拡散方程式

by tikal 16 Mar 2014

Embed

/**
 * Copyright tikal ( http://wonderfl.net/user/tikal )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/eD1y
 */

package {
    import flash.text.TextField;
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.events.MouseEvent;
    [SWF(frameRate="30", width="465", height="465")]
    public class Diff extends Sprite {
        private var isMouseDown_:Boolean;
        private var lastX:int;
        private var lastY:int;
        private var length:Number = stage.stageWidth;
        private var pt : Array = new Array(length);
        private var sp:Sprite;
        private var lb:TextField;
        public function Diff() {
            stage.addEventListener(MouseEvent.MOUSE_DOWN,
                function():void {
                    isMouseDown_ = true;
                    lastX = mouseX;
                    lastY = mouseY;
                });
            stage.addEventListener(MouseEvent.MOUSE_UP,
                function():void {
                    isMouseDown_ = false;
                });
            stage.addEventListener(MouseEvent.MOUSE_OUT,
                function():void {
                    isMouseDown_ = false;
                });
            stage.addEventListener(MouseEvent.MOUSE_OVER,
                function():void {
                    isMouseDown_ = false;
                });
            addEventListener(Event.ENTER_FRAME, update );
            for(var i:int=0;i<pt.length;++i){
                pt[i] = 0;
            }
            sp = new Sprite();
            sp.graphics.lineStyle(5, 0x00ffffff);
        }
       // アップデート
        private function update(event:Event):void {
            // マウスダウン中はパーティクル生成
            var i:int;
            if (isMouseDown_) {
                var len:Number = Math.abs(mouseX-lastX);
                for(i=0; i<=len; ++i ) {
                    pt[lastX + (mouseX-lastX)*i/len] = stage.stageHeight - (lastY + (mouseY-lastY)*i/len);
                }
                lastX = mouseX;
                lastY = mouseY;
            }else{
                var f:Function = function(idx:int):Number{
                    if(idx < 0 || idx >= pt.length){
                        return 0;
                    }else{
                        return pt[idx];
                    }
                }
                var alpha:Number = 0.1;
                for(var j:int=0;j<200;++j){
                var npt:Array = new Array(pt.length);
                    for(i=0; i<pt.length; ++i ) {
                        npt[i] = (alpha * f(i-1)) + ((1-(2*alpha)) * f(i)) + (alpha * f(i+1));
                    }
                    this.pt = npt;
                }
            }
            this.graphics.clear();
            this.graphics.lineStyle(10, 0x00ff0000);
            this.graphics.moveTo(0,stage.stageHeight);
            for(i=0;i<pt.length;++i){
                this.graphics.lineTo(i, stage.stageHeight - pt[i]);
            }
        }
    }
}