// forked from miniapp's Processingの流体サンプル
/**
 * 
 * ここのをas3に書き換えたもの。
 * http://processing.org/learning/topics/fluid.html
 *
 **/
package {
	import flash.display.Bitmap;
	import flash.display.BitmapData;
	import flash.display.Sprite;
	import flash.display.StageQuality;
	import flash.events.Event;
	import flash.events.MouseEvent;
	import flash.geom.Rectangle;
	
	[SWF(backgroundColor="0x0", width="465", height="465", frameRate="30")]
	public class Main extends Sprite {
		
		public function Main():void {
			if (stage) init();
			else addEventListener(Event.ADDED_TO_STAGE, init);
		}
		
		private var pmouseX:Number;
		private var pmouseY:Number;
		
		private function init(e:Event = null):void {
			removeEventListener(Event.ADDED_TO_STAGE, init);
			stage.addEventListener(MouseEvent.MOUSE_UP, mouseUpHandler);
			stage.addEventListener(MouseEvent.MOUSE_DOWN, mouseDownHandler);
			stage.quality = StageQuality.MEDIUM;
			
			addChild(new Bitmap(canvas));
			
			lwidth = width / res;
			lheight = height / res;
			v = new Vector.<Vector.<vsquare>>(lheight + 1);
			vbuf = new Vector.<Vector.<vbuffer>>(lheight + 1);
			
			for (var i:int = 0; i < pnum; i++) {
				p[i] = new particle(Math.random() * width, Math.random() * height);
			}
			
			for (i = 0; i <= lwidth; i++) { 
				v[i] = new Vector.<vsquare>(lwidth + 1);
				vbuf[i] = new Vector.<vbuffer>(lwidth + 1);
				for (var u:int = 0; u <= lheight; u++) { 
					v[i][u] = new vsquare(i * res, u * res);
					vbuf[i][u] = new vbuffer(i * res, u * res);
				}
				
				v[i].fixed = true;//付け足し
				vbuf[i].fixed = true;//付け足し
			}
			
			v.fixed = true;//付け足し
			vbuf.fixed = true;//付け足し
			
			addEventListener(Event.ENTER_FRAME, draw);
		}
		
		private function draw(e:Event):void {
			mouseX = this.mouseX;
			mouseY = this.mouseY;
			
			var axvel:int = mouseX - pmouseX;
			var ayvel:int = mouseY - pmouseY;
			
			mouseXvel = (axvel != mouseXvel) ? axvel : 0;
			mouseYvel = (ayvel != mouseYvel) ? ayvel : 0;
			
			for (var i:int = 0; i < lwidth; i++) {
				for (var u:int = 0; u < lheight; u++) {
					vbuf[i][u].updatebuf(i, u);
					v[i][u].col = 32;
				}
			}
			for (i = 0; i < pnum-1; i++) {
				p[i].updatepos();
			}
			
			canvas.lock();//付け足し
			for (i = 0; i < lwidth; i++) {
				for (u = 0; u < lheight; u++) {
					v[i][u].addbuffer(i, u);
					v[i][u].updatevels(axvel, ayvel);
					v[i][u].display(i, u);
				}
			}
			canvas.unlock();//付け足し
			
			pmouseX = mouseX;
			pmouseY = mouseY;
		}
		
		private function mouseDownHandler(e:Event):void {
			mousePressed = true;
		}
		
		private function mouseUpHandler(e:Event):void {
			mousePressed = false;
		}
	}
	
}

import flash.display.BitmapData;
var width:int = 400;
var height:int = 400;
var mousePressed:Boolean;
var mouseX:Number = 0;
var mouseY:Number = 0;
var res:int = 5;
var penSize:int = 50;
var lwidth:int = 0;
var lheight:int = 0;
var pnum:int =10000;
var v:Vector.<Vector.<vsquare>>;
var vbuf:Vector.<Vector.<vbuffer>>;
var p:Vector.<particle> = new Vector.<particle>(pnum, true);
var pcount:int = 0;
var mouseXvel:int = 0;
var mouseYvel:int = 0;
var canvas:BitmapData = new BitmapData(width, height, false, 0x0);

class particle{	
	public function particle(xIn:Number, yIn:Number) {
		x = xIn;
		y = yIn;
	}
	
	public var x:Number = 0;
	public var y:Number = 0;
	public var xvel:Number = 0;
	public var yvel:Number = 0;
	public var pos:int = 0;
	
	public function updatepos():void {
		var col1:Number;
		if (x > 0 && x < width && y > 0 && y < height) { 
			var vi:int = int(x / res);
			var vu:int = int(y / res);
			var o:vsquare = v[vi][vu];
			
			var ax:Number = (x % res) / res;
			var ay:Number = (y % res) / res;
			
			xvel += (1 - ax) * v[vi][vu].xvel * 0.05;
			yvel += (1 - ay) * v[vi][vu].yvel * 0.05;
			
			xvel += ax * v[vi + 1][vu].xvel * 0.05;
			yvel += ax * v[vi + 1][vu].yvel * 0.05;
			
			xvel += ay * v[vi][vu + 1].xvel * 0.05;
			yvel += ay * v[vi][vu + 1].yvel * 0.05;
			
			o.col += 4;
			
			x += xvel;
			y += yvel;
		}
		else {
			x = Math.random() * width;
			y = Math.random() * height;
			xvel = 0;
			yvel = 0;
		}
			
		xvel *= 0.5;
		yvel *= 0.5;
		
	}	
}

class vbuffer{
		
	public function vbuffer(xIn:int, yIn:int) {
		x = xIn;
		y = yIn;
		pressurex = 0;
		pressurey = 0;
	}
	
	public var x:int = 0;
	public var y:int = 0;
	public var xvel:Number = 0;
	public var yvel:Number = 0;
	public var pressurex:Number = 0;
	public var pressurey:Number = 0;
	public var pressure:Number = 0;
	
	public function updatebuf(i:int, u:int):void {
		if (i > 0 && i < lwidth && u > 0 && u < lheight) { 
			pressurex = (v[i - 1][u - 1].xvel * 0.5 + v[i - 1][u].xvel + v[i - 1][u + 1].xvel * 0.5 - v[i + 1][u - 1].xvel * 0.5 - v[i + 1][u].xvel - v[i + 1][u + 1].xvel * 0.5);
			pressurey = (v[i - 1][u - 1].yvel * 0.5 + v[i][u - 1].yvel + v[i + 1][u - 1].yvel * 0.5 - v[i - 1][u + 1].yvel * 0.5 - v[i][u + 1].yvel - v[i + 1][u + 1].yvel * 0.5);
			pressure = (pressurex + pressurey) * 0.25;
		}
		
	}
	
}

import flash.geom.Rectangle;
class vsquare{
	
	public function vsquare(xIn:int, yIn:int) {
		x = xIn;
		y = yIn;
	}
	
	public var x:int = 0;
	public var y:int = 0;
	public var xvel:Number = 0;
	public var yvel:Number = 0;
	public var col:Number = 0;
	
	public function addbuffer(i:int, u:int):void {
		if (i > 0 && i < lwidth && u > 0 && u < lheight) { 
			xvel += (vbuf[i - 1][u - 1].pressure * 0.5
			+vbuf[i - 1][u].pressure
			+vbuf[i - 1][u + 1].pressure * 0.5
			-vbuf[i + 1][u - 1].pressure * 0.5
			-vbuf[i + 1][u].pressure
			-vbuf[i + 1][u + 1].pressure * 0.5
			) * 0.25;
			
			yvel += (vbuf[i - 1][u - 1].pressure * 0.5
			+vbuf[i][u - 1].pressure
			+vbuf[i + 1][u - 1].pressure * 0.5
			-vbuf[i - 1][u + 1].pressure * 0.5
			-vbuf[i][u + 1].pressure
			-vbuf[i + 1][u + 1].pressure * 0.5
			) * 0.25;
			
		}
	}
		
	public function updatevels(mvelX:int, mvelY:int):void {
		if (mousePressed) {
			var adj:Number = x - mouseX;
			var opp:Number = y - mouseY;
			
			var dist:Number = Math.sqrt(opp * opp + adj * adj);
			if (dist < penSize) { 
				if (dist < 4) dist = penSize;
				var mod:Number = penSize / dist;
				xvel += mvelX * mod;
				yvel += mvelY * mod;
			}
		}
		
		xvel *= 0.99;
		yvel *= 0.99;
	}
		
	public function display(i:int, u:int):void {
		var tcol:Number = 0;
		
		if (col > 255) col = 255;
		if (i > 0 && i < lwidth - 1 && u > 0 && u < lheight - 1) { 
			tcol = ( v[i][u + 1].col 
			+ v[i + 1][u].col
			+ v[i + 1][u + 1].col * 0.5
			) * 0.4;
			tcol = int(tcol + col * 0.5);
		}
		else {
			tcol = int(col);
		}
		
		var coler:uint = tcol << 16 | tcol << 8 | tcol;
		canvas.fillRect(new Rectangle(x, y, res, res), coler);
	}
}

forked from: Processingの流体サンプル