ScaleRotationTranslationMatrix.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreTypes.h"
#include "Math/UnrealMathUtility.h"
#include "Math/Matrix.h"
 
 
namespace UE {
namespace Math {
        
template<typename T>
struct TScaleRotationTranslationMatrix
    : public TMatrix<T>
{
public:
    using TMatrix<T>::M;
    
    TScaleRotationTranslationMatrix(const TVector<T>& Scale, const TRotator<T>& Rot, const TVector<T>& Origin);
    
    // Conversion to other type.
    template<typename FArg UE_REQUIRES(!std::is_same_v<T, FArg>)>
    explicit TScaleRotationTranslationMatrix(const TScaleRotationTranslationMatrix<FArg>& From)
        : TMatrix<T>(From)
    {
    }
};
 
namespace
{
    template<typename T>
    void GetSinCos(T& S, T& C, T Degrees)
    {
        if (Degrees == 0.f)
        {
            S = 0.f;
            C = 1.f;
        }
        else if (Degrees == 90.f)
        {
            S = 1.f;
            C = 0.f;
        }
        else if (Degrees == 180.f)
        {
            S = 0.f;
            C = -1.f;
        }
        else if (Degrees == 270.f)
        {
            S = -1.f;
            C = 0.f;
        }
        else
        {
            FMath::SinCos(&S, &C, FMath::DegreesToRadians(Degrees));
        }
    }
}
 
template<typename T>
inline TScaleRotationTranslationMatrix<T>::TScaleRotationTranslationMatrix(const TVector<T>& Scale, const TRotator<T>& Rot, const TVector<T>& Origin)
{
    T SP, SY, SR;
    T CP, CY, CR;
    GetSinCos(SP, CP, (T)Rot.Pitch);
    GetSinCos(SY, CY, (T)Rot.Yaw);
    GetSinCos(SR, CR, (T)Rot.Roll);
 
    M[0][0] = (CP * CY) * Scale.X;
    M[0][1] = (CP * SY) * Scale.X;
    M[0][2] = (SP) * Scale.X;
    M[0][3] = 0.f;
 
    M[1][0] = (SR * SP * CY - CR * SY) * Scale.Y;
    M[1][1] = (SR * SP * SY + CR * CY) * Scale.Y;
    M[1][2] = (- SR * CP) * Scale.Y;
    M[1][3] = 0.f;
 
    M[2][0] = ( -( CR * SP * CY + SR * SY ) ) * Scale.Z;
    M[2][1] = (CY * SR - CR * SP * SY) * Scale.Z;
    M[2][2] = (CR * CP) * Scale.Z;
    M[2][3] = 0.f;
 
    M[3][0] = Origin.X;
    M[3][1] = Origin.Y;
    M[3][2] = Origin.Z;
    M[3][3] = 1.f;
}
    
} // namespace Math
} // namespace UE
 
UE_DECLARE_LWC_TYPE(ScaleRotationTranslationMatrix, 44);
 
template<> struct TIsUECoreVariant<FScaleRotationTranslationMatrix44f> { enum { Value = true }; };
template<> struct TIsUECoreVariant<FScaleRotationTranslationMatrix44d> { enum { Value = true }; };