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oct 12

New site !

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Feel free to visit my fresh new personal site !!!

http://www.lecrabe.net

Credits:
GFX : Kassad / www.frak.fr
Code: well, hum me...

jan 19

AS3 while loops performance

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Recently i made a quick visual effect including the latest Flash Player 10 classes : Vector & Vector3D classes.

As the Vector and Vector3D classes are well optimized, I wanted to optimized my own loops.

So came again the question : "What is the most optimized loop system for these classes ?"

So i wrote a quick "while loops" performance test where i use a huge Vector array of Vector3D instances where i tried several systems.

I firstly thought that there was no way using the "for loops", but i read this quite interesting article :

http://www.experts-exchange.com/articles/Software/Photos_Graphics/Web_Graphics/Macromedia_Flash/ActionScript/20-Tips-to-Optimize-your-ActionScript.html

and i finally put the for loop test as the last test.

Each test performs a vector crossproduct on each Vector3D, and this for 2 millions vectors !!!

clear here to start the while-loop test

I was used to coding my loops with the first loop test :

i = vect.length;
while(i--){}

but apparently the most optimized loop on my mac (imac 27") should be the 3rd test :

i=vect.length;
while (--i>=0) {}

For my computer (Mac/Firefox) each test of the benchmark is almost the same, even the "for loop" which is quite efficient.

But I look closely, the fact is was using the less optimized while loop (according to this test)...

It's up to you to test your own computer and may choose one of these loop.

jan 13

Add Flex 3.5 SDK path to Snow Leopard

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As i was installing Alchemy toolkit for some experiment, i was first stuck in installing the Flex 3.5 SDK : to get the flex sdk linked to your system you are supposed to add the "flex/bin" directory in your system path.

Looking on the web, the ".profile" file has to be changed, but i couldn't find it... the reason : I had no ".profile" file on my system....

So if you don't have any ".profile" file in your home directory (your nickname directory), here are the steps to follow :

1) First of all, you may want to show hidden files on your mac to see exactly what you do, to do so type the following lines in your terminal:

defaults write com.apple.finder AppleShowAllFiles TRUE killall Finder

change TRUE/FALSE to activate/deactivate the option
killall Finder will close all finders as it has to be restarted

2) Then create a new file in TextEdit for example and add this :

export PATH=$PATH:/usr/local/bin:/Applications/flex_sdk_3.5/bin

(in my example I unzipped the flex sdk in my Applications generic folder)

This will add the flex bin folder path in your system path.

3) Now save the file as ".profile" in your your home directory

4) Now you have to load/reload your ".profile" to make it active, type this in the terminal :

open a new Terminal so that it opens in your home directory and type:

. ./.profile

this will reload the file

5) test if your path has been integrated in the $Path variable, type

echo $PATH

6) Final step, check if Flex SDK is now available :

just type "adt" in your terminal and you should not have any error

That's it, if you want to check if your path

déc 16

AS3 + PHP Crypto classes – secured exchanges between Flash and PHP

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The facts :

As you may know, some tools like firebug helps you tracing incoming and outcoming data between flash and scripts, even if you use POST data.

See below how firebug can trace all variables sent through the POST data :

firebug tracing

So i tried to figure out how to implement a crypted system to secure (a little bit more) these data, with an encryption key if possible.

I found the useful project on the web : as3crypto project

Thanks to this class, you can crypt/decrypt in flash but as far as i looked the sources, there was no information about crypt/decrypt on php side.

But i found another message in a forum where a php code was given, so i mixed both to provide you a simple way to set both sides.

In my example, flash send some data to php using crypted message and PHP answer another crypted message (+ the original decrypted flash message for verification):

pnm_preview

Using the php class : cryptlib.php

create an instance of the class, and call the init with the crypted key as parameter
decrypt the sent message (using POST object)

include_once "lib/cryptlib.php";

// init a new instance of Crypto Class
$crypto = new Crypt;

// init with the encryption key
$result = $crypto->init("PASSWORD");

// get the POST data
$messagefromflash = $_POST ["message"];

// decrypt data
$decrypted_messagefromflash = $crypto->decrypt(utf8_decode($messagefromflash));

but you can also send back crypted data to flash using the "encrypt" method

// return a crypted result to flash
$resultmsg = "Ok, i received your data, everything is fine !";
echo "result=".$crypto->encrypt(utf8_encode($resultmsg));

Using the as3 class : CryptoCode.as

in your main class, create an instance of the CryptoCode class that will crypt/decrypt your data.
call the init method with the same key as PHP (just like PHP code)
then call "encrypt(s:String)" or ""decrypt(s:String)" methods through your crypto instance

// instance of crypto class
 private var _crypto : CryptoCode;
 public var myLoader : URLLoader;

// create instance with encryption key
 _crypto = new CryptoCode("PASSWORD");

// send crypted string to php script
 var variables : URLVariables = new URLVariables();
 variables.message = _crypto.encrypt(tosend_in.text);

// create request with POST method
 var request : URLRequest = new URLRequest("http://www.lecrabe.net/wordpress/demo/crypt/scripts/testcrypto.php");
 request.method = URLRequestMethod.POST;
 request.data = variables;

 // send request
 myLoader.load(request);

If you want to get the whole example, please download the sources.

Enjoy.

sept 29