starling game class

game.as

package  
{
	import flash.display.Sprite;
	import fr.kouma.starling.utils.Stats;
	import nape.geom.Vec2;
	import nape.phys.Body;
	import nape.phys.BodyType;
	import nape.phys.Material;
	import nape.shape.Circle;
	import nape.shape.Polygon;
	import nape.space.Space;
	import nape.util.BitmapDebug;
	import nape.util.ShapeDebug;
	import starling.core.Starling;
	import starling.display.DisplayObject;
	import starling.display.Image;
	import starling.display.Sprite;
	import starling.events.Event;
	
	public class Game extends Sprite 
	{
		[Embed(source = "assets/back.png")]
		private var bg:Class;
		private var space:Space;
		
		private const DEBUG_ENABLE:Boolean = false;
		//private var debug:BitmapDebug;
		private var debug:ShapeDebug;
		
		public function Game() 
		{
			addEventListener(Event.ADDED_TO_STAGE, init);
		}
		
		private function init(e:Event):void 
		{
			removeEventListener(Event.ADDED_TO_STAGE, init);

			// background image
			addChild(Image.fromBitmap(new bg()));
			// 設定場景 重力(影響掉落的速度)
			space = new Space(new Vec2(0, 3000));
			// 設置地板
			var floor:Body = new Body(BodyType.STATIC);
			floor.shapes.add(new Polygon(Polygon.rect(0, 600, 800, 20)));
			floor.space = space;

			// add starling stats
			addChild(new Stats());
			
			// debug
			if (DEBUG_ENABLE) {
				debug = new ShapeDebug(800, 600, 0x333333);
				// faster render(but....need fucking adobe license)
				//debug = new BitmapDebug(800, 600, 0x333333);
				debug.draw(space);

				// flash sprite
				var _container_debug:flash.display.Sprite = new flash.display.Sprite();
				// debug.display is a flash DisplayObject, it's not a starling Sprite.
				_container_debug.addChild(debug.display);
				Starling.current.nativeOverlay.addChild(_container_debug);
			}

			addEventListener(Event.ENTER_FRAME, loop);
		}
		
		
		private function loop(e:Event):void 
		{
			if (DEBUG_ENABLE) {
				debug.clear();
				space.step(1 / 60);
				debug.draw(space);
				debug.flush()
			}
			else space.step(1 / 60);

			if (Math.random() < 0.03)
				addBall();
		}
		
		private function addBall():void 
		{
			// 設定種類及座標
			var ball:Body = new Body(BodyType.DYNAMIC, new Vec2(Math.random() * 750, 100));
			// 設定球的規格及材質
			ball.shapes.add(new Circle(51.5, null, new Material(20)));
			// 預設提供幾種材質wood/steel/ice/rubber/glass/sand 
			//ball.shapes.add(new Circle(51.5, null, Material.rubber()));
			ball.space = space;
			// 貼上球的圖檔
			if (!DEBUG_ENABLE) {
				ball.graphic = new Basketball();
				ball.graphicUpdate = updateGraphic;
				addChild(ball.graphic);
			}
		}
		
		private function updateGraphic(b:Body):void 
		{
			// fixed memory leak
			var gr:DisplayObject = b.graphic;
			gr.x = b.position.x;
			gr.y = b.position.y;
			gr.rotation = b.rotation;
		}
		
	}

}