BsdfPdfQuery.h

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#pragma once
 
#include "Core/SurfaceBehavior/bsdf_query_fwd.h"
#include "Core/SurfaceBehavior/BsdfQueryContext.h"
#include "Math/TVector3.h"
#include "Core/SurfaceHit.h"
#include "Core/LTA/PDF.h"
 
#include <Common/assertion.h>
 
#include <string>
 
namespace ph
{
 
class BsdfPdfInput final
{
public:
    void set(const BsdfEvalInput& evalInput);
    void set(const BsdfSampleQuery& sample);
    void set(const BsdfSampleInput& sampleInput, const BsdfSampleOutput& sampleOutput);
 
    void set(
        const SurfaceHit&     X, 
        const math::Vector3R& L,
        const math::Vector3R& V);
 
    const SurfaceHit& getX() const;
    const math::Vector3R& getL() const;
    const math::Vector3R& getV() const;
 
private:
    SurfaceHit     m_X;
    math::Vector3R m_L;
    math::Vector3R m_V;
#if PH_DEBUG
    bool           m_hasSet{false};
#endif
};
 
class BsdfPdfOutput final
{
public:
    void setSampleDirPdf(const lta::PDF& pdf);
 
    real getSampleDirPdfW() const;
 
    const lta::PDF& getSampleDirPdf() const;
 
    operator bool () const;
 
private:
    lta::PDF m_sampleDirPdf{};
};
 
class BsdfPdfQuery final
{
public:
    using Input  = BsdfPdfInput;
    using Output = BsdfPdfOutput;
 
    BsdfQueryContext context = BsdfQueryContext{};
    Input            inputs;
    Output           outputs;
 
    BsdfPdfQuery() = default;
    explicit BsdfPdfQuery(BsdfQueryContext context);
};
 
// In-header Implementations:
 
inline BsdfPdfQuery::BsdfPdfQuery(BsdfQueryContext context)
    : BsdfPdfQuery()
{
    this->context = std::move(context);
 
    // (rest of the fields are initialized via setters)
}
 
inline void BsdfPdfInput::set(
    const SurfaceHit&     X,
    const math::Vector3R& L,
    const math::Vector3R& V)
{
    // Not querying from uninitialized surface hit
    PH_ASSERT(!X.getReason().hasExactly(ESurfaceHitReason::Invalid));
 
    PH_ASSERT_IN_RANGE(L.lengthSquared(), 0.9_r, 1.1_r);
    PH_ASSERT_IN_RANGE(V.lengthSquared(), 0.9_r, 1.1_r);
 
    m_X = X;
    m_L = L;
    m_V = V;
 
#if PH_DEBUG
    m_hasSet = true;
#endif
}
 
inline const SurfaceHit& BsdfPdfInput::getX() const
{
    PH_ASSERT(m_hasSet);
 
    return m_X;
}
 
inline const math::Vector3R& BsdfPdfInput::getL() const
{
    PH_ASSERT(m_hasSet);
 
    return m_L;
}
 
inline const math::Vector3R& BsdfPdfInput::getV() const
{
    PH_ASSERT(m_hasSet);
 
    return m_V;
}
 
inline void BsdfPdfOutput::setSampleDirPdf(const lta::PDF& pdf)
{
    m_sampleDirPdf = pdf;
}
 
inline real BsdfPdfOutput::getSampleDirPdfW() const
{
    return getSampleDirPdf().getPdfW();
}
 
inline const lta::PDF& BsdfPdfOutput::getSampleDirPdf() const
{
    PH_ASSERT(*this);
 
    return m_sampleDirPdf;
}
 
inline BsdfPdfOutput::operator bool () const
{
    return m_sampleDirPdf;
}
 
}// end namespace ph