Droste / Escher Effect in AGAL

by Devon O.· December 31, 2015· in Actionscript, Shaders· 0 comments tags: agal, effect
One last bonus post for the new year, seeing as how I remembered I had a blog. This is really just a snippet I would ordinarily post on Wonderfl, but Wonderfl seems not to be working for me lately (if anyone wants to check out my Wonderfl profile and let me know if they can view any of my posted codes, I’d appreciate it. But I can’t). [crayon-5fbc831030563999979928/] Happy New Year!
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Starling Filter Collection

by Devon O.· July 05, 2013· in Actionscript, Shaders· 9 comments tags: agal, starling
I mentioned this earlier, but it was really just a footnote at the bottom of a previous post, so it may have been easily overlooked. In any case, I’ve set up a Github repo containing a collection of filters for the Starling framework I’ve written (or ported as the case may be) which may be used for personal or professional projects. Of course, if you’re not a fan of Starling or are using another Stage3D framework, you could always just grab the AGAL from these and use it elsewhere. At the the moment, the collection contains these items: Warp Filter: does bezier curve warping on the left and right edges of the display object being filtered. Could be animated to produce a Mac ‘genie’ style effect. example God Rays Filter: creates a god rays or fake volumetric lighting effect on the filtered display object. Not compatible with Context3DProfile.BASELINE_CONSTRAINED mode. example Two Spotlight Filters: The first is an oldie that has a decent flicker effect example The thing I disliked most about the original version though, is that on rectangular textures, the effect will be oval shaped (stretched by the texture itself). The new version (Spotlight2Filter.as) remains round on any texture and […]
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Warp Filter for Starling

by Devon O.· May 26, 2013· in Actionscript, Flash, Shaders· 5 comments tags: agal, starling
So, perusing teh internets once again, looking for something interesting to play around with, I came across this blog post of Pavan Podila (from 2008!). In the post, Pavan presents a WPF pixel shader which warps an image using bezier curves. I thought I’d have a go and reproduce the effect in AGAL and plunk it into a Starling filter. Essentially, the filter adds 8 control/anchor points to the filtered display object – 4 on the left edge and 4 on the right. You can move those points from 0 (far left) to 1 (far right) and the image will warp and curve to fit those points. You can check out the end product here. In theory, with a little patience and finesse, you could animate those points to create a nice looking Mac style genie effect. Or, whatever. As I was working on that filter, though, I realized I had a decent sized Starling filter collection built up and spread out all over the shop. For that reason, I decided to put them all together and upload them to Github. So, now, you can download all the filters I’ve posted about (and one or two that I haven’t), including […]
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Alpha in Starling Filters and Basic Branching in AGAL

by Devon O.· December 09, 2012· in Actionscript, Shaders· 3 comments tags: agal, starling
Back in September, a Chris posted a comment on this blog asking about a Starling filter that would create a circular mask over an image. Being the lazy sort I am, I never got back to the commenter (Sorry, Chris). Some stuff I was doing at work the other day reminded me of the question, though; and, although it’s a relatively simple thing to do, the task raises two interesting problems I thought deserved a whole post rather than just a quick response. In plain English to create a circular mask we would want to do something like this: Find the distance of every pixel in an image from the center of our circle. If that distance is greater than the radius of our circle then we should set its alpha to zero. Well, to find distances we can turn to the good ol’ Pythagorean theorem – distance equals the square root of distance x times distance x plus distance y times distance y (I’m still amazed I use information I learned in high school in my day to day life. Who’d a thunk those teachers were on to something?). In a sort of pseudo/AS3 code, our operation may look […]
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Filters in Starling

by Devon O.· September 08, 2012· in Actionscript, Flash, Shaders· 15 comments tags: agal, starling
Just in case you happened to miss it, the most recent version of the Starling Framework (the one which you can pull from Github, that is) now supports custom filters. You can check out the official announcement here. Using filters in Starling couldn’t be easier – you just assign a filter to the filter property of any Starling DisplayObject, like so: myStarlingMovieclip.filter = myStarlingFilter; Creating your own filters is also pretty easy – assuming, that is, you have a moderate handle on AGAL and can write a decent fragment shader. To do so, just extend the FragmentFilter class and in the createPrograms method drop in your own fragment shader. In the activate method, you can upload whatever constants the shader requires to the Context3D instance (which is accessible as the variable ‘context’). I’ve written two myself, so far: a PixelateFilter (which was improved by Daniel Sperl of the Starling / Gamua team), and a NewsprintFilter which produces a kind of black and white halftone effect (the controls of this filter are kinda touchy and can produce some very bizarre and unexpected results. The default settings make a nice effect, in my opinion, and you could just leave them as is if […]
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Devon O. Wolfgang

AIR | Unity3D | AR/VR

Unity Certified Developer

Technical Reviewer of “The Essential Guide to Flash CS4 AIR Development” and “Starling Game Development Essentials”

Reviewer of “The Starling Handbook”

Unity Engineer at Touch Press.

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