[Mesa-users] trouble with mipmap minification filtering

[Brian Paul]

Can you create an apitrace of the problem?

-Brian

On 09/28/2014 11:33 PM, David Hart wrote:
>
> So, I'm still trying to get mipmapping to work. I've spent countless
> hours now trying to build and link Mesa the right way on mac and linux
> and realizing I may be in over my head trying to reproduce this problem
> in a C program.
>
> But I have discovered one very important detail: Mip-mapping is working
> fine for me when I use the old fixed-function pipeline in Mesa, it only
> breaks as soon as I start using shaders.
>
> Also, I can nudge the LOD level manually even when using shaders, but
> the default LOD with Mesa & shaders is always sampling the base level
> mipmap for me.
>
> Here is a pyopengl sketch of all the combinations of Mesa vs native
> OpenGL, fixed-function vs shaders, and using the default LOD vs
> modifying the LOD level manually. I'm drawing two polygons, one is
> distorted by perspective, the other is drawn with an ortho projection
> and distorted by moving two verts close together. I have dyed each
> mipmap level with a different color, so the only thing I'm looking for
> is multiple colors in both polygons. As you can see, there is only one
> case where I don't get any colors other than the blue base mipmap level,
> which is Mesa+shaders without manually setting LOD.
>
> https://dl.dropboxusercontent.com/u/364079/mesa-mipmap/version3/mipmap.html
> <https://urldefense.proofpoint.com/v1/url?u=https://dl.dropboxusercontent.com/u/364079/mesa-mipmap/version3/mipmap.html&k=oIvRg1%2BdGAgOoM1BIlLLqw%3D%3D%0A&r=lGQMzzTgII0I7jefp2FHq7WtZ%2BTLs8wadB%2BiIj9xpBY%3D%0A&m=YWDgaf5wt4vbH78LYD%2BMiwdBEZIo0l8AuOweqeck6Yk%3D%0A&s=7565e0f1a3c57faeb1f859fd73ca22479517783cc484d8d92f6f77c32c8acee3>
>
> I'm still running the exact same code through native OpenGL vs Mesa and
> getting wildly different results when using shaders. Am I doing
> something wrong?
>
> --
> David.
>