// forked from fladdict's FITC: Cool Japan side A / Particle sample of SMOKE
/**
*
* Sample code for FITC
* Smoke particle effect
*
*/
package {
import flash.display.Sprite;
import flash.display.Bitmap;
import flash.display.BitmapData;
import flash.display.BlendMode;
import flash.events.Event;
import flash.filters.BlurFilter;
import flash.geom.ColorTransform;
import flash.geom.Matrix;
import flash.geom.Point;
import flash.utils.ByteArray;
public class FlashTest extends Sprite {
//View
protected var canvas:BitmapData;
protected var canvasBitmap:Bitmap;
//BitmapData that contains the actual froce that is applied to particles.
protected var forceMap:BitmapData;
//BitmapData that contains the force of the storm.
protected var stormMap0:BitmapData;
protected var stormMap1:BitmapData;
//BitmapData that contains the mouse repulsion force of the stage.
protected var repulsionMap:BitmapData;
protected var repulsionHistoryMap:BitmapData;
protected var repulsionFadeMap:BitmapData;
//the number of particles. 5000-200000
protected var particleNum:int = 10000;
protected var particles:Vector.<Particle>
//
protected var stormScaleRatioX:Number;
protected var stormScaleRatioY:Number;
protected var stormCycle:Number = 0;
//color transform that guradually changes canvas.
protected var fadeCanvasColt:ColorTransform;
protected var canvasBlurFilter:BlurFilter;
//temporaly variables
protected var tempColt:ColorTransform = new ColorTransform();
protected var tempPt:Point = new Point();
protected var tempMat:Matrix = new Matrix();
public function FlashTest() {
init();
reset();
}
protected function init():void
{
//build View
canvasBitmap = new Bitmap(null, "auto", false);
// because canvas is 25% size of screen, we make view 400% bigger.
canvasBitmap.scaleX = 4;
canvasBitmap.scaleY = 4;
addChild(canvasBitmap);
//initialize the map that contains force of the storm;
stormMap0 = new BitmapData(256,256,false,0x000000);
stormMap0.perlinNoise(128,128,3,Math.random()*100,false,true,3,false);
stormMap1 = new BitmapData(256,256,false,0x000000);
stormMap1.perlinNoise(128,128,3,Math.random()*100,false,true,3,false);
//
forceMap = new BitmapData(256,256,false,0x000000);
//initialize repulsionMap
repulsionHistoryMap = new BitmapData(256,256,false,0x000000);
repulsionFadeMap = new BitmapData(256,256,true,0x20808000);
repulsionMap = new BitmapData(256,256,false,0);
/**
* First we preculculate the repulsion force field that mouse cursor generates as a bitmapdata.
* Red channel of bitmap data contains horizontal force.
* Green channel of bitmap data contains vertical force.
*/
var dx:int, dy:int;
var dist:Number, fx:Number, fy:Number;
var col:int;
for(var yy:int=0; yy<256; yy++)
{
for(var xx:int=0; xx<256; xx++){
dx = xx-128;
dy = yy-128;
dist = Math.sqrt(dx*dx+dy*dy);
if(dist<1){
fx = 0;
fy = 0;
}else{
fx = dx / dist / dist / dist * 50000;
fy = dy / dist / dist / dist * 50000;
}
fx = (fx<-128)? -128 : (fx>127)? 127 : fx;
fy = (fy<-128)? -128 : (fy>127)? 127 : fy;
fx += 128;
fy += 128;
col = (fx<<16) + (fy<<8)
repulsionMap.setPixel(xx,yy,col);
}
}
//You can see
canvasBitmap.bitmapData = repulsionMap;
//initialize particle
particles = new Vector.<Particle>(particleNum);
var particle:Particle;
var rr:int;
for(var i:int=0; i<particleNum; i++)
{
particle = new Particle();
particle.x = Math.random() * stage.stageWidth >> 2;
particle.y = Math.random() * stage.stageHeight >> 2;
//Customize the range of the particle color according to the amount of the particle and stage size.
particle.r = particle.g = particle.b = Math.min(Math.random()*8+4,255);
//Customize the rage of the scaleFactor according to the amount of the particle and stage size.
particle.scaleFactor = (Math.random()*0.1 + 0.95) * 0.003;
particles[i] = particle;
}
fadeCanvasColt = new ColorTransform(1,1,1,1,-2,-1,-1,0);
canvasBlurFilter = new BlurFilter(2,2,3);
//set event listeners
stage.addEventListener(Event.ENTER_FRAME, enterFrameHandler);
stage.addEventListener(Event.RESIZE, resizeHandler);
}
/**
*
* Called when you need reset the view. E.G. resizing screen.
*/
protected function reset():void
{
if(canvas)
canvas.dispose();
//build view, to optimize we use 25% size BitmapData of actual screensize.
canvas = new BitmapData((stage.stageWidth>>2)+1, (stage.stageHeight>>2)+1, false, 0x000000);
canvasBitmap.bitmapData = canvas;
//precalculate ratio that converts screen coordinate to stomMapBitmap coodinate;
stormScaleRatioX = 1 / (stage.stageWidth>>2)*255;
stormScaleRatioY = 1 / (stage.stageHeight>>2)*255;
//canvasBitmap.bitmapData = stormMap1; //if you want to see stormMap;
//canvasBitmap.bitmapData = repulsionHistoryMap;
//canvasBitmap.bitmapData = forceMap; //if you want to see forceMap;
//canvasBitmap.scaleX = 1;
//canvasBitmap.scaleY = 1;
}
//We rebuild screen when swf is reseized.
//It is not required if you only run it on wonderfl.
protected function resizeHandler(e:Event):void
{
reset();
}
//Update storm and particle every frame.
protected function enterFrameHandler(e:Event):void
{
updateStormMap();
updateRepulsionMap();
updateForceMap();
updateParticles();
}
/**
* We calculate current forcefielde's state by blending two stormMap.
* Therefore force field gradually changes every frame.
*/
protected function updateStormMap():void
{
stormCycle++;
if(stormCycle == 180){
stormMap0.perlinNoise(256,256,3,Math.random()*100,false,true,3,false);
}else if(stormCycle==360){
stormMap1.perlinNoise(256,256,3,Math.random()*100,false,true,3,false);
stormCycle = 0;
}
}
/**
* We update repulsionMap according to the current mouse position.
*/
protected function updateRepulsionMap():void
{
tempMat.a = 1;
tempMat.b = 0;
tempMat.c = 0;
tempMat.d = 1;
tempMat.tx = 0;
tempMat.ty = 0;
repulsionHistoryMap.draw(repulsionFadeMap, tempMat);
tempMat.translate(-128,-128);
tempMat.translate(mouseX, mouseY);
tempMat.scale(1/stormScaleRatioX, 1/stormScaleRatioY);
repulsionHistoryMap.draw(repulsionMap, tempMat, null, BlendMode.HARDLIGHT);
}
protected function updateForceMap():void
{
//generate current force fieldes state with blending two stormMaps.
forceMap.copyPixels(stormMap1, stormMap0.rect, tempPt);
tempColt.alphaMultiplier = Math.cos(stormCycle*Math.PI/180)*0.5+0.5;
forceMap.draw(stormMap0, null, tempColt);
//add mouse repulsion force
forceMap.draw(repulsionHistoryMap,null,null,BlendMode.HARDLIGHT);
forceMap.draw(repulsionHistoryMap,null,null,BlendMode.HARDLIGHT);
}
protected function updateParticles():void
{
var forceBytes:ByteArray = forceMap.getPixels(forceMap.rect);
var stageW:int = canvas.width;
var stageH:int = canvas.height;
var loopW:int = stageW-1;
var loopH:int = stageH-1;
var byteIndex:int;
canvas.lock();
canvas.colorTransform(canvas.rect, fadeCanvasColt);
//Update Paritcle position and draw.
var col:int, r:int, g:int, b:int;
for(var i:int=0; i<particleNum; i++)
{
var prt:Particle = particles[i];
byteIndex = (int(prt.y*stormScaleRatioY)*256 + int(prt.x*stormScaleRatioX))<<2;
prt.vx = prt.vx * 0.96 + (forceBytes[byteIndex+1]-128)*prt.scaleFactor;
prt.vy = prt.vy * 0.96 + (forceBytes[byteIndex+2]-128)*prt.scaleFactor;
prt.x += prt.vx;
prt.y += prt.vy;
if(prt.x<0){
prt.x = loopW;
}else if(prt.x > loopW){
prt.x = 1;
}
if(prt.y<0){
prt.y = loopH;
}else if(prt.y > loopH){
prt.y = 1;
}
//Self implimentation of addtive color blend mode.
//Because there is too many particle, blending particle with low brightness color is much effective.
col = canvas.getPixel(int(prt.x), int(prt.y));
r = (col>>16&0xff) + prt.r;
g = (col>>8&0xff) + prt.g;
b = (col&0xff) + prt.b;
r = (r<0xff)? r : 0xff;
g = (g<0xff)? g : 0xff;
b = (b<0xff)? b : 0xff;
canvas.setPixel(int(prt.x), int(prt.y), (r<<16)|(g<<8)|b);
}
canvas.unlock();
}
}
}
class Particle
{
//particle position
public var x:Number = 0;
public var y:Number = 0;
public var vx:Number = 0;
public var vy:Number = 0;
//particle color
public var r:int;
public var g:int;
public var b:int;
//scale factor that affects the force applied to the particle.
public var scaleFactor:Number;
}