src/matrix.h

#pragma once
#include <QGenericMatrix>

template<int Rows, int Columns, typename T = double>
struct Matrix
{
	T values[Rows][Columns];
	T& operator()(int row, int column)
	{
		return this->values[row][column];
	}
	T operator()(int row, int column) const
	{
		return this->values[row][column];
	}
};

template<int Rows, int Columns, typename T>
QGenericMatrix<Rows, Columns, T> matrixToQGenericMatrix(const Matrix<Rows, Columns, T>& matrix)
{
	return {matrix.values};
}

template<int Rows, int Columns, typename T>
Matrix<Rows, Columns, T> matrixFromQGenericMatrix(const QGenericMatrix<Rows, Columns, T&> matrix)
{
	Matrix<Rows, Columns, T> result;
	for (int row = 0; row < Rows; row += 1)
	{
		for (int column = 0; column < Columns; column += 1)
		{
			result(row, column) = matrix(row, column);
		}
	}
	return result;
}

using Matrix3x3 = Matrix<3, 3>;
Q_DECLARE_METATYPE(Matrix3x3);
using Matrix4x4 = Matrix<4, 4>;
Q_DECLARE_METATYPE(Matrix4x4);

template<int Rows, int Columns, typename T>
QDataStream& operator<<(QDataStream& stream, const Matrix<Rows, Columns, T>& matrix)
{
	return stream << matrixToQGenericMatrix(matrix);
}

template<int Rows, int Columns, typename T>
QDataStream& operator>>(QDataStream& stream, Matrix<Rows, Columns, T>& matrix)
{
	QGenericMatrix<Rows, Columns, T> qmatrix;
	stream >> qmatrix;
	matrix = matrixFromQGenericMatrix(matrix);
	return stream;
}