More comment

com.unity.render-pipelines.high-definition/HDRP/Lighting/LightEvaluation.hlsl

 #endif
 
     // We test NdotL >= 0.0 to not sample the shadow map if it is not required.
-    // Note that volumetric use N of 0 so it still work
     UNITY_BRANCH if (lightData.shadowIndex >= 0 && (dot(N, L) >= 0.0))
     {
         // TODO: make projector lights cast shadows.

com.unity.render-pipelines.high-definition/HDRP/Lighting/Volumetrics/VolumetricLighting.compute

 
             float3 color; float attenuation;
             light.contactShadowIndex = -1; // Disable shadow contact if any
+            // Note: We provide a normal of 0 here that work with the NdotL >= 0 test inside the EvaluateLight_Punctual call
             EvaluateLight_Directional(context, posInput, light, unused, 0, L,
                                       color, attenuation);
 
 
                     float3 color; float attenuation;
                     light.contactShadowIndex = -1; // Disable shadow contact if any
+                    // Note: We provide a normal of 0 here that work with the NdotL >= 0 test inside the EvaluateLight_Punctual call
                     EvaluateLight_Punctual(context, posInput, light, unused,
                                            0, L, lightToSample, distances,
                                            color, attenuation);
 
                     float3 color; float attenuation;
                     light.contactShadowIndex = -1; // Disable shadow contact if any
+                    // Note: We provide a normal of 0 here that work with the NdotL >= 0 test inside the EvaluateLight_Punctual call
                     EvaluateLight_Punctual( context, posInput, light, unused,
                                             0, L, lightToSample, distances,
                                             color, attenuation);