Fix billboard shader lighting

Hi guys i made a simple script to generate BillboardAssets from anything

Now the problem is that its too dark when facing away from light source.


This can be fixed if i crank up ambient lighting

So when ambient is at max it looks just like it should at normal
I am using a slightly cut down version of SpeedTreeBillboard shader
from which i removed crap like wind and hue,
now my idea is to force it to have max ambient value,
but i am unable to find the way to do so.

If i simply insert o.Emission = .. it says its a wrong subscript, but the doc says use Emission,
so im out of ideas on how to achieve this.

Code (CSharp):

1. // Unity built-in shader source. Copyright (c) 2016 Unity Technologies. MIT license (see license.txt)
2.  
3. Shader "BillboardMaker/Billboard"
4. {
5.     Properties
6.     {
7.         _Color ("Main Color", Color) = (1,1,1,1)
8.         _MainTex ("Base (RGB)", 2D) = "white" {}
9.         _Cutoff ("Alpha cutoff", Range(0,1)) = 0.5
10.         [MaterialEnum(None,0,Fastest,1)] _WindQuality ("Wind Quality", Range(0,1)) = 0
11.     }
12.  
13.     // targeting SM3.0+
14.     SubShader
15.     {
16.         Tags
17.         {
18.             "Queue"="AlphaTest"
19.             "IgnoreProjector"="True"
20.             "RenderType"="TransparentCutout"
21.             "DisableBatching"="LODFading"
22.         }
23.         LOD 400
24.  
25.         CGPROGRAM
26.             #pragma surface surf Lambert vertex:SpeedTreeBillboardVert nolightmap addshadow dithercrossfade
27.             #pragma target 3.0
28.             #pragma multi_compile __ BILLBOARD_FACE_CAMERA_POS
29.             #include "SpeedTreeBillboardCommon.cginc"
30.  
31.             void surf(Input IN, inout SurfaceOutput OUT)
32.             {
33.                 SpeedTreeFragOut o;
34.                 SpeedTreeFrag(IN, o);
35.                 SPEEDTREE_COPY_FRAG(OUT, o)
36.             }
37.         ENDCG
38.  
39.         Pass
40.         {
41.             Tags { "LightMode" = "Deferred" }
42.  
43.             CGPROGRAM
44.                 #pragma vertex vert
45.                 #pragma fragment frag
46.                 #pragma target 3.0
47.                 #pragma multi_compile_fog
48.                 #pragma multi_compile __ LOD_FADE_CROSSFADE
49.                 #pragma multi_compile __ BILLBOARD_FACE_CAMERA_POS
50.                 #include "SpeedTreeBillboardCommon.cginc"
51.  
52.                 struct v2f
53.                 {
54.                     UNITY_POSITION(vertex);
55.                     UNITY_FOG_COORDS(0)
56.                     Input data      : TEXCOORD1;
57.                     UNITY_VERTEX_OUTPUT_STEREO
58.                 };
59.  
60.                 v2f vert(SpeedTreeBillboardData v)
61.                 {
62.                     v2f o;
63.                     UNITY_SETUP_INSTANCE_ID(v);
64.                     UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
65.                     SpeedTreeBillboardVert(v, o.data);
66.                     o.data.color.rgb *= ShadeVertexLightsFull(v.vertex, v.normal, 4, true);
67.                     //o.data.color.rgb *= unity_AmbientSky;
68.                     o.vertex = UnityObjectToClipPos(v.vertex);
69.                     UNITY_TRANSFER_FOG(o,o.vertex);
70.                     return o;
71.                 }
72.  
73.                 fixed4 frag(v2f i) : SV_Target
74.                 {
75.                     SpeedTreeFragOut o;
76.                     SpeedTreeFrag(i.data, o);
77.                     UNITY_APPLY_DITHER_CROSSFADE(i.vertex.xy);
78.                     fixed4 c = fixed4(o.Albedo, o.Alpha);
79.                    
80.                     UNITY_APPLY_FOG(i.fogCoord, c);
81.                     return c;
82.                 }
83.             ENDCG
84.         }
85.     }
86.  
87.    
88.     FallBack "Transparent/Cutout/VertexLit"
89. }
90.  

 

Upclose


"quality" speed tree billboards

 

I suppose you are use planes or quads to show your billboard texture.
How are the normals of the quad ? Are they perpendicular to the plane of the quad, or pointing up ?

 

No im using BillboardAsset with BillboardRenderer, its native unity functionality and it handles the geometry internally. And geometry is correct.

 

Why does your shader have both a surface shader and a deferred pass? The deferred pass you have written out will just be ignored since the surface shader should be generating one and I believe Unity still only runs the first deferred pass in a shader.

The "o.Emission" is for the surf function of a surface shader; Emission is a value in the SurfaceOutput struct, which in that setup is actually assigned to the "OUT" variable as "o" is the SpeedTreeFragOut struct.

I suspect it'll work more like you expect if you delete the entire additional pass (lines 39 to 84), remove the SPEEDTREE_COPY_FRAG line from the surf function, and replace it with this:

OUT.Emission = o.Albedo;
OUT.Alpha = o.Alpha;

 

@bgolus

Thanks, it's certainly better now, ill try adding ambient there, but later, cheers!