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View Full Version : FBO's + post-processing + multiple renderings



hardtop
06-27-2006, 04:07 AM
Just a thought: what is the preferable solution (for glow/bloom effect):

* Use a FBO and several render textures, each texture is generated from the previous one, using a 4x4 downsampling shader? (each step has the same size, the original one, hence the use of a single FBO)
* Use multiple FBO's (one per downsampled texture), each FBO rendered into a smaller viewport each frame? (must use several FBO's because texture sizes are different)

> The first solution implies less FBO switching, but larger textures processing into the fragment shader,
> the second one implies more FBO switching, but less and less pixels to process as the texture becomes smaller

Your ideas? :confused:

HT

k_szczech
06-27-2006, 10:04 AM
Use one FBO per render target - similar topic was just discussed.
http://www.opengl.org/discussion_boards/ubb/ultimatebb.php?ubb=get_topic;f=3;t=014567

And you just started a topic on blooming - have you allready forgot about it?
http://www.opengl.org/discussion_boards/ubb/ultimatebb.php?ubb=get_topic;f=3;t=014574

hardtop
06-28-2006, 01:33 AM
Hi,

I didn't, but I found this topic more appropriate and more specific to this particular issue. I didn't mean to crosspost/flood, sorry ;)

HT