Unity Multi Pass Surface Shader

As you guys know, in Unity we can write shaders in some different ways. We can have Fixed Pipeline Shaders, Surface Shaders and CGPrograms (vertex and fragment shaders).
Surface Shaders are great to write lightning models, but I always believed that it limit the shader to just one pass. Well, yesterday I discovered that I was WRONG. I found a very interesting topic in Unity forum about this and I started to play around with it.

Here follows a very simple shader that illustrate how is possible to combine those languages and have a multi pass shader. Just uncomment the pass blocks to see the effect.

Shader "ZGreaterTest" 
{
 Properties 
 {
     _Color ("Main Color", Color) = (1,1,1,1)
     _MainTex ("Base (RGB)", 2D) = "white" {}
     _Indicator ("Indicator Color", Color) = (1,1,1,1)
     _Cutoff ("Alpha cutoff", Range (0,1)) = 0.0
 }
 
 SubShader 
 {
  Tags { "Queue" = "Geometry+1" "RenderType" = "Opaque" }
 
  CGPROGRAM
  #pragma surface surf BlinnPhong alphatest:_Cutoff
  uniform float4 _Color;
  uniform float4 _Indicator;
  uniform sampler2D _MainTex;
   
  struct Input 
  {
      float2 uv_MainTex;
      float3 viewDir;
  };
  
  void surf (Input IN, inout SurfaceOutput o) 
  {
      o.Albedo = tex2D ( _MainTex, IN.uv_MainTex).rgb * _Color;
  }
  ENDCG

// Pass: Surface SHADER
//     ZWrite Off
//     ZTest Greater
//     Blend DstColor Zero
//     
//  CGPROGRAM
//  #pragma surface surf BlinnPhong
//  uniform float4 _Color;
//  uniform float4 _Indicator;
//  uniform sampler2D _MainTex;
//
//  struct Input 
//  {
//      float2 uv_MainTex;
//      float3 viewDir;
//  };
//  
//  void surf (Input IN, inout SurfaceOutput o) 
//  {
//   //o.Albedo =_Indicator;
//      o.Albedo = tex2D ( _MainTex, IN.uv_MainTex).rgb * _Indicator;
//  }
//  ENDCG 

// Pass: CG SHADER
//  Pass
//        {
//         Tags { "LightMode" = "Always" }
//         AlphaTest Greater [_Cutoff]
//         ZWrite Off
//         ZTest Greater
//         
//            CGPROGRAM
//            #pragma vertex vert
//            #pragma fragment frag
//            #pragma fragmentoption ARB_precision_hint_fastest
//            #include "UnityCG.cginc"
//
//   sampler2D _MainTex;
//   float4 _MainTex_ST;
//   uniform float4 _Indicator;
//   
//            struct v2f 
//            {
//                float4 pos          : POSITION;
//                float2 uv           : TEXCOORD1;
//            };
//
//            v2f vert (appdata_full v)
//            {
//                v2f o;
//                o.pos = mul(UNITY_MATRIX_MVP, v.vertex);    
//                o.uv = TRANSFORM_TEX (v.texcoord, _MainTex);
//                return o;
//            }
//            
//            half4 frag( v2f i ) : COLOR
//            {
//             half4 texcol = tex2D (_MainTex, i.uv);
//               return texcol * _Indicator;
//            }
//          ENDCG           
//        }
        
// Pass: Fixed pipeline
//        Pass 
//  {          
//         Tags { "LightMode" = "Always" }
//         AlphaTest Greater [_Cutoff]
//         ZWrite Off
//         ZTest Greater
// 
//         SetTexture [_MainTex] 
//         {
//             constantColor [_Indicator]
//             //combine constant, texture
//             combine constant* texture
//         }
//  }
  
 }

 Fallback " Glossy", 0
}
 

I would like to thank Sycle and Farfarer to share this tip. :)

I think that the next post will be about a voxelizer that I'm writing. Stay tuned!

Voxel Engine Part 3 (Final)

As promised, here is the Voxel Engine Unity Project:
Unity Package (1.36mb)
Alternative download link

The webplayer demo is available in my previous post.

There is a "Read-me" file inside the package pointing out some directions for those who are trying to understand the project.

I would like to thanks Paul of the BlockStory project that wrote some very useful articles that helped me a lot to get started in the Voxel World. Some classes are heavily based on his samples.

Thanks as well to the Unity community that have this great topic about voxels and to Jeff Standen that wrote the Simplex3D Noise that I'm using.

This demo works on iOS, Android, Mac, Windows and Webplayer. It was tested on my Android Galaxy S2 and Apple iPad4.

The main bottleneck is the CPU while the player is creating and destroying blocks. In the code I left some hints of things that I would have done differently now, or links to articles that offers a better solution for what I did. Remember, this is just a prototype that emerged from a study. There is a lot of stuff to change if you are planning to use this in a real project.

The textures and sounds came from Minecraft ( https://minecraft.net/ ), and the pickaxe is a model that I did trying to reproduce the Minecraft pickaxe. So those assets are not my property and should not be used in any commercial way.

Fell free to use all the other assets and scripts in the way you like.
If you did something cool using this project, please let me know. :)

Thread

Voxel Engine Part 1

Voxel Engine Part 2

Voxel Engine Part 3 (Final)
Voxel Engine "Based" Projects