BEPUutilities.Matrix3x3.Multiply C# (CSharp) Method

        public static void Multiply(ref Matrix a, ref Matrix3x3 b, out Matrix3x3 result)
        {
            float resultM11 = a.M11 * b.M11 + a.M12 * b.M21 + a.M13 * b.M31;
            float resultM12 = a.M11 * b.M12 + a.M12 * b.M22 + a.M13 * b.M32;
            float resultM13 = a.M11 * b.M13 + a.M12 * b.M23 + a.M13 * b.M33;

            float resultM21 = a.M21 * b.M11 + a.M22 * b.M21 + a.M23 * b.M31;
            float resultM22 = a.M21 * b.M12 + a.M22 * b.M22 + a.M23 * b.M32;
            float resultM23 = a.M21 * b.M13 + a.M22 * b.M23 + a.M23 * b.M33;

            float resultM31 = a.M31 * b.M11 + a.M32 * b.M21 + a.M33 * b.M31;
            float resultM32 = a.M31 * b.M12 + a.M32 * b.M22 + a.M33 * b.M32;
            float resultM33 = a.M31 * b.M13 + a.M32 * b.M23 + a.M33 * b.M33;

            result.M11 = resultM11;
            result.M12 = resultM12;
            result.M13 = resultM13;

            result.M21 = resultM21;
            result.M22 = resultM22;
            result.M23 = resultM23;

            result.M31 = resultM31;
            result.M32 = resultM32;
            result.M33 = resultM33;
        }

        /// <summary>
        /// Multiplies the two matrices.
        /// </summary>
        /// <param name="a">First matrix to multiply.</param>
        /// <param name="b">Second matrix to multiply.</param>
        /// <returns>Product of the multiplication.</returns>
        public static Matrix3x3 operator *(Matrix3x3 a, Matrix3x3 b)
        {
            Matrix3x3 result;

            Matrix3x3.Multiply(ref a, ref b, out result);
            return(result);
        }