Reflections shader example in the Built-In Render Pipeline
Example of a shader that renders a reflection of the sky.
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중요
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.
For more information on migration, refer to Migrating from the Built-In Render Pipeline to the Universal Render Pipeline and Render pipeline feature comparison.
A cat-like character with a metallic surface that reflects the scene.
When a Skybox is used in the scene as a reflection source (see Lighting window), then essentially a "default" Reflection Probe is created, containing the skybox data. A reflection probe is internally a Cubemap texture; we will extend the world-space normals shader above to look into it.
The code is starting to get a bit involved by now. Of course, if you want shaders that automatically work with lights, shadows, reflections and the rest of the lighting system, it's way easier to use surface shaders. This example is intended to show you how to use parts of the lighting system in a "manual" way.
Shader "Unlit/SkyReflection"{ SubShader { Pass { HLSLPROGRAM #pragma vertex vert #pragma fragment frag #include "UnityCG.cginc" struct v2f { half3 worldRefl : TEXCOORD0; float4 pos : SV_POSITION; }; v2f vert (float4 vertex : POSITION, float3 normal : NORMAL) { v2f o; o.pos = UnityObjectToClipPos(vertex); // compute world space position of the vertex float3 worldPos = mul(_Object2World, vertex).xyz; // compute world space view direction float3 worldViewDir = normalize(UnityWorldSpaceViewDir(worldPos)); // world space normal float3 worldNormal = UnityObjectToWorldNormal(normal); // world space reflection vector o.worldRefl = reflect(-worldViewDir, worldNormal); return o; } half4 frag (v2f i) : SV_Target { // sample the default reflection cubemap, using the reflection vector half4 skyData = UNITY_SAMPLE_TEXCUBE(unity_SpecCube0, i.worldRefl); // decode cubemap data into actual color half3 skyColor = DecodeHDR (skyData, unity_SpecCube0_HDR); // output it! half4 c = 0; c.rgb = skyColor; return c; } ENDHLSL } }}
The example above uses several things from the built-in shader include files:
- unity_SpecCube0, unity_SpecCube0_HDR, Object2World, UNITY_MATRIX_MVP from the built-in shader variables. unity_SpecCube0 contains data for the active reflection probe.
- UNITY_SAMPLE_TEXCUBE is a built-in macro to sample a cubemap. Most regular cubemaps are declared and used using standard HLSL syntax (samplerCUBE and texCUBE), however the reflection probe cubemaps in Unity are declared in a special way to save on sampler slots. If you don't know what that is, don't worry, just know that in order to use unity_SpecCube0 cubemap you have to use UNITY_SAMPLE_TEXCUBE macro.
- UnityWorldSpaceViewDir function from UnityCG.cginc, and DecodeHDR function from the same file. The latter is used to get actual color from the reflection probe data -- since Unity stores reflection probe cubemap in specially encoded way.
- reflect is just a built-in HLSL function to compute vector reflection around a given normal.