[SOLVED] Strange artefacts when moving camera

[demostenes]

When moving towards some objects, I see white dots blinking on surface. When camera stops, everything is OK. I ve figured out, that lowering normal intensity under cca 0,7 solves the problems. This wasnt happening before Unigine  2.2, so what changed? I would like to have full normal intensity on these surfaces. Thanks.

 

http://www.endor.cz/demo/art.webm

(vlc can play this)

[silent]

Hi Jirka,

 

It looks more like that surface is too glossy. Could you please check if decreasing Specular multiplier will help?

If it doesn't help, we would really like to check your content and settings that produced such issue to find out the root cause of that issue. 

 

Thanks!

[demostenes]

Specular was 0,5. In case it is 0, it is OK. But anything above zero produces these artefacts. What was changed in 2.2? I would like to keep these specular values for most these materials.

[silent]

Hi Jirka,

 

It seems that there might be a small bug inside our specular BRDF calculations.

 

Could you please change the float2 getBRDF(float gloss,float F0,float translucent_scale,float3 N,float3 L,float3 V) function inside data/core/shaders/common/fragment.h:241 so it look more like this:

float2 getBRDF(float gloss,float F0,float translucent_scale,float3 N,float3 L,float3 V) {
    
    float3 H = normalize(L + V);
    float dotLH = dotFixed(L,H);
    float dotNH = dotFixed(N,H);
    float dotNV = dotFixed(N,V);
    float dotVL = dotFixed(-V,L);
    float dotNL = dotFixed(N,L);
    
    return getBRDF(gloss,F0,translucent_scale,dotNV,dotLH,dotNL,dotNH,dotVL);
}

Does this help in your case?

Thanks!

[demostenes]

It didnt help, artefacts are still there.

[demostenes]

I ve uploaded on your ftp asset (roof.zip) which suffers with these artefacts (majority of assets does). Artefacts are visible only with point lights, with world light everything is OK.

[silent]

Hi Jirka,

 

You can also modify data/core/shaders/common/fragment.h:165 to remove sparks with camera movement:

//replace this line
specular /= (dotNL * (1.0f - k) + k) * (dotNV * (1.0f - k) + k) * PI * pow2(denom);

//with this one
specular /= max(0.001, (dotNL * (1.0f - k) + k) * (dotNV * (1.0f - k) + k) * PI * pow2(denom));

It will change the specular look.

 

Thanks!

[demostenes]

Thanks, we will try. Is this modification bug fix, or modification for our use case? 

[silent]

Hi Jirka,

 

This is temporary workaround, complete fix will be available only in 2.3 SDK update.

 

Thanks!

[demostenes]

Hi Jirka,

 

This is temporary workaround, complete fix will be available only in 2.3 SDK update.

 

Thanks!

 

I ve tried the workaround, white blinking is gone, but now there are yellow arfefacts even when camera is not moving :)

[silent]

Hi Jirka,

 

This is expected behavior. We will try to minimize this effect in 2.3 SDK update.

[demostenes]

Ok, thanks.

[demostenes]

Still present in 2.3

[silent]

Hi Jirka,

 

I'm pretty sure that I don't have any specular flickering with your attached roof node. Even if I will disable motion blur and TAA everything is looking good.

 

Here is the video from 2.3 (i've just added default omni light and disabled world light):

no_flickering.avi

 

Thanks!

[demostenes]

Ok, I will prepare more complex test scene.

[demostenes]

I ve manualy replaced whole <render> </render> in world file by settings from lately generated worlds and it is OK now. Probably some garbage in settings cased by many years of upgrades.