PerspectiveMatrix.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreTypes.h"
#include "Math/UnrealMathUtility.h"
#include "Math/Plane.h"
#include "Math/Matrix.h"
 
namespace UE {
namespace Math {
 
template<typename T>
struct TPerspectiveMatrix
    : public TMatrix<T>
{
public:
 
// Note: the value of this must match the mirror in Common.usf!
#define Z_PRECISION 0.0f
 
    TPerspectiveMatrix(T HalfFOVX, T HalfFOVY, T MultFOVX, T MultFOVY, T MinZ, T MaxZ);
 
    TPerspectiveMatrix(T HalfFOV, T Width, T Height, T MinZ, T MaxZ);
 
    TPerspectiveMatrix(T HalfFOV, T Width, T Height, T MinZ);
 
    // Conversion to other type.
    template<typename FArg UE_REQUIRES(!std::is_same_v<T, FArg>)>
    explicit TPerspectiveMatrix(const TPerspectiveMatrix<FArg>& From)
        : TMatrix<T>(From)
    {
    }
};
 
 
template<typename T>
struct TReversedZPerspectiveMatrix : public TMatrix<T>
{
public:
    TReversedZPerspectiveMatrix(T HalfFOVX, T HalfFOVY, T MultFOVX, T MultFOVY, T MinZ, T MaxZ);
    TReversedZPerspectiveMatrix(T HalfFOV, T Width, T Height, T MinZ, T MaxZ);
    TReversedZPerspectiveMatrix(T HalfFOV, T Width, T Height, T MinZ);
    
    // Conversion to other type.
    template<typename FArg UE_REQUIRES(!std::is_same_v<T, FArg>)>
    explicit TReversedZPerspectiveMatrix(const TReversedZPerspectiveMatrix<FArg>& From)
        : TMatrix<T>(From)
    {
    }
};
 
 
#ifdef _MSC_VER
#pragma warning (push)
// Disable possible division by 0 warning
#pragma warning (disable : 4723)
#endif
 
 
template<typename T>
inline TPerspectiveMatrix<T>::TPerspectiveMatrix(T HalfFOVX, T HalfFOVY, T MultFOVX, T MultFOVY, T MinZ, T MaxZ)
    : TMatrix<T>(
        TPlane<T>(MultFOVX / FMath::Tan(HalfFOVX),  0.0f,                               0.0f,                                                                   0.0f),
        TPlane<T>(0.0f,                             MultFOVY / FMath::Tan(HalfFOVY),    0.0f,                                                                   0.0f),
        TPlane<T>(0.0f,                             0.0f,                               ((MinZ == MaxZ) ? (1.0f - Z_PRECISION) : MaxZ / (MaxZ - MinZ)),         1.0f),
        TPlane<T>(0.0f,                             0.0f,                               -MinZ * ((MinZ == MaxZ) ? (1.0f - Z_PRECISION) : MaxZ / (MaxZ - MinZ)), 0.0f)
    )
{ }
 
 
template<typename T>
inline TPerspectiveMatrix<T>::TPerspectiveMatrix(T HalfFOV, T Width, T Height, T MinZ, T MaxZ)
    : TMatrix<T>(
        TPlane<T>(1.0f / FMath::Tan(HalfFOV),   0.0f,                                   0.0f,                           0.0f),
        TPlane<T>(0.0f,                         Width / FMath::Tan(HalfFOV) / Height,   0.0f,                           0.0f),
        TPlane<T>(0.0f,                         0.0f,                                   ((MinZ == MaxZ) ? (1.0f - Z_PRECISION) : MaxZ / (MaxZ - MinZ)),         1.0f),
        TPlane<T>(0.0f,                         0.0f,                                   -MinZ * ((MinZ == MaxZ) ? (1.0f - Z_PRECISION) : MaxZ / (MaxZ - MinZ)), 0.0f)
    )
{ }
 
 
template<typename T>
inline TPerspectiveMatrix<T>::TPerspectiveMatrix(T HalfFOV, T Width, T Height, T MinZ)
    : TMatrix<T>(
        TPlane<T>(1.0f / FMath::Tan(HalfFOV),   0.0f,                                   0.0f,                           0.0f),
        TPlane<T>(0.0f,                         Width / FMath::Tan(HalfFOV) / Height,   0.0f,                           0.0f),
        TPlane<T>(0.0f,                         0.0f,                                   (1.0f - Z_PRECISION),           1.0f),
        TPlane<T>(0.0f,                         0.0f,                                   -MinZ * (1.0f - Z_PRECISION),   0.0f)
    )
{ }
 
 
template<typename T>
inline TReversedZPerspectiveMatrix<T>::TReversedZPerspectiveMatrix(T HalfFOVX, T HalfFOVY, T MultFOVX, T MultFOVY, T MinZ, T MaxZ)
    : TMatrix<T>(
        TPlane<T>(MultFOVX / FMath::Tan(HalfFOVX),  0.0f,                               0.0f,                                                   0.0f),
        TPlane<T>(0.0f,                             MultFOVY / FMath::Tan(HalfFOVY),    0.0f,                                                   0.0f),
        TPlane<T>(0.0f,                             0.0f,                               ((MinZ == MaxZ) ? 0.0f : MinZ / (MinZ - MaxZ)),         1.0f),
        TPlane<T>(0.0f,                             0.0f,                               ((MinZ == MaxZ) ? MinZ : -MaxZ * MinZ / (MinZ - MaxZ)), 0.0f)
    )
{ }
 
 
template<typename T>
inline TReversedZPerspectiveMatrix<T>::TReversedZPerspectiveMatrix(T HalfFOV, T Width, T Height, T MinZ, T MaxZ)
    : TMatrix<T>(
        TPlane<T>(1.0f / FMath::Tan(HalfFOV),   0.0f,                                   0.0f,                                                   0.0f),
        TPlane<T>(0.0f,                         Width / FMath::Tan(HalfFOV) / Height,   0.0f,                                                   0.0f),
        TPlane<T>(0.0f,                         0.0f,                                   ((MinZ == MaxZ) ? 0.0f : MinZ / (MinZ - MaxZ)),         1.0f),
        TPlane<T>(0.0f,                         0.0f,                                   ((MinZ == MaxZ) ? MinZ : -MaxZ * MinZ / (MinZ - MaxZ)), 0.0f)
    )
{ }
 
 
template<typename T>
inline TReversedZPerspectiveMatrix<T>::TReversedZPerspectiveMatrix(T HalfFOV, T Width, T Height, T MinZ)
    : TMatrix<T>(
        TPlane<T>(1.0f / FMath::Tan(HalfFOV),   0.0f,                                   0.0f, 0.0f),
        TPlane<T>(0.0f,                         Width / FMath::Tan(HalfFOV) / Height,   0.0f, 0.0f),
        TPlane<T>(0.0f,                         0.0f,                                   0.0f, 1.0f),
        TPlane<T>(0.0f,                         0.0f,                                   MinZ, 0.0f)
    )
{ }
 
#ifdef _MSC_VER
#pragma warning (pop)
#endif
 
 
} // namespace Math
} // namespace UE
 
UE_DECLARE_LWC_TYPE(PerspectiveMatrix, 44);
UE_DECLARE_LWC_TYPE(ReversedZPerspectiveMatrix, 44);
 
template<> struct TIsUECoreVariant<FPerspectiveMatrix44f> { enum { Value = true }; };
template<> struct TIsUECoreVariant<FPerspectiveMatrix44d> { enum { Value = true }; };
template<> struct TIsUECoreVariant<FReversedZPerspectiveMatrix44f> { enum { Value = true }; };
template<> struct TIsUECoreVariant<FReversedZPerspectiveMatrix44d> { enum { Value = true }; };