I have a problem to decide wheather to use texture filtering (biliner,trilinear) on a normal map sampler. I could not see the difference between no filtering and filtering. My question is wheather artifactes can appear, theoreticaly, and under what circumstances, if no filtering si applied. Thanks much!
what textures to use filtering on?
Moderators - Reputation: 10539
Posted 01 September 2013 - 04:09 PM
If you apply POINT filtering, your texture will appear "blocky" and exhibit aliasing artifacts whenever the texture is scaled or rotated. It can get really bad if the texture is heavily downscaled, and you don't have mipmaps (or if you disable them). There are almost no circumstances where you wouldn't want to use the best filtering possible when using normal maps on 3D geometry.
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Posted 01 September 2013 - 04:11 PM
Assuming, I'm not misunderstanding your question and you want to use something like diffuse texture + normal map (and maybe a bump map), I'd say that a problem could arise if the normal map is much smaller than the diffuse texture, since if could convey incorrect vertex normals due to sampling.
In my opinion, if you don't see a difference, then use linear filtering, since it's the least expensive.
Hope it helps.