urp-hlsl-templates

URP HLSL Shader Code Templates

TRIGGER

Use this skill when the user wants to write a Unity shader in HLSL/ShaderLab code (not Shader Graph) for Universal Render Pipeline. Triggers include: "URP shader", "HLSL", "ShaderLab", "write a shader", "custom shader", "vertex fragment shader", "SRP Batcher", "CBUFFER", "custom lit shader", "unlit shader", or any code-based shader authoring in URP. Also trigger when converting Built-in pipeline shaders to URP, or when the user references Cyanilux templates, phi-lira gists, or NedMakesGames tutorials.

CORE RULES — URP HLSL

1. Always use HLSLPROGRAM / ENDHLSL, never CGPROGRAM / ENDCG. URP uses HLSL, not CG. CG blocks will compile but miss URP-specific includes and macros.

2. All material properties must be in a CBUFFER_START(UnityPerMaterial) / CBUFFER_END block for SRP Batcher compatibility. Without this, each material breaks batching and gets its own draw call.

3. Include URP Core, not legacy Unity includes.

   // CORRECT (URP)
   #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
   #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"
   
   // WRONG (Built-in / legacy)
   #include "UnityCG.cginc"
   #include "Lighting.cginc"
   

4. Use URP transform macros, not legacy ones:

   // URP                              // Legacy equivalent
   TransformObjectToHClip(posOS)       // UnityObjectToClipPos(v.vertex)
   TransformObjectToWorld(posOS)       // mul(unity_ObjectToWorld, v.vertex)
   TransformObjectToWorldNormal(nOS)   // UnityObjectToWorldNormal(v.normal)
   TransformWorldToHClip(posWS)        // mul(UNITY_MATRIX_VP, float4(posWS, 1))
   GetVertexPositionInputs(posOS)      // (convenience struct)
   GetVertexNormalInputs(nOS, tanOS)   // (convenience struct)
   

5. Tags must include "RenderPipeline" = "UniversalPipeline" or the shader won't be recognized by URP.

6. Use TEXTURE2D and SAMPLER macros instead of sampler2D:

   TEXTURE2D(_MainTex);
   SAMPLER(sampler_MainTex);
   // Sample with:
   half4 col = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, uv);