matmul.cpp

struct M44
{
	union
	{
		struct
		{
			float m00, m01, m02, m03;
			float m10, m11, m12, m13;
			float m20, m21, m22, m23;
			float m30, m31, m32, m33;
		};

		float data[16];
	};
};

inline M44 operator*(M44 a, M44 b)
{
#define DOTROW(row,col) a.m##row##0 * b.m0##col + a.m##row##1 * b.m1##col + a.m##row##2 * b.m2##col + a.m##row##3 * b.m3##col

	M44 result =
	{
		DOTROW(0, 0), DOTROW(0, 1), DOTROW(0, 2), DOTROW(0, 3),
		DOTROW(1, 0), DOTROW(1, 1), DOTROW(1, 2), DOTROW(1, 3),
		DOTROW(2, 0), DOTROW(2, 1), DOTROW(2, 2), DOTROW(2, 3),
		DOTROW(3, 0), DOTROW(3, 1), DOTROW(3, 2), DOTROW(3, 3)
	};

#undef DOTROW

	return result;
}