rayobject_instance.cpp

Go to the documentation of this file.

/*
 * ***** 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) 2009 Blender Foundation.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): André Pinto.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include <assert.h>

#include "MEM_guardedalloc.h"

#include "BLI_math.h"
#include "BLI_utildefines.h"

#include "rayintersection.h"
#include "rayobject.h"

#define RE_COST_INSTANCE (1.0f)

static int  RE_rayobject_instance_intersect(RayObject *o, Isect *isec);
static void RE_rayobject_instance_free(RayObject *o);
static void RE_rayobject_instance_bb(RayObject *o, float *min, float *max);
static float RE_rayobject_instance_cost(RayObject *o);

static void RE_rayobject_instance_hint_bb(RayObject *UNUSED(o), RayHint *UNUSED(hint),
                                          float *UNUSED(min), float *UNUSED(max))
{}

static RayObjectAPI instance_api =
{
    RE_rayobject_instance_intersect,
    NULL, //static void RE_rayobject_instance_add(RayObject *o, RayObject *ob);
    NULL, //static void RE_rayobject_instance_done(RayObject *o);
    RE_rayobject_instance_free,
    RE_rayobject_instance_bb,
    RE_rayobject_instance_cost,
    RE_rayobject_instance_hint_bb   
};

typedef struct InstanceRayObject
{
    RayObject rayobj;
    RayObject *target;

    void *ob; //Object represented by this instance
    void *target_ob; //Object represented by the inner RayObject, needed to handle self-intersection
    
    float global2target[4][4];
    float target2global[4][4];
    
} InstanceRayObject;


RayObject *RE_rayobject_instance_create(RayObject *target, float transform[][4], void *ob, void *target_ob)
{
    InstanceRayObject *obj= (InstanceRayObject*)MEM_callocN(sizeof(InstanceRayObject), "InstanceRayObject");
    assert( RE_rayobject_isAligned(obj) ); /* RayObject API assumes real data to be 4-byte aligned */   
    
    obj->rayobj.api = &instance_api;
    obj->target = target;
    obj->ob = ob;
    obj->target_ob = target_ob;
    
    copy_m4_m4(obj->target2global, transform);
    invert_m4_m4(obj->global2target, obj->target2global);
    
    return RE_rayobject_unalignRayAPI((RayObject*) obj);
}

static int  RE_rayobject_instance_intersect(RayObject *o, Isect *isec)
{
    InstanceRayObject *obj = (InstanceRayObject*)o;
    float start[3], dir[3], idot_axis[3], dist;
    int changed = 0, i, res;
    
    // TODO - this is disabling self intersection on instances
    if(isec->orig.ob == obj->ob && obj->ob)
    {
        changed = 1;
        isec->orig.ob = obj->target_ob;
    }
    
    // backup old values
    copy_v3_v3(start, isec->start);
    copy_v3_v3(dir, isec->dir);
    copy_v3_v3(idot_axis, isec->idot_axis);
    dist = isec->dist;

    // transform to target coordinates system
    mul_m4_v3(obj->global2target, isec->start);
    mul_mat3_m4_v3(obj->global2target, isec->dir);
    isec->dist *= normalize_v3(isec->dir);
    
    // update idot_axis and bv_index
    for(i=0; i<3; i++)
    {
        isec->idot_axis[i]      = 1.0f / isec->dir[i];
        
        isec->bv_index[2*i]     = isec->idot_axis[i] < 0.0 ? 1 : 0;
        isec->bv_index[2*i+1]   = 1 - isec->bv_index[2*i];
        
        isec->bv_index[2*i]     = i+3*isec->bv_index[2*i];
        isec->bv_index[2*i+1]   = i+3*isec->bv_index[2*i+1];
    }

    // raycast
    res = RE_rayobject_intersect(obj->target, isec);

    // map dist into original coordinate space
    if(res == 0)
    {
        isec->dist = dist;
    }
    else
    {
        // note we don't just multiply dist, because of possible
        // non-uniform scaling in the transform matrix
        float vec[3];

        mul_v3_v3fl(vec, isec->dir, isec->dist);
        mul_mat3_m4_v3(obj->target2global, vec);

        isec->dist = len_v3(vec);
        isec->hit.ob = obj->ob;

#ifdef RT_USE_LAST_HIT  
        // TODO support for last hit optimization in instances that can jump
        // directly to the last hit face.
        // For now it jumps directly to the last-hit instance root node.
        isec->last_hit = RE_rayobject_unalignRayAPI((RayObject*) obj);
#endif
    }

    // restore values
    copy_v3_v3(isec->start, start);
    copy_v3_v3(isec->dir, dir);
    copy_v3_v3(isec->idot_axis, idot_axis);
    
    if(changed)
        isec->orig.ob = obj->ob;

    // restore bv_index
    for(i=0; i<3; i++)
    {
        isec->bv_index[2*i]     = isec->idot_axis[i] < 0.0 ? 1 : 0;
        isec->bv_index[2*i+1]   = 1 - isec->bv_index[2*i];
        
        isec->bv_index[2*i]     = i+3*isec->bv_index[2*i];
        isec->bv_index[2*i+1]   = i+3*isec->bv_index[2*i+1];
    }
        
    return res;
}

static void RE_rayobject_instance_free(RayObject *o)
{
    InstanceRayObject *obj = (InstanceRayObject*)o;
    MEM_freeN(obj);
}

static float RE_rayobject_instance_cost(RayObject *o)
{
    InstanceRayObject *obj = (InstanceRayObject*)o;
    return RE_rayobject_cost(obj->target) + RE_COST_INSTANCE;
}

static void RE_rayobject_instance_bb(RayObject *o, float *min, float *max)
{
    //TODO:
    // *better bb.. calculated without rotations of bb
    // *maybe cache that better-fitted-BB at the InstanceRayObject
    InstanceRayObject *obj = (InstanceRayObject*)o;

    float m[3], M[3], t[3];
    int i, j;
    INIT_MINMAX(m, M);
    RE_rayobject_merge_bb(obj->target, m, M);

    //There must be a faster way than rotating all the 8 vertexs of the BB
    for(i=0; i<8; i++)
    {
        for(j=0; j<3; j++) t[j] = i&(1<<j) ? M[j] : m[j];
        mul_m4_v3(obj->target2global, t);
        DO_MINMAX(t, min, max);
    }
}