Help for deferred shading noob: Specularity

[Rastar]

I am used to a calculation of specular reflection along the lines of

 

pow( saturate( NdotH ), specularHardness )

 

maybe multiplied by an additional factor. Yet, when I look into the provided shaders, I see nothing of the sort, just a multiplication of specular texture times specular color, and then some sort of packing this into frag1.a

 

Where is my usual specular reflection?

[shadmar]

For specular using normals just color:

 

fragData1.a = materialcolorspecular;

 

for using specularmap : (standard luminance used by the television industry, rgb=0.299,0.587,0.114) (says google)

 

 

color_specular = texture(texture2,ex_texcoords0) * materialcolorspecular;
..
fragData1.a = color_specular.r * 0.299 + color_specular.g * 0.587 + color_specular.b * 0.114;

[shadmar]

In deferred shading all lighting is done in a prepass. So you don't have the same control you do in forward rendering.

[Rastar]

I was hoping you would jump in... Oh, OK, so this means I can only control the relative contributions of the three color channels to a materials specularity, but cannot really control e.g. the size of the specular dot (meaning: if the material is shiny or matte)?

[shadmar]

Yes you can, look in the pointlight.shader

 

specular = lightspecular * specularity * pow(clamp(-dot(lightreflection,screennormal),0.0,1.0),GLOSS);

 

GLOSS would control this. It's default 10.0, you could simply just send that through an uniform if you change the lighting shaders.

[Rastar]

Ah, but that is my NdotH formula from above, isn't it? Great, thanks!

[shadmar]

Yes.

[Josh]

Although we don't have room for a per-material gloss value, one thing I have considered it packing a few extra flags into the material flags value. We could have two flags that would control four possible gloss values; low, medium, high, very high, or something like that.