what kind of filtering do you use for normal maps?
I always disable stuff like anisotropic filtering but how
do you setup GL_TEXTURE_MIN_FILTER and GL_TEXTURE_MAG_FILTER?
I guess bilinear and trilinear filtering are a bad choice
when dealing with normals stored as rgb values, right?
trilinear/aniso is not so bad as sharp bump detail will be smoothed, which avoid a lot a aliasing when you have sharp speculars. Might want to widen the specular exponent along as well if you aim for perfection.
I would say test both, rendering side to side on exact same animated scene.
Binilear/trilinear filtering is usually used for normal maps as well. Anisotropic filtering may be less useful, though it may provide better results in certain scenarios.
You can and should use filtering with normal maps. But you should take extra care when computing mipmaps for normal maps. For example, you should normalize the normals. NVIDIA texture tools has a special mode for normal maps. And if you really want to get things more “right”, this can be worth reading: