source: 2017/30/MikkoH/Sq/Sq/Sq/Sq.cs @ 9261

using System;
using System.Collections.Generic;
using Jypeli;

public class Sq : PhysicsGame
{
    List<Vector> ps = new List<Vector>(), crc = new List<Vector>();
    double x, y, z, a, fac = Math.Pow(2, -15), rad = 200, radc = 0.02;

    public override void Begin()
    {
        Window.Width = 1200; Window.Height = 800;
        Level.Background.Color = Color.Black;
        Mouse.IsCursorVisible = true;

        for (int i = -300; i <= 300; i += 10) ps.Add(new Vector(-300, i));
        for (int i = -300; i <= 300; i += 10) ps.Add(new Vector(i, 300));
        for (int i = 300; i >= -300; i -= 10) ps.Add(new Vector(300, i));
        for (int i = 300; i >= -300; i -= 10) ps.Add(new Vector(i, -300));

        for (int i = 0; i <= 100; i += 1)
            crc.Add(new Vector(Math.Sin(i) * rad, Math.Cos(i) * rad));

        //for (int i = 0; i < 100; i++) trans.Add(new Vector(1, 1));
        //for (int i = 0; i < 100; i++) trans.Add(new Vector(-1, -1));
    }

    protected override void Paint(Canvas c)
    {
        c.BrushColor = Color.Red;
        double d = Time.SinceLastUpdate.TotalSeconds; //Mouse.PositionOnScreen.Angle.Degrees/1000;

        for (int i = 0; i < ps.Count; i++)
            c.DrawLine(ps[i % ps.Count], ps[(i + ps.Count / 4) % ps.Count]);

        c.BrushColor = Color.Blue;
           
        for (int i = 0; i < crc.Count; i++)
        {
            c.DrawLine(crc[i % crc.Count], crc[(i + 1) % crc.Count]);
            crc[i % crc.Count] = new Vector(Math.Sin(i) * rad, Math.Cos(i) * rad);
            if (rad > 200 || rad < 1) radc = -radc; rad -= radc;
        }

        Rotate(ps, d); Rotate(crc, d, true);

        //Squeeze(ps);

        base.Paint(c);
    }

    void Rotate(List<Vector> vs, double d, bool reverse = false)
    {
        if (reverse) d = -d;
        for (int i = 0; i < vs.Count; i++)
            vs[i] = new Vector(vs[i].X * Math.Cos(-d) - vs[i].Y * Math.Sin(-d),
                               vs[i].X * Math.Sin(-d) + vs[i].Y * Math.Cos(-d));
    }

    void Squeeze(List<Vector> vs)
    {
        //if (ps[0].X > -300) fac = -Math.Pow(2, -15);
        //if (ps[ps.Count - 1].X < -300) fac = -Math.Pow(2, -15);

        for (int i = 0; i < vs.Count / 4; i++) vs[i] = new Vector(vs[i].X + (x -= fac), vs[i].Y + (y -= fac));
        for (int i = vs.Count / 4 * 3; i < vs.Count; i++) vs[i] = new Vector(vs[i].X + (x -= fac), vs[i].Y + (y -= fac));
        for (int i = vs.Count / 4; i < vs.Count / 2; i++) vs[i] = new Vector(vs[i].X + (z += fac), vs[i].Y + (a += fac));
        for (int i = vs.Count / 2; i < vs.Count / 4 * 3; i++) vs[i] = new Vector (vs[i].X + (z += fac), vs[i].Y + (a += fac));
    }
}