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Mayrel

Mipmaps too blurry

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I find that my mipmaps jump to lower detail levels too quickly, so my textures are blurry, whatever distance I view them at. Is the problem that I''m using glu to generate the mipmaps, or should I tell OpenGL to change the distance at which we jump down a mipmap level? If I should, can I, and how?
Just Plain Wrong

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I recently received some advice on this from a professional game programmer. He said that glu uses a box filter to create the mipmaps, and that this tends to produce blurry results. He advised me to use a "mitchell" filter to create the mipmaps.

I have not yet tested his assertion.

- josh

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I don''t know if this is the best solution, but you can influence when the mipmap levels change using the EXT_texture_lod_bias extension.


Dave "Myopic Rhino" Astle
Executive Producer and COO, GameDev.net
Game Programmer, Avalanche Software
Author, OpenGL Game Programming

"Leaking and bleeding... that''s what happens when you don''t relax"

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i dont think thats the problem, the solution i believe is to use anosphic(sp) filtering ill do a search

>>
EXT_texture_filter_anisotropic
Texture mapping using OpenGL''s existing mipmap texture filtering
modes assumes that the projection of the pixel filter footprint into
texture space is a square (ie, isotropic). In practice however, the
footprint may be long and narrow (ie, anisotropic). Consequently,
mipmap filtering severely blurs images on surfaces angled obliquely
away from the viewer.
<<

http://uk.geocities.com/sloppyturds/gotterdammerung.html

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Hmm. Thanks for the replies. I don''t think I have either of the extensions listed, so I can''t test them (although I''ll try and have my engine support them). I''ll have a look for stuff on Mitchell filtering.

Also: I don''t think the anisotropic filter will help with this particular problem unless it also does some other stuff because it''s too blurry even when the surfaces are seen face on. But I still get problems with surfaces seen at accute angles, so it will help the engine generally.

I should really get Mesa at some point, so I can test these extensions my hardware doesn''t have.



Just Plain Wrong

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