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VanKurt

Extreme textures

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Today I wondered if it is possible to use textures of EXTREME sizes (8192x8192 or more)? 1) Would it be better to use a single file or split it up into smaller pieces? 2) What fileformats (compression?) would be suitable? 3) How would I load these textures (Compression with S3TC?) ? 4) Would mipmapping be possible? 5) Can graphic cards handle these things? ( I remember that my old Vodoo2 was limited to 256x256 or something ;-) )

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Usually it depends from the OpenGL implementation what will be the max possible image sizes.One thing is for sure.They cannot be 8192x8192 or more cause that''s really extremely and will consume the whole AGP memory.Normal max sizes are usually 1024 and 2048.I''ve heard that Doom 3 doesn''t use more than 1024x1024(my engine too )

The PAIN is coming...this summer!!!In cinemas everywhere.

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Well, I've heard that Pixar use shadowmaps of up to 4096x4096 in RenderMan, which must mean that some implementations of OpenGL support truly massive textures. Then again, they run high-end SGI workstations, with the most expensive 3D cards money can buy, and you most definitely get what you pay for there...



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[edited by - iNsAn1tY on May 6, 2003 7:15:32 PM]

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Well, 4096 is the standard size of my terrain-textures. But I took a look at Battlefield1942''s textures:
They use 8192 maps split up into 64 1024 textures. So I guess they have to use some kind of compression (S3TC?), because 192 MB +Mipmaps are a little to much... ;-)

I''ve also noticed that they store their textures in an intersesting way: A 1024x1024 texture is stored WITH mipmaps and is only 7XX KB big!
(The fileformat is .dds)
Does anyone know how that is possible?

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Hmm seems like some strange combination of indexed images,small palette and ultra cool compress methods.

The PAIN is coming...this summer!!!In cinemas everywhere.

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I havn''t seen that ppl use monitors witx res higher than 2???x1900 So there is almost no need for such a textures. I know that Rads9700 & FX where able to keep 4???x4??? textures, check at www.delphi3d.net
But usually it''s better to have few smaller textures, and unload unneded part (at some scenes).

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i wouldnt compare the relevance of texture resolution to the display resolution. its true display res almost neva get that high, but in the texture domain, the res is important when it concerns filtering. try this: render a simple quad in the center of the screen, preferably smaller than the screen space. now apply texture(s) of varying size on em. as u flip from one to the other, u WILL notice the difference in detail that the texture contributes. of course, the smaller the object the lesser this effect, hence comes mipmapping.

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quote:
Original post by VanKurt
Well, 4096 is the standard size of my terrain-textures. But I took a look at Battlefield1942''s textures:
They use 8192 maps split up into 64 1024 textures. So I guess they have to use some kind of compression (S3TC?), because 192 MB +Mipmaps are a little to much... ;-)

I''ve also noticed that they store their textures in an intersesting way: A 1024x1024 texture is stored WITH mipmaps and is only 7XX KB big!
(The fileformat is .dds)
Does anyone know how that is possible?


.dds = DirectX texture file... that means they use DXT1/3 or 5

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You can use DXT1/3/5 texture formats in OpenGL. See the ARB_texture_compression and EXT_texture_compression_s3tc extension specs.

If you want a DDS loader for OpenGL, you can find one here:

http://cvs1.nvidia.com/DEMOS/OpenGL/inc/shared/nv_dds.h
http://cvs1.nvidia.com/DEMOS/OpenGL/src/shared/nv_dds.cpp

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