Pixel shading is a feature supported on graphics hardware starting with the Radeon R200 based cards (8500-9250) and the GeForce FX series. Though pixel shading was first specified in OpenGL 1.1 and DirectX 8, it wasn’t implemented by consumer grade hardware until OpenGL 1.4 and DirectX 8.1. These consumer grade cards are enumerated on the Adobe Labs AIF toolkit page . Before shaders existed the graphics pipeline for real-time rasterisation (via a GPU) was fully procedural and the only means by which a programmer could interact with that processing pipeline was to use the standard APIs. However with shaders, any 3D author has the power to fully control the rasterisation algorithm at the frame buffer level. The only downside to this level of control is that the shader must be pre-compiled before put into use. Nvidia has recently opened the doors up more by introducing CUDA. It would be really interesting to see Adobe produce something similar (but cross-platform) with some future version of Flash. Whether that would be a good or bad thing can be debated and discussed for a long time.
Last night I decided to break out the AIF toolkit again and work some mathy expressions into a filter. Up to this point most of the filters that I’ve seen are along the lines of what you will find in Photoshop’s menus. Those filters certainly aren’t bad, but I’ve always been more interested in how an image can be sampled and reconstructed in a manner not unlike what’s found in the 90’s DJ scene. So with that introduction I’d like to demonstrate my latest filter.
Just like in Flash, you can think of the canvas as a 2D coordinate plane. For this filter I used a few trigonometric and polynomial expressions in combination. Most of the polynomial coefficients are also parameters that you can manipulate which is where all the fun is. More to come, stay tuned.
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