AS3 Easing
Monday, August 14th, 2006 | Author: dehash
Using the Penner easing equations directly:
Actionscript:
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// DoEasing.as
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package {
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import flash.display.Sprite;
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import flash.events.Event;
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public class DoEasing extends Sprite {
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private var ball:TweenBall;
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public function DoEasing() {
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ball = new TweenBall();
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ball.x = 50;
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ball.y = 100;
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addChild(ball);
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}
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}
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}
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// TweenBall.as
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package {
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import flash.display.Sprite;
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import flash.events.Event;
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public class TweenBall extends Sprite {
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private var t:Number;
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private var b:Number;
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private var c:Number;
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private var d:Number;
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private var a:Number;
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private var p:Number;
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public function TweenBall() {
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t=0; b=50; c=300; d=600; a=c; p=d/2;
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graphics.beginFill(0xFF6600);
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graphics.drawCircle(0, 0, 20);
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addEventListener(Event.ENTER_FRAME, onEnterFrame);
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}
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private function onEnterFrame(evt:Event):void {
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x=easeInOut(t,b,c,d,a,p);
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if(++t>d){
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xtrace([x,"complete"]); t=0;b=x;c=-c;
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}
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}// Elastic Easing from http://www.robertpenner.com/easing/
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private function easeInOut (t:Number, b:Number, c:Number, d:Number, a:Number, p:Number):Number {
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if (t==0) return b; if ((t/=d/2)==2) return b+c; if (!p) p=d*(.3*1.5);
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var s:Number; if (!a || a <Math.abs(c)) { a=c; s=p/4; } else s = p/(2*Math.PI) * Math.asin (c/a);
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if (t <1) return -.5*(a*Math.pow(2,10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )) + b;
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return a*Math.pow(2,-10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )*.5 + c + b;
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}
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}
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}
