sampler2DRect & ATI

[glitch]

Hi

does rect texture lookup work on ati glsl implementation?
i m getting the error: "sampler2DRect : reserved keyword"

thx for any response

cheers

[Humus]

Rect texture lookups isn't included in the current version of GLSL. That keyword is only reserved in case it will be added in the future.

[glitch]

however it seems to work on the nvidia GLSL implementation ... do u know if ati plan to release this important feature soon ?

[Korval]

Yeah. nVidia likes adding keywords and functionality to standards. Make that whole portability thing harder, which only serves to help nVidia.

[Humus]

Rectangles are so limited anyway so I'd personally prefer if it's left out of the GLSL. If everyone can implement GL_ARB_texture_non_power_of_two (http://oss.sgi.com/projects/ogl-sample/registry/ARB/texture_non_power_of_two.txt) we can just forget about the sorry story of rects.

[Korval]

Rectangles are so limited anyway so I'd personally prefer if it's left out of the GLSL. If everyone can implement GL_ARB_texture_non_power_of_two we can just forget about the sorry story of rects.Rectangle textures do have one key feature. They are the preferred (performance-wise) targets for render-to-texture operations. Generally, they are not swizzled, so render ops work optimally.

[Chris Lux]

Originally posted by Korval:
Rectangle textures do have one key feature. They are the preferred (performance-wise) targets for render-to-texture operations. Generally, they are not swizzled, so render ops work optimally.[/QB]PLUS, they are not addressed with normalized texture coordinates, which makes offset calculations for imageprocessing very easy and simple.

[Humus]

I consider not using normalized features to be another weak point of rectangles. In some limited cases it might be more convenient, but in most situations normalized coordinates are much more convenient.