WebGL textureCube bias causing seams

问题

I am experimenting with a dds texture and cubemap mip maps. When changing the bias in textureCube() i get really nasty normal artifacts. I have no idea what is causing this and cant find much reference on the bias parameter.

Live: (need to switch to uv and turn off normal)

http://dusanbosnjak.com/test/webGL/new/poredjenjeNM/poredjenjeNormalaBias.html

Screen:

More Screens:

Bias 4

edit

Also of note, when you orbit around at say bias 6, you can clearly see the cubemap looking more or less correct (there is an edge seam between the faces) these normals breaking seem to be a different issue.

回答1:

So, i've omitted the bias part, and added a sampler. This is what it looks like with 8 samples samples:

http://dusanbosnjak.com/test/webGL/new/pbr/poredjenjeNormalaBias.html

The last parameter multiplies the spec map (it's almost black on the tire) and mipbias (has nothing to do with mips, need to change the name) will actually blur it.

I tried to randomize things a bit by using a noise texture and by putting the sampling pattern in the texture but im not really sure what the implications are.

With the textureCubeLod a lot of this noise could be removed?

来源：https://stackoverflow.com/questions/22977236/webgl-texturecube-bias-causing-seams