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miko
03-03-2003, 03:11 AM
what about performace of 3d texture? when i try to render a sigle triangle coverted by a 3d texture (filter is set GL_NEAREST) i get about 40 fps. when i use GL_LINEAR perfomace is even much worse.

i have geforce2mx400. i'm running in 640x480 window on 1027x768 16-bit desktop.

is there a way how to improve this horrible performace (some specific texture format - RGB, RGBA, color depth?? or someting else?? or my card does not support it??), please...

Asgard
03-03-2003, 03:53 AM
A GeForce2 doesn't support 3D textures in hardware. Therefore, performance is bad because you're rendering in software.

Jan
03-03-2003, 04:42 AM
Why does no one believe what i say?

miko
03-03-2003, 04:56 AM
'coz everybody says something else (ok, it's 2:1 now so it's probably not supported) http://www.opengl.org/discussion_boards/ubb/eek.gif

Tom Nuydens
03-03-2003, 05:14 AM
Originally posted by miko:
'coz everybody says something else (ok, it's 2:1 now so it's probably not supported) http://www.opengl.org/discussion_boards/ubb/eek.gif

The only NVIDIA cards that support 3D texturing are NV20 and up. This means GF3, GF4 Ti and GF FX. On all other cards, 3D texturing will be implemented in software (they're required to do so because it's part of the OpenGL core).

All ATI cards since the Radeon also accelerate 3D texturing, although I believe there were some peculiar restrictions on the original Radeon.

-- Tom

Jan
03-03-2003, 05:35 AM
There is a very easy way to find out which extensions are supported. Go to nehe.gamedev.net and download lesson 24. This program lists all extensions, which are supported by your hardware. And GL_EXT_ TEXTURE_3D won´t be listed.

Jan.

Prophet
03-03-2003, 08:55 AM
Originally posted by Jan2000:
There is a very easy way to find out which extensions are supported. Go to nehe.gamedev.net and download lesson 24. This program lists all extensions, which are supported by your hardware. And GL_EXT_ TEXTURE_3D won´t be listed.

Jan.

The extention is listed. It just implemented on software for a Geforce 2MX like vertex shader in DirectX : a DX7 card can use it, but it is in software.

Zeno
03-03-2003, 10:11 AM
The best way to tell support for an extension on nvidia hardware is to look at the chart at the beginning of their OpenGL extensions specification here:

http://developer.nvidia.com/view.asp?IO=nvidia_opengl_specs

3D textures are supported in hardware on Geforce3 and up only.

-- Zeno

miko
03-03-2003, 11:50 AM
thnx you people....

Humus
03-03-2003, 03:25 PM
Originally posted by Tom Nuydens:
All ATI cards since the Radeon also accelerate 3D texturing, although I believe there were some peculiar restrictions on the original Radeon.

It uses two texture units. So with the three TMUs you can either use one 3D and one 2D, or three 2D.