Custom lightmap Surface Shader

Hey there,

After couple hours of research and testing, I found the perfect Surface Shader traduction of my old 1.1 Lightmap Shader.
Before, when I used traditional passes, it would be written :

Code (csharp):

1.  
2. SetTexture [_Selfillum] {
3.       combine texture +  primary
4.  }
5.  
6. SetTexture [_MainTex] {
7.       combine texture * previous , texture
8.  }
9.  

where _MainTex is your main texture, and _SelfIllum your custom black white lightmap. The more white a zone is, the more self-lit it is, without burning the color or overshooting its lighting (those were the 2 reasons why I didn't use Emission parameter instead).

So now that Surface Shaders are in, here is how it would be perfectly traduced.
Everything necessary is contained in the surf function :

Code (csharp):

1.  
2.  void surf (Input IN, inout SurfaceOutput o) {
3.  
4.       half4 _lightmap = tex2D (_Selfillum, IN.uv_MainTex);
5.       half4 tex = tex2D(_MainTex, IN.uv_MainTex);
6.  
7.           o.Albedo = tex.rgb*(1-_lightmap.rgb);
8.  
9.           o.Emission = tex.rgb*_lightmap.rgb;
10.  
11.           o.Alpha = tex.a;
12.  
13.  }
14.  

It's basically masking the Albedo zones with the Lightmap, as the Emission channel is added over it.

Hope it helps !

edit : I forgot to mention that this Surface Shader should not interfere with Beast lightmaps.

 

thanks! can you post some pics showing the difference between the old a new surface shader?

 

Sure ^^

Here, a comparison on a lightly self-lit level :



It's not very visible here, because the colorburn overshoot effect really expresses itself on highly emissive zones, and when hit by a strong light. The only difference seems to be a smoother feeling overall at the bottom.


Here is a nice proof :



Even dramatically lowering the Emission does no justice, and even messes up the mesh borders which have the same color the same self-light (like the circle on the upper right). It's because of scene light not reflecting toward the same direction.
Emission is just a color addition to the base lit texture. So basically, putting this (1-_lightmap.rgb) in the base lit layer evens out this addition, creating the correct overall exposure balance.

Hope it helps.

 

thanks for sharing!