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ScriptableRenderPipeline/Core/ShaderLibrary/ImageBasedLighting.hlsl

 
         if (usePrecomputedSamples)
         {
+            // Performance warning: using a texture LUT will generate a vector load,
+            // which increases both the VGPR pressure and the workload of the
+            // texture unit. A better solution here is to load from a Constant, Raw
+            // or Structured buffer, or perhaps even declare all the constants in an
+            // HLSL header to allow the compiler to inline everything.
             float3 localL = LOAD_TEXTURE2D(ggxIblSamples, uint2(i, index)).xyz;
 
             L     = mul(localL, localToWorld);