// Returns raw matrix (row-major)
func (m *Mat4) Raw() []float32 {
    out := make([]float32, 16)
    for i := 0; i < 4; i++ {
        for j := 0; j < 4; j++ {
            out[i*4+j] = m[i][j]
        }
    }
    return out
}

// Usage:
glctx.UniformMatrix4fv(mvp, MVP.Raw())

// Ortho sets m to be the GL orthographic matrix
func (m *Mat4) Ortho(width, height, near, far float32) {
    m[0][0] = 2 / width
    m[1][1] = -2 / height
    m[2][2] = -2 / (far - near)
    m[3][2] = -(far + near) / (far - near)
    m[3][3] = 1 
}