Texture compression problem on a GeForce2

OpenGL OpenGL: Advanced Coding
1

I upload a 2D texture using :
GL_COMPRESSED_RGB_ARB as internal format and
GL_RGBA as format because my pixels (not compressed) are store on 4 bytes but I only use 3 components. So I don’t care about alpha value. Nevertheless the rasterisation use the alpha component of the texture even if I not use the GL_COMPRESSED_RGBA_ARB ! Thus I must to set to 255 the alpha value (If I set 0 the texture appear black).

Any idea ?

David.
NB : PixelStorage = 4

2

Is there any reason why you can’t just convert the image to RGB?
It’s not difficult, and you’ll save memory that way, which I assume is what you want to do if you’re using compression.

3

Yes of course, but I would like to keep the alignment…

Originally posted by Don’t Disturb:
Is there any reason why you can’t just convert the image to RGB?
It’s not difficult, and you’ll save memory that way, which I assume is what you want to do if you’re using compression.

Moreover, I was not sure before but now I’m sure that NVidia driver (about this extension) has a bad behaviour !

4

I think this is a real bug. In the meantime, use alpha of 128 or higher or use RGB, not RGBA.

  • Matt
5

Sancho,

Can you provide a simple test app that illustrates the bug?

This will expedite getting it fixed. Otherwise it’ll have to wait until I get the opportunity to write one.

If you have something, please email it to cass@nvidia.com.

Thanks -
Cass