UE4 视图矩阵

左手系的视图矩阵，与右手系只差一个负号，如下取负即为右手系的视图矩阵。

const FVector ZAxis = (LookAtPosition - EyePosition).GetSafeNormal();

struct FLookAtMatrix : FMatrix
{
	/** 
	 * Creates a view matrix given an eye position, a position to look at, and an up vector. 
	 * This does the same thing as D3DXMatrixLookAtLH.
	 */
	FLookAtMatrix(const FVector& EyePosition, const FVector& LookAtPosition, const FVector& UpVector);
};


FORCEINLINE FLookAtMatrix::FLookAtMatrix(const FVector& EyePosition, const FVector& LookAtPosition, const FVector& UpVector)
{
	const FVector ZAxis = (LookAtPosition - EyePosition).GetSafeNormal();
	const FVector XAxis = (UpVector ^ ZAxis).GetSafeNormal();
	const FVector YAxis = ZAxis ^ XAxis;

	for (uint32 RowIndex = 0; RowIndex < 3; RowIndex++)
	{
		M[RowIndex][0] = (&XAxis.X)[RowIndex];
		M[RowIndex][1] = (&YAxis.X)[RowIndex];
		M[RowIndex][2] = (&ZAxis.X)[RowIndex];
		M[RowIndex][3] = 0.0f;
	}
	M[3][0] = -EyePosition | XAxis;
	M[3][1] = -EyePosition | YAxis;
	M[3][2] = -EyePosition | ZAxis;
	M[3][3] = 1.0f;
}

参考链接

UE4 视图矩阵