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amigocz

OpenGL npot textures and ATI

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amigocz    122
Hi, I'm trying to find out how to draw a non pow2 texture. I searched the forum and I guess that I've got few options. 1) I can use GL_TEXTURE_RECTANGLE_ARB BUT if I did so I would not be able to use mipmaps, texture coordinates are different and there is a difference in the shader code as well (Sampler2DRect). I'm using either DX and OpenGL with CG for shaders and I don't want the different shader code. 2) I can use ARB_texture_non_power_of_two extension but my graphics card does not support it (ATI RadeonX1950pro). I found a topic from the year 2002 saying that ATI cards do not fully support it. Well but we have 2008 now and my graphics card is not that old. Is there any special extension for ATI cards? BTW glGetString(GL_VERSION) tells me that I'm running version 2.1 and I'm using Windows Vista.

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Lord Crc    234
If the driver reports 2.x it supports NPOT. However since ATI's support isn't complete, they decided not to expose the extension string. I can't find the pdf describing what's missing right now though :(

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MARS_999    1627
Quote:
Original post by Lord Crc
If the driver reports 2.x it supports NPOT. However since ATI's support isn't complete, they decided not to expose the extension string. I can't find the pdf describing what's missing right now though :(


LOL how about everything!

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Yann L    1802
Quote:
Original post by MARS_999
LOL how about everything!

Nah, NPTs seem to work alright on ATI with recent drivers. Although I never tried them with mipmaps, only as screensize render textures.

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rosewell    102
If you want to use NPOT textures with ATI cards, just follow the same rules as GL_TEXTURE_RECTANGLE_ARB to be safe.
No mipmaps, clamp to edge (no repeat), no filtering.

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MARS_999    1627
Quote:
Original post by rosewell
If you want to use NPOT textures with ATI cards, just follow the same rules as GL_TEXTURE_RECTANGLE_ARB to be safe.
No mipmaps, clamp to edge (no repeat), no filtering.


Then what is the point, IMO...

Anyway are you using the latest drivers? If not go get them.

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scratt    102
On most up to date ATI cards right now both NPOT and Point Sprites are pretty solid in most cases.

If you start getting too exotic with texture settings, shaders, VBOs, and particularly binding attributes then you may run into some problems.

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rosewell    102
Quote:
Original post by MARS_999
Then what is the point, IMO...
Anyway are you using the latest drivers? If not go get them.


The point is getting NPOT textures to work when the "ARB_texture_non_power_of_two" extension is not explicitly listed.
And this is not just for himself, but for other people who probably won't have the latest drivers installed.

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swiftcoder    18437
Quote:
Original post by amigocz
1) I can use GL_TEXTURE_RECTANGLE_ARB BUT if I did so I would not be able to use mipmaps, texture coordinates are different and there is a difference in the shader code as well (Sampler2DRect). I'm using either DX and OpenGL with CG for shaders and I don't want the different shader code.

2) I can use ARB_texture_non_power_of_two extension but my graphics card does not support it (ATI RadeonX1950pro). I found a topic from the year 2002 saying that ATI cards do not fully support it. Well but we have 2008 now and my graphics card is not that old. Is there any special extension for ATI cards? BTW glGetString(GL_VERSION) tells me that I'm running version 2.1 and I'm using Windows Vista.
On my Mac X1600 (slightly different drivers, and does export ARB_texture_non_power_of_two), nonPoT textures basically work according to the same rules as rectangular textures, so as long as you don't get fancy, you should be ok.

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