forked from: Using Box2D as a Physics Simulation Engine

/**
 * Copyright damionfeller ( http://wonderfl.net/user/damionfeller )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/uZqI
 */

// forked from 9re's Using Box2D as a Physics Simulation Engine
package  
{
    import Box2D.Collision.b2AABB;
    import Box2D.Collision.Shapes.b2PolygonDef;
    import Box2D.Collision.Shapes.b2PolygonShape;
    import Box2D.Collision.Shapes.b2Shape;
    import Box2D.Collision.Shapes.b2ShapeDef;
    import Box2D.Common.Math.b2Vec2;
    import Box2D.Dynamics.b2Body;
    import Box2D.Dynamics.b2BodyDef;
    import Box2D.Dynamics.b2DebugDraw;
    import Box2D.Dynamics.b2World;
    import flash.display.StageAlign;
    import flash.display.StageScaleMode;
    import flash.display.Sprite;
    import flash.events.Event;
    /**
     * ...
     * @author 9re
     */
    [SWF(frameRate="30", backgroundColor="#666666")]
    public class CreatingWorld extends Sprite
    {
        private var world:b2World;
        private var simulator:b2World;
        
        public function CreatingWorld() 
        {
            stage.scaleMode = StageScaleMode.NO_SCALE;
            stage.align = StageAlign.TOP_LEFT;
            
            var worldAABB:b2AABB = new b2AABB();
            worldAABB.lowerBound.Set( -10, -10);
            worldAABB.upperBound.Set(60, 60);
            
            var gravity:b2Vec2 = new b2Vec2(0, 9.8);
            var doSleep:Boolean = true;
            
            world = new b2World(worldAABB, gravity, doSleep);
            simulator = new b2World(worldAABB, gravity, doSleep);
            
            var floorDef:b2BodyDef = new b2BodyDef();
            floorDef.position.Set(20, 20);
            floorDef.angle = Math.PI / 10;
            var floor:b2Body = world.CreateBody(floorDef);
            
            var floorShapeDef:b2PolygonDef = new b2PolygonDef();
            floorShapeDef.SetAsBox(10, 0.3);
            floor.CreateShape(floorShapeDef);
            
            var floor2Def:b2BodyDef = new b2BodyDef();
            floor2Def.position.Set(30, 78);
            floor2Def.angle = -Math.PI / 78;
            
            var floor2:b2Body = world.CreateBody(floor2Def);
            floor2.CreateShape(floorShapeDef);
            
            
            var object0Def:b2BodyDef = new b2BodyDef();
            object0Def.position.Set(20, 1);
            var object0:b2Body = world.CreateBody(object0Def);
            var object0ShapeDef:b2PolygonDef = new b2PolygonDef();
            object0ShapeDef.SetAsBox(0.8, 0.8);
            object0ShapeDef.density = 1;
            object0ShapeDef.restitution = 4.25;
            
            object0.CreateShape(object0ShapeDef);
            object0.SetMassFromShapes();
            
            var object1Def:b2BodyDef = new b2BodyDef();
            object1Def.position.Set(15, 1);
            var object1:b2Body = world.CreateBody(object1Def);
            object1.SetLinearVelocity(new b2Vec2(5, 0));
            object1.SetAngularVelocity(-Math.PI * 2);
            object1.CreateShape(object0ShapeDef);
            object1.SetMassFromShapes();
            
            
            var floorInSimulator:b2Body = simulator.CreateBody(floorDef);
            floorInSimulator.CreateShape(floorShapeDef);
            var floor2InSimulator:b2Body = simulator.CreateBody(floor2Def);
            floor2InSimulator.CreateShape(floorShapeDef);
            
            
            var object0InSimulator:b2Body = simulator.CreateBody(object0Def);
            object0InSimulator.SetUserData("object0");
            object0InSimulator.CreateShape(object0ShapeDef);
            object0InSimulator.SetMassFromShapes();
        
            var object1InSimulator:b2Body = simulator.CreateBody(object1Def);
            object1InSimulator.SetUserData("object1");
            object1InSimulator.CreateShape(object0ShapeDef);
            object1InSimulator.SetLinearVelocity(new b2Vec2(5, 0));
            object1InSimulator.SetAngularVelocity(-Math.PI * 2);
            object1InSimulator.SetMassFromShapes();
            
            var j:int;
            for (var i:int = 1; i < 31; ++i) {
                for (j = 0; j < 10; ++j)
                    simulator.Step(1 / 30, 8);
                drawSimulation();
            }
            
            
            var debugDraw:b2DebugDraw = new b2DebugDraw();
            debugDraw.m_alpha = 1;
            debugDraw.m_drawFlags = b2DebugDraw.e_shapeBit;
            debugDraw.m_sprite = this;
            debugDraw.m_drawScale = 10;
            world.SetDebugDraw(debugDraw);
            
            addEventListener(Event.ENTER_FRAME, onEnterFrameHandler);
        }
        
        private function drawSimulation():void {
            for (var i:b2Body = simulator.GetBodyList(); i; i = i.GetNext()) {
                switch (i.GetUserData()) {
                case "object0":
                case "object1":
                    var color:uint = (i.GetUserData() == "object0") ? 0xff0000 : 0xff;
                    var sp:Sprite = new Sprite();
                    sp.graphics.beginFill(color, 0.1);
                    sp.graphics.drawRect( -8, -8, 16, 16);
                    sp.x = i.GetPosition().x * 100;
                    sp.y = i.GetPosition().y * 10;
                    sp.rotation = i.GetAngle() * 180 / Math.PI;
                    addChild(sp);
                    break;
                default:
                    break;
                }
            }
        }
        
        private function onEnterFrameHandler(e:Event):void 
        {
            world.Step(1 / 39, 8);
        }
        
    }

}