nape examples - base class

package example
{
    import flash.display.DisplayObjectContainer;
    import flash.display.Sprite;
    import flash.events.MouseEvent;
    import flash.geom.Matrix;
    import flash.geom.Point;
    import nape.constraint.PivotJoint;
    import nape.geom.Vec2;
    import nape.phys.Body;
    import nape.phys.BodyList;
    import nape.phys.BodyType;
    import nape.shape.Circle;
    import nape.shape.Polygon;
    import nape.space.Space;
    import nape.util.BitmapDebug;
    import nape.util.ShapeDebug;

    /**
     * ...
     * @author zver
     *
     */

    public class baseExample extends Sprite
    {
        protected var space:Space;

        protected var debugRender:BitmapDebug;

        private var hand:PivotJoint = null;

        public function baseExample(prnt:DisplayObjectContainer):void
        {
            super();

            prnt.addChild(this);

            init();
        }

        protected function init():void
        {
            space = new Space(new Vec2(0, 98 * 1));
            space.worldLinearDrag = 0.25;
            space.worldAngularDrag = 0.25;

            debugRender = new BitmapDebug(640, 480, 0xbebebe);
            addChild(debugRender.display);
        }

        protected function removeHand(removeListenersToo:Boolean = true):void
        {
            if (hand)
            {
                hand.active = false;
                hand.space = null;
                hand = null;

                if (removeListenersToo)
                {
                    if (stage.hasEventListener(MouseEvent.MOUSE_DOWN))
                        stage.removeEventListener(MouseEvent.MOUSE_DOWN, onMouseDown);

                    if (stage.hasEventListener(MouseEvent.MOUSE_UP))
                        stage.removeEventListener(MouseEvent.MOUSE_UP, onMouseUp);
                }
            }
        }

        protected function addHand():void
        {
            removeHand(false);

            hand = new PivotJoint(space.world, null, Vec2.weak(), Vec2.weak());
            hand.active = false;
            hand.stiff = false;
            hand.maxForce = 1e5;
            hand.space = space;

            stage.addEventListener(MouseEvent.MOUSE_UP, onMouseUp);
            stage.addEventListener(MouseEvent.MOUSE_DOWN, onMouseDown);
        }

        private function onMouseDown(event:MouseEvent):void
        {
            var mp:Vec2;
            var m:Matrix = debugRender.transform.toMatrix();
            m.invert();
            mp = Vec2.fromPoint(m.transformPoint(new Point(mouseX, mouseY)));

            if (hand)
            {
                // re-use same list each time.
                var bodyList:BodyList = space.bodiesUnderPoint(mp, null, bodyList);

                var k:int = bodyList.length;
                var i:int;
                for (i = 0; i < k; i++)
                {
                    var body:Body = bodyList.at(i);
                    if (body.isDynamic())
                    {
                        hand.body2 = body;
                        hand.anchor2 = body.worldPointToLocal(mp, true);
                        hand.active = true;
                        break;
                    }
                }

                // recycle nodes.
                bodyList.clear();
            }

            mp.dispose();
        }

        private function onMouseUp(event:MouseEvent):void
        {
            if (hand)
                hand.active = false;
        }

        protected function addRectangle(xx:Number, yy:Number, ww:Number, hh:Number, angle:Number = 0, isStatic:Boolean = true):Body
        {
            var tmp:Body;

            if (isStatic)
                tmp = new Body(BodyType.STATIC, new Vec2(xx, yy))
            else
                tmp = new Body(BodyType.DYNAMIC, new Vec2(xx, yy));

            tmp.shapes.add(new Polygon(Polygon.box(ww, hh)));
            tmp.rotation = angle;
            tmp.space = space;

            return tmp;
        }

        protected function addCircle(xx:Number, yy:Number, radius:Number, angle:Number = 0, isStatic:Boolean = false):Body
        {
            var tmp:Body;

            if (isStatic)
                tmp = new Body(BodyType.STATIC, new Vec2(xx, yy))
            else
                tmp = new Body(BodyType.DYNAMIC, new Vec2(xx, yy));

            tmp.shapes.add(new Circle(radius));
            tmp.rotation = angle;
            tmp.space = space;

            return tmp;
        }

        protected function addWalls():void
        {
            addRectangle(320, 0, 640, 10);
            addRectangle(320, 480, 640, 10);
            addRectangle(0, 240, 10, 480);
            addRectangle(640, 240, 10, 480);
        }

        public function free():void
        {
            removeHand();

            space.clear();
            space = null;

            removeChild(debugRender.display);
            debugRender = null;
        }

        protected function random(min:Number, max:Number):Number
        {
             return (Math.floor(Math.random() * (max - min + 1)) + min);
        }

        protected function miniUpdate(delta:Number):void
        {

        }

        protected function miniPostUpdate(delta:Number):void
        {

        }

        public function update():void
        {
            if (space == null)
                return;

            var k:int = 4;
            var i:int;

            for (i = 0; i < k;i++)
            {
                miniUpdate(1 / (30 * k));

                space.step(1 / (30 * k));

                miniPostUpdate(1 / (30 * k));
            }

            if (hand)
            {
                /*
                var mp:Vec2 = Vec2.get(mouseX, mouseY);
                mp.x -= debugRender.transform.tx;
                mp.y -= debugRender.transform.ty;
                */

                var mp:Vec2;
                var m:Matrix = debugRender.transform.toMatrix();
                m.invert();
                mp = Vec2.fromPoint(m.transformPoint(new Point(mouseX, mouseY)));

                hand.anchor1.set(mp);
            }

            if (debugRender.display.visible)
            {
                debugRender.clear();
                debugRender.draw(space);
                debugRender.flush();
            }
        }
    }

}