sine_superposition.mdtlbl

#**
* 简单的正弦波叠加可视化的有趣玩意
*#

take Builtin.BindSep['.'];

const Draw = (match @ => H {
    const B=H->Binder;

    draw linePoly B.x B.y 72 H.Range 0 0;
    draw poly H.x H.y 72 2 0 0;
});

const Make = (match @ => Binder Range Speed {
    const $.Binder = Binder;
    const $.Range = Range;
    const $.Run = ([H:$ B:Binder &Draw Range Speed](
        H.x, H.y = cos(H.i)*Range, sin(H.i)*Range;
        H.x, H.y += B.x, B.y;

        H.i += Speed;
        H.i %= 360;

        take Draw[H];
    ));
    const Binder.Run = ([&Run:Binder->Run Child:$](
        take Run[] Child.Run[];
    ));
    const $.Make = (setres Make[.. @];);
});

take Tail
    = Make[start 20 1]
    ->Make[15 3]
    ->Make[10 7]
    ->Make[5 10];

start.x, start.y = 88;

i = 0;
do {
    draw clear 0 0 0 0 0 0;
    draw color 0xFF 0xFF 0xFF 0 0 0;
    take start.Run[];
    draw rect 0 Tail.y 176 1 0 0;
    drawflush display1;

    draw color 0 0 0 0 0 0;
    draw rect i 0 1 176 0 0;
    draw color 0xFF 0xFF 0xFF 0 0 0;
    draw rect i Tail.y 1 1 0 0;
    drawflush display2;

    i++; i %= 176;
} while;