rayobject_svbvh.cpp

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

#include "MEM_guardedalloc.h"

#include "BLI_utildefines.h"

#include "vbvh.h"
#include "svbvh.h"
#include "reorganize.h"

#ifdef __SSE__

#define DFS_STACK_SIZE  256

struct SVBVHTree
{
    RayObject rayobj;

    SVBVHNode *root;
    MemArena *node_arena;

    float cost;
    RTBuilder *builder;
};

/*
 * Cost to test N childs
 */
struct PackCost
{
    float operator()(int n)
    {
        return (n / 4) + ((n % 4) > 2 ? 1 : n%4);
    }
};


template<>
void bvh_done<SVBVHTree>(SVBVHTree *obj)
{
    rtbuild_done(obj->builder, &obj->rayobj.control);
    
    //TODO find a away to exactly calculate the needed memory
    MemArena *arena1 = BLI_memarena_new(BLI_MEMARENA_STD_BUFSIZE, "svbvh arena");
                       BLI_memarena_use_malloc(arena1);

    MemArena *arena2 = BLI_memarena_new(BLI_MEMARENA_STD_BUFSIZE, "svbvh arena2");
                       BLI_memarena_use_malloc(arena2);
                       BLI_memarena_use_align(arena2, 16);

    //Build and optimize the tree
    if(0)
    {
        VBVHNode *root = BuildBinaryVBVH<VBVHNode>(arena1, &obj->rayobj.control).transform(obj->builder);

        if(RE_rayobjectcontrol_test_break(&obj->rayobj.control))
        {
            BLI_memarena_free(arena1);
            BLI_memarena_free(arena2);
            return;
        }
        
        reorganize(root);
        remove_useless(root, &root);
        bvh_refit(root);

        pushup(root);
        pushdown(root);
        pushup_simd<VBVHNode,4>(root);

        obj->root = Reorganize_SVBVH<VBVHNode>(arena2).transform(root);
    }
    else
    {
        //Finds the optimal packing of this tree using a given cost model
        //TODO this uses quite a lot of memory, find ways to reduce memory usage during building
        OVBVHNode *root = BuildBinaryVBVH<OVBVHNode>(arena1,&obj->rayobj.control).transform(obj->builder);          

        if(RE_rayobjectcontrol_test_break(&obj->rayobj.control))
        {
            BLI_memarena_free(arena1);
            BLI_memarena_free(arena2);
            return;
        }

        if(root) {
            VBVH_optimalPackSIMD<OVBVHNode,PackCost>(PackCost()).transform(root);
            obj->root = Reorganize_SVBVH<OVBVHNode>(arena2).transform(root);
        }
        else
            obj->root = NULL;
    }
    
    //Free data
    BLI_memarena_free(arena1);
    
    obj->node_arena = arena2;
    obj->cost = 1.0;

    rtbuild_free( obj->builder );
    obj->builder = NULL;
}

template<int StackSize>
int intersect(SVBVHTree *obj, Isect* isec)
{
    //TODO renable hint support
    if(RE_rayobject_isAligned(obj->root)) {
        if(isec->mode == RE_RAY_SHADOW)
            return svbvh_node_stack_raycast<StackSize,true>(obj->root, isec);
        else
            return svbvh_node_stack_raycast<StackSize,false>(obj->root, isec);
    }
    else
        return RE_rayobject_intersect( (RayObject*) obj->root, isec );
}

template<class Tree>
void bvh_hint_bb(Tree *tree, LCTSHint *hint, float *UNUSED(min), float *UNUSED(max))
{
    //TODO renable hint support
    {
        hint->size = 0;
        hint->stack[hint->size++] = (RayObject*)tree->root;
    }
}
/* the cast to pointer function is needed to workarround gcc bug: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11407 */
template<class Tree, int STACK_SIZE>
RayObjectAPI make_api()
{
    static RayObjectAPI api = 
    {
        (RE_rayobject_raycast_callback) ((int(*)(Tree*,Isect*)) &intersect<STACK_SIZE>),
        (RE_rayobject_add_callback)     ((void(*)(Tree*,RayObject*)) &bvh_add<Tree>),
        (RE_rayobject_done_callback)    ((void(*)(Tree*))       &bvh_done<Tree>),
        (RE_rayobject_free_callback)    ((void(*)(Tree*))       &bvh_free<Tree>),
        (RE_rayobject_merge_bb_callback)((void(*)(Tree*,float*,float*)) &bvh_bb<Tree>),
        (RE_rayobject_cost_callback)    ((float(*)(Tree*))      &bvh_cost<Tree>),
        (RE_rayobject_hint_bb_callback) ((void(*)(Tree*,LCTSHint*,float*,float*)) &bvh_hint_bb<Tree>)
    };
    
    return api;
}

template<class Tree>
RayObjectAPI* bvh_get_api(int maxstacksize)
{
    static RayObjectAPI bvh_api256 = make_api<Tree,1024>();
    
    if(maxstacksize <= 1024) return &bvh_api256;
    assert(maxstacksize <= 256);
    return 0;
}

RayObject *RE_rayobject_svbvh_create(int size)
{
    return bvh_create_tree<SVBVHTree,DFS_STACK_SIZE>(size);
}

#else

RayObject *RE_rayobject_svbvh_create(int size)
{
    puts("WARNING: SSE disabled at compile time\n");
    return NULL;
}

#endif