Trouble with alpha when drawing into FBO

Sage
Posts: 1,482
Joined: 2002.09
Post: #16
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

Scott Lembcke - Howling Moon Software
Author of Chipmunk Physics - A fast and simple rigid body physics library in C.
Quote this message in a reply
Sage
Posts: 1,234
Joined: 2002.10
Post: #17
(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...
Quote this message in a reply
Sage
Posts: 1,482
Joined: 2002.09
Post: #18
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

Scott Lembcke - Howling Moon Software
Author of Chipmunk Physics - A fast and simple rigid body physics library in C.
Quote this message in a reply
Moderator
Posts: 3,579
Joined: 2003.06
Post: #19
(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
Quote this message in a reply
Sage
Posts: 1,199
Joined: 2004.10
Post: #20
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.
Quote this message in a reply
Post Reply 

Possibly Related Threads...
Thread: Author Replies: Views: Last Post
  png without alpha fine, png with alpha, nothing dave05 6 7,004 Jun 11, 2005 10:31 AM
Last Post: dave05
  Premultiplied alpha trouble Fenris 21 12,104 Nov 8, 2004 12:47 AM
Last Post: aaronsullivan