BLI_freelistN(&pose->agroups);
    BLI_duplicatelist(&pose->agroups, &frompose->agroups);
    pose->active_group= frompose->active_group;
    
    for (pchan= pose->chanbase.first; pchan; pchan= pchan->next) {
        pchanp= get_pose_channel(frompose, pchan->name);

        if (pchan->bone->layer & layer_protected) {
            ListBase proxylocal_constraints = {NULL, NULL};
            
            /* copy posechannel to temp, but restore important pointers */
            pchanw= *pchanp;
            pchanw.prev= pchan->prev;
            pchanw.next= pchan->next;
            pchanw.parent= pchan->parent;
            pchanw.child= pchan->child;
            
            /* this is freed so copy a copy, else undo crashes */
            if(pchanw.prop) {
                pchanw.prop= IDP_CopyProperty(pchanw.prop);

                /* use the values from the the existing props */
                if(pchan->prop) {
                    IDP_SyncGroupValues(pchanw.prop, pchan->prop);
                }
            }

            /* constraints - proxy constraints are flushed... local ones are added after 
             *  1. extract constraints not from proxy (CONSTRAINT_PROXY_LOCAL) from pchan's constraints
             *  2. copy proxy-pchan's constraints on-to new
             *  3. add extracted local constraints back on top 
             *
             *  note for copy_constraints: when copying constraints, disable 'do_extern' otherwise we get the libs direct linked in this blend.
             */
            extract_proxylocal_constraints(&proxylocal_constraints, &pchan->constraints);
            copy_constraints(&pchanw.constraints, &pchanp->constraints, FALSE);
            BLI_movelisttolist(&pchanw.constraints, &proxylocal_constraints);
            
            /* constraints - set target ob pointer to own object */
            for (con= pchanw.constraints.first; con; con= con->next) {
                bConstraintTypeInfo *cti= constraint_get_typeinfo(con);
                ListBase targets = {NULL, NULL};
                bConstraintTarget *ct;
                
                if (cti && cti->get_constraint_targets) {
                    cti->get_constraint_targets(con, &targets);
                    
                    for (ct= targets.first; ct; ct= ct->next) {
                        if (ct->tar == from)
                            ct->tar = ob;
                    }
                    
                    if (cti->flush_constraint_targets)
                        cti->flush_constraint_targets(con, &targets, 0);
                }
            }
            
            /* free stuff from current channel */
            free_pose_channel(pchan);
            
            /* the final copy */
            *pchan= pchanw;
        }
        else {
            /* always copy custom shape */
            pchan->custom= pchanp->custom;
            pchan->custom_tx= pchanp->custom_tx;

            /* ID-Property Syncing */
            {
                IDProperty *prop_orig= pchan->prop;
                if(pchanp->prop) {
                    pchan->prop= IDP_CopyProperty(pchanp->prop);
                    if(prop_orig) {
                        /* copy existing values across when types match */
                        IDP_SyncGroupValues(pchan->prop, prop_orig);
                    }
                }
                else {
                    pchan->prop= NULL;
                }
                if (prop_orig) {
                    IDP_FreeProperty(prop_orig);
                    MEM_freeN(prop_orig);
                }
            }
        }
    }
}

static int rebuild_pose_bone(bPose *pose, Bone *bone, bPoseChannel *parchan, int counter)
{
    bPoseChannel *pchan = verify_pose_channel (pose, bone->name);   // verify checks and/or adds

    pchan->bone= bone;
    pchan->parent= parchan;
    
    counter++;
    
    for(bone= bone->childbase.first; bone; bone= bone->next) {
        counter= rebuild_pose_bone(pose, bone, pchan, counter);
        /* for quick detecting of next bone in chain, only b-bone uses it now */
        if(bone->flag & BONE_CONNECTED)
            pchan->child= get_pose_channel(pose, bone->name);
    }
    
    return counter;
}

/* only after leave editmode, duplicating, validating older files, library syncing */
/* NOTE: pose->flag is set for it */
void armature_rebuild_pose(Object *ob, bArmature *arm)
{
    Bone *bone;
    bPose *pose;
    bPoseChannel *pchan, *next;
    int counter=0;
        
    /* only done here */
    if(ob->pose==NULL) {
        /* create new pose */
        ob->pose= MEM_callocN(sizeof(bPose), "new pose");
        
        /* set default settings for animviz */
        animviz_settings_init(&ob->pose->avs);
    }
    pose= ob->pose;
    
    /* clear */
    for(pchan= pose->chanbase.first; pchan; pchan= pchan->next) {
        pchan->bone= NULL;
        pchan->child= NULL;
    }
    
    /* first step, check if all channels are there */
    for(bone= arm->bonebase.first; bone; bone= bone->next) {
        counter= rebuild_pose_bone(pose, bone, NULL, counter);
    }

    /* and a check for garbage */
    for(pchan= pose->chanbase.first; pchan; pchan= next) {
        next= pchan->next;
        if(pchan->bone==NULL) {
            free_pose_channel(pchan);
            free_pose_channels_hash(pose);
            BLI_freelinkN(&pose->chanbase, pchan);
        }
    }
    // printf("rebuild pose %s, %d bones\n", ob->id.name, counter);
    
    /* synchronize protected layers with proxy */
    if(ob->proxy) {
        object_copy_proxy_drivers(ob, ob->proxy);
        pose_proxy_synchronize(ob, ob->proxy, arm->layer_protected);
    }
    
    update_pose_constraint_flags(ob->pose); // for IK detection for example
    
    /* the sorting */
    if(counter>1)
        DAG_pose_sort(ob);
    
    ob->pose->flag &= ~POSE_RECALC;
    ob->pose->flag |= POSE_WAS_REBUILT;

    make_pose_channels_hash(ob->pose);
}


/* ********************** SPLINE IK SOLVER ******************* */

/* Temporary evaluation tree data used for Spline IK */
typedef struct tSplineIK_Tree {
    struct tSplineIK_Tree *next, *prev;
    
    int     type;                   /* type of IK that this serves (CONSTRAINT_TYPE_KINEMATIC or ..._SPLINEIK) */
    
    short free_points;              /* free the point positions array */
    short chainlen;                 /* number of bones in the chain */
    
    float *points;                  /* parametric positions for the joints along the curve */
    bPoseChannel **chain;           /* chain of bones to affect using Spline IK (ordered from the tip) */
    
    bPoseChannel *root;             /* bone that is the root node of the chain */
    
    bConstraint *con;               /* constraint for this chain */
    bSplineIKConstraint *ikData;    /* constraint settings for this chain */
} tSplineIK_Tree;

/* ----------- */

/* Tag the bones in the chain formed by the given bone for IK */
static void splineik_init_tree_from_pchan(Scene *scene, Object *UNUSED(ob), bPoseChannel *pchan_tip)
{
    bPoseChannel *pchan, *pchanRoot=NULL;
    bPoseChannel *pchanChain[255];
    bConstraint *con = NULL;
    bSplineIKConstraint *ikData = NULL;
    float boneLengths[255], *jointPoints;
    float totLength = 0.0f;
    short free_joints = 0;
    int segcount = 0;
    
    /* find the SplineIK constraint */
    for (con= pchan_tip->constraints.first; con; con= con->next) {
        if (con->type == CONSTRAINT_TYPE_SPLINEIK) {
            ikData= con->data;
            
            /* target can only be curve */
            if ((ikData->tar == NULL) || (ikData->tar->type != OB_CURVE))  
                continue;
            /* skip if disabled */
            if ( (con->enforce == 0.0f) || (con->flag & (CONSTRAINT_DISABLE|CONSTRAINT_OFF)) )
                continue;
            
            /* otherwise, constraint is ok... */
            break;
        }
    }
    if (con == NULL)
        return;
        
    /* make sure that the constraint targets are ok 
     *  - this is a workaround for a depsgraph bug...
     */
    if (ikData->tar) {
        Curve *cu= ikData->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(scene, ikData->tar, 0);
    }
    
    /* find the root bone and the chain of bones from the root to the tip 
     * NOTE: this assumes that the bones are connected, but that may not be true...
     */
    for (pchan= pchan_tip; pchan && (segcount < ikData->chainlen); pchan= pchan->parent, segcount++) {
        /* store this segment in the chain */
        pchanChain[segcount]= pchan;
        
        /* if performing rebinding, calculate the length of the bone */
        boneLengths[segcount]= pchan->bone->length;
        totLength += boneLengths[segcount];
    }
    
    if (segcount == 0)
        return;
    else
        pchanRoot= pchanChain[segcount-1];
    
    /* perform binding step if required */
    if ((ikData->flag & CONSTRAINT_SPLINEIK_BOUND) == 0) {
        float segmentLen= (1.0f / (float)segcount);
        int i;
        
        /* setup new empty array for the points list */
        if (ikData->points) 
            MEM_freeN(ikData->points);
        ikData->numpoints= ikData->chainlen+1; 
        ikData->points= MEM_callocN(sizeof(float)*ikData->numpoints, "Spline IK Binding");
        
        /* bind 'tip' of chain (i.e. first joint = tip of bone with the Spline IK Constraint) */
        ikData->points[0] = 1.0f;
        
        /* perform binding of the joints to parametric positions along the curve based 
         * proportion of the total length that each bone occupies
         */
        for (i = 0; i < segcount; i++) {
            /* 'head' joints, travelling towards the root of the chain
             *  - 2 methods; the one chosen depends on whether we've got usable lengths
             */
            if ((ikData->flag & CONSTRAINT_SPLINEIK_EVENSPLITS) || (totLength == 0.0f)) {
                /* 1) equi-spaced joints */
                ikData->points[i+1]= ikData->points[i] - segmentLen;
            }
            else {
                /*  2) to find this point on the curve, we take a step from the previous joint
                 *    a distance given by the proportion that this bone takes
                 */
                ikData->points[i+1]= ikData->points[i] - (boneLengths[i] / totLength);
            }
        }
        
        /* spline has now been bound */
        ikData->flag |= CONSTRAINT_SPLINEIK_BOUND;
    }
    
    /* apply corrections for sensitivity to scaling on a copy of the bind points,
     * since it's easier to determine the positions of all the joints beforehand this way
     */
    if ((ikData->flag & CONSTRAINT_SPLINEIK_SCALE_LIMITED) && (totLength != 0.0f)) {
        Curve *cu= (Curve *)ikData->tar->data;
        float splineLen, maxScale;
        int i;
        
        /* make a copy of the points array, that we'll store in the tree 
         *  - although we could just multiply the points on the fly, this approach means that
         *    we can introduce per-segment stretchiness later if it is necessary
         */
        jointPoints= MEM_dupallocN(ikData->points);
        free_joints= 1;
        
        /* get the current length of the curve */
        // NOTE: this is assumed to be correct even after the curve was resized
        splineLen= cu->path->totdist;
        
        /* calculate the scale factor to multiply all the path values by so that the 
         * bone chain retains its current length, such that
         *  maxScale * splineLen = totLength
         */
        maxScale = totLength / splineLen;
        
        /* apply scaling correction to all of the temporary points */
        // TODO: this is really not adequate enough on really short chains
        for (i = 0; i < segcount; i++)
            jointPoints[i] *= maxScale;
    }
    else {
        /* just use the existing points array */
        jointPoints= ikData->points;
        free_joints= 0;
    }
    
    /* make a new Spline-IK chain, and store it in the IK chains */
    // TODO: we should check if there is already an IK chain on this, since that would take presidence...
    {
        /* make new tree */
        tSplineIK_Tree *tree= MEM_callocN(sizeof(tSplineIK_Tree), "SplineIK Tree");
        tree->type= CONSTRAINT_TYPE_SPLINEIK;
        
        tree->chainlen= segcount;
        
        /* copy over the array of links to bones in the chain (from tip to root) */
        tree->chain= MEM_callocN(sizeof(bPoseChannel*)*segcount, "SplineIK Chain");
        memcpy(tree->chain, pchanChain, sizeof(bPoseChannel*)*segcount);
        
        /* store reference to joint position array */
        tree->points= jointPoints;
        tree->free_points= free_joints;
        
        /* store references to different parts of the chain */
        tree->root= pchanRoot;
        tree->con= con;
        tree->ikData= ikData;
        
        /* AND! link the tree to the root */
        BLI_addtail(&pchanRoot->siktree, tree);
    }
    
    /* mark root channel having an IK tree */
    pchanRoot->flag |= POSE_IKSPLINE;
}

/* Tag which bones are members of Spline IK chains */
static void splineik_init_tree(Scene *scene, Object *ob, float UNUSED(ctime))
{
    bPoseChannel *pchan;
    
    /* find the tips of Spline IK chains, which are simply the bones which have been tagged as such */
    for (pchan= ob->pose->chanbase.first; pchan; pchan= pchan->next) {
        if (pchan->constflag & PCHAN_HAS_SPLINEIK)
            splineik_init_tree_from_pchan(scene, ob, pchan);
    }
}

/* ----------- */

/* Evaluate spline IK for a given bone */
static void splineik_evaluate_bone(tSplineIK_Tree *tree, Scene *scene, Object *ob, bPoseChannel *pchan, int index, float ctime)
{
    bSplineIKConstraint *ikData= tree->ikData;
    float poseHead[3], poseTail[3], poseMat[4][4]; 
    float splineVec[3], scaleFac, radius=1.0f;
    
    /* firstly, calculate the bone matrix the standard way, since this is needed for roll control */
    where_is_pose_bone(scene, ob, pchan, ctime, 1);
    
    copy_v3_v3(poseHead, pchan->pose_head);
    copy_v3_v3(poseTail, pchan->pose_tail);
    
    /* step 1: determine the positions for the endpoints of the bone */
    {
        float vec[4], dir[3], rad;
        float tailBlendFac= 1.0f;
        
        /* determine if the bone should still be affected by SplineIK */
        if (tree->points[index+1] >= 1.0f) {
            /* spline doesn't affect the bone anymore, so done... */
            pchan->flag |= POSE_DONE;
            return;
        }
        else if ((tree->points[index] >= 1.0f) && (tree->points[index+1] < 1.0f)) {
            /* blending factor depends on the amount of the bone still left on the chain */
            tailBlendFac= (1.0f - tree->points[index+1]) / (tree->points[index] - tree->points[index+1]);
        }
        
        /* tail endpoint */
        if ( where_on_path(ikData->tar, tree->points[index], vec, dir, NULL, &rad, NULL) ) {
            /* apply curve's object-mode transforms to the position 
             * unless the option to allow curve to be positioned elsewhere is activated (i.e. no root)
             */
            if ((ikData->flag & CONSTRAINT_SPLINEIK_NO_ROOT) == 0)
                mul_m4_v3(ikData->tar->obmat, vec);
            
            /* convert the position to pose-space, then store it */
            mul_m4_v3(ob->imat, vec);
            interp_v3_v3v3(poseTail, pchan->pose_tail, vec, tailBlendFac);
            
            /* set the new radius */
            radius= rad;
        }
        
        /* head endpoint */
        if ( where_on_path(ikData->tar, tree->points[index+1], vec, dir, NULL, &rad, NULL) ) {
            /* apply curve's object-mode transforms to the position 
             * unless the option to allow curve to be positioned elsewhere is activated (i.e. no root)
             */
            if ((ikData->flag & CONSTRAINT_SPLINEIK_NO_ROOT) == 0)
                mul_m4_v3(ikData->tar->obmat, vec);
            
            /* store the position, and convert it to pose space */
            mul_m4_v3(ob->imat, vec);
            copy_v3_v3(poseHead, vec);
            
            /* set the new radius (it should be the average value) */
            radius = (radius+rad) / 2;
        }
    }
    
    /* step 2: determine the implied transform from these endpoints 
     *  - splineVec: the vector direction that the spline applies on the bone
     *  - scaleFac: the factor that the bone length is scaled by to get the desired amount
     */
    sub_v3_v3v3(splineVec, poseTail, poseHead);
    scaleFac= len_v3(splineVec) / pchan->bone->length;
    
    /* step 3: compute the shortest rotation needed to map from the bone rotation to the current axis 
     *  - this uses the same method as is used for the Damped Track Constraint (see the code there for details)
     */
    {
        float dmat[3][3], rmat[3][3], tmat[3][3];
        float raxis[3], rangle;
        
        /* compute the raw rotation matrix from the bone's current matrix by extracting only the
         * orientation-relevant axes, and normalising them
         */
        copy_v3_v3(rmat[0], pchan->pose_mat[0]);
        copy_v3_v3(rmat[1], pchan->pose_mat[1]);
        copy_v3_v3(rmat[2], pchan->pose_mat[2]);
        normalize_m3(rmat);
        
        /* also, normalise the orientation imposed by the bone, now that we've extracted the scale factor */
        normalize_v3(splineVec);
        
        /* calculate smallest axis-angle rotation necessary for getting from the
         * current orientation of the bone, to the spline-imposed direction
         */
        cross_v3_v3v3(raxis, rmat[1], splineVec);
        
        rangle= dot_v3v3(rmat[1], splineVec);
        rangle= acos( MAX2(-1.0f, MIN2(1.0f, rangle)) );
        
        /* multiply the magnitude of the angle by the influence of the constraint to 
         * control the influence of the SplineIK effect 
         */
        rangle *= tree->con->enforce;
        
        /* 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(dmat, raxis, rangle);
        
        /* combine these rotations so that the y-axis of the bone is now aligned as the spline dictates,
         * while still maintaining roll control from the existing bone animation
         */
        mul_m3_m3m3(tmat, dmat, rmat); // m1, m3, m2
        normalize_m3(tmat); /* attempt to reduce shearing, though I doubt this'll really help too much now... */
        copy_m4_m3(poseMat, tmat);
    }
    
    /* step 4: set the scaling factors for the axes */
    {
        /* only multiply the y-axis by the scaling factor to get nice volume-preservation */
        mul_v3_fl(poseMat[1], scaleFac);
        
        /* set the scaling factors of the x and z axes from... */
        switch (ikData->xzScaleMode) {
            case CONSTRAINT_SPLINEIK_XZS_ORIGINAL:
            {
                /* original scales get used */
                float scale;
                
                /* x-axis scale */
                scale= len_v3(pchan->pose_mat[0]);
                mul_v3_fl(poseMat[0], scale);
                /* z-axis scale */
                scale= len_v3(pchan->pose_mat[2]);
                mul_v3_fl(poseMat[2], scale);
            }
                break;
            case CONSTRAINT_SPLINEIK_XZS_VOLUMETRIC:
            {
                /* 'volume preservation' */
                float scale;
                
                /* calculate volume preservation factor which is 
                 * basically the inverse of the y-scaling factor 
                 */
                if (fabsf(scaleFac) != 0.0f) {
                    scale= 1.0f / fabsf(scaleFac);
                    
                    /* we need to clamp this within sensible values */
                    // NOTE: these should be fine for now, but should get sanitised in future
                    CLAMP(scale, 0.0001f, 100000.0f);
                }
                else
                    scale= 1.0f;
                
                /* apply the scaling */
                mul_v3_fl(poseMat[0], scale);
                mul_v3_fl(poseMat[2], scale);
            }
                break;
        }
        
        /* finally, multiply the x and z scaling by the radius of the curve too, 
         * to allow automatic scales to get tweaked still
         */
        if ((ikData->flag & CONSTRAINT_SPLINEIK_NO_CURVERAD) == 0) {
            mul_v3_fl(poseMat[0], radius);
            mul_v3_fl(poseMat[2], radius);
        }
    }
    
    /* step 5: set the location of the bone in the matrix */
    if (ikData->flag & CONSTRAINT_SPLINEIK_NO_ROOT) {
        /* when the 'no-root' option is affected, the chain can retain
         * the shape but be moved elsewhere
         */
        copy_v3_v3(poseHead, pchan->pose_head);
    }
    else if (tree->con->enforce < 1.0f) {
        /* when the influence is too low
         *  - blend the positions for the 'root' bone
         *  - stick to the parent for any other
         */
        if (pchan->parent) {
            copy_v3_v3(poseHead, pchan->pose_head);
        }
        else {
            // FIXME: this introduces popping artifacts when we reach 0.0
            interp_v3_v3v3(poseHead, pchan->pose_head, poseHead, tree->con->enforce);
        }
    }
    copy_v3_v3(poseMat[3], poseHead);
    
    /* finally, store the new transform */
    copy_m4_m4(pchan->pose_mat, poseMat);
    copy_v3_v3(pchan->pose_head, poseHead);
    
    /* recalculate tail, as it's now outdated after the head gets adjusted above! */
    where_is_pose_bone_tail(pchan);
    
    /* done! */
    pchan->flag |= POSE_DONE;
}

/* Evaluate the chain starting from the nominated bone */
static void splineik_execute_tree(Scene *scene, Object *ob, bPoseChannel *pchan_root, float ctime)
{
    tSplineIK_Tree *tree;
    
    /* for each pose-tree, execute it if it is spline, otherwise just free it */
    while ((tree = pchan_root->siktree.first) != NULL) {
        int i;
        
        /* walk over each bone in the chain, calculating the effects of spline IK
         *  - the chain is traversed in the opposite order to storage order (i.e. parent to children)
         *    so that dependencies are correct
         */
        for (i= tree->chainlen-1; i >= 0; i--) {
            bPoseChannel *pchan= tree->chain[i];
            splineik_evaluate_bone(tree, scene, ob, pchan, i, ctime);
        }
        
        /* free the tree info specific to SplineIK trees now */
        if (tree->chain) MEM_freeN(tree->chain);
        if (tree->free_points) MEM_freeN(tree->points);
        
        /* free this tree */
        BLI_freelinkN(&pchan_root->siktree, tree);
    }
}

/* ********************** THE POSE SOLVER ******************* */

/* loc/rot/size to given mat4 */
void pchan_to_mat4(bPoseChannel *pchan, float chan_mat[4][4])
{
    float smat[3][3];
    float rmat[3][3];
    float tmat[3][3];
    
    /* get scaling matrix */
    size_to_mat3(smat, pchan->size);
    
    /* rotations may either be quats, eulers (with various rotation orders), or axis-angle */
    if (pchan->rotmode > 0) {
        /* euler rotations (will cause gimble lock, but this can be alleviated a bit with rotation orders) */
        eulO_to_mat3(rmat, pchan->eul, pchan->rotmode);
    }
    else if (pchan->rotmode == ROT_MODE_AXISANGLE) {
        /* axis-angle - not really that great for 3D-changing orientations */
        axis_angle_to_mat3(rmat, pchan->rotAxis, pchan->rotAngle);
    }
    else {
        /* quats are normalised before use to eliminate scaling issues */
        float quat[4];
        
        /* NOTE: we now don't normalise the stored values anymore, since this was kindof evil in some cases
         * but if this proves to be too problematic, switch back to the old system of operating directly on 
         * the stored copy
         */
        normalize_qt_qt(quat, pchan->quat);
        quat_to_mat3(rmat, quat);
    }
    
    /* calculate matrix of bone (as 3x3 matrix, but then copy the 4x4) */
    mul_m3_m3m3(tmat, rmat, smat);
    copy_m4_m3(chan_mat, tmat);
    
    /* prevent action channels breaking chains */
    /* need to check for bone here, CONSTRAINT_TYPE_ACTION uses this call */
    if ((pchan->bone==NULL) || !(pchan->bone->flag & BONE_CONNECTED)) {
        copy_v3_v3(chan_mat[3], pchan->loc);
    }
}

/* loc/rot/size to mat4 */
/* used in constraint.c too */
void pchan_calc_mat(bPoseChannel *pchan)
{
    /* this is just a wrapper around the copy of this function which calculates the matrix 
     * and stores the result in any given channel
     */
    pchan_to_mat4(pchan, pchan->chan_mat);
}

#if 0 /* XXX OLD ANIMSYS, NLASTRIPS ARE NO LONGER USED */

/* NLA strip modifiers */
static void do_strip_modifiers(Scene *scene, Object *armob, Bone *bone, bPoseChannel *pchan)
{
    bActionModifier *amod;
    bActionStrip *strip, *strip2;
    float scene_cfra= (float)scene->r.cfra;
    int do_modif;

    for (strip=armob->nlastrips.first; strip; strip=strip->next) {
        do_modif=0;
        
        if (scene_cfra>=strip->start && scene_cfra<=strip->end)
            do_modif=1;
        
        if ((scene_cfra > strip->end) && (strip->flag & ACTSTRIP_HOLDLASTFRAME)) {
            do_modif=1;
            
            /* if there are any other strips active, ignore modifiers for this strip - 
             * 'hold' option should only hold action modifiers if there are 
             * no other active strips */
            for (strip2=strip->next; strip2; strip2=strip2->next) {
                if (strip2 == strip) continue;
                
                if (scene_cfra>=strip2->start && scene_cfra<=strip2->end) {
                    if (!(strip2->flag & ACTSTRIP_MUTE))
                        do_modif=0;
                }
            }
            
            /* if there are any later, activated, strips with 'hold' set, they take precedence, 
             * so ignore modifiers for this strip */
            for (strip2=strip->next; strip2; strip2=strip2->next) {
                if (scene_cfra < strip2->start) continue;
                if ((strip2->flag & ACTSTRIP_HOLDLASTFRAME) && !(strip2->flag & ACTSTRIP_MUTE)) {
                    do_modif=0;
                }
            }
        }
        
        if (do_modif) {
            /* temporal solution to prevent 2 strips accumulating */
            if(scene_cfra==strip->end && strip->next && strip->next->start==scene_cfra)
                continue;
            
            for(amod= strip->modifiers.first; amod; amod= amod->next) {
                switch (amod->type) {
                case ACTSTRIP_MOD_DEFORM:
                {
                    /* validate first */
                    if(amod->ob && amod->ob->type==OB_CURVE && amod->channel[0]) {
                        
                        if( strcmp(pchan->name, amod->channel)==0 ) {
                            float mat4[4][4], mat3[3][3];
                            
                            curve_deform_vector(scene, amod->ob, armob, bone->arm_mat[3], pchan->pose_mat[3], mat3, amod->no_rot_axis);
                            copy_m4_m4(mat4, pchan->pose_mat);
                            mul_m4_m3m4(pchan->pose_mat, mat3, mat4);
                            
                        }
                    }
                }
                    break;
                case ACTSTRIP_MOD_NOISE:    
                {
                    if( strcmp(pchan->name, amod->channel)==0 ) {
                        float nor[3], loc[3], ofs;
                        float eul[3], size[3], eulo[3], sizeo[3];
                        
                        /* calculate turbulance */
                        ofs = amod->turbul / 200.0f;
                        
                        /* make a copy of starting conditions */
                        copy_v3_v3(loc, pchan->pose_mat[3]);
                        mat4_to_eul( eul,pchan->pose_mat);
                        mat4_to_size( size,pchan->pose_mat);
                        copy_v3_v3(eulo, eul);
                        copy_v3_v3(sizeo, size);
                        
                        /* apply noise to each set of channels */
                        if (amod->channels & 4) {
                            /* for scaling */
                            nor[0] = BLI_gNoise(amod->noisesize, size[0]+ofs, size[1], size[2], 0, 0) - ofs;
                            nor[1] = BLI_gNoise(amod->noisesize, size[0], size[1]+ofs, size[2], 0, 0) - ofs;    
                            nor[2] = BLI_gNoise(amod->noisesize, size[0], size[1], size[2]+ofs, 0, 0) - ofs;
                            add_v3_v3(size, nor);
                            
                            if (sizeo[0] != 0)
                                mul_v3_fl(pchan->pose_mat[0], size[0] / sizeo[0]);
                            if (sizeo[1] != 0)
                                mul_v3_fl(pchan->pose_mat[1], size[1] / sizeo[1]);
                            if (sizeo[2] != 0)
                                mul_v3_fl(pchan->pose_mat[2], size[2] / sizeo[2]);
                        }
                        if (amod->channels & 2) {
                            /* for rotation */
                            nor[0] = BLI_gNoise(amod->noisesize, eul[0]+ofs, eul[1], eul[2], 0, 0) - ofs;
                            nor[1] = BLI_gNoise(amod->noisesize, eul[0], eul[1]+ofs, eul[2], 0, 0) - ofs;   
                            nor[2] = BLI_gNoise(amod->noisesize, eul[0], eul[1], eul[2]+ofs, 0, 0) - ofs;
                            
                            compatible_eul(nor, eulo);
                            add_v3_v3(eul, nor);
                            compatible_eul(eul, eulo);
                            
                            loc_eul_size_to_mat4(pchan->pose_mat, loc, eul, size);
                        }
                        if (amod->channels & 1) {
                            /* for location */
                            nor[0] = BLI_gNoise(amod->noisesize, loc[0]+ofs, loc[1], loc[2], 0, 0) - ofs;
                            nor[1] = BLI_gNoise(amod->noisesize, loc[0], loc[1]+ofs, loc[2], 0, 0) - ofs;   
                            nor[2] = BLI_gNoise(amod->noisesize, loc[0], loc[1], loc[2]+ofs, 0, 0) - ofs;
                            
                            add_v3_v3v3(pchan->pose_mat[3], loc, nor);
                        }
                    }
                }
                    break;
                }
            }
        }
    }
}

#endif

/* calculate tail of posechannel */
void where_is_pose_bone_tail(bPoseChannel *pchan)
{
    float vec[3];
    
    copy_v3_v3(vec, pchan->pose_mat[1]);
    mul_v3_fl(vec, pchan->bone->length);
    add_v3_v3v3(pchan->pose_tail, pchan->pose_head, vec);
}

/* The main armature solver, does all constraints excluding IK */
/* pchan is validated, as having bone and parent pointer
 * 'do_extra': when zero skips loc/size/rot, constraints and strip modifiers.
 */
void where_is_pose_bone(Scene *scene, Object *ob, bPoseChannel *pchan, float ctime, int do_extra)
{
    Bone *bone, *parbone;
    bPoseChannel *parchan;
    float vec[3];
    
    /* set up variables for quicker access below */
    bone= pchan->bone;
    parbone= bone->parent;
    parchan= pchan->parent;
    
    /* this gives a chan_mat with actions (ipos) results */
    if(do_extra)    pchan_calc_mat(pchan);
    else            unit_m4(pchan->chan_mat);

    /* construct the posemat based on PoseChannels, that we do before applying constraints */
    /* pose_mat(b)= pose_mat(b-1) * yoffs(b-1) * d_root(b) * bone_mat(b) * chan_mat(b) */
    
    if(parchan) {
        float offs_bone[4][4];  // yoffs(b-1) + root(b) + bonemat(b)
        
        /* bone transform itself */
        copy_m4_m3(offs_bone, bone->bone_mat);
        
        /* The bone's root offset (is in the parent's coordinate system) */
        copy_v3_v3(offs_bone[3], bone->head);
        
        /* Get the length translation of parent (length along y axis) */
        offs_bone[3][1]+= parbone->length;
        
        /* Compose the matrix for this bone  */
        if((bone->flag & BONE_HINGE) && (bone->flag & BONE_NO_SCALE)) { // uses restposition rotation, but actual position
            float tmat[4][4];
            /* the rotation of the parent restposition */
            copy_m4_m4(tmat, parbone->arm_mat);
            mul_serie_m4(pchan->pose_mat, tmat, offs_bone, pchan->chan_mat, NULL, NULL, NULL, NULL, NULL);
        }
        else if(bone->flag & BONE_HINGE) {  // same as above but apply parent scale
            float tmat[4][4];

            /* apply the parent matrix scale */
            float tsmat[4][4], tscale[3];

            /* the rotation of the parent restposition */
            copy_m4_m4(tmat, parbone->arm_mat);

            /* extract the scale of the parent matrix */
            mat4_to_size(tscale, parchan->pose_mat);
            size_to_mat4(tsmat, tscale);
            mult_m4_m4m4(tmat, tsmat, tmat);

            mul_serie_m4(pchan->pose_mat, tmat, offs_bone, pchan->chan_mat, NULL, NULL, NULL, NULL, NULL);
        }
        else if(bone->flag & BONE_NO_SCALE) {
            float orthmat[4][4];
            
            /* do transform, with an ortho-parent matrix */
            copy_m4_m4(orthmat, parchan->pose_mat);
            normalize_m4(orthmat);
            mul_serie_m4(pchan->pose_mat, orthmat, offs_bone, pchan->chan_mat, NULL, NULL, NULL, NULL, NULL);
        }
        else
            mul_serie_m4(pchan->pose_mat, parchan->pose_mat, offs_bone, pchan->chan_mat, NULL, NULL, NULL, NULL, NULL);
        
        /* in these cases we need to compute location separately */
        if(bone->flag & (BONE_HINGE|BONE_NO_SCALE|BONE_NO_LOCAL_LOCATION)) {
            float bone_loc[3], chan_loc[3];

            mul_v3_m4v3(bone_loc, parchan->pose_mat, offs_bone[3]);
            copy_v3_v3(chan_loc, pchan->chan_mat[3]);

            /* no local location is not transformed by bone matrix */
            if(!(bone->flag & BONE_NO_LOCAL_LOCATION))
                mul_mat3_m4_v3(offs_bone, chan_loc);

            /* for hinge we use armature instead of pose mat */
            if(bone->flag & BONE_HINGE) mul_mat3_m4_v3(parbone->arm_mat, chan_loc);
            else mul_mat3_m4_v3(parchan->pose_mat, chan_loc);

            add_v3_v3v3(pchan->pose_mat[3], bone_loc, chan_loc);
        }
    }
    else {
        mult_m4_m4m4(pchan->pose_mat, bone->arm_mat, pchan->chan_mat);

        /* optional location without arm_mat rotation */
        if(bone->flag & BONE_NO_LOCAL_LOCATION)
            add_v3_v3v3(pchan->pose_mat[3], bone->arm_mat[3], pchan->chan_mat[3]);
        
        /* only rootbones get the cyclic offset (unless user doesn't want that) */
        if ((bone->flag & BONE_NO_CYCLICOFFSET) == 0)
            add_v3_v3(pchan->pose_mat[3], ob->pose->cyclic_offset);
    }
    
    if(do_extra) {

#if 0   /* XXX OLD ANIMSYS, NLASTRIPS ARE NO LONGER USED */
        /* do NLA strip modifiers - i.e. curve follow */
        do_strip_modifiers(scene, ob, bone, pchan);
#endif

        /* Do constraints */
        if (pchan->constraints.first) {
            bConstraintOb *cob;

            /* make a copy of location of PoseChannel for later */
            copy_v3_v3(vec, pchan->pose_mat[3]);

            /* prepare PoseChannel for Constraint solving
             * - makes a copy of matrix, and creates temporary struct to use
             */
            cob= constraints_make_evalob(scene, ob, pchan, CONSTRAINT_OBTYPE_BONE);

            /* Solve PoseChannel's Constraints */
            solve_constraints(&pchan->constraints, cob, ctime); // ctime doesnt alter objects

            /* cleanup after Constraint Solving
             * - applies matrix back to pchan, and frees temporary struct used
             */
            constraints_clear_evalob(cob);

            /* prevent constraints breaking a chain */
            if(pchan->bone->flag & BONE_CONNECTED) {
                copy_v3_v3(pchan->pose_mat[3], vec);
            }
        }
    }
    
    /* calculate head */
    copy_v3_v3(pchan->pose_head, pchan->pose_mat[3]);
    /* calculate tail */
    where_is_pose_bone_tail(pchan);
}

/* This only reads anim data from channels, and writes to channels */
/* This is the only function adding poses */
void where_is_pose (Scene *scene, Object *ob)
{
    bArmature *arm;
    Bone *bone;
    bPoseChannel *pchan;
    float imat[4][4];
    float ctime;
    
    if(ob->type!=OB_ARMATURE) return;
    arm = ob->data;
    
    if(ELEM(NULL, arm, scene)) return;
    if((ob->pose==NULL) || (ob->pose->flag & POSE_RECALC)) 
        armature_rebuild_pose(ob, arm);
       
    ctime= BKE_curframe(scene); /* not accurate... */
    
    /* In editmode or restposition we read the data from the bones */
    if(arm->edbo || (arm->flag & ARM_RESTPOS)) {
        
        for(pchan= ob->pose->chanbase.first; pchan; pchan= pchan->next) {
            bone= pchan->bone;
            if(bone) {
                copy_m4_m4(pchan->pose_mat, bone->arm_mat);
                copy_v3_v3(pchan->pose_head, bone->arm_head);
                copy_v3_v3(pchan->pose_tail, bone->arm_tail);
            }
        }
    }
    else {
        invert_m4_m4(ob->imat, ob->obmat);  // imat is needed 
        
        /* 1. clear flags */
        for(pchan= ob->pose->chanbase.first; pchan; pchan= pchan->next) {
            pchan->flag &= ~(POSE_DONE|POSE_CHAIN|POSE_IKTREE|POSE_IKSPLINE);
        }
        
        /* 2a. construct the IK tree (standard IK) */
        BIK_initialize_tree(scene, ob, ctime);
        
        /* 2b. construct the Spline IK trees 
         *  - this is not integrated as an IK plugin, since it should be able
         *    to function in conjunction with standard IK
         */
        splineik_init_tree(scene, ob, ctime);
        
        /* 3. the main loop, channels are already hierarchical sorted from root to children */
        for(pchan= ob->pose->chanbase.first; pchan; pchan= pchan->next) {
            /* 4a. if we find an IK root, we handle it separated */
            if(pchan->flag & POSE_IKTREE) {
                BIK_execute_tree(scene, ob, pchan, ctime);
            }
            /* 4b. if we find a Spline IK root, we handle it separated too */
            else if(pchan->flag & POSE_IKSPLINE) {
                splineik_execute_tree(scene, ob, pchan, ctime);
            }
            /* 5. otherwise just call the normal solver */
            else if(!(pchan->flag & POSE_DONE)) {
                where_is_pose_bone(scene, ob, pchan, ctime, 1);
            }
        }
        /* 6. release the IK tree */
        BIK_release_tree(scene, ob, ctime);
    }
        
    /* calculating deform matrices */
    for(pchan= ob->pose->chanbase.first; pchan; pchan= pchan->next) {
        if(pchan->bone) {
            invert_m4_m4(imat, pchan->bone->arm_mat);
            mult_m4_m4m4(pchan->chan_mat, pchan->pose_mat, imat);
        }
    }
}


/* Returns total selected vgroups,
 * wpi.defbase_sel is assumed malloc'd, all values are set */
int get_selected_defgroups(Object *ob, char *dg_selection, int defbase_tot)
{
    bDeformGroup *defgroup;
    unsigned int i;
    Object *armob= object_pose_armature_get(ob);
    int dg_flags_sel_tot= 0;

    if(armob) {
        bPose *pose= armob->pose;
        for (i= 0, defgroup= ob->defbase.first; i < defbase_tot && defgroup; defgroup = defgroup->next, i++) {
            bPoseChannel *pchan= get_pose_channel(pose, defgroup->name);
            if(pchan && (pchan->bone->flag & BONE_SELECTED)) {
                dg_selection[i]= TRUE;
                dg_flags_sel_tot++;
            }
            else {
                dg_selection[i]= FALSE;
            }
        }
    }
    else {
        memset(dg_selection, FALSE, sizeof(char) * defbase_tot);
    }

    return dg_flags_sel_tot;
}