draw_ngon.gml

function draw_ngon(x, y, n, length, rot) {
    draw_primitive_begin(pr_trianglefan);
    draw_vertex_colour(x, y, c_white, 1);
    for (var i = 0; i <= n; i++) {
        var angle = 2 * pi / n * i + rot;
        draw_vertex_colour(x + length * cos(angle), y - length * sin(angle), make_colour_hsv(255 / (n + 1) * i, 255, 255), 1);
    }
    draw_primitive_end();
}