I've done some more tweaking, and I've managed to draw an opaque quad with a transparent window in its center. The reason one of the quads was clipping before seems to have been depth (I was drawing a couple of its vertices with 0.5 depth and for some reason it wasn't playing nice). The "window" is created by drawing a 0.0 alpha quad in the appropriate location with alpha func set to GL_ONE, GL_ZERO. The next thing I need is to be able to achieve the desired effect by subtracting the alpha of the "window" from the opaque quad (this way I could do overlapping lights and gradients). alpha func GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA doesn't seem to work for this. Any suggestions?
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Posted 15 June 2012 - 09:40 AM
After lots more tweaking and digging around, the blending proof of concept is now functional (after some fiddling and experimentation with the blend subract and minmax extensions). Thanks for your help @Ohforf sake.
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