source: 2010/30/heanjule/Pong/Pong/Peli.cs @ 1315

using System;
using Jypeli;
using Jypeli.Widgets;
using Jypeli.Assets;

public class Peli : PhysicsGame
{
    Vector nopeusYlos = new Vector(0, 200);
    Vector nopeusAlas = new Vector(0, -200);

    PhysicsObject pallo;

    PhysicsObject maila1;
    PhysicsObject maila2;

    protected override void Begin()
    {
        LuoKentta();
        Keyboard.Listen(Key.Escape, ButtonState.Pressed, Exit, "Poistu");
        AloitaPeli();
        AsetaOhjaimet();
    }

    void LuoKentta()
    {
        pallo = new PhysicsObject(40.0, 40.0);
        pallo.Shape = Shapes.Circle;
        pallo.Color = Color.Green;
        pallo.X = -200.0;
        pallo.Y = 0.0;
        pallo.Restitution = 1.0;
        Add(pallo);

        maila1 = LuoMaila(Level.Left + 20.0, 0.0);
        maila2 = LuoMaila(Level.Right - 20.0, 0.0);

        Level.CreateBorders(1.0, false);
        Level.BackgroundColor = Color.Black;

        Camera.ZoomToLevel();
    }

    void AloitaPeli()
    {
        Vector impulssi = new Vector(600.0, 0.0);
        pallo.Hit(impulssi);
    }

    PhysicsObject LuoMaila(double x, double y)
    {
        PhysicsObject maila = PhysicsObject.CreateStaticObject(20.0, 100.0);
        maila.Shape = Shapes.Rectangle;
        maila.X = x;
        maila.Y = y;
        maila.Restitution = 1.0;
        Add(maila);

        return maila;
    }

    void AsetaOhjaimet()
    {
        Keyboard.Listen(Key.A, ButtonState.Down, AsetaNopeus, "Pelaaja 1: Liikuta mailaa Ylos", maila1, nopeusYlos);
        Keyboard.Listen(Key.A, ButtonState.Released, AsetaNopeus, null, maila1, Vector.Zero);
        Keyboard.Listen(Key.Z, ButtonState.Down, AsetaNopeus, "Pelaaja 1: Liikuta mailaa Ylos", maila1, nopeusAlas);
        Keyboard.Listen(Key.Z, ButtonState.Released, AsetaNopeus, null, maila1, Vector.Zero);

        Keyboard.Listen(Key.Up, ButtonState.Down, AsetaNopeus, "Pelaaja 2: Liikuta mailaa Ylos", maila2, nopeusYlos);
        Keyboard.Listen(Key.Up, ButtonState.Released, AsetaNopeus, null, maila2, Vector.Zero);
        Keyboard.Listen(Key.Down, ButtonState.Down, AsetaNopeus, "Pelaaja 2: Liikuta mailaa Ylos", maila2, nopeusAlas);
        Keyboard.Listen(Key.Down, ButtonState.Released, AsetaNopeus, null, maila2, Vector.Zero);

        Keyboard.Listen(Key.F1, ButtonState.Pressed, ShowControlHelp, "Näytä ohjeet");
        Keyboard.Listen(Key.Escape, ButtonState.Pressed, Exit, "Poistu");
    }
    void AsetaNopeus(PhysicsObject maila, Vector nopeus)
    {
        if ((nopeus.Y < 0) && (maila.Bottom < Level.Bottom))
        {
            maila.Velocity = Vector.Zero;
            return;
        }
        if ((nopeus.Y > 0) && (maila.Top > Level.Top))
        {
            maila.Velocity = Vector.Zero;
            return;
        } 
            
        maila.Velocity = nopeus;
    }

}