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Flashing textures in OGL

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Wow, I''ve written a lot of posts this week. Last one, I promise . Any hoo, I''m doing a project in openGL for my GL class. I''m doing a chess board out of numerouse quads, and I have this problem where at certain angles, the entire board doubles in brightness. This is really distracting as it will cause a flashing effect when just casually walking. This only happens when I''m using extures, however, and it happens regardless of what texture filtering I use, or wether lighting is on or off. Also, I thought my tex coords might be wrong( which is hard to believe for quads), so I turned on auto tex coord generation, and still it persists. Has this happened to anyone else?

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Sometimes, stuff like that can happen as a result of OpenGL state or settings not being properly set/cleared between different types of rendering. For instance, if you enable color arrays for one portion of rendering, and another portion needs them disabled but nobody does the disabling. Or you accidentally leave a multi-texture stage enabled when it should be disabled, and random "junk" tex-coords are fed to it. Or something somewhere sets a bogus or invalid texture. Stuff like that can wreak rendering havoc, and it''s hard to tell where it might be happening or what might be the exact problem without code to look at.

Go through your code, and carefully consider what OpenGL state should be set or cleared for each part of the rendering task set, and make sure that no "dangling" state from previous tasks is screwing things up. Make sure also that no invalid texture handles are being used, etc... Without seeing the code, that is about all I can suggest.


Golem
Blender--The Gimp--Python--Lua--SDL
Nethack--Crawl--ADOM--Angband--Dungeondweller

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No specific answers, but ...

Sometimes when I am having an extremely weird OGL problem, I''ll place a software version of OpenGL32.dll in my exec. directory, to force software emulation and see if it is just a driver issue. Thw two I use most often are the old SGI reference (http://www.berkelium.com/OpenGL/sgi-download.html), and the newest Mesa version (www.mesa3d.org, but it will be called MesaGL.dll and needs to be renamed).

You may also want to consider logging some key OpenGL state variables just before the draw board function, and see if any toggle.

Good luck

lonesock

Piranha are people too.

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