[Mesa-users] trouble with mipmap minification filtering

[Brian Paul]

On 08/10/2014 03:46 PM, David Hart wrote:
>
> Hi, I'm having a little trouble getting texture mipmap minification
> filtering to work with Mesa, I'm wondering if one of you gurus might be
> able to spot what I'm doing wrong. I've setup a test program that runs
> the same code once via Mesa and once via glut, and with glut I see
> proper mipmap sampling, but with Mesa I don't - only the base level
> texture is sampled, no matter what GL_TEXTURE_MIN_FILTER settings I use.
> Maybe I've done something stupid or in the wrong order?
>
> I'm constructing my mip levels manually with different colors, so I can
> see them. My base texture is blue, and when I render several quads at
> different sizes using Mesa, the entire image is blue indicating base
> texture.
>
> I'm on Mac (OSX 10.9.4) + PyOpengl 3.0.2 + Mesa 8.0.5 (via macports)
>
> Glut results:
> https://dl.dropboxusercontent.com/u/364079/mesa-mipmap/mip_test_glut.png
> <https://urldefense.proofpoint.com/v1/url?u=https://dl.dropboxusercontent.com/u/364079/mesa-mipmap/mip_test_glut.png&k=oIvRg1%2BdGAgOoM1BIlLLqw%3D%3D%0A&r=lGQMzzTgII0I7jefp2FHq7WtZ%2BTLs8wadB%2BiIj9xpBY%3D%0A&m=178IiCEt0ce%2BVVUdiIn1f60HqblZIj8qMyY4aZvMwTg%3D%0A&s=c937bf0f1177a430842276acb5b562c4652b3655aec32f38956461e392ba4a3e>
> Mesa results:
> https://dl.dropboxusercontent.com/u/364079/mesa-mipmap/mip_test_mesa.png
> <https://urldefense.proofpoint.com/v1/url?u=https://dl.dropboxusercontent.com/u/364079/mesa-mipmap/mip_test_mesa.png&k=oIvRg1%2BdGAgOoM1BIlLLqw%3D%3D%0A&r=lGQMzzTgII0I7jefp2FHq7WtZ%2BTLs8wadB%2BiIj9xpBY%3D%0A&m=178IiCEt0ce%2BVVUdiIn1f60HqblZIj8qMyY4aZvMwTg%3D%0A&s=f6c11a494050189558750db6242c659d88c7596aad0d77ab38b07db526e5d015>
> Code:
> https://dl.dropboxusercontent.com/u/364079/mesa-mipmap/mesa_mip_test.py
> <https://urldefense.proofpoint.com/v1/url?u=https://dl.dropboxusercontent.com/u/364079/mesa-mipmap/mesa_mip_test.py&k=oIvRg1%2BdGAgOoM1BIlLLqw%3D%3D%0A&r=lGQMzzTgII0I7jefp2FHq7WtZ%2BTLs8wadB%2BiIj9xpBY%3D%0A&m=178IiCEt0ce%2BVVUdiIn1f60HqblZIj8qMyY4aZvMwTg%3D%0A&s=d5563982883e6f35aafc9960ccfa09fe3345d17573ccb24fb82295936dffdf16>
> (Images were generated by running "mesa_mip_test.py 0 &&
> mesa_mip_test.py 1")
>
> I've tried a lot of searching, attempted (so far, unsuccessfully) to
> build a newer Mesa version locally, re-read OpenGl's "Common mistakes",
> etc. I also ran the same code in a linux/Xvfb environment, and there
> both versions have the same results -- both the Glut and Mesa versions
> come out all blue; minification filtering seems to not work.
>
> ---------
> FWIW, here's my environment. I'm on a very old version of Mesa, but for
> now I am assuming my problem is with my code, not Mesa, and unlikely to
> be version dependent.
>
>  > uname -a
> Darwin porkchop.local 13.3.0 Darwin Kernel Version 13.3.0: Tue Jun  3
> 21:27:35 PDT 2014; root:xnu-2422.110.17~1/RELEASE_X86_64 x86_64 i386
> MacBookPro8,2 Darwin
>
>  > port list installed | grep mesa
> mesa                           @8.0.5          x11/mesa
>
>  > pip list | grep -i gl
> PyOpenGL (3.0.2)
> PyOpenGL-accelerate (3.0.2)
>

Your terminology is a bit mixed up.  GLUT is a window system toolkit 
that can be used with Mesa or any other OpenGL implementation.  It is 
not an alternative to Mesa.

I suspect that when you're using GLUT you're using the native OpenGL 
library on MacOS.  Printing the value of glGetString(GL_VENDOR) in your 
code would probably clear that up.

That said, I don't know why you're seeing different results.  I took a 
quick look at your code.  The only thing that seemed a bit off was the 
different wrap modes for the S/T texcoords:

     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT        )
     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );

-Brian