3. Matrix

Mathematically, a matrix is a set of numbers arranged in uniform rows and columns

OpenGL understands column-primary layout for matrices: in a 4x4 matrix, the first four elements of an array provide the first column of the matrix, followed by second column, and so on.

    float matrix4x4[] = {
        a, e, i, 0,   // 1st column
        b, f, j, 0,   // 2nd column
        c, g, k, 0,   // 3rd column
        d, h, l, 1    // 4th column
    };