Bug with bump + reflection when roughness param used

[Vousk-prod.]

Hi everyone,

 

With DK we spotted a bug in the standardMaterial when materials are using combination of bump / reflexion / roughness.

 

If a reflexionTexture (CubeTexture) is used, the roughness param is perfect to blur it.

When a reflexionTexture and a bumpTexture are used together, everything is ok.

But when we activate roughness on that combinaison of reflexion and bump - bang - awful artifacts appears.

 

You can see that in this playground :

http://www.babylonjs-playground.com/#1MYQJJ#71

(comment / uncomment lines 43, 44)

 

It's a bit tricky to debug because the shaders calculations seem correct. Could other eyes dive into it and help us spot the culprit function ?

 

 

[Vousk-prod.]

The more I observe this, the more I think it looks like the bump texture become too much sensitive to image compression artifacts when roughness is activated, making the speculars produced by reflexion covered with "too high value" spots.

 

The bump texture used here is a png but if we check it deeply enough in photoshop, we can see a (very very) little bit of compression artifacts, and those area can correspond to the ugly dots in the PG.

[NasimiAsl]

i think replace bump map with normal map in this case not correct computed new normal .

 

thats why you need normal map

[Vousk-prod.]

I don't get what you mean, the texture used for the bump is a normal map...

[Vousk-prod.]

Other strange fact, on the sphere, with no bump, only reflection texture and roughness :

http://www.babylonjs-playground.com/#1MYQJJ#72

[GameMonetize]

These are seams.A known issue with WebGL as we cannot use GL_SEAMLESS

[Vousk-prod.]

You mean "seams" for the problem on the sphere ?

Yes but why the higher the roughness value the harder those seams are visible ? If we totally disable roughness, no seams are visible at all.

[NasimiAsl]

 create bump with normal map but not like your pic

 

you can make from here and dont change any thing

 http://cpetry.github.io/NormalMap-Online/

 

http://185.88.152.218/pub/preview#23

 

 vec3 newNrm  = vec3(normalize(normal-(normalize(  nrmTextureColor  )*2.0-1.)*-0.5));

 

it work fine

 

only reflect :  http://185.88.152.218/pub/preview#10209

[jerome]

impressive !

[Vousk-prod.]

 create bump with normal map but not like your pic

 

you can make from here and dont change any thing

 http://cpetry.github.io/NormalMap-Online/

 

Thanks for the help but my pic is already a "real" normal map.

In the bump slot of the first cube only - on the left -, the second cube uses a classical black and white pic as bump data, that was on purpose, to check if the bug is or not related to actual normal map information (but it seems not).

 

I already know the online tool you mentionned, usually I use SSBumpGenerator (or sometimes the good old fellow CrazyBump) to generate my normal maps but this one is nice also (just a little lack of params to my taste).

However, to check you proposal, I've switched my normal map in the PG with the default normal map created with this online tool.

And the result is exactly the same :

http://www.babylonjs-playground.com/#1MYQJJ#73

 

Here we can check the pic exported by the online tool and see that it has some noise in it (no problem, that's often required, many material simulations need some noise in the bump). We can then clearly see that this noise acts logically when no roughness, and acts strangely when roughness activated.

 

To do more checks, I exported an other normal map with this tool, from a very clean starting pic and adjusting the blur/sharp param to avoid unwanted additional noise :

http://www.babylonjs-playground.com/#1MYQJJ#74

Same problem (in fact, we can even better see it, just go near the different sides of the cube and look at a sharp angle).

 

The artifacts are not due to my previous normal pic used, it is related to the way the calculations are done when roughness is activated.

[GameMonetize]

For the bump issue, this is one thing I cannot fix so far because I have no fraking idea what is the root cause

 

Seams appears when glossiness is on because it forces the shader to use different mipmap levels which introduce the "connection" issue between cubemap faces

[Vousk-prod.]

Ok that make sense for the seams.

 

Yep I know for the bump issue, that's why I've been calling for some assistance in the forum.

(Come one boys !! DK has no clue, it is a unique occasion for someone to outperform god himself, don't miss that, it's the chance of a lifetime ! :lol: )