Browsing the archives for the simulation category.


Actionscript 3 – as3 | Rorschach mask (realtime animated inkblots)

actionscript 3, BitmapData, classes, fluids, fun, morphing, perlinNoise, simulation, threshold

Everybody knows about Rorschach inkblot tests, and they always charmed me… It’s like looking clouds and recognizing different shapes.

However I must admit the real turn on came after watching Watchmen the movie. Seeing those animated inkblots on the face of the character symbolically named Rorschach is something really fascinating. So here we are, after about an hour of coding fun this is what I came up with.


Click to start

Here after adding a cool persistence of the ink (call it motion blur if you like), and the face oval:


Click to start

How it’s made is quite simple:

- perlinNoise a bitmapData
- draw a circular gradient mask (I used a beginGradientFill on a Shape/Sprite)
- BitmapData.draw() the mask onto the perlinNoise bitmapData
- threshold
- (optional) a little blur to simulate antialias

Since a picture is worth a thousand words:


Click to see it moving

I’ve built a class to do this easily. Six parameters are optional to instance it:

public function Rorschach(w:uint=400, h:uint=400, mirror:Boolean=true, seed:uint=0, ovalClass:Class=null, ovalScale:Number=1, ovalYOffset:Number=0)

ovalClass is the (optional) reference to the class containing the face background.

So the usage is very simple, here an example:

import com.oaxoa.fx.Rorschach;
addChild(new Rorschach(300,300));
//addChild(new Rorschach(300,300,true,0,blankMaskImage, 1.2, -20));

Download Rorschach class for your experimentation pleasure.

All nice, but the aim of this simple experiment is seeing Rorschach animated face in action so here we go… we will be using this class in a practical example.

To simulate 3D volume and perspective we need flash CS4 (or any 3D engine):
we create a MovieClip which has the Rorschach class instanced and a rectangular solid background for composition reference in it. Then we set layer visibility to wireframe and add another instance to the stage, which is flipped horizontally.
Just position the two instances using 3D rotations and we are ready.

Just build et voilà!


Click to start

Rorschach’s Journal. October 12th, 1985. Dog Carcass in alley this morning, tire tread on burst stomach. This city is afraid of me. I have seen its true face. The streets are extended gutters and the gutters are full of blood and when the drains finally scab over, all the vermin will drown. The accumulated filth of all their sex and murder will foam up about their waists and all the whores and politicians will look up and shout ‘Save us!’ And I’ll look down, and whisper ‘no.’

The last (and D-E-F-I-N-I-T-I-V-E! :-D ) usage for this is apply it to a realtime webcam face detection algorithm. I used this originally created by Ohtsuka Masakazu and optimized by Mario Klingemann. The result is totally weird (don’t expect photoreal hollywood effect LOL) but it’s funny, even if the face detection algorithm is not perfectly smooth.

Have fun being the definitive comics anti-hero:


Click to start

6 Comments

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 »

86 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;
smooth.graphics.beginGradientFill(GradientType.LINEAR, [grey, grey, grey, grey], [1, 0, 0, 1], [0, ratioOffset, 255-ratioOffset, 255], matrix);
smooth.graphics.drawRect(0, 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.

12 Comments

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.

13 Comments

Actionscript 3 – Fun with isometrics (part 1)

actionscript 3, fun, morphing, simulation

Hi there,

I was just wandering around on some flash blogs when I found this post on bit-101 that reminded me of an old fetish of mine: isometric representations!

So I just wrote this demo… The best result is achived when staring at it for a couple of minutes cause it changes conformation very quickly and displays a lot of different patterns.

No source code here, just a quick post after a while, but I wil be on the subject again (with source code).

View sample #1View sample #2

Leave a comment if you like it. Cheers

5 Comments
« Older Posts