Question

I am wanting to make a 2D Game but I am having trouble finding the best and most efficient way to draw to a 2D Surface/Canvas using a BufferStrategy. I will be using a JFrame as the main window and want to draw to the surface of that. I would love to see some example code of how this is done (if this is a good way to do it) aswell as other examples. It would be great if someone could also explain some advantages and disadvantages of doing so.

I am currently adding my drawing class to my JFrame using ‘frame.add(new Painter());’ and then overriding the paintComponent method. The only problem I have found with this is it seems to only call this method once.

this is my Painter class:

public class Painter extends JPanel{

    public static Player player;

    public Painter() {
        player = new Player(300, 300);

    }

    public void paint(Graphics g) {
        player.x++;
        g.setColor(Color.white);
        g.fillRect(player.x, player.y, 32, 32);
    }

}

Answer 1

In the simplest case, where your game needs to update the screen based on user actions only, you will need to call repaint() (on the JFrame for instance) when you update something.

In other cases, you need to construct a so called Game Loop, where you update the game state and render updated game state in a timely manner. A nice tutorial on a simple Game Loop with Java code can be found here: http://obviam.net/index.php/the-android-game-loop/

In case you develop a serious game, you should stick with a game engine for managing the game loop and other routine game development aspects. A good Java game engine can be found here: http://code.google.com/p/playn/