My solution was to create an indexed collection which i can benefit both worlds of Dictionary and ArrayCollection , with that in mind I designed and implemented the IndexedArrayCollection.

The collection extends ArrayCollection and adds the capability of indexing a single member of an object in the collection (I assume that each element is an object).

IndexArrayCollection constructor receives two arguments first is a source array and second is the index field name (attribute name).

box2d is an overkill for pong , but what do you know, it’s damn easy.

the gist of it is :

• layout
• world setup
• event handling

Full source code hosted in github Pong in Box2DFlex.

The layout

a SkinnablePhysicsContainer holding two border containers (named p1 and p2) which are the player bars and corelating p1Goal and p2Goal which will act as hit area for the ball graphics element (Ellipse).

Setting Up the World

when the application loads it maps all elements in the physics container to box2d bodies , in woldSetup method i specified different mapping types to components

The key thing you need to know is that you want  p1, p2 and the goals controls to be kinematic bodies so

• they are not affected by collations and
• they do not collide with each other
• they affect dynamic bodies colliding into them

and an event handler onBodiesContact that triggers when two bodies collide .

Event Hadnling

onBodiesContact is triggered each time two bodies collide indie it i do a simple test to see which to bodies collided and triggers the respective indicator.

world_mouseMoveHandler is handling the translation of mouse position and movement of p2

for that box2d flex employs several algorithms and converts a complex shape to a set of polygons (I took the idea from 3d modeling)

at this point i would like to give credits to

• sakri.net for he’s shape outline algorithm
• makc.coverthesky.com for he’s polygon2d

both state that their algorithms are far from perfect but for a v0.2 it’s a good start.

in this case I’ll start from the demo and then go into the code so see how the doll bellow is segmented to several triangles.

first thing is to understand how what the doll constructs of , in our case it’s a graphics

our object can be comprised of anything , graphic shapes , ui controls, images etc’ it has only one caveat - It’s edges must be transparent .

The next thing it to take a look at our physics container

you can see that autoStartPhysicsEngine is set to false. By default SkinnablePhysicsContainer maps all it’s flex objects to box2d shapes on creation, this time we want to interfere before hand and give the engine a different directive to try and map the shape not by it’s boundingBox but by it’s actual edges.

This is done by actionscript code, in which we tell our physics container to parse complex shape and pass it with the shape id and a parsing object, afterwards we call the physics engine to start.

you can see the the shape parser receives an argument specifying the quality of it’s mapping , this is done for performance  improvement but might impair edges fidelity.

First thing we create add a SkinableContentContainer to and drop some contorls inside it

This, still, does not do anything fancy it just initializes box2d and registers & measures all controls inside our physics container.

next step we add some bindable controls that will change our physics gravity and debug

and the bindable properties to our physics container

now we can play with the gravity sliders and see flex controls bounce around

In a previous post demonstrating box2d integration with flex I made a promise (mainly to myself) to share the demo code. When I started to review with sharing in mind it looked cumbersome and overly verbose. So I started cranking on it fixing and straightening the code & architecture and step by step I realized that I’m creating a small Integration layer rather then a POC.

Announcing Box2DFlex

Getting Started

In order to play with Box2dFlex you will need flash builder 4 and Box2DFlex source which is hosted on GitHub.

and in four simple steps you should

1. download the source code
2. inport the Box2DFlex and Demos  projects into flash builder 4
3. compile
4. Play with the eamples in Box2Demos project

Building Your Own b2d World

1. download the framework
2. create a new project
3. add refrence to <Box2DFlex dir>/Box2dFlexLib/bin/Box2DFlexLib.swc
4. in your MXML add a new SkinnablePhysicsContainer
5. set the container’s yGravity property to 10 and autoStartPhysicsEngine to true (yGravity=”10 autoStartPhysicsEngine=”true”)
6. if you want your world to contains walls use setBoundries=”true” attribute
7. place a button inside SkinnablePhysicsContainer and set it’s properties (width / height / label)
8. run the project

Not so elegant solution, but a solution non the less. the trick is to pass the flex component coordinate and position the HTML input accordingly , and on the HTML side handle keyboard and mouse event to let the flex developer feel @ home with regular focus and key press events.

Add the following MXML component to your flex project

Add the following code to your html page

we write in right to left order – that means  in the opposite direction of most languages. Letters and words are left to right, though  numbers and other symbols remain right to left.

Through the years I’ve seen (and even wrote) noumerous attempts to build an AS class that will provide this functionality to flash, all of them suffered from quirks and different edge cases.

About a year a go Adobe published a new text rendering engine (TLF) which wasn’t integrated into Flex3 framework , and though flex4 includes the new TLF some still need to work with the 3.x framework so here is a simple example of implementing true RTL label in flex 3 note that you need to download and install Text Layout Framework on your development machine in order to compile the code.

XpostCS .

Besides collapsing the form you can also drag N drop the items to see collusion and gravity. code will follow soon .. I hope ..

In the application I use TransformGestureEvent dispatched from flash 10.1 player. unfortunately this is the only event fired in Mac and only in AIR mode – adobe it’s lame.

TransformGestureEvent event availability

TouchEvent availability - windows only (and iPhone but i guess it’s not applicable any more)

the first version was a bit stale so I’ve added KineticMovementManager which adds a drift effect (like when scrolling an iPhone scroll) but it’s still a work in progress so don’t relay on it.

download source

download installer