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REF_Cracker

Member Since 22 Feb 2000
Offline Last Active Yesterday, 11:54 PM

Posts I've Made

In Topic: Verify my GGX + Lambert Directional light

Yesterday, 04:37 PM

In conclusion I'm just doing what looks good.... I've combined various formulas for D, F and G from this Brian Karis page until I was happy with the look!

http://graphicrants.blogspot.ca/2013/08/specular-brdf-reference.html

Thanks!


In Topic: Verify my GGX + Lambert Directional light

Yesterday, 10:03 AM

Thanks for the input so far everyone.
I'm going to dive back into it here this morning and see if I can get some better results out of my specular.
I still feel a scalar value to control the specular contribution would be helpful with my high sun light environments.


 


In Topic: Verify my GGX + Lambert Directional light

30 July 2015 - 09:29 PM

How bright is your sun? smile.png (and how rough is your roughness?)

I get this as well in-game with my super-bright sun, but it doesn't show up as an issue in the artist's tools because they don't have such bright lights in there...
 

My sun is currently a yellowish white multiplied with a slider ..... I've got that slider pumped up to exp2(3.5) ..... so it's at ~11.31
That's where it starts to feel hot enough but not blow everything out to white. The specular is WAY overpowering though.

Thank you!

Edit: The roughness is about 0.75 on the ground!


In Topic: Verify my GGX + Lambert Directional light

30 July 2015 - 09:09 PM

 

What you have is fine for what it is, but you will likely want more control over specular, either as a material property or through specular texture maps.
When this happens you will want to accumulate these terms separately and combine them at the end.

L. Spiro

 

 

 

 

I guess you're right as I already want to scale the specular... in fact when I hardcode a constant of (0.25 * specular) I get quite a good looking result.
Would this material param be a 3 component color or a simple single scaler?

Thanks,


 


In Topic: Verify my GGX + Lambert Directional light

30 July 2015 - 09:03 PM

Hi Hodgman,

So other than those tweaks to roughness.... the code for that directional light looks alright to you?

The only thing I modified from John Hable's GGX code was to 3 component the F0 term and feed in my specular color there.

 

Then I added the
 

Diffuse * PI_INV * NdotL

For a lambert diffuse contribution. I guess I can try the fresnel on diffuse as per L. Spiro's suggestion.

Right now I'm just struggling with the fact that the specular seems way too overpowering in sun light. Even for materials with 0.04 for F0 and a high roughness.

Thanks,


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