source: 2017/30/MikkoH/Sq/Sq/Sq/Sq.cs @ 9290

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

public class Sq : PhysicsGame
{
    //List<Vector> ps, crc;
    //int initsqmag = 50, initsqdist = 2; //killSwitch = 1;
    //double rad = 50, radc = 0.01;

    List<Square> sqs = new List<Square>();

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

        sqs.Add(new Square(100, 5));
        //crc = CreateCircle(rad, pts);
    }   

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

    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));
    }

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

        // checks if squeeze direction should be reversed
        // merging this into the above loop will fuck everything up
        // also tries to create new squares
        for (int i = 0; i < sqs.Count; i++)
        {
            for (int j = 0; j < sqs[i].Count; j++)
                if (sqs[i][j].Magnitude < sqs[i].minmag)
                {
                    Square newsq = new Square(sqs[i].mag-1, sqs[i].dist+1);
                    //newsq.mag = 10;
                    sqs.Add(newsq);
                    sqs.Remove(sqs[i]);
                    //sqs[i].magc = -sqs[i].magc;
                    break;
                }
                else if (sqs[i][j].Magnitude > sqs[i].maxmag)
                {
                    sqs[i].magc = -sqs[i].magc;
                    break;
                }
        }

        // draws and squeezes the square
        foreach (Square sq in sqs)
            for (int i = 0; i < sq.Count; i++)
            {
                c.DrawLine(sq[i % sq.Count], sq[(i + sq.Count / 4) % sq.Count]);
                sq[i] = Vector.FromLengthAndAngle(sq[i].Magnitude + sq.magc, sq[i].Angle);                     
            }     
            
        c.BrushColor = Color.Blue;

        // draws and squeezes the circle
        //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 < minrad || rad > maxrad) radc = -radc;
        //    rad -= radc;
        //}

        //foreach (Square sq in sqs) Rotate(sq);/* Rotate(crc, true);*/

        base.Paint(c);
    }
}

class Square : List<Vector>
{
    public double dist = 5, mag = 100, minmag = 5, maxmag = 300, magc = 2;

    public Square(double s, double d)
    {
        for (double i = -s; i <= s; i += d) Add(new Vector(-s, i));
        for (double i = -s; i <= s; i += d) Add(new Vector(i, s));
        for (double i = s; i >= -s; i -= d) Add(new Vector(s, i));
        for (double i = s; i >= -s; i -= d) Add(new Vector(i, -s));
        dist = d; maxmag = mag * 5;

    }
}