bpt.subpath.h

/*
    Lightmetrica : A research-oriented renderer

    Copyright (c) 2014 Hisanari Otsu

    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 3 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, see <http://www.gnu.org/licenses/>.
*/

#pragma once
#ifndef LIB_LIGHTMETRICA_BPT_SUBPATH_H
#define LIB_LIGHTMETRICA_BPT_SUBPATH_H

#include "bpt.common.h"
#include "math.types.h"
#include "surfacegeometry.h"
#include "transportdirection.h"
#include "align.h"
#include <vector>

LM_NAMESPACE_BEGIN

class GeneralizedBSDF;
class Emitter;
class Light;
class Camera;

enum class BPTPathVertexType
{
    None,                                   
    EndPoint,                               
    IntermediatePoint,                      
};

class BPTPathVertex : public SIMDAlignedType
{
public:

    LM_PUBLIC_API BPTPathVertex();

private:

    LM_DISABLE_COPY_AND_MOVE(BPTPathVertex);

public:

    bool Degenerated() const;

    void DebugPrint() const;

public:

                                            // # General information
                                            // --------------------------------------------------
    BPTPathVertexType type;                 
    SurfaceGeometry geom;                   

                                            // # Variables associated with Emitter.
                                            // \a type is EndPoint
                                            // --------------------------------------------------
    Math::PDFEval pdfP;                     
    const Emitter* emitter;                 

                                            // # Variables associated with generalized BSDF.
                                            // \a type is either EndPoint or IntermediatePoint
                                            // --------------------------------------------------
    Math::Vec3 weight[2];                   
    Math::PDFEval pdfD[2];                  
    Math::PDFEval pdfRR;                    
    TransportDirection transportDir;        
    int componentType;                      
    const GeneralizedBSDF* bsdf;            
    const Light* areaL;                     
    const Camera* areaE;                    
    Math::Vec3 wi;                          
    Math::Vec3 wo;                          

};

class BPTPathVertexPool;
class Scene;
class Sampler;

class BPTSubpath
{
public:

    LM_PUBLIC_API BPTSubpath(TransportDirection transportDir);
    
private:

    LM_DISABLE_COPY_AND_MOVE(BPTSubpath);

public:

    LM_PUBLIC_API void Clear();

    LM_PUBLIC_API void DebugPrint() const;

    LM_PUBLIC_API void DebugPrint(size_t n) const;

    LM_PUBLIC_API void Sample(const Scene& scene, Sampler& sampler, BPTPathVertexPool& pool, int rrDepth, int maxPathVertices);

    Math::Vec3 EvaluateSubpathAlpha(int vs, Math::Vec2& rasterPosition) const;

    Math::Float SubpathSelectionProbability(int vs) const;

    LM_PUBLIC_API int NumVertices() const;

    LM_PUBLIC_API BPTPathVertex* Vertex(int i) const;

public:

    TransportDirection transportDir;
    std::vector<BPTPathVertex*> vertices;

};

LM_NAMESPACE_END

#endif // LIB_LIGHTMETRICA_BPT_SUBPATH_H