Browsing the archives for the algorithms category.

Actionscript 3 – as3 Lightning / Thunderbolt / Electric discharge Class

actionscript 3, algorithms, BitmapData, classes, fun, Math, morphing, perlinNoise, simulation

Finally here we come!

Yup, sry for the delay, I’ve had a lot of work recently.

I have prepared three demos and a publishable (but far from perfect and not yet documented) class. The demos are FLA based… you can find the timeline code to assemble the demos at the bottom of the post. I’ll publish some documentation in the next days, so until then just look at the demos’ code to unserstand the basic of the class usage.

Download Lightning classes

Demo N°1:
This demo shows the two different behaviours the class can mimic: Electric discharge/beam or lightning. Drag the ball near or far to the coil to see different behaviors.

Click to start

Demo N°2:
This demos show the maxLength and maxLengthVary properties in action.
Bring the fingers near to the plug to have continuos electricity. Bringing the hand far from the plug lowers the discharge probability. Reaching the max distance simply disables it.

Click to start

Demo N°3:
This demo is a good reason for the publishing delay :P

A nice sandbox to play with (some of) the properties.
The class is recursive to create children so many properties have also a decay twin property which rule how the property is passed to children.
As instance if you set a childrenMaxCount = 6 to the main Lightning instance it will have a maximum of 6 direct children. Its children will have a childrenMaxCount value which depends on the main instance childrenMaxCount and childrenMaxCountDecay.
So if you set childrenMaxCount = 6 and childrenMaxCountDecay = .5 the children of the main instance will have childrenMaxCount = 3.
If you set childrenMaxCount = 6 and childrenMaxCountDecay = 0 the children of the main instance will have childrenMaxCount = 6 (no decay).

This value can be very useful to optimize the speed of execution cause smaller branches don’t need many children or many steps of detail.

Click to start

Ok, I’m too tired to write more. I’ll publish some documentation in the next days.
Feel free to ask everything question you can have in the comments, and as usual if you like this stuff scream it in the comments!

Demos’ code after the break. Waiting for your comments I will surf through the website of fatcow and see if they have any good hosting plans.

Continue Reading »


Actionscript 3 | Speedcoding video – session #1: Black Branches

actionscript 3, algorithms, BitmapData, classes, fun, Math, perlinNoise

Yesterday night I wanted to have some “no-purpose coding session” and thought it was a nice idea to record the session and do a speedcoding video. The original video has been collapsed from 45 minutes to 3 minutes circa.

The main concept is once again based on perlinNoise which (I am sure you already guessed) is something I do like very much. So please start call me “The PerlinNoise Guy” or “Perlinator”. :-D

So this is my first speedcoding video (be sure to look at it in high quality):

Here’s the interactive demo:

Click to launch. Move mouse (x position) to change smoothness (my favourite values are around 100)

The code consist on a class file (click to download) and some timeline code to assemble the demo:

import com.oaxoa.fx.Branch;

const w:uint=stage.stageWidth;
const h:uint=stage.stageHeight;

var ct:ColorTransform=new ColorTransform(1,1,1,1,1,1,1);
var renderView:BitmapData=new BitmapData(w, h, true);
var bmp:Bitmap=new Bitmap(renderView);

var tf:TextFormat=new TextFormat("_sans", 16, 0, true);
var label:TextField=new TextField();

var timer:Timer=new Timer(10);
timer.addEventListener(TimerEvent.TIMER, ontimer);

function ontimer(event:TimerEvent):void {
function addNew():void {
	label.text="Smoothness: "+String(mouseX-w/2);
	var tt:Branch=new Branch(mouseX-w/2);
	tt.addEventListener(Event.COMPLETE, oncomplete);
	renderView.colorTransform(renderView.rect, ct);
function oncomplete(event:Event):void {
	var t:Branch=event.currentTarget as Branch;
	var matrix:Matrix=new Matrix();
	matrix.translate(t.x, t.y);
	renderView.draw(t, matrix);
	t.removeEventListener(Event.COMPLETE, oncomplete);

I didn’t forget about the lightning class part 3 that I will publish soon :)

As usual if you liked this drop a line in the comments.


Actionscript 3 Lightning class – step 2

actionscript 3, algorithms, BitmapData, fluids, fun, Math, perlinNoise, simulation

The first rule for the good blogger I read 18 months ago (when I started this blog) was: “Never, ever post on Sunday… people coming back to the office on monday morning will find tons of weekend rss notifications and miss your post among them”.

But… since I am not a good blogger and since this blog is mine… I do post whenever I want :-D

Here we are with the second post dedicated to the lightning class I’m working on. It had to force myself to sit down here and write again about this, I am working on other 3 nice experiments and the fun part of this class for me has already gone, now starts the boring part: optimize/parametrize/explainize. But I think it could be interesting for someone, so here we are.

Still no code, I still have to optimize/parametrize but I can start to “explain-ize”. In the first post we just saw a couple of samples running. Some people asked me for the raw logic behind this.

The key here are two perlinNoise, one for simulate the macro behaviour and one for the micro variations. As often a monodimensional (1px height) perlinNoise is perfect to simulate bidimensional effects, since perlinNoise images contain an additional dimension defined by luminosity variations.

So, if from a 2D perlinNoise image you can easily get a 3D voxelTerrain (X+Y+Height), from a 1D image you can easily get for instance 2D mountains (X+Height).
1px height perlinNoise images are very fast to render so they do not kill your cpu even if many of them are used.

I have prepared two “debug” sample movies. The first is to show how the two perlinNoise bitmapDatas affect the movement of the final shape (children are disabled for clarity purpose).

Debug sample #1

As you can see there are 3 different grey bars under the lightning:

  • The first one is the perlinNoise used to displace the discharge on a micro scale
  • the second one for the macro movements (this is really what makes it feel as real)
  • the third one is the image merged onto the second one to smooth the edges.

Obviously the 3 bitmaps are 1 pixel height, I just stretched them here to 30px to make ‘em visible.

Speaking about perlinNoise edges smoothing this is the fact: without any smoothing the extremities of the perlinNoise have a random value between 0×000000 and 0xffffff which stand for black and white. Black value will displace the beam in a negative direction, white value will displace it in a positive direction. To be sure the edges are sticked to the x/y coords of the graphic that simulates the origin of the discharge, we need no displacement at the beginning and at the end.
No displacement=grey value (0×808080).

The easiest way to do this is to create a vector shape, fill it with a gradient (alphas=[1,0,0,1]), adjust ration accordingly to the smooth percentage and draw it onto the macro variations bitmap (Bitmap.draw(…)). Is off course possible to to this directly using bitmap methods. But I found this being the most natural for me. I like the idea to mix vector and bitmaps using the easiest way for what I need.

Naturally you cannot set the last pixels to medium gray without some smooth transition, and so we use the gradient. Check this sample with code snippet:

perlinNoise edges smoothing

const grey:uint=0x808080;
var smooth:Sprite=new Sprite();
var ratioOffset:uint=smoothPercentage/100*128;, [grey, grey, grey, grey], [1, 0, 0, 1], [0, ratioOffset, 255-ratioOffset, 255], matrix);, 0, w, 1);

I used the smoothing only on the macro bitmap, not one the micro too save some cpu cycle on a barely visible detail and because I like the micro variations on the edges too.

The second one shows the same concept applied also to children with a slider to vary the children birth probability:

[demo removed cause I overwrote the files LOL. Don't ask to get them from backups please, simply refer to part 3 post :) ]

The main beam can create bridges of electricity, or “children”. A child is simply another instance of the class with a “generationNumber” parameter to manage descendant probability and avoid infite recursion. All the rules described until now applies to children too. Children need to be sticked to the parent beam so they always have a non-variable smoothing of 50%.

Coming soon with part 3 and the full class.
As always leave a comment if you find something interesting.


Actionscript 3 Lightning class – First tests

actionscript 3, advanced image editing, algorithms, fun, game, Math, perlinNoise, Physics, simulation

Here again with the first test of a Fx class.

The class can render lightnings with these specs:

- different shapes and aspect
- variable edge-smoothness to keep the extremities sticked to the origin
- runtime children generation (every trunk can generate children)

Sample #1

Sample #2

Perhaps not that useful but could be nice to implement in some game or demo.
Code soon.


My 25lines and tweetcoding contests entries (finally)

3D, actionscript 3, algorithms, BitmapData, competitions, fun, Math, morphing, perlinNoise, voxels

Hi there, back from an awesome week in Playa del Carmen Mexico… the most incredible vacation ever had. I’ll not post about this holiday (is or isn’t this a technical blog?). So in this last day before going back to work, I am here to post my 25lines contest and my four twittercoding entries. contest

Sadly is dying just after a couple of editions, I really enjoy this kind of stuff, but unfortunately after the first (december ’08) edition entries count started to diminish. I am the one who contributed in this premature departure as I entered only the first contest and then was to busy to work to contributing again.

However this was what I came with:

 * 25-Line ActionScript Contest Entry
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 25 lines Voxel Landscape Engine by Pierluigi Pesenti

// 3 free lines! Alter the parameters of the following lines or remove them.
// Do not substitute other code for the three lines in this section
[SWF(width=512, height=400, backgroundColor=0x7ddafd, frameRate=31)]
stage.align = StageAlign.TOP_LEFT;
stage.scaleMode = StageScaleMode.NO_SCALE;
// 25 lines begins here!
var paletteMap:Array=[13209,13465,13722,14235,14492,14749,15262,15519,16032,16288,16545,17058,17315,17572,18085,18342,18855,19111,19368,19881,20138,20395,20908,21165,21678,21934,22191,22704,22961,23218,23731,23988,24501,24757,25014,25527,25784,26041,26554,26811,27324,27580,27837,28350,28607,28864,29377,29634,30147,30403,30660,31173,31430,31687,32200,32457,32970,33226,33483,33996,34253,34510,35023,35280,35793,36049,36306,36819,37076,37333,37846,38103,38616,38872,39129,39642,39899,40156,40669,40926,106975,3322853,6604267,9820402,13101816,16383487,16119793,15856100,15658199,15394506,15196605,14671798,14212528,13753258,13293987,12834973,12375703,11916433,11457162,10997892,10538878,10014072,9554801,9095531,8636261,8177247,7717976,7258706,6799436,6340165,5881151,5356345,4897075,4437804,3978534,3519520,3060250,2600979,2141709,1682439,1223425,1223169,1288706,1353987,1419524,1484804,1550341,1615878,1681159,1746695,1811976,1877513,1943050,2008330,2073867,2139148,2204685,2269965,2335502,2401039,2466320,2531856,2597137,2662674,2728211,2793491,2859028,2924309,2989846,3055126,3120663,3120664,3185945,3251481,3316762,3382299,3447836,3513116,3578653,3643934,3709471,3774751,3840288,3905825,3971106,4036642,4101923,4167460,4232997,4298277,4363814,4429095,4494632,4559912,4625449,4690986,4756267,4821803,4887084,4952621,5018158,5214768,5411635,5608501,5805112,6001979,6198845,6460992,6657858,6854725,7051592,7248202,7445069,7641935,7904082,8100949,8297815,8494426,8691292,8888159,9150562,9347172,9544039,9740905,9937516,10134383,10331249,10593396,10790262,10987129,11183996,11380606,11577473,11774339,12036486,12233353,12430219,12626830,12823696,13020563,13282966,13349274,13415583,13481892,13613736,13680045,13746354,13812663,13944763,14011072,14077381,14143690,14275534,14341843,14408152,14540253,14540253,14540253,14540253,14540253,14540253,14540253,14540253,14540253,14540253,14540253,14540253,14540253,14540253,14540253,14540253,14540253,14540253,14540253,14540253,14540253];
var offs:Array=[new Point(0,0),new Point(0,0),new Point(0,0),new Point(0,0)];
var bdHeight:BitmapData=new BitmapData(256*2,256,false);
var bdColor:BitmapData=new BitmapData(256*2,256,false);
var bdNoise:BitmapData=new BitmapData(256*2,256,false);
var bdOutput:BitmapData=new BitmapData(256, 256, false);
addChild(new Bitmap(bdOutput));
addEventListener(Event.ENTER_FRAME, function(event:Event):void {
	bdHeight.perlinNoise(150, 150, 3, 5, false, true, 7, true, offs);
	bdColor.copyPixels(bdHeight, bdHeight.rect, new Point(0,0),bdHeight);
	bdHeight.threshold(bdHeight, bdHeight.rect, new Point(0,0), "<", 0xff555555, 0xff555555);
	bdNoise.perlinNoise(5, 5, 1, 5, false, true, 7, true, offs);
	bdColor.paletteMap(bdColor, bdColor.rect, new Point(), paletteMap, [], []);
	bdColor.draw(bdNoise, null, new ColorTransform(1,1,1,.2), BlendMode.OVERLAY);
	bdOutput.fillRect(bdOutput.rect, 0x7ddafd);
	for (var i:int=0; i<256; i++) {
		for (var j:int=0; j<256*2; j++) {
			for (var k:int=0; k<3; k++) {
				if (bdOutput.getPixel(256/2+(j-256)*(120/(120+i)),50+((-bdHeight.getPixel(j,i)/(0xffffff/125)+200)*(120/(120+i)))+k)==0x7ddafd) {
					bdOutput.setPixel(256/2+(j-256)*(120/(120+i)),50+(((-bdHeight.getPixel(j,i)/(0xffffff/125)+200)*(120/(120+i)))+k), bdColor.getPixel(j, i));
				} else {
// 25 lines ends here!

Which renders like this:

Yeah, yeah, know what u thinking: "He repacked the same old stuff of previous "voxels landscape" posts in 25 lines and submit to the contest! Booo".
You're right, but compacting that code in 25 lines was not that easy, and most of all this has dinamically generated map and not bitmap based like the voxels landscape post... lakes are rendered flat on the surface but still has depth gradients, there's a noise filter on the surface to mimic lesser hue variations and the loss of speed compared to the "unpacked" version is visible but not drastical.


See the winners, runners-up and mentions here.

After preparing four tweetcoding entries (140 chars only) going back to 25 lines of code would feel like absolute freedom. 140 chars is less than a sms, and as3 is quite verbose for some things. Thankfully the other 140 chars of (common) gimmick code made this contest possible.

The gimmick code:

function f(e){
// paste your 140 chars here

Alien lifeform

Mouse interactive, move mouse left/right to change the shape.
Big part of the code used to cycle colors, if you wait some minutes you will see cycling all the rgb colors. Some shape displays really fun colors pattern.

a=mouseX;x=y=200;i+=.01;g.clear();for(c=600;c--;) {g.beginFill(c*i);d=m.sqrt(m.abs(s(i)*600-c))*8;g.drawCircle(s(1.6-c*a)*d,s(c*a)*d,c/50);}

Rotating black & white alien lifeform (variation)

Mouse interactive, move mouse left/right to change the shape.
Sacrified the color cycling and implemented a simple 3d spinning. All the color fill is black, with a single beginFill to display the NAND effect very trendy in this contest because very cheap.

This got a notable mention... ;-) thank you guys. However the first version with color cycling has been more challenging for me and is still my favorite.

a=mouseX/999;x=y=200;i+=.01;g.clear();g.beginFill(0);for(c=500;c--;) {d=m.sqrt(m.abs(s(i)*500-c))*8;g.drawCircle(s(i-c*a)*d,s(c*a)*d,c/50);}

Oh no! My f****** horn!

Not interactive. Just look at it if you like.
Not much to say here, just a credit to the movie "Tenacious D and the Pick of Destiny" for the title and inspiration.

i+=4;if(i<220) {m=addChild(new Sprite);m.rotationX=i*2;;k.lineStyle(1);k.drawCircle(0,i,i/2);x=y=i;}rotationY+=2;rotationX+=.9

Numeric sequence spiral

Not interactive.
Ok, ok, the sequence sucks (multiples of 8 are displayed). Wanted to have a Fibonacci one but too much code needed for the sequence to leave some spare char for the spiral. Number are interval created and the place to form a 3D spiral which is sine spinning slowly.
Totally lame here cause numbers are continuosly created and never removed, so after a minute or so, better you close the window before looking at your CPU freezing ;-)

if(i%8==0) {t=addChild(new TextField);t.text=i;t.x=s(i/30)*i/4;t.y=s(1.6-i/30)*i/4;t.z=i/2;}rotationY=s(i++/99)*150;x=y=200

Don't forget to leave a comment if you find this code and examples someway useful.

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