View Matrix

@Kwyrky wrote:

I don't understand why the View Matrix is calculated different in MonoGame and DIrectX.

In DirectX the D3DXMatrixLookAtRH function is calculated like this:

D3DXMatrixLookAtRH.PNG1011x409 35.7 KB

And in MonoGame:

        public static void CreateLookAt(ref Vector3 cameraPosition, ref Vector3 cameraTarget, ref Vector3 cameraUpVector, out Matrix result)
        {
            var vector = Vector3.Normalize(cameraPosition - cameraTarget);
            var vector2 = Vector3.Normalize(Vector3.Cross(cameraUpVector, vector));
            var vector3 = Vector3.Cross(vector, vector2);
            result.M11 = vector2.X;
            result.M12 = vector3.X;
            result.M13 = vector.X;
            result.M14 = 0f;
            result.M21 = vector2.Y;
            result.M22 = vector3.Y;
            result.M23 = vector.Y;
            result.M24 = 0f;
            result.M31 = vector2.Z;
            result.M32 = vector3.Z;
            result.M33 = vector.Z;
            result.M34 = 0f;
            result.M41 = -Vector3.Dot(vector2, cameraPosition);
            result.M42 = -Vector3.Dot(vector3, cameraPosition);
            result.M43 = -Vector3.Dot(vector, cameraPosition);
            result.M44 = 1f;
        }

Why is there a minus sign in the matrix elements 41, 42, 43?

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