my approach to an hdri compensation shader

Hi!

I'm working on a modified Lightmapped Vertex Lit shader.

The special things on my version are:

Unity lights don't brighten the object - they just add a specular highlight.

The lightmapped is QUAD multiplied:
I render my lightmaps as 96 bit HDR files, lower their exposure while converting to 24 bit PSD files (to retain nuances in overexposed areas like sunlight falling through a window on the floor).

Code (csharp):

1. Shader "Lightmapped/justSpec" {
2. Properties {
3.    
4.     _SpecColor ("Spec Color", Color) = (1,1,1,1)
5.     _Shininess ("Shininess", Range (0.01, 1)) = 0.7
6.     _MainTex ("Base (RGB)", 2D) = "white" {}
7.     _LightMap ("LightMap (RGB)", 2D) = "black" {}
8.     _BumpMap ("Bumpmap (RGB)", 2D) = "bump" {}
9.    
10. }
11.  
12.  
13.  
14. SubShader {
15.      
16.   // Ambient pass
17.     Pass {
18.         Name "BASE"
19.         Tags {"LightMode" = "PixelOrNone"}
20.         BindChannels {
21.             Bind "Vertex", vertex
22.             Bind "normal", normal
23.             Bind "texcoord1", texcoord0 // lightmap uses 2nd uv
24.             Bind "texcoord", texcoord1 // main uses 1st uv
25.         }
26.         SetTexture [_LightMap]  {combine texture}
27.         SetTexture [_MainTex] {
28.         combine texture * previous quad, texture * constant
29.         }
30.         }
31.  
32.   // Specular Pass
33.     Pass {
34.         Name "BASE"
35.         Tags {"LightMode" = "Vertex"}
36.         Material {
37.             Shininess [_Shininess]
38.             Specular [_SpecColor]
39.         }
40.  
41.         Lighting On
42.         SeperateSpecular On
43.        
44.             BindChannels {
45.             Bind "Vertex", vertex
46.             Bind "normal", normal
47.             Bind "texcoord1", texcoord0 // lightmap uses 2nd uv
48.             Bind "texcoord1", texcoord1 // lightmap uses 2nd uv
49.             Bind "texcoord", texcoord2 // main uses 1st uv
50.         }
51.         SetTexture [_LightMap]  {combine texture}
52.         SetTexture [_MainTex] {
53.         combine texture * previous quad, texture * constant
54.         }
55.         }
56.     }
57. }
58.  

Now I need to add the bump effect.
But when I add the grabpass command

Code (csharp):

1. UsePass " Bumped/PPL"

the shader gets super bright.

What's the better / correct way to add the bumpmap to my shader?

Maye some of the shaderlab heroes out there can help me a little?

 

The thing is: Pulling in bumped/PPL will get you both diffuse and specular lighting. Since you don't have a _Color property, that will get its default value (which is white).

The easy way is to just add the _Color property and set it to black. The proper way is to take a look at the built-in shaders, find the bumped specular shader and copy/paste the code in. Then remove the parts of the calculation where _Color gets multiplied in.

Oh, and you probably want to UsePass " Bumped Specular/PPL" to get the specular stuff. Bumped is just diffuse lighting. (I'm not sure about the exact name, but take a look in the shader dropdown).

 

Thanks for your reply David !

I guess I need some more help on that. Maybe you or someone else would be so kind ...

That's the code for the bump effect:

Code (csharp):

1. // Pixel lights
2.         Pass { 
3.             Name "PPL"
4.             Tags {
5.                 "LightMode" = "Pixel"  
6.                 "LightTexCount" = "012"
7.             }
8.                
9. CGPROGRAM
10. // profiles arbfp1
11. // fragment frag
12. // fragmentoption ARB_fog_exp2
13. // fragmentoption ARB_precision_hint_fastest
14.  
15. // vertex vert
16. // autolight 7
17. #include "UnityCG.cginc"
18. #include "AutoLight.cginc"
19.  
20. struct v2f {
21.     V2F_POS_FOG;
22.     float2  uv          : TEXCOORD0;
23.     float2  uv2         : TEXCOORD1;
24.     float3  lightDirT   : TEXCOORD2;
25.     V2F_LIGHT_COORDS(TEXCOORD3);
26. };
27. struct v2f2 {
28.     V2F_POS_FOG;
29.     float2  uv          : TEXCOORD0;
30.     float2  uv2         : TEXCOORD1;
31.     float3  lightDirT   : TEXCOORD2;
32. };
33.  
34.  
35. v2f vert (appdata_tan v)
36. {
37.     v2f o;
38.     PositionFog( v.vertex, o.pos, o.fog );
39.     o.uv = TRANSFORM_UV(1);
40.     o.uv2 = TRANSFORM_UV(0);
41.    
42.     TANGENT_SPACE_ROTATION;
43.     o.lightDirT = mul( rotation, ObjSpaceLightDir( v.vertex ) );   
44.    
45.     PASS_LIGHT_COORDS(2);
46.     return o;
47. }
48.  
49. uniform sampler2D _BumpMap : register(s0);
50. uniform sampler2D _MainTex : register(s1);
51.  
52. float4 frag (v2f2 i, LIGHTDECL(TEXUNIT2)) : COLOR
53. {
54.     float4 texcol = tex2D(_MainTex,i.uv);
55.    
56.     // get normal from the normal map
57.     float3 normal = tex2D(_BumpMap, i.uv2).xyz * 2 - 1;
58.    
59.     return DiffuseLight( i.lightDirT, normal, texcol, LIGHTATT );
60. }
61. ENDCG  
62.             SetTexture [_BumpMap] {combine texture}
63.             SetTexture [_MainTex] {combine texture}
64.             SetTexture [_LightTexture0] {combine texture}
65.             SetTexture [_LightTextureB0] {combine texture}
66.         }

How would I modify the code so that light sources only cause the bumps but do NOT make the diffuse texture brighter?

Is that possible somehow?

 

Yes that's right.

The lightmapped MainTex should not be affected by diffuse light.

I only want the bump and gloss effect on top of my lightmapped texture.

 

PS: I copied and pasted the glossy pass from the builtin shaders and it works well as there's no additional brightness caused by light sources - just the specular.

But I guess the bumpmap part kicks in diffuse light so there's some brightness at all that can actually be affected by the bump effect (darkened/brightened).

My shader should work like:

- multiply Lightmap with MainTex
- brighten up 4 times
- add specular highlight on top
- add bump effect to all that's been calculated so far

 

Thanks for the shader - now I see what I've missed when writing my version :wink:

I really appreciate that !

Let me try to understand this:

Obviously when I set "_Color" to black I get the bump effect only on the specular highlight.

I have to set "_Color" to any value above black to get the bumpmapping effect working everywhere on the surface of my object - right?
Since without any diffuse light precalculated, there's no "light information" that bumpmapping can actually affect?


Now what I thought of as a possible solution is to turn on diffuse lighting, add the bump effect and finally make the whole texture darker to compensate the diffuse lighting that was added at the beginning.

Do I have to add another pass for that? Or can that be done in the CG script?