All posts by Aymeric

About Aymeric

Freelance Interactive & Game Developer.

The Citrus Engine goes on Haxe NME, welcome to the CitruxEngine

AS3, Box2D, Citrus Engine, Flash, Games, Haxe, NME, Physics, Programming, , , , , , , , , , ,

One month ago I started to work on the CitruxEngine. I was very confident with Haxe performance on mobile and NME cross platform opportunities. And now, I can say those are awesome!

In April 14-15th, I was in Paris to assist to the Haxe conf 2012. It was really cool, Silex Labs has made a good job! Conferences were very interested and the community greatly friendly. And I had the opportunity to make a lightning talk concerning my contribution to the Citrus Engine 2D game framework and its port on Haxe NME. The presentation was a bit from scratch, but that was a good experience! I’m very happy to be the first to start the lightning talk, since there were very serious projects 😀

CitruxEngine Github.
CitruxEngine Demo. Simple demo which have been tested on Flash & CPP (using left/right key and spacebar) and iOS (touch & accelerometer). There are sound, animations (idle, walk and jump) and physics.
The port is currently not finished!

I will not present some code here. If you are already familiar with the Citrus Engine, there will be no problem. Take a look on the example on Github.

HTML5
When I started the port, I would the CitruxEngine be as cross platform as possible. HTML5 is promising, and Niel Drummond the man behind Jeash has made an incredible job! However I found that the Haxe NME Box2D port has not very good performance with HTML5. So I’ve dropped the HTML5 target at the moment, but I keep an eye on Jeash!

Box2D
Thanks to Haxe NME, Box2D runs very well on mobile! This is mostly the reason why I’ve started the CitruxEngine. The Citrus Engine uses the AS3 Alchemy version of Box2D which has some differences with the original. It seems there is a bug with the Haxe NME Box2D port : the beginContact & endContact listeners are fired all the time if a dynamic body is on a static body (like a hero on a platform), whereas it fires only once if there are 2 dynamics bodies. This behavior is blocking me.

SpriteSheets
I made my test with the spritesheet haxelib which uses SpriteLoq. At the moment it works well. I’ve not made serious test with animations.

Level Editor
I love how the Citrus Engine handles Flash Pro as a Level Editor. I would like the Haxe NME version handles it as well. But at the moment we can’t read AS3 code in a SWF file (it is the way that class and properties are defined), so I need to think to an external way. Maybe it’s time to reconsider the Level Architect!

Console
The console is really a cool feature of the Citrus Engine, it will be available in the CitruxEngine too. I’ve started to implement it, but it’s not ready yet.

I will continue to work on the CitruxEngine, but now I’ve to focus on my school project using Objective-C, it’s really hard to get back when you have tested Haxe power ! In less than two months I will be graduate and looking for a job, future is exciting.

Thanks to postite & elsassph for their help!

From Box2D to Chipmunk

Box2D, Chipmunk, Physics, ,

Hey there, I’ve been very busy this last weeks working hard on my 2nd school year project, a mobile game. In a few weeks, I will explain it, but for now let’s do some programming stuff!
The game is a side-scrolling 2D game. See Canabalt or Jetpack Joyride, they are great games!
Developing for iOS, I used Sparrow framework. It is awesome, and really easy to learn coming from AS3 & Starling.

Why did I develop in Objective-C since AIR 3.2 is out ? Refer to my previous post about my personal preference and the future of web development ; I decided to learn Objective-C and this project is really a good opportunity! I have followed the news about HTML5 and my opinion didn’t change… Moreover, for a long range project it is preferable to have the best workflow!

Since I used the Citrus Engine, I felt in love with physics engine and particularly Box2D. It is very useful & powerful for game development, but it has some hard constraints. With this project, I wanted to try an other physics engine. My choice was Chipmunk.

This post will not compare features, there are already a great post there, but how to move quickly from Box2D to Chipmunk. Thanks Scott Lembcke (Chipmunk’s author), for your clarifications.

QUICK OVERVIEW :
– Box2D : Box2D is an open source C++ engine for simulating rigid bodies in 2D. Box2D is developed by Erin Catto and has the zlib license. While the zlib license does not require acknowledgement, we encourage you to give credit to Box2D in your product. The manual.
– Chipmunk : Chipmunk is a fast and lightweight 2D rigid body physics library written in C. The documentation.

UNITS :
Box2D uses meter/kilogram/second (MKS), Chipmunk uses pixel. There is no units for the mass, you defined the value you want, but stay logical between objects. The time is not clearly mentioned in Chipmunk, it doesn’t express in seconds but floats. Box2D uses real world units because it has a number of tuning threshold values, and the default values are set to be sane values for life-sized objects. Chipmunk’s algorithms mostly avoid the need for tuning values so that you can use whatever arbitrary units makes most sense to you (pixels, meters, inches, etc). Likewise for time and mass.

SET UP WORLD :
Box2D uses the term “world” whereas Chipmunk uses “space”. Both defined gravity & iteration step. Body’s gravity is difficult to manage in Box2D and Chipmunk if you want your objects to have a different one. You may set up a gravity(0, 0) to your world/space and manage the gravity into each object using a variable and updating its velocity.

REGISTRATION POINT :
Both have body’s center as registration point.

RIGID BODIES :
Box2D uses two objects to define a body : body (user data, position, velocity, forces, torques, impulse…) & bodyDef (body type definitions, and init values). Chipmunk uses only one object defining mass (which is automatically calculated in Box2D) and moment which represent inertia for the body.
Box2D has 3 body types : static, kinematic, dynamic ; Chipmunk kinematic bodies are named rogue.

FIXTURES :
Box2D fixture/fixtureDef defined shape, density, friction, restitution and filters. There is no fixture in Chipmunk. Restitution is the elasticity property on shapes. It doesn’t store density on a per shape basis though. You have to calculate that into the mass manually..

SHAPES :
In Chipmunk, you can attach as many shapes to a single body as you need to in order to define a complex shape. Shapes contain the surface properties of an object such as how much friction or elasticity it has. It means than you can create a simple platform body and add all the shapes to it even if they are not close (a border bottom, a wall…).

COLLISIONS :
With Box2D you can know dynamically which is the other body you collide, in Chipmunk you may use this method too. You may also defined a collision handler’s function between the typeA and the typeB with function references defining collision start/end & pre/post solve. In Box2D you managed collision thanks to the fixture, in Chipmunk you add the “listener” to the space.

JavaScript slider made with haXe and JQuery

Haxe, JavaScript, , , ,

After playing with haXe and Php, it was time to try haXe and JavaScript! I used the JQuery library included in haXe. For more information on haXe JS take a look on its website.

Click here to see the slider in action. It uses keyboards and a timer. The slider centers a picture with a 50px margin, there is also a red or green filter.

Continue reading JavaScript slider made with haXe and JQuery →

Using native Php with haXe Php

Haxe, Php, , , ,

Recently I had some time to dig more with haXe Php. The major question was how does it integrate with existing native Php ? I’m glad to say that it works fine!
Let’s start a quick overview of our native Php file test (Simple.class.php) :

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<?php
function makeSimple($text) {
    return new Simple($text);
}
 
function affichText($text) {
    echo $text;
}
 
class Simple {
 
    public $text;
    public $tab;
 
    public function __construct($text) {
        $this->text = $text;
        $this->tab[0] = "index 0";
        $this->tab[1] = "index 1";
    }
 
    public function doPrint() {
        echo $this->text;
    }
 
    protected function changeText($text) {
        $this->text = $text;
    }
}
 
class Simple2 extends Simple {
 
    public function __construct($text) {
        parent::__construct($text);
    }
 
    public function makeChange($text) {
        $this->changeText($text);
    }
 
    public function associativeArray() {
 
        $tab["num1"] = "number 1";
        $tab["num2"] = "number 2";
        return $tab;
    }
}
?>

There are a simple function, some inheritance stuff and an associative array which is very common in Php.

Now the haXe part :

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package;
 
import php.Lib;
 
class Test {
 
    static function main() {
 
    	new Test();
    }
 
    public function new() {
 
        // import php file
    	untyped __call__("require_once", "Simple.class.php");
 
        // call a php function with an arg
    	untyped __call__("affichText", "first msg </br>");
 
        // create a php object with an arg
    	var myPhpObject:Dynamic = untyped __call__('new Simple2', 'second msg </br>');
 
        // manipulate the object
    	myPhpObject.doPrint();
    	myPhpObject.makeChange("some new text </br>");
    	myPhpObject.doPrint();
 
        // print an array
        Lib.print(myPhpObject.tab);
 
        // trace the index 0 value
        trace(myPhpObject.tab[0]);
 
        // make some native php
        untyped __php__("echo '</br>php native from haXe !</br>'");
 
        // we need a Hashtable to parse an associative array from php :
        var phpAssociativeArray:Hash<String> = Lib.hashOfAssociativeArray(myPhpObject.associativeArray());
 
        // trace the key value num2
        trace(phpAssociativeArray.get("num2"));
    }
 
}

The output log : 

first msg
second msg
some new text
["index 0", "index 1"]Test.hx:32: index 0
php native from haXe !
Test.hx:41: number 2

If you are using everyday libraries/tools written in Php, you may wrap them with haXe for more comfort. Take a look there : Wrapping External PHP Libraries & the haXe Magic.

Unfortunately, there isn’t lots of ressources/tutorials for haXe Php on the website, I will update this post if I go deeper in haXe Php development. It is very pleasant to write Php this way. Give it a try!
haXe API.

And because memes are fashion :

haXe workflow with Sublime Text 2, Php & nme examples

Haxe, NME, Php, Programming, , , ,

A good IDE is the developer’s best friend. FDT is my favorite one to code AS3 stuff, however I’m not very satisfied with haXe integration… it could be better. A good source code editor is also an amazing tool. I’ve found Sublime Text 2 some months ago, and it sounds always awesome to me. There is an extension which add Package control management to ST2 for adding new plugin, like haXe one.

Come on, download Sublime Text 2, install the Package control and haXe plugins!

That’s ok ? Now we can create a simple Php project.
Create a new file, save it as Test.hx and add this code :

package;
 
class Test {
 
    static function main() {
 
    	new Test();
    }
 
    public function new() {
 
    	var number:Float = 4;
 
        trace(number + 5);
    }
}

Then press ctrl (even if you use a mac) + shift + b. A new file called build.hxml is opened with some code generated to compile. You should just need that :

# Autogenerated build.hxml

# www
-php www
-main Test

Then press ctrl + enter. Your php files are generated. Pretty easy!

Now let’s make more stuff, a PDO connection with a simple query.

var cnx:Connection = PDO.open('mysql:host=localhost;dbname=igobelins', 'myUsr', 'myPwd');

If you press ctrl + space you have some greats auto-completion features! ctrl + i and the class is imported. If you make some mistake your code is highlighted in pink.

Our php stuff :

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package;
 
import php.db.Connection;
import php.db.Mysql;
import php.db.Object;
import php.db.PDO;
import php.db.ResultSet;
 
class Test {
 
	public var cnx:Connection
 
    static function main() {
 
    	new Test();
    }
 
    public function new() {
 
      cnx = PDO.open('mysql:host=localhost;dbname=igobelins', 'myUsr', 'myPWd');
 
      var sql:String = "SELECT * FROM configs";
 
      var results:ResultSet = cnx.request(sql);
 
      for (result in results) {
       	trace(result.user);
       }
 
       cnx.close();
    }
}

According that you have a field user in your database, it will show the names.

Ok that was pretty cool, what about nme ? Go on this page and download the haXe project. In ST2 go in File/Open Folder… and select the Folder you have just unzipped. It should show the different folders & files in a left panel. Browse the Source and open SimpleBox2DExample.hx and then press ctrl + enter. It is compiled for flash and open quickly the result in the Flash Player. Ok but with NME I would like to target cpp. No problem press ctrl + shift + b then select cpp and compile. This way you can quickly change the target.
He wait, there isn’t html5 target !? I don’t know the reason but it is not offered. But you can add it (thanks to Julien Roche for the tips) : on Mac open the file Users/YourUserName/Library/Application Support/Sublime Text 2/Packages/HaXe/HaxeComplete.py and add html5 to nme_targets on line 124. Restart ST2, press ctrl + shift + b select html5 then compile. You have a new target 😉

Sublime Text 2 and the haXe plugin are awesome, but so far it can not be as powerful as an IDE for debugging. No breakpoint for example, anyway it is already a great tool for a simple code editor!

Recently, JetBrains has released a haXe plugin for IntelliJ. We should keep an eye on it!

Air NativeProcess and bash file to compile haXe nme project

AS3, Flash, Flex, Haxe, NME, Programming, , , ,

Last week I’ve made some test with haXe nme and box2d. The result is awesome : beautiful perf and a quick export on the target required! When I tried to run box2d from flash on a iPhone there was really bad performance : 10 dynamics objects – 5 fps. With haXe nme, more than 80 dynamics objects and 30 fps… that the power of native app. And for the fun I had an html5 box2d export, but not running smoothly.
At the moment, what I’m really missing is a powerful IDE for writing code and don’t use the console (even if it works great). FlashDevelop is the best one, but runs only on windows. Sadly, FDT supports haXe but not the nme. However it seems that JetBrains are working on a plugin for haXe and nme! But right now, I use Sublime Text 2 with the haXe plugin.

Anyway, I thought it would be cool to have a simple utilitarian app to create nmml files and compile projects with options (targets, mode, …). An Air application seemed to be an elegant way. Let’s go for a proof of concept on this last part :

The problem was how to run terminal command line with Air? The NativeProcess class provides command line integration and general launching capabilities. The NativeProcess class lets an AIR application execute native processes on the host operating system.
So it means that if I write a simple bash file, I’m able to run it with AIR!

Continue reading Air NativeProcess and bash file to compile haXe nme project →

CitrusEngine goes Stage3D with Starling

AS3, Box2D, Citrus Engine, Flash, Games, Programming, Starling, , , , ,

Hey folks, happy new year! My previous post go back from 1st december, I’ve been really busy : adding Starling in the CitrusEngine, learning iOS and working on my 2nd year school project. And obviously some great holidays between christmas & the new year.

Today I’m very pleased to share with you the Citrus Engine working on Starling! For those who don’t know it, it’s a platformer game engine using Box2D Alchemy and Signal libraries. However, it’s not only made for platformer games, you can use it for every 2D contents even if it isn’t a game thanks to its great Box2D management. So before this update, it has supported : Box2D physics, Signals event, a Sound Manager, a Console for quick debugging & tools, Input management, lots of defined objects like Hero, Baddy, Platform, Coin, Sensor, Moving Platform…, parallax, a Loader manager, level editors thanks to its own (the Level Architect made with Air), or using Flash Pro, or Gleed2D. 2 views : the flash display list and blitting, and a layer management!

Thanks to this update, the CitrusEngine now support the great stage3d framework Starling and I’ve also added 3 new objects Cannon, Teleporter & Treadmill, a Level Manager and an abstract class to store the game’s data. This two last things are optional you may use it or not. In this blog post I will explain how I’ve adapted the CE for Starling, and my updates with some examples. For a quick getting start with the engine please refer on its website or to the tutorials on this blog.

But let’s stop chatting, it’s time to test the demo :
Click here for the demo.

Continue reading CitrusEngine goes Stage3D with Starling →

Objective-C basic interface

iOS, Mac, Objective-C, ,

In this tutorial, we will see how to create a basic interface in Objective-C with code only. It will be one TextField and one Button. Yeah, just that and we will need 6 files! And maybe we will use some inheritance.

ActionScript 3 is really a smart language, it is very quick to create what we will do. Something like 10 lines of code… Anyway, in this tutorial I will not make comparisons between ActionScript 3 and Objective-C like the previous one unless it is really useful.

Open Xcode and create a new iOS empty application, disable everything. Many files are created, but we will use only AppDelegate.h and AppDelegate.m In the AppDelegate we will init our applications.

Continue reading Objective-C basic interface →

Box2D Sound Spectrum

AS3, Box2D, Citrus Engine, Flash, Physics, , , , , , , ,

This week is really challenging : my second year school project has started this week. It’s a team project with a graphic designer, a designer, a project manager and me as a developer. Our concept sounds very promising!

No matter, this short introduction explained that I’m really busy, so this experimentation is not perfect due to a lack of time…
Anyway, click here to see a sound spectrum made with Box2D and the Citrus Engine using BitmapData.

Continue reading Box2D Sound Spectrum →

From AS3 to Objective-C

AS3, Objective-C, Programming, , , , , , , ,

Some days after my article about what is happening to Flash developers, I have started to learn Objective-C and I already like it!
In this post, I will try to compare ActionScript 3 to Objecitive-C. I’m really new to Objective-C so if you find any errors in what I say, please add a comment to correct me.

According to Wikipedia : Objective-C is a reflective, object-oriented programming language that adds Smalltalk-style messaging to the C programming language. Today, it is used primarily on Apple’s Mac OS X and iOS. Objective-C is the primary language used for Apple’s Cocoa API.

Continue reading From AS3 to Objective-C →