Killer Game Programming in Java

Storing Brick Information

The Brick class stores coordinate information for a brick and a reference to its image. The coordinate details are the brick's map indices and its y-axis pixel position inside the map.

Tip

The x-axis position isn't stored since it changes as the bricks map is moved horizontally.

Brick's display() method is short:

    public void display(Graphics g, int xScr)
    // called by BricksManager's drawBricks()
    {  g.drawImage(image, xScr, locY, null);  }

Tip

xScr is the current JPanel x coordinate for the brick.

The capabilities of the Brick class could be extended. One common feature in side-scrollers is animated tiles, such as flames and rotating balls. If the animation is local to the tile's allocated map location, then the effect can be coded by adding an ImagesPlayer to Brick. One issue is whether to assign a unique ImagesPlayer to each Brick (costly if there are many bricks) or to store a reference to a single ImagesPlayer. The drawback with the reference solution is that all the bricks referring to a given animation will be animated in the same way on the screen. This can look overly regimented in most games. A compromise is to create an AnimatedBrick subclass, which will be used rarely, so it can support the overhead of having its own ImagesPlayer.

If tiles can move about in the game world (e.g., a platform that moves up and down), then bricks will need more sprite-like capabilities. This will complicate BricksManager as a Brick object can no longer be relied on to stay ...