Create a terrain like the one in Tiny Wings with Flash and Box2D – Scrolling

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Some days ago I posted an example of a Box2D terrain like the Tiny Wings one.

Today I tried to make it endless and scrollable.

It’s very easy as it requires only a little modification to the original script.

Basically you have to attach a new hill to the right before the last hills will be completely visible , and remove the slices when they leave the screen to the left side, to save memory.

In this example, I am removing slices 20 pixels before they leave the screen, to make you see it works:

If you are afraid about Box2D world boundaries, I tested the terrain scrolling it for more than two million pixels, and everything worked like a charm.

Do you think it could be enough?

This is the script:

package {
	import flash.display.Sprite;
	import flash.geom.Point;
	import flash.events.MouseEvent;
	import flash.events.Event;
	import Box2D.Dynamics.*;
	import Box2D.Collision.*;
	import Box2D.Collision.Shapes.*;
	import Box2D.Common.Math.*;
	public class Main extends Sprite {
		private var world:b2World=new b2World(new b2Vec2(0,10),true);
		private var worldScale:int=30;
		private var nextHill:Number=140+Math.random()*200;
		public function Main() {
			world=new b2World(new b2Vec2(0,10),true);
			debugDraw();
			nextHill=drawHill(10,0,nextHill);
			addEventListener(Event.ENTER_FRAME,updateWorld);
		}
		private function debugDraw():void {
			var worldDebugDraw:b2DebugDraw=new b2DebugDraw();
			var debugSprite:Sprite = new Sprite();
			addChild(debugSprite);
			worldDebugDraw.SetSprite(debugSprite);
			worldDebugDraw.SetDrawScale(worldScale);
			worldDebugDraw.SetFlags(b2DebugDraw.e_shapeBit|b2DebugDraw.e_jointBit);
			worldDebugDraw.SetFillAlpha(0.5);
			world.SetDebugDraw(worldDebugDraw);
		}
		private function drawHill(pixelStep:int,xOffset:Number,yOffset:Number):Number {
			var hillStartY:Number=yOffset;
			var hillWidth:Number=640;
			var hillSliceWidth=hillWidth/pixelStep;
			var hillVector:Vector.;
			var randomHeight:Number=Math.random()*100;
			if (xOffset!=0) {
				hillStartY-=randomHeight;
			}
			for (var j:int=0; j();
				hillVector.push(new b2Vec2((j*pixelStep+xOffset)/worldScale,480/worldScale));
				hillVector.push(new b2Vec2((j*pixelStep+xOffset)/worldScale,(hillStartY+randomHeight*Math.cos(2*Math.PI/hillSliceWidth*j))/worldScale));
				hillVector.push(new b2Vec2(((j+1)*pixelStep+xOffset)/worldScale,(hillStartY+randomHeight*Math.cos(2*Math.PI/hillSliceWidth*(j+1)))/worldScale));
				hillVector.push(new b2Vec2(((j+1)*pixelStep+xOffset)/worldScale,480/worldScale));
				var sliceBody:b2BodyDef=new b2BodyDef  ;
				var centre:b2Vec2=findCentroid(hillVector,hillVector.length);
				sliceBody.position.Set(centre.x,centre.y);
				for (var z:int=0; z, count:uint):b2Vec2 {
			var c:b2Vec2 = new b2Vec2();
			var area:Number=0.0;
			var p1X:Number=0.0;
			var p1Y:Number=0.0;
			var inv3:Number=1.0/3.0;
			for (var i:int = 0; i < count; ++i) {
				var p2:b2Vec2=vs[i];
				var p3:b2Vec2=i+1

Next time I think I am adding a little car... No need to download anything, just replace the code used in the original example.

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