Fix hiding receiver disabling light/shadow linking

Turns out it is not enough to check for the receiver/blocker set,
as the object might be hidden. This should not change the light
behavior.

Pull Request: https://projects.blender.org/blender/blender/pulls/108307

intern/cycles/scene/light.cpp

@@ -174,6 +174,24 @@ bool Light::has_contribution(Scene *scene)
   return !is_zero(effective_shader->emission_estimate);
 }
 
+bool Light::has_light_linking() const
+{
+  if (get_light_set_membership() != LIGHT_LINK_MASK_ALL) {
+    return true;
+  }
+
+  return false;
+}
+
+bool Light::has_shadow_linking() const
+{
+  if (get_shadow_set_membership() != LIGHT_LINK_MASK_ALL) {
+    return true;
+  }
+
+  return false;
+}
+
 /* Light Manager */
 
 LightManager::LightManager()

intern/cycles/scene/light.h

@@ -82,6 +82,10 @@ class Light : public Node {
   /* Check whether the light has contribution the scene. */
   bool has_contribution(Scene *scene);
 
+  /* Check whether this light participates in light or shadow linking. */
+  bool has_light_linking() const;
+  bool has_shadow_linking() const;
+
   friend class LightManager;
   friend class LightTree;
 };

intern/cycles/scene/object.cpp

@@ -403,6 +403,32 @@ bool Object::usable_as_light() const
   return false;
 }
 
+bool Object::has_light_linking() const
+{
+  if (get_receiver_light_set()) {
+    return true;
+  }
+
+  if (get_light_set_membership() != LIGHT_LINK_MASK_ALL) {
+    return true;
+  }
+
+  return false;
+}
+
+bool Object::has_shadow_linking() const
+{
+  if (get_blocker_shadow_set()) {
+    return true;
+  }
+
+  if (get_shadow_set_membership() != LIGHT_LINK_MASK_ALL) {
+    return true;
+  }
+
+  return false;
+}
+
 /* Object Manager */
 
 ObjectManager::ObjectManager()

intern/cycles/scene/object.h

@@ -113,6 +113,11 @@ class Object : public Node {
   /* Check whether this object can be used as light-emissive. */
   bool usable_as_light() const;
 
+  /* Check whether the object participates in light or shadow linking, either as a receiver/blocker
+   * or emitter. */
+  bool has_light_linking() const;
+  bool has_shadow_linking() const;
+
  protected:
   /* Specifies the position of the object in scene->objects and
    * in the device vectors. Gets set in device_update. */

intern/cycles/scene/scene.cpp

@@ -491,10 +491,10 @@ void Scene::update_kernel_features()
     else if (geom->is_pointcloud()) {
       kernel_features |= KERNEL_FEATURE_POINTCLOUD;
     }
-    if (object->get_receiver_light_set()) {
+    if (object->has_light_linking()) {
       kernel_features |= KERNEL_FEATURE_LIGHT_LINKING;
     }
-    if (object->get_blocker_shadow_set()) {
+    if (object->has_shadow_linking()) {
       kernel_features |= KERNEL_FEATURE_SHADOW_LINKING;
     }
   }
@@ -503,6 +503,13 @@ void Scene::update_kernel_features()
     if (light->get_use_caustics()) {
       has_caustics_light = true;
     }
+
+    if (light->has_light_linking()) {
+      kernel_features |= KERNEL_FEATURE_LIGHT_LINKING;
+    }
+    if (light->has_shadow_linking()) {
+      kernel_features |= KERNEL_FEATURE_SHADOW_LINKING;
+    }
   }
 
   dscene.data.integrator.use_caustics = false;