Matrix4x4 result; for (int row = 0; row < 4; ++row) { for (int col = 0; col < 4; ++col) { result.matrix[row][col] = left.matrix[row][0] * right.matrix[0][col] + left.matrix[row][1] * right.matrix[1][col] + left.matrix[row][2] * right.matrix[2][col] + left.matrix[row][3] * right.matrix[3][col]; } } left = result; return left;