Combining surface and vertex/fragment shader

Hello!
We use the nature pack trees in our project, but their shaders has no lighting and cast no shadow (and for some reason they use double polygons in all foliage, instead of turning off backface cull). So i thought it would be great to combine them with built in transparency diffuse cutout shader, since it looks much more juicy and gets illuminated by the lights. The main reason to combine them is the animation. Their trees is animated by vertex transformation in shader. I don't know economywise how efficient this solution is, but it works fine and since some maps already contain their trees i think correcting the shader is the right thing to do.
I've deal with some simple shaders before, but this seems too complicated to me since these shaders works diffirently. I thought to mess up with passes and subshaders, but this is a mobile game and the solution got to be light and simple, si i'm asking for your help.
First of all - i can't get which is the best - implement the animation cycle in surface shader, or try to use the lambent lighting model in 2-pass nature pack shader.
Also there's one thing that disturbs me: i can't get adequate source of information for shader programming. I mean the scripting in that case is pretty obvious, you have the issue, you google it, read about it and it works. In shader code it just isn't, and i can't get any information source that would tell me why that happens and how to fix it. All i get is extensive advices to read books, but since i'm a all-in-one person, i'm gonna blow my head this way, so it would be great if you have some adequate shader manuals and command lists.

So, the shader is

Code (CSharp):

1. // - Unlit
2.  
3. Shader "atsGrass-Unlit-Wind" {
4. Properties {
5.     _MainTex ("Base (RGB) Alpha (A)", 2D) = "white" {}
6.     _Cutoff ("Alpha cutoff", Range(0,1)) = 0.5
7. }
8.  
9. SubShader {
10.     Tags {"Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" "LightMode"="ForwardBase"}
11.     LOD 100
12.     Cull Off
13.     ZWrite Off
14.     Blend SrcAlpha OneMinusSrcAlpha
15.    
16.    
17.     CGINCLUDE
18.     #include "UnityCG.cginc"
19.     sampler2D _MainTex;
20.     half4 _MainTex_ST;
21.    
22.     float4 _GrassWind; //is not defined in terrainengine.cginc
23.  
24.     struct v2f {
25.         float4 pos : SV_POSITION;
26.         float2 uv : TEXCOORD0;
27.     };
28.  
29. inline float4 AnimateGrass(float4 pos, float3 normal, float animParams)
30. {  
31.     // animParams stored in color
32.     // animParams = primary factor = blue
33.     // Primary bending
34.     // Displace position
35.     pos.xyz += animParams * _GrassWind.xyz * _GrassWind.w; // controlled by vertex color blue
36.     return pos;
37. }
38.  
39.  
40.    
41.     v2f vert (appdata_full v)
42.     {
43.         v2f o;
44.         float4    windParams    = float(v.color.b);      
45.         // call vertex animation
46.         float4 mdlPos = AnimateGrass(v.vertex, v.normal, windParams);
47.         o.pos = mul(UNITY_MATRIX_MVP,mdlPos);
48.         o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
49.         return o;
50.     }
51.     ENDCG
52.  
53.     Pass {
54.         CGPROGRAM
55.         #pragma debug
56.         #pragma vertex vert
57.         #pragma fragment frag
58.         #pragma fragmentoption ARB_precision_hint_fastest      
59.         fixed4 frag (v2f i) : COLOR
60.         {
61.             fixed4 tex = tex2D (_MainTex, i.uv);
62.            
63.             fixed4 c;
64.             c.rgb = tex.rgb;
65.             c.a = tex.a;
66.            
67.             return c;
68.         }
69.         ENDCG
70.     }  
71. }
72. }
73.  
74.  

Thanks in advance!

 

So, for now i've managed to get the assets lighted correctly, cast and recieve shadows. But there's a problem with blending and the shadows won't move with the leaves, There's temporary version. Still will appreciate any possible help.

Code (CSharp):

1. Shader "Wind Trees" {
2. Properties {
3.          _MainTex ("Base (RGB) Alpha (A)", 2D) = "white" {}
4.          _Color ("Main Color", Color) = (1,1,1,1)
5.          _Cutoff ("Alpha cutoff", Range(0,1)) = 0.5
6. }
7. SubShader {
8.          Pass {
9.          Tags {"Queue"="Transparent+1" "IgnoreProjector"="True" "RenderType"="TransparentCutout"}
10.     LOD 200
11.     Cull Off
12.         CGPROGRAM
13.         #pragma vertex vert
14.         #pragma fragment frag
15.         #pragma multi_compile_fwdbase
16.         #pragma fragmentoption ARB_precision_hint_fastest
17.         #include "UnityCG.cginc"
18.         #include "AutoLight.cginc"
19.     sampler2D _MainTex;
20.     float4 _Color;
21.     float4 _LightColor0;
22.     half4 _MainTex_ST;
23.     float4 _GrassWind; //is not defined in terrainengine.cginc
24.     struct v2f {
25.                  float4 pos : SV_POSITION;
26.                  float3 lightDir : TEXCOORD0;
27.                  float3 normal : TEXCOORD1;
28.                  float2 uv : TEXCOORD2;
29.                  LIGHTING_COORDS(3, 4)
30.     };
31. inline float4 AnimateGrass(float4 pos, float3 normal, float animParams)
32. {
33.     pos.xyz += animParams * _GrassWind.xyz * _GrassWind.w; // controlled by vertex color blue
34.     return pos;
35. }
36.     v2f vert (appdata_full v)
37.     {
38.         v2f o;
39.         float4    windParams    = float(v.color.b);
40.         float4 mdlPos = AnimateGrass(v.vertex, v.normal, windParams);
41.         o.pos = mul(UNITY_MATRIX_MVP,mdlPos);
42.                  o.uv = v.texcoord;
43.                  o.lightDir = normalize(ObjSpaceLightDir(v.vertex));
44.                  o.normal = normalize(v.normal).xyz;
45.         TRANSFER_VERTEX_TO_FRAGMENT(o);
46.         return o;
47.     }
48.         fixed4 frag (v2f i) : COLOR
49.         {
50.                  float3 L = normalize(i.lightDir);
51.                  float3 N = normalize(i.normal);    
52.                  float attenuation = LIGHT_ATTENUATION(i) * 2;
53.                  float4 ambient = UNITY_LIGHTMODEL_AMBIENT * 2;
54.                  float NdotL = saturate(dot(N, L));
55.                  float4 diffuseTerm = NdotL * _LightColor0 * _Color * attenuation;
56.                  fixed4 tex = tex2D(_MainTex, i.uv);
57.                  fixed4 c = ((ambient + diffuseTerm) * tex.rgba) * _Color;
58.                  return c;
59.         }
60.         ENDCG    
61. }
62.  
63.     // Pass to render object as a shadow caster
64.     Pass {
65.         Name "Caster"
66.         Tags { "LightMode" = "ShadowCaster" }
67.         Offset 1, 1
68.         Fog {Mode Off}
69.         ZWrite On ZTest LEqual Cull Off
70. CGPROGRAM
71. #pragma vertex vert
72. #pragma fragment frag
73. #pragma fragmentoption ARB_precision_hint_fastest
74. #include "UnityCG.cginc"
75. struct v2f {
76.     V2F_SHADOW_CASTER;
77.     float2  uv : TEXCOORD1;
78. };
79. uniform float4 _MainTex_ST;
80. v2f vert( appdata_base v )
81. {
82.     v2f o;
83.     TRANSFER_SHADOW_CASTER(o)
84.     o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
85.     return o;
86. }
87. uniform sampler2D _MainTex;
88. uniform fixed _Cutoff;
89. uniform fixed4 _Color;
90. float4 frag( v2f i ) : COLOR
91. {
92.     fixed4 texcol = tex2D( _MainTex, i.uv );
93.     clip( texcol.a*_Color.a - _Cutoff );
94.     SHADOW_CASTER_FRAGMENT(i)
95. }
96. ENDCG
97.     }
98.         // Pass to render object as a shadow collector
99.     Pass {
100.         Name "ShadowCollector"
101.         Tags { "LightMode" = "ShadowCollector" }
102.         Fog {Mode Off}
103.         ZWrite On ZTest LEqual
104. CGPROGRAM
105. #pragma vertex vert
106. #pragma fragment frag
107. #pragma fragmentoption ARB_precision_hint_fastest
108. #define SHADOW_COLLECTOR_PASS
109. #include "UnityCG.cginc"
110. struct v2f {
111.     V2F_SHADOW_COLLECTOR;
112.     float2  uv : TEXCOORD5;
113. };
114. uniform float4 _MainTex_ST;
115. v2f vert (appdata_base v)
116. {
117.     v2f o;
118.     TRANSFER_SHADOW_COLLECTOR(o)
119.     o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
120.     return o;
121. }
122. uniform sampler2D _MainTex;
123. uniform fixed _Cutoff;
124. uniform fixed4 _Color;
125. fixed4 frag (v2f i) : COLOR
126. {
127.     fixed4 texcol = tex2D( _MainTex, i.uv );
128.     clip( texcol.a*_Color.a - _Cutoff );
129.     SHADOW_COLLECTOR_FRAGMENT(i)
130. }
131. ENDCG
132.     }
133.  
134. }
135. }

 

So, after some experiments i came up with this - surface shader that well lit, animated, casts and recieves shadow. HOWEVER.. the shadows is not animated with the leaves. I still don't know how to solve this. Should i modify the shadow caster(no need to tweak the shadow reciever, it works fine with the non-animated shadows saving some performance) or the main pass. Here's the code:

Code (CSharp):

1. Shader "Wind Trees2" {
2. Properties {
3.     _Color ("Main Color", Color) = (1,1,1,1)
4.     _MainTex ("Base (RGB) Trans (A)", 2D) = "white" {}
5.     _Cutoff ("Alpha cutoff", Range(0,1)) = 0.5
6. }
7.  
8. SubShader {
9.     Tags {"Queue"="AlphaTest" "IgnoreProjector"="True" "RenderType"="TransparentCutout"}
10.     LOD 200
11.     Cull Off
12.    
13. CGPROGRAM
14. #pragma surface surf Lambert alphatest:_Cutoff vertex:vert
15. #pragma addshadow
16. sampler2D _MainTex;
17. fixed4 _Color;
18. float4 _GrassWind; //is not defined in terrainengine.cginc
19.  
20.  
21. struct Input {
22.     float2 uv_MainTex;
23.     float4 pos : SV_POSITION;
24. };
25.  
26. inline float4 AnimateGrass(float4 pos, float3 normal, float animParams)
27. {
28.     pos.xyz += animParams * _GrassWind.xyz * _GrassWind.w; // controlled by vertex color blue
29.     return pos;
30. }
31.  
32. void vert (inout appdata_full v, out Input o) {
33.         UNITY_INITIALIZE_OUTPUT(Input,o);
34.         float4    windParams    = float(v.color.b);
35.         float4 mdlPos = AnimateGrass(v.vertex, v.normal, windParams);
36.     //    o.pos = mul(UNITY_MATRIX_MVP,mdlPos);
37.         v.vertex = mdlPos;
38.     //    v.vertex.xyz += v.normal * v.vertex.xyz * _Cutoff ;
39.           }
40.  
41. void surf (Input IN, inout SurfaceOutput o) {
42.     fixed4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color;
43.     o.Albedo = c.rgb;
44.     o.Alpha = c.a;
45. }
46. ENDCG
47.  
48.  
49.     }
50.  
51. Fallback "Transparent/Cutout/VertexLit"
52. }
53.  

If you want some custom shadow caster/reciever you should add after the final ENDCG this:

Code (CSharp):

1.     // Pass to render object as a shadow caster
2.     Pass {
3.         Name "Caster"
4.         Tags { "LightMode" = "ShadowCaster" }
5.         Offset 1, 1
6.         Fog {Mode Off}
7.         ZWrite On ZTest LEqual Cull Off
8. CGPROGRAM
9. #pragma vertex vert
10. #pragma fragment frag
11. #pragma fragmentoption ARB_precision_hint_fastest
12. #include "UnityCG.cginc"
13. struct v2f {
14.     V2F_SHADOW_CASTER;
15.     float2  uv : TEXCOORD1;
16. };
17. uniform float4 _MainTex_ST;
18. v2f vert( appdata_base v )
19. {
20.     v2f o;
21.     TRANSFER_SHADOW_CASTER(o)
22.     o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
23.     return o;
24. }
25. uniform sampler2D _MainTex;
26. uniform fixed _Cutoff;
27. uniform fixed4 _Color;
28. float4 frag( v2f i ) : COLOR
29. {
30.     fixed4 texcol = tex2D( _MainTex, i.uv );
31.     clip( texcol.a*_Color.a - _Cutoff );
32.     SHADOW_CASTER_FRAGMENT(i)
33. }
34. ENDCG
35.     }
36.         // Pass to render object as a shadow collector
37.     Pass {
38.         Name "ShadowCollector"
39.         Tags { "LightMode" = "ShadowCollector" }
40.         Fog {Mode Off}
41.         ZWrite On ZTest LEqual
42. CGPROGRAM
43. #pragma vertex vert
44. #pragma fragment frag
45. #pragma fragmentoption ARB_precision_hint_fastest
46. #define SHADOW_COLLECTOR_PASS
47. #include "UnityCG.cginc"
48. struct v2f {
49.     V2F_SHADOW_COLLECTOR;
50.     float2  uv : TEXCOORD5;
51. };
52. uniform float4 _MainTex_ST;
53. v2f vert (appdata_base v)
54. {
55.     v2f o;
56.     TRANSFER_SHADOW_COLLECTOR(o)
57.     o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
58.     return o;
59. }
60. uniform sampler2D _MainTex;
61. uniform fixed _Cutoff;
62. uniform fixed4 _Color;
63. fixed4 frag (v2f i) : COLOR
64. {
65.     fixed4 texcol = tex2D( _MainTex, i.uv );
66.     clip( texcol.a*_Color.a - _Cutoff );
67.     SHADOW_COLLECTOR_FRAGMENT(i)
68. }
69. ENDCG
70.     }

and delete the Fallback line at the end.
Still hope someone can help me find the solution.