GLSL Glitch effect

I was speaking earlier with Dan about some QC programming / GLSL stuff and accidentally hit on an interesting effect with a GLSL Shader -> GLSL Grid within a Render to Image patch in Quartz Composer, and I quickly made it an effect to use within the in progress QC App. The basic effect is actually neglecting to add a Clear patch within the GLSL Shader macro patch. I was showing Dan how to do something and prototyped a quick QC patch. I noticed some funky gitching and thought I may have done something wrong (the GLSL shader code is simply a texture passthrough and does nothing in and of itself). The fun happens when disabling the Clear patch, the Render to Image macro outputs some fun pixel trash, but, its actually a proper QCImage image prototype, so you can safely apply effects to it and treat it as a proper effect input. Whats nice is you dont know exactly what you will get – this is real glitch. Im curious how this looks on folks with ATI graphics cards, and if this effect will react differently on different OS revisions and OpenGL driver updates.

QT Video:


3 Responses to “GLSL Glitch effect”

  1. karl Says:

    uncle nice glitch, looks very unexpected, vade! is the offset color also a glitch or is it in the patch? do you have some parameter to have a sense of control? i would love to have this as a app!! wanna trade

  2. Bryan Teoh Says:

    Wow! So this is specific to quartz composer or do you think the same thing could be done in jitter?

  3. vade Says:

    The chromatic delay effect can be done in jitter, but the glitch is taking advantage an actual real rendering issue (if the user exploits it on purpose) with a patch or two in QC, so, alas, I dont think this can be done with Jitter unless you could emulate the rendering pipeline of the QC patch.

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