[Bf-blender-cvs] [00a20aec074] master: Fix T103403: Lightgroup passes can contain lighting on shadow catchers

[Lukas Stockner]

Commit: 00a20aec074c3a10a2d2e1142c14cc533c90a6b3
Author: Lukas Stockner
Date:   Fri Jan 6 02:32:03 2023 +0100
Branches: master
https://developer.blender.org/rB00a20aec074c3a10a2d2e1142c14cc533c90a6b3

Fix T103403: Lightgroup passes can contain lighting on shadow catchers

===================================================================

M	intern/cycles/kernel/film/light_passes.h

===================================================================

diff --git a/intern/cycles/kernel/film/light_passes.h b/intern/cycles/kernel/film/light_passes.h
index dbc527f2d5d..4cfd1aef43a 100644
--- a/intern/cycles/kernel/film/light_passes.h
+++ b/intern/cycles/kernel/film/light_passes.h
@@ -364,7 +364,9 @@ ccl_device_inline void film_write_emission_or_background_pass(
   }
 #  endif /* __DENOISING_FEATURES__ */
 
-  if (lightgroup != LIGHTGROUP_NONE && kernel_data.film.pass_lightgroup != PASS_UNUSED) {
+  const bool is_shadowcatcher = (path_flag & PATH_RAY_SHADOW_CATCHER_HIT) != 0;
+  if (!is_shadowcatcher && lightgroup != LIGHTGROUP_NONE &&
+      kernel_data.film.pass_lightgroup != PASS_UNUSED) {
     film_write_pass_spectrum(buffer + kernel_data.film.pass_lightgroup + 3 * lightgroup,
                              contribution);
   }
@@ -373,13 +375,12 @@ ccl_device_inline void film_write_emission_or_background_pass(
     /* Directly visible, write to emission or background pass. */
     pass_offset = pass;
   }
-  else if (kernel_data.kernel_features & KERNEL_FEATURE_LIGHT_PASSES) {
+  else if (is_shadowcatcher) {
     /* Don't write any light passes for shadow catcher, for easier
      * compositing back together of the combined pass. */
-    if (path_flag & PATH_RAY_SHADOW_CATCHER_HIT) {
-      return;
-    }
-
+    return;
+  }
+  else if (kernel_data.kernel_features & KERNEL_FEATURE_LIGHT_PASSES) {
     if (path_flag & PATH_RAY_SURFACE_PASS) {
       /* Indirectly visible through reflection. */
       const Spectrum diffuse_weight = INTEGRATOR_STATE(state, path, pass_diffuse_weight);