source: 2017/30/MikkoH/Sq/Sq/Sq/Sq.cs @ 9285

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

public class Sq : PhysicsGame
{
    List<Vector> ps, crc;
    double rad = 50, radc = 0.01, mag = 2;

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

        ps = CreateSquare(100, 10);
        crc = CreateCircle(50, 150);      
    }

    // s = length of side, d = distance between pts
    List<Vector> CreateSquare(int s, int d)
    {
        List<Vector> sq = new List<Vector>();
        for (int i = -s; i <= s; i += d) sq.Add(new Vector(-s, i));
        for (int i = -s; i <= s; i += d) sq.Add(new Vector(i, s));
        for (int i = s; i >= -s; i -= d) sq.Add(new Vector(s, i));
        for (int i = s; i >= -s; i -= d) sq.Add(new Vector(i, -s));
        return sq;
    }

    // rad = starting radius, n = number of pts
    List<Vector> CreateCircle(int rad, int n)
    {
        List<Vector> crc = new List<Vector>();
        for (int i = 0; i <= n; i++)
            crc.Add(new Vector(Math.Sin(i) * rad, Math.Cos(i) * rad));
        return crc;
    }

    // rotates any shape clockwise or anti if reversed
    void Rotate(List<Vector> vs, bool reverse = false)
    {
        double d = Time.SinceLastUpdate.TotalSeconds;
        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));
    }

    // does everything
    protected override void Paint(Canvas c)
    {
        c.BrushColor = Color.Red;

        // draws the square and squeezes it
        for (int i = 0; i < ps.Count; i++)
        {
            c.DrawLine(ps[i % ps.Count], ps[(i + ps.Count / 4) % ps.Count]);
            //ps[i] = Vector.FromLengthAndAngle(ps[i].Magnitude + mag, ps[i].Angle);
            if (ps[i].Magnitude < 1 || ps[i].Magnitude > 200) mag = -mag;
            ps[i] += new Vector(5, 5);
        }

        c.BrushColor = Color.Blue;

        // draws the circle and squeezes it
        for (int i = 0; i < crc.Count; i++)
        {
            c.DrawLine(crc[i % crc.Count], crc[(i + 2) % crc.Count]);
            crc[i] = new Vector(Math.Sin(i) * rad, Math.Cos(i) * rad);
            if (rad < 1 || rad > 100) radc = -radc;
            rad -= radc;
        }

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

        base.Paint(c);
    }
}