DoubleSpring

by crossisland 07 Nov 2011

Embed

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

package {
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.events.MouseEvent;
    
    public class DoubleSpring extends Sprite {
        private var ball0:Ball;
        private var ball1:Ball;
        private var ball0Dragging:Boolean = false;
        private var ball1Dragging:Boolean = false;
        private var spring:Number = .1;
        private var friction:Number = .95;
        private var springLength:Number = 100;
        
        public function DoubleSpring() {
            init();
        }
        
        private function init():void {
            ball0 = new Ball(20);
            ball0.x = Math.random() * stage.stageWidth;
            ball0.y = Math.random() * stage.stageHeight;
            ball0.addEventListener(MouseEvent.MOUSE_DOWN, onPress);
            addChild(ball0);
            
            ball1 = new Ball(20);
            ball1.x = Math.random() * stage.stageWidth;
            ball1.y = Math.random() * stage.stageHeight;
            ball1.addEventListener(MouseEvent.MOUSE_DOWN, onPress);
            addChild(ball1);
            
            addEventListener(Event.ENTER_FRAME, onEnterFrame);
            stage.addEventListener(MouseEvent.MOUSE_UP, onRelease);
        }
        
        private function onEnterFrame(event:Event):void {
            if (!ball0Dragging) {
                springTo(ball0, ball1);
            }
            if (!ball1Dragging) {
                springTo(ball1, ball0);
            }
            graphics.clear();
            graphics.lineStyle(2);
            graphics.moveTo(ball0.x, ball0.y);
            graphics.lineTo(ball1.x, ball1.y);
        }
        
        private function springTo(ballA:Ball, ballB:Ball):void {
            var dx:Number = ballB.x - ballA.x;
            var dy:Number = ballB.y - ballA.y;
            var angle:Number = Math.atan2(dy, dx);
            var targetX:Number = ballB.x - Math.cos(angle) * springLength;
            var targetY:Number = ballB.y - Math.sin(angle) * springLength;
            ballA.vx += (targetX - ballA.x) * spring;
            ballA.vy += (targetY - ballA.y) * spring;
            ballA.vx *= friction;
            ballA.vy *= friction;
            ballA.x += ballA.vx;
            ballA.y += ballA.vy;
        }
        
        private function onPress(event:MouseEvent):void {
            event.target.startDrag();
            if (event.target == ball0) {
                ball0Dragging = true;
            }
            if (event.target == ball1) {
                ball1Dragging = true;
            }
        }
        
        private function onRelease(event:MouseEvent):void {
            ball0.stopDrag();
            ball1.stopDrag();
            ball0Dragging = false;
            ball1Dragging = false;
        }
    }
}

import flash.display.Sprite;

class Ball extends Sprite {
    public var radius:Number;
    private var color:uint;
    public var vx:Number = 0;
    public var vy:Number = 0;
    
    public function Ball(radius:Number=40, color:uint=0x000000) {
        this.radius = radius;
        this.color = color;
        init();
    }
    
    public function init():void {
        graphics.beginFill(color);
        graphics.drawCircle(0, 0, radius);
        graphics.endFill();
    }
}