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Reflection Surface Shader examples in the Built-In Render Pipeline

An example of a Surface Shader that renders reflections of the sky.
Read time 1 minuteLast updated 14 days ago
Important
The Built-In Render Pipeline is deprecated and will be made obsolete in a future release.
It remains supported, including bug fixes and maintenance, through the full Unity 6.7 LTS lifecycle.
The Universal Render Pipeline (URP) doesn't support surface shaders. For more information on how to replace surface shaders in URP, refer to Convert custom shaders for URP compatibility.
Here's a Shader that does cubemapped reflection using built-in 
worldRefl
input. It's very similar to built-in Reflective/Diffuse Shader:
  Shader "Example/WorldRefl" {    Properties {      _MainTex ("Texture", 2D) = "white" {}      _Cube ("Cubemap", CUBE) = "" {}    }    SubShader {      Tags { "RenderType" = "Opaque" }      CGPROGRAM      #pragma surface surf Lambert      struct Input {          float2 uv_MainTex;          float3 worldRefl;      };      sampler2D _MainTex;      samplerCUBE _Cube;      void surf (Input IN, inout SurfaceOutput o) {          o.Albedo = tex2D (_MainTex, IN.uv_MainTex).rgb * 0.5;          o.Emission = texCUBE (_Cube, IN.worldRefl).rgb;      }      ENDCG    }     Fallback "Diffuse"  }
Because it assigns the reflection color as Emission, we get a very shiny soldier:

Surface shader example that uses the world reflection texture as emission texture.

If you want to do reflections that are affected by normal maps, it needs to be slightly more involved: 
INTERNAL_DATA
needs to be added to the 
Input
structure, and 
WorldReflectionVector
function used to compute per-pixel reflection vector after you've written the Normal output.
  Shader "Example/WorldRefl Normalmap" {    Properties {      _MainTex ("Texture", 2D) = "white" {}      _BumpMap ("Bumpmap", 2D) = "bump" {}      _Cube ("Cubemap", CUBE) = "" {}    }    SubShader {      Tags { "RenderType" = "Opaque" }      CGPROGRAM      #pragma surface surf Lambert      struct Input {          float2 uv_MainTex;          float2 uv_BumpMap;          float3 worldRefl;          INTERNAL_DATA      };      sampler2D _MainTex;      sampler2D _BumpMap;      samplerCUBE _Cube;      void surf (Input IN, inout SurfaceOutput o) {          o.Albedo = tex2D (_MainTex, IN.uv_MainTex).rgb * 0.5;          o.Normal = UnpackNormal (tex2D (_BumpMap, IN.uv_BumpMap));          o.Emission = texCUBE (_Cube, WorldReflectionVector (IN, o.Normal)).rgb;      }      ENDCG    }     Fallback "Diffuse"  }
Here's a normal-mapped shiny soldier:

Surface shader example that uses the world reflection texture as emission texture and applies a normal texture to it.