Vertex color blending shader

Question

Hi,

i'm trying to create a 3 layer terrain shader that uses the vertex colors in the mesh painted by the vertex painter modifier in 3ds max

Now i tried to make this shader but it gives me errors that doesn't make any sense to me.

So here's the shader:

 Shader "Debug/Vertex color" {
 Properties {
         _Color ("Color", Color) = (0,0,0,1)
         _Layer1 ("Layer1", 2D) = "white" {}
         _Layer2 ("Layer2", 2D) = "white" {}
         _Layer3 ("Layer3", 2D) = "white" {}
     }
 SubShader {
     Pass {
         Fog { Mode Off }
         CGPROGRAM
 
         #pragma vertex vert
         #pragma fragment frag
 
         sampler2D _Layer1;
         sampler2D _Layer2;
         sampler2D _Layer3;
         float _Color;
 
         // vertex input: position, color
         struct appdata {
             float4 vertex : POSITION;
             fixed4 color : COLOR;
         };
 
         struct v2f {
             float4 pos : SV_POSITION;
             fixed4 color : COLOR;
             float2 uv_Layer1 : TEXCOORD0;
             float2 uv_Layer2 : TEXCOORD0;
             float2 uv_Layer3 : TEXCOORD0;
         };
         
         v2f vert (appdata v) {
             v2f o;
             o.pos = mul( UNITY_MATRIX_MVP, v.vertex );
             o.color = v.color;
             return o;
         }
         
         float4 frag (v2f i) : COLOR0
         { 
             half4 l1 = tex2D (_Layer1, i.uv_Layer1);
             half4 l2 = tex2D (_Layer2, i.uv_Layer2);
             half4 l3 = tex2D (_Layer3, i.uv_Layer3);
 
             float4 out;
 
             out = (l1.rgb * i.color.r) + (l2.rgb * i.color.g) + (l3.rgb * i.color.b);
 
             return out; 
         }
         ENDCG
     }
 }
 }

and this is the error log:

 Shader error in 'Debug/Vertex color': Shader program had errors at line 12
 
 Shader error in 'Debug/Vertex color': Program 'frag', cast not allowed at line 50
 
 Shader error in 'Debug/Vertex color': Program 'frag', syntax error, unexpected '=' at token "=" at line 50
 
 Shader error in 'Debug/Vertex color': Program 'frag', type name expected at token "=" at line 50
 
 Shader error in 'Debug/Vertex color': Program 'vert', cast not allowed at line 50
 
 Shader error in 'Debug/Vertex color': Program 'vert', syntax error, unexpected '=' at token "=" at line 50
 
 Shader error in 'Debug/Vertex color': Program 'vert', type name expected at token "=" at line 50
 
 Shader error in 'Debug/Vertex color': Program 'frag', syntax error, unexpected ';' at token ";" at line 52
 
 Shader error in 'Debug/Vertex color': Program 'frag', type name expected at token ";" at line 52
 
 Shader error in 'Debug/Vertex color': Program 'vert', syntax error, unexpected ';' at token ";" at line 52
 
 Shader error in 'Debug/Vertex color': Program 'vert', type name expected at token ";" at line 52

I would appreciate some corrections here.

Thanks!

Answer 1

Best Answer

Answer by MaT227 · Jul 17, 2014 at 08:32 AM

Here you have no more errors: As @Bunny83 said the out keyword was causing the error.

 Shader "Debug/Vertex color" {
     Properties
     {
         _Color    ("Color", Color) = (0,0,0,1)
         _Layer1 ("Layer1", 2D) = "white" {}
         _Layer2 ("Layer2", 2D) = "white" {}
         _Layer3 ("Layer3", 2D) = "white" {}
     }
     SubShader
     {
         Pass
         {
             Fog { Mode Off }
             CGPROGRAM
             #pragma vertex vert
             #pragma fragment frag
              
             sampler2D    _Layer1;
             sampler2D    _Layer2;
             sampler2D    _Layer3;
             float         _Color;
             
             struct appdata
             {
                 float4 vertex : POSITION;
                 fixed4 color : COLOR;
             };
              
             struct v2f
             {
                 float4 pos : SV_POSITION;
                 fixed4 color : COLOR;
                 float2 uv_Layer1 : TEXCOORD0;
                 float2 uv_Layer2 : TEXCOORD1;
                 float2 uv_Layer3 : TEXCOORD2;
             };
              
             v2f vert (appdata v)
             {
                 v2f o;
                 o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
                 o.color = v.color;
                 return o;
             }
              
             float4 frag (v2f i) : COLOR
             {
                 half4 l1 = tex2D (_Layer1, i.uv_Layer1);
                 half4 l2 = tex2D (_Layer2, i.uv_Layer2);
                 half4 l3 = tex2D (_Layer3, i.uv_Layer3);
                  
                 float4 color = float4(1, 1, 1, 1);
                 color.rgb = (l1.rgb * i.color.r) + (l2.rgb * i.color.g) + (l3.rgb * i.color.b);
                 return color;
             }
         ENDCG
         }
     }
 }

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kilian277 · Jul 17, 2014 at 11:10 AM 1

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thanks man it helped to fix the errors , but 3ds max does not correctly save the vertex colors in de fbx file so i have to look into that also , but thanks :D

MaT227 · Jul 17, 2014 at 11:21 AM 0

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You're welcome, there are several example of vertex color blending shaders. You should also take a look at them.

kilian277 · Jul 17, 2014 at 11:44 AM 0

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Also when i apply the shader only the colors are shown on the mesh , the textures are not applied to it , something weird have a look at this pic. link text

Bunny83 · Jul 17, 2014 at 11:48 AM 1

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@kilian277: Just in case you still don't know what the problem was: "out" is a keyword like in C#.

kilian277 · Jul 17, 2014 at 01:15 PM 0

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@Bunny83: oh i didn't know that , anyways the texturing per vertex color is now working so everyone thanks for the input !

Vertex color blending shader

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