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dithering

Started by vanne Jul 17, 2001 at 9:48 AM 2 replies 650+ views

Original Post

Jul 17, 2001 at 9:48 AM

sorry for spamming the forum, but ah

I have trouble with something that looks like dithering when I blend together alot of polys on top of eachother, say smoke in a particle system. just textured quads. I set these states: glBlendFunc(GL_SRC_ALPHA,GL_ONE); glShadeModel(GL_SMOOTH); glHint(GL_POINT_SMOOTH_HINT,GL_NICEST); and even though I have 32bit enabled in windows it sure doesn''t look like it. (I have a GeForce1.) any clues?

Obelix

Jul 17, 2001 at 11:03 AM

Check the internal format and the range of the alpha values.
Another thing to try is from the MSDN documentation:
"To optimize polygon antialiasing, use glBlendFunc(GL_SRC_ALPHA_SATURATE, GL_ONE)"

mittens

Jul 17, 2001 at 4:05 PM

Dithering is an incredibly annoying problem (unless of course, you want it to happen).

I
haven''t really figured out a great way to stop the ugly stuff from happening in some of my demos
yet... but I''m working on it. I''ve found it extremely common in my particle demos, and I found
it INCREDIBLY often in Deus Ex.... annoying stuff.

------------------------------
Trent (ShiningKnight)
E-mail me
OpenGL Game Programming Tutorials

zedzeek

Jul 17, 2001 at 5:44 PM

i dont think its dithering thats the cause but lack of colour depth precision, not much u can do about it apart from use 32 bit colour + high quality internal format textures.some sgi machines can handle 48bit colour. carmack in a quite recent plan wrote about the need for greater colour depths for the same reason. an interesting read.

http://members.xoom.com/myBollux

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