template<typename T>
struct matrix4 {
    T
        x1, y1, z1, w1,
        x2, y2, z2, w2,
        x3, y3, z3, w3,
        x4, y4, z4, w4;

    matrix4(const T* f){
        x1 = f[0],  y1 = f[1],  z1 = f[2],  w1 = f[3];
        x2 = f[4],  y2 = f[5],  z2 = f[6],  w2 = f[7];
        x3 = f[8],  y3 = f[9],  z3 = f[10], w3 = f[11];
        x4 = f[12], y4 = f[13], z4 = f[14], w4 = f[15];
    }

    static const matrix4<T> identity(){
        static T tmp[4*4] = {
            1, 0, 0, 0,
            0, 1, 0, 0,
            0, 0, 1, 0,
            0, 0, 0, 1
        };
        static matrix4<T> id = matrix4<T>(tmp);
        return id;
    };
};