Actionscript3, Flash, Java, C#, C++, Algorithms & Imageprocessing
Ralph Hauwert put a very interesting blog post up no his blog about Adobe Alchemy. Basically he was reading my mind with this post.
I want to a step further now. But please keep in mind that I am definitly not a compiler expert or have deep knowledge of the Flash Player. Everything I write about is in my opinion common sense and comes from a long time of reverse engineering and autodidactic learning.
PixelBender Outline is a simple view for Eclipse. It allows you to browse through compiled PixelBender kernel files (pbj). Usually it is quite annoying when working with PixelBender. You always have to debug the shader if you did not write it yourself to know about parameters and stuff. The PixelBender Outline view allows you to navigate through that information in a comfortable way.
PixelBender Outline is working with FDT only. Just grab the JAR file and place it into your Eclipse plugins folder (…/Eclipse/plugins/) to install it. After restarting Eclipse you can open the view using Window->Show View->Other->PixelBender->PixelBender Outline.
The outline is updated everytime you select a *.pbj file in the Flash Explorer.
At the end of my FOTB session I wanted to show you my latest tool called AS3V. Time was short and there was a small glitch so I could not show it. But now I can explain what AS3V really is without having to rush.
AS3V is basically a tool that can check for syntactical correctness. It will do with your code what a compiler does but it keeps formatting metadata. That way it can generate an XML skeleton of your code and apply rules on the XML.
You can have a look at the first output AS3V produces here. The original source code is included in the comment at the top.
As you can see it will be possible to force coding standards for instance and to warn if code could be optimized. I hope that it will be possible to have a first version of a stable parser soon. ANTLR is still giving me a lot of trouble but it is the first time for me working with such a tool as well.
Here are the slides from my Flash On The Beach 2008 session “AudioTool’s Private Parts”. 2mb without a prelaoder. You will need Flash Player 10 to pass through to version detection or you can save the SWF directly to disk and watch it with Flash Player 9.
I wrote a while ago about our tween engine at Hobnox but I did not post any performance demos.
Here are the results for 1000 DisplayObjects with manipulation on their scaleX, scaleY, alpha, x, y and rotation properties. It is also very important that you take a look at the memory behaviour. A click starts the tweening.
As you can see it makes a lot of sense to stay type-safe and to manage the memory you are using on your own.
I will talk about those concepts in my next session AudioTool’s Private Parts in Brighton and Boston. Since optimization on a code level is trivial the main performance boost is achieved by re-thinking algorithms, structures and concepts. I guess one of the most interesting topics will be the optimization of our cable solver which was running O(n^2) (really!), then O(n(n+1)/2) and could be minimized to a rare O(n(n-4)/2) worst-case.
Tinic posted today his PixelBender assembler and disassembler. This makes me happy, because now I can post an experiment I could not show for a while.
If you know PixelBender, than you know that you can not create loops. What you could do is unroll all constant loops with a fixed length. If you know simple convolution filters like a blur, you know that you need an xy-loop and you know it should not be possible with PixelBender at all. Let me prove you wrong and have a look at dynamic loop unrolling with PixelBender (be careful with high values!).
I built a library to assemble and disassemble PixelBender kernels at runtime. I wrapped it also in a high level API so basically you can create a new Kernel by doing var kernel: Kernel = new Kernel();. Then when you need your shader as a ByteArray you simple call kernel.compile(). There are still some glitches here and there but I hope that I can release the source code pretty soon.
Last night I spent about 9 hours writing a build script for the AudioTool allowing us to compile each plugin into its own SWF container. I think it is the first time a Flash project is taking more than 5 minutes for me to compile completly.
I figured out that it is definitly not easy to handle the mxmlc or compc in a way we needed it to be. The point is that we have for each plugin three modules A, B, C and a library D. A depends on D. B depends on A and D. C depends on A, B and D. Now to make it even more complex we have A, B, C and D in one project so that developing in this environment stays still simple. The solution to compile all modules in a way we need them to be was first generating unique entry points for the SWF files because we do not want to work with SWC libraries (or the SWF inside the SWC package). After having the unique entry points we compile D (and its dependencies as well) without including the source of A, B or C. Afterwards we can compile A. But B is dependent on A so we have to compile a SWF for A and then a SWC for A so B can link to A as an external library. C is also analog to this but needs B as a library as well. In the end it was 5am and I was happy to have the complete build working which generates a lot of SWF files and SWC libraries.
Since it is very hard to configure Ant for this (I was using XSL in the beginning for automated code generation) I started developing my own Ant tasks. I have to say that it is really simple and saved us hours of work. We have now one single XML file containing the dependencies and the Ant task will do the rest (code generation, compile tasks, etc.).
This FDT update makes me so happy that I have to post about it. The Powerflasher FDT developers implemented the new Vector.<T> syntax. Hooray — we can make full use of the Vector class!
FDT is implementing it also in a nice way. So for instance if you have a Vector.<int> named vec and you write var sprite: Sprite = vec[0] this will result in an error because FDT knows that your Vector was typed int.
There are still some glitches here and there but I hope this will be fixed soon as well.
By the way I am using the beta site to update my FDT — so if you want to have Vector support too you should use the beta update site.
I have started working on AS3C at the end of last year. After a quick prototype the development stagnated and I added just several fixes and tests to the code. Basically I started AS3C as a complete C# newcommer and because of that the code is very ugly.
Due to the fact that I do not have much free time to continue developing AS3C I think it is the right time to release the source-code on the one hand and to let people experiment with it on the other hand.
You can either download the sources and build AS3C manually (you will need zlib.net) or download a binary from trunk/bin/.
When using AS3C you will need the ActionScript from the SVN. Remember that you write real ActionScript code which gets translated by AS3C. There is also one undocumented and very experimental feature existing. If you run as3c.exe -optimize main.swf you could get some speed improvements if you have heavy loops using the Math class. But it could also destroy the SWF so do not forget to make a backup :o)
A quine is a programm emitting its own source-code. I guess this is the most simple variant one could produce.
