bvh_pbrt.h

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/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2015-2016 Mario Luzeiro <[email protected]>
 * Copyright (C) 2015-2020 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * 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, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */
 
#ifndef _BVH_PBRT_H_
#define _BVH_PBRT_H_
 
#include "accelerator_3d.h"
#include <cstdint>
#include <list>
 
// Forward Declarations
struct BVHBuildNode;
struct BVHPrimitiveInfo;
struct MortonPrimitive;
 
struct LinearBVHNode
{
    // 24 bytes
    BBOX_3D bounds;
 
    // 4 bytes
    union
    {
        int primitivesOffset;   
        int secondChildOffset;  
    };
 
    // 4 bytes
    uint16_t nPrimitives;  
    uint8_t  axis;         
    uint8_t  pad[1];       
};
 
 
enum class SPLITMETHOD
{
    MIDDLE,
    EQUALCOUNTS,
    SAH,
    HLBVH
};
 
 
class BVH_PBRT : public ACCELERATOR_3D
{
public:
    BVH_PBRT( const CONTAINER_3D_BASE& aObjectContainer, int aMaxPrimsInNode = 4,
              SPLITMETHOD aSplitMethod = SPLITMETHOD::SAH );
 
    ~BVH_PBRT();
 
    bool Intersect( const RAY& aRay, HITINFO& aHitInfo ) const override;
    bool Intersect( const RAY& aRay, HITINFO& aHitInfo, unsigned int aAccNodeInfo ) const override;
    bool Intersect( const RAYPACKET& aRayPacket, HITINFO_PACKET* aHitInfoPacket ) const override;
    bool IntersectP( const RAY& aRay, float aMaxDistance ) const override;
 
private:
    BVHBuildNode* recursiveBuild( std::vector<BVHPrimitiveInfo>& primitiveInfo, int start,
                                  int end, int* totalNodes, CONST_VECTOR_OBJECT& orderedPrims );
 
    BVHBuildNode* HLBVHBuild( const std::vector<BVHPrimitiveInfo>& primitiveInfo,
                              int* totalNodes, CONST_VECTOR_OBJECT& orderedPrims );
 
    BVHBuildNode* emitLBVH( BVHBuildNode* &buildNodes,
                            const std::vector<BVHPrimitiveInfo>& primitiveInfo,
                            MortonPrimitive* mortonPrims, int nPrimitives, int* totalNodes,
                            CONST_VECTOR_OBJECT& orderedPrims, int* orderedPrimsOffset, int bit );
 
    BVHBuildNode* buildUpperSAH( std::vector<BVHBuildNode*>& treeletRoots, int start, int end,
                                 int* totalNodes );
 
    int flattenBVHTree( BVHBuildNode* node, uint32_t* offset );
 
    // BVH Private Data
    const int           m_maxPrimsInNode;
    SPLITMETHOD         m_splitMethod;
    CONST_VECTOR_OBJECT m_primitives;
    LinearBVHNode*      m_nodes;
 
    std::list<void*>    m_nodesToFree;
 
    // Partition traversal
    unsigned int m_I[RAYPACKET_RAYS_PER_PACKET];
};
 
#endif  // _BVH_PBRT_H_