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wiseman303

OpenGL GL_EXT_packed_pixels_12? (resolved)

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Hi, I'm curious about an extension called EXT_packed_pixels_12. There is no specification for it on http://oss.sgi.com/projects/ogl-sample/registry/ or anywhere else that I can find. Searching google has revealed that most (if not all) Intel cards advertise this extension, and it's only advertised by Intel cards. My guess is it shows support of the extra packed pixel formats introduced in OpenGL 1.2 which are not part of the original EXT_packed_pixels specification, such as GL_UNSIGNED_SHORT_5_6_5. Does anyone know if that's right? [Edited by - wiseman303 on March 31, 2005 4:23:46 PM]

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20 views and no replies? Okay I guess nobody knows it, so I'll just have to try it and see if glGetError() says anything...

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Okay since I couldn't find any info on the internet, I decided to do some testing myself. I'll post my results here in case anyone else is curious.

For testing I used an Intel 82810E, which supports OpenGL 1.1.2, EXT_packed_pixels and EXT_packed_pixels_12.

I created an array of unsigned shorts, zeroed it, and called glTexImage2D with GL_UNSIGNED_SHORT_5_6_5 as type. Then I check glGetError() for various errrors, especially GL_INVALID_ENUM.

Running this test produced no errors, and drawing a quad with the texture showed it black. Next I changed it to fill every element of the array with 63488 instead of 0, recompiled, and ran it again. This time the quad showed up as bright red.

From this I conclude that the Intel 82810E supports at least one of the packed pixel formats introduced in OpenGL 1.2 that are not part of OpenGL 1.1 or the original EXT_packed_pixels extension. It seems likely that EXT_packed_pixels_12 is an indicator that these formats are supported.

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