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Trouble with alpha when drawing into FBO - Printable Version

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RE: Trouble with alpha when drawing into FBO - Skorche - Oct 22, 2012 10:52 AM

Neat, didn't know OpenGL Profiler could do shader edit and continue. That is super helpful.

I forgot about separate color/alpha despite bringing it up yesterday... That makes for a lot more permutations. O_o


RE: Trouble with alpha when drawing into FBO - arekkusu - Oct 22, 2012 01:13 PM

(Oct 22, 2012 10:52 AM)Skorche Wrote:  Neat, didn't know OpenGL Profiler could do shader edit and continue.

It's had that since 2006... before iOS existed...


RE: Trouble with alpha when drawing into FBO - Skorche - Oct 23, 2012 06:23 AM

Irrelevant if it's had the feature since before some other random platform/OS existed if I didn't know it had the feature at all. Rasp


RE: Trouble with alpha when drawing into FBO - AnotherJake - Oct 23, 2012 11:26 AM

(Oct 22, 2012 10:20 AM)arekkusu Wrote:  Math is your friend.

It would help if I didn't suck at math so much!

(Oct 22, 2012 10:20 AM)arekkusu Wrote:  In recent GL versions, you have 19 blend factors (fully orthogonal) and 5 equations. And separate factors and equations for RGB and Alpha. And separate enables, factors, and equations for up to eight draw buffers. That's lots of combinations. ... The number of possible combinations is really, really big.

Holy cow, I've fallen behind the times. Looks like I might need to brush up on my blending math Rasp


RE: Trouble with alpha when drawing into FBO - TomorrowPlusX - Oct 23, 2012 02:07 PM

So, as a followup - this morning I used OpenGL profiler for examining GL state and found my bug in about 30 seconds.

And guess what? GL_BLEND had been disabled. There aren't enough facepalms for how I feel.

But the good news is I learned how to use GL Profiler's state examination features. And I found a few bugs while completely taking my game apart to figure out what was going on.