Merge branch 'yaobin/fixVisibilityValidation' into 'main'

Fix a bug in restir gi visibility validation

See merge request lightspeedrtx/dxvk-remix-nv!788

src/dxvk/rtx_render/rtx_restir_gi_rayquery.h

@@ -119,7 +119,7 @@ namespace dxvk {
     RTX_OPTION("rtx.restirGI", float, fireflyThreshold, 50.f, "Clamps specular input to suppress boiling.");
     RTX_OPTION("rtx.restirGI", float, roughnessClamp, 0.01f, "Clamps minimum roughness a sample's importance is evaluated.");
     RTX_OPTION("rtx.restirGI", bool, validateLightingChange, true, "Remove samples when direct light has changed.");
-    RTX_OPTION("rtx.restirGI", bool, validateVisibilityChange, false, "Remove samples when visibility has changed. This feature is automatically disabled when virtual sample is enabled.");
+    RTX_OPTION_ENV("rtx.restirGI", bool, validateVisibilityChange, false, "DXVK_RESTIR_GI_VISIBILITY_VALIDATION", "Remove samples when visibility has changed. This feature is automatically disabled when virtual sample is enabled.");
     RTX_OPTION_ENV("rtx.restirGI", float, lightingValidationThreshold, 0.5, "DXVK_RESTIR_GI_SAMPLE_VALIDATION_THRESHOLD", "Invalidate a sample when pixel change ratio is above this value.");
     RTX_OPTION("rtx.restirGI", float, visibilityValidationRange, 0.05, "Check actual hit distance of a shadow ray, invalidate a sample if hit length is longer than one plus this portion, compared to the distance from the surface to the sample.");
   };

src/dxvk/shaders/rtx/algorithm/visibility.slangh

@@ -317,10 +317,17 @@ VisibilityResult traceVisibilityRay(
 
         f16vec3 surfaceAttenuation = handleVisibilityVertex(visibilityRay, rayHitInfo, visibilityMode, usePreviousTLAS);
 
+        f16vec3 prevAttenuation = result.attenuation;
         result.attenuation *= surfaceAttenuation;
 
+        // Find an opaque hit
         if ((float16_t(1) - calcBt709Luminance(result.attenuation)) >= cb.resolveOpaquenessThreshold)
         {
+          // If opaque hit is not considered in the attenuation term, need to recover previous attenuation.
+          if(!clearOpaqueHitAttenuation)
+          {
+            result.attenuation = prevAttenuation;
+          }
           rayQuery.CommitNonOpaqueTriangleHit();
           break;
         }