Archive for the 'filters' Category

AS3: Array.filter R0xr!

Array in AS3 has some nifty features that make managing and manipulating active data much easier. Thanks to Brandon Hall's nooks and crannies presentation at LA Flash for getting me to look. Here's an example of using Array.filter

Here's the minimum filter that doesn't do anything. I default the last parameters as often filters are useful outside of iterating over arrays, but the filter method nicely tells the filter where it is via the 'index' and a reference back to the Array.

Inside com.troyworks.data.filters. I've created a family of filters, in particular RangeFilter that allows inclusive and exclusive of a given range. Here's what a 3-8 filter looks like:


3-8 filter.. 0123456789012345678
* inclusive ---[PASS]----------
noninclusive ---]PASS[----------


The real power of filters is they can be stacked. Here's an example of using a color filter, that looks for color values in the midgray band, but adds an additional filter so that values to close to gray are thrown out.

AS3: Prelude to Tweeny, a fast and flexible Tweening engine

So I've been working over the weekend on the Tweening engine based on Cogs affectionately called Tweeny. I find it highly amusing as I've been working in Flash since Flash 4, I have built so many presentation engines it borders on comical when every new client inevitably asks for a powerpoint lite clone, and consider myself relatively advanced,..yet how much of a loop this one threw me for.

WhileI had an AS2.0 class already working, it's taken me 3 days to get the basics working in AS3.0. This is because yesterday I totally got schooled on Matrixes with Senocular's most excellent tutorial, (my brain still hurts) and then excited by Penner's lurking MatrixTransform and ended up scrapping several paragraphs that comprise most the standard tween engines. I find myself building this next presentation engine in a way that bears no resemblence to most engines I've used or seen, partly due on the architecture difference between AS3.0 and prior, and partly expanding the role of Tweening beyond the simple display classes. Every time I added a new feature or solved a bug, I found a way to make things simpler.
Matrixes are cool, as you can get away with just easing the Begin and End matrixes rather than doing every calculation, plus you get the ability to offset the registration point and skew, features both very useful for the Authoring type interfaces and kids content I'm creating. More power and more speed to boot! In running performance tests, it's about 2x faster than setting DisplayObject.rotate, DisplayObject.width, scale etc as most tween engines do. Not that running those scripts are typically the limiting factor relative to the overhead in rendering, but still it's nice to know that the underlying code isn't a bottle neck.
Like most Tween engines, Tweeny supports a pluggable easing that affects multiple properties (x, y, width etc) with individual ranges (x[-5, 100], pan[-1,1]). But something my math-whiz girlfriend help me realize was that since duration is fixed, the easing equasion (often filled with expensive Math operations) can be calculated once as the 'normal' and then scaled to the others ranges, cheaply with simple * + . This should significantly reduce tweening calculation overhead,...and dammit I like smart particles flying at 60fps!

To further that I realized that the normalized calculation, is easy to broadcast, so that other listeners keep in synch, and can conceivably modularize or patchwork tweens. One of the things that I've wanted to try for awhlie was a way to balance out top-down easing approaches with bottom up physics routine. This usually involves Euler or Verlet accumulation and integration of forces, but most tweening engines are rather possessive when it comes to updating display objects...only one at a time else they start overwriting, where's the fun in that?
Some other features I like, Sound or SoundChannel volume and pan, colorTransform tweening (which I use a lot for configuration dynamically styled UI's) easier constructors for Bounce and Elastic's extra params which I use with kids games.

One thing that I'm not currently planning on supporting soon is a JSON or XML based interface. I find it poor programming practice to do

TweenEngine.create(target, duration, {x:1,y:2, ....})


in AS3.0 when you can do:

var t:Tweeny = new Tweeny();
t.initFrom(target,duration);
t.x = 1;
t.y = 2;

t.addEventListener(...)

t.startFromBeginning();

Because using fully typed classes allow for autocomplete to help fill out the values, offer stricter type checking and setting of defaults. When they are on a line by line they are easy to comment out to turn on and off. There isn't any overhead to parse XML or JSON into useable values. Since it's part of the Class definition it should also be significantly faster than dynamically allocated Object properties on the prototype.
Keeping a tween around, keeps memory and garbage collection from churning, especially for most applications where the tween is reused over and over again to put thing back and forth. I realize why many tween engines opt not to go this route as managing transitions on top of other transitions can get tricky. But know that I know about these issues I'm glad I spent the extra time. Since Tweeny uses the Playhead API, it supports stop, rewind, play, playbackward etc, it's not really different than keeping an mp3 or swf around.
So far it's about 10K, so 3x larger than say Tweenlite, but much of that is the inclusion of the framework/Cogs is useful for many other things, websites and games especially, and I'm still working on it.
The morning had an epiphany and I was able to tie together many of the related ideas into a cohesive model, so I have a roadmap for the next few months, and even a relatively simple Authoring UI for all the features exposed. Looking at the one pager of noteobook, probably 7 boxes, and only a few UI elements, in that largely what I'm working on is creating much of the same metaphors (e.g. timeline) of Flash inside of Flash...just like Web 2.0 is largely recreating the OS inside of the WebBrowser. And Virtualization is recreating the connectivity of electronics. One that note, if your looking for good book on self-referentiality check out Gödel, Escher, Bach .

Flash CS3: Drop Shadow Filter dissapearing on art Bug +MovieExplorer rescue

Took me a bit to find this. We are importing several characters drawn in Illustrator, adding any Filter, while the filter appears fine on the timeline, it dissapears when published.
After some digging errant empty TextFields are getting inserted into the art with no name and no text, and removing them fixes the issue. Though getting to them can be tricky.

Open up Window>Movie Explorer, make sure the first button at the top with "A" is depressed but nothing else, and in the far right icon, press it and make sure symbol definitions is turned on. Then start looking for TextFields that look like "--A (empty)" in the display. Double click on it and insert a long string like "AAAAAAAAAAAAAAAAAAAAAAA" as soon as you click off you should start seeing the text start poking out of the art. If you need help, look at the bottom path on the MovieExplorer "Scene 1-> Layer 1-> Frame 1->" what may be happening is the TextField isn't on the first frame so right-click 'go to location' won't actually get you to it.
I'm unsure what is causing them, it could be the designers just clicking the Text creation tool by accident, or an Illustrator to Flash import bug. I'm pretty sure it's a bug in Flash not to render the filters, but at present I'm too busy to dig deeper.