HitInfo.h

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#pragma once
 
#include "Math/TVector3.h"
#include "Math/TOrthonormalBasis3.h"
#include "Math/math.h"
#include "Core/ECoordSys.h"
 
#include <Common/assertion.h>
 
namespace ph
{
 
class Primitive;
 
class HitInfo final
{
public:
    HitInfo();
 
    void setAttributes(
        const math::Vector3R& pos,
        const math::Vector3R& geometryNormal,
        const math::Vector3R& shadingNormal);
 
    void setDerivatives(
        const math::Vector3R& dPdU,
        const math::Vector3R& dPdV,
        const math::Vector3R& dNdU,
        const math::Vector3R& dNdV);
 
    void computeBases();
 
    math::Vector3R getPos() const;
    math::Vector3R getShadingNormal() const;
    math::Vector3R getGeometryNormal() const;
    math::Vector3R getdPdU() const;
    math::Vector3R getdPdV() const;
    math::Vector3R getdNdU() const;
    math::Vector3R getdNdV() const;
    const math::Basis3R& getGeometryBasis() const;
    const math::Basis3R& getShadingBasis() const;
 
private:
    math::Vector3R m_pos;
 
    math::Vector3R m_dPdU;
    math::Vector3R m_dPdV;
    math::Vector3R m_dNdU;
    math::Vector3R m_dNdV;
 
    math::Basis3R m_geometryBasis;
    math::Basis3R m_shadingBasis;
 
#if PH_DEBUG
    bool m_isBasesComputed{false};
#endif
};
 
// In-header Implementations:
 
inline math::Vector3R HitInfo::getPos() const
{
    return m_pos;
}
 
inline math::Vector3R HitInfo::getShadingNormal() const
{
    return m_shadingBasis.getYAxis();
}
 
inline math::Vector3R HitInfo::getGeometryNormal() const
{
    return m_geometryBasis.getYAxis();
}
 
inline math::Vector3R HitInfo::getdPdU() const
{
    return m_dPdU;
}
 
inline math::Vector3R HitInfo::getdPdV() const
{
    return m_dPdV;
}
 
inline math::Vector3R HitInfo::getdNdU() const
{
    return m_dNdU;
}
 
inline math::Vector3R HitInfo::getdNdV() const
{
    return m_dNdV;
}
 
inline const math::Basis3R& HitInfo::getGeometryBasis() const
{
    PH_ASSERT(m_isBasesComputed);
    return m_geometryBasis;
}
 
inline const math::Basis3R& HitInfo::getShadingBasis() const
{
    PH_ASSERT(m_isBasesComputed);
    return m_shadingBasis;
}
 
inline void HitInfo::setAttributes(
    const math::Vector3R& pos,
    const math::Vector3R& geometryNormal,
    const math::Vector3R& shadingNormal)
{
    m_pos = pos;
    m_geometryBasis.setYAxis(geometryNormal);
    m_shadingBasis.setYAxis(shadingNormal);
 
#if PH_DEBUG
    m_isBasesComputed = false;
#endif
}
 
inline void HitInfo::setDerivatives(
    const math::Vector3R& dPdU,
    const math::Vector3R& dPdV,
    const math::Vector3R& dNdU,
    const math::Vector3R& dNdV)
{
    m_dPdU = dPdU;
    m_dPdV = dPdV;
    m_dNdU = dNdU;
    m_dNdV = dNdV;
 
#if PH_DEBUG
    m_isBasesComputed = false;
#endif
}
 
inline void HitInfo::computeBases()
{
    // FIXME: currently this is a hacky way to avoid crossing two parallel vectors
    // (this condition can rarely happen)
    // (which will result in 0-length vector and cause normalization to fail)
 
    m_geometryBasis.setXAxis(m_geometryBasis.getYAxis().cross(m_dPdU));
    if(m_geometryBasis.getXAxis().lengthSquared() > 0.0_r)
    {
        m_geometryBasis.renormalizeXAxis();
        m_geometryBasis.setZAxis(m_geometryBasis.getXAxis().cross(m_geometryBasis.getYAxis()));
    }
    else
    {
        m_geometryBasis = math::Basis3R::makeFromUnitY(m_geometryBasis.getYAxis());
    }
 
    m_shadingBasis.setXAxis(m_shadingBasis.getYAxis().cross(m_dNdU));
    if(m_shadingBasis.getXAxis().lengthSquared() > 0.0_r)
    {
        m_shadingBasis.renormalizeXAxis();
        m_shadingBasis.setZAxis(m_shadingBasis.getXAxis().cross(m_shadingBasis.getYAxis()));
    }
    else
    {
        m_shadingBasis = math::Basis3R::makeFromUnitY(m_shadingBasis.getYAxis());
    }
 
    PH_ASSERT_MSG(m_geometryBasis.getYAxis().isFinite() && m_shadingBasis.getYAxis().isFinite(), "\n"
        "m_geometryBasis.getYAxis() = " + m_geometryBasis.getYAxis().toString() + "\n"
        "m_shadingBasis.getYAxis()  = " + m_shadingBasis.getYAxis().toString() + "\n");
 
#if PH_DEBUG
    m_isBasesComputed = true;
#endif
}
 
}// end namespace ph