Blit Scrolling in a Tile-Based World - The Essential Guide to Flash Games - page 447

The tileRect and tilePoint instances will be used to blit each tile to the screen in the
right place inside of our render loop. The tileRect will always be a 32 32 square, but

the tilePoint x and y values will change based on the location of the tile (column and
row) in the screen buffer.

The canvasBitmap will be added to the Game's display list and will contain the 384

384
canvasBitmapdata of our main output canvas. The camera.bufferBitmapData will be
painted into this on each frame tick.

The backgroundBitmap will be added to the display list behind the canvasBitmap . It will
contain the backgroundBitmapData that in turn will be filled with the 12 12 background

tiles specified in the level data XML.

The backgroundBitmap and the canvasBitmap are added to the display list.

Our lookAheadPoints list is set to contain three LookAheadPoint instances. All three are
added to the display list, but you will want to comment out these three lines when your
testing is complete. This is created using the ActionScript 3.0 (Flash Player 10 and
above only) Vector class. The Vector class allows the developer to create an optimized
array with a predefined size and only a single data type. Flash can manage memory
better and is much faster at accessing data that is organized in this manner. We have
used it here as an example. If you are using Flash Player 9, it can be swapped out with
an Array class instance.

The newGame function
This is the full code for the newGame function:
override public function newGame():void {
switchSystemState( STATE_SYSTEM_GAMEPLAY );
initTileSheetData();

player = new CarBlitSprite(tileSheet, playerFrameList, 0);

addChild(player);
level = 0;
score = 0;
gameOver = false;

dispatchEvent(new CustomEventScoreBoardUpdate(CustomEventScoreBoardUpdate.

UPDATE_TEXT, Main.SCORE_BOARD_SCORE, String(score)));
dispatchEvent(new CustomEventScoreBoardUpdate(CustomEventScoreBoardUpdate.

UPDATE_TEXT,Main.SCORE_BOARD_TIME_LEFT,"00"));

dispatchEvent(new CustomEventScoreBoardUpdate(CustomEventScoreBoardUpdate.

UPDATE_TEXT,Main.SCORE_BOARD_HEARTS,String(0)));

//key listeners
if (!keyListenersInit) {
stage.addEventListener(KeyboardEvent.KEY_DOWN,keyDownListener);
stage.addEventListener(KeyboardEvent.KEY_UP, keyUpListener);