Refactor: move #object_usable_as_light() from #LightManager class to #Object

so that the function can also be used by other classes.
Also change `!bounds.valid()` to `!is_traceable()` so zero-sized objects
are skipped.

intern/cycles/scene/light.cpp

@@ -239,34 +239,6 @@ void LightManager::test_enabled_lights(Scene *scene)
   }
 }
 
-bool LightManager::object_usable_as_light(Object *object)
-{
-  Geometry *geom = object->get_geometry();
-  if (geom->geometry_type != Geometry::MESH && geom->geometry_type != Geometry::VOLUME) {
-    return false;
-  }
-  /* Skip objects with NaNs */
-  if (!object->bounds.valid()) {
-    return false;
-  }
-  /* Skip if we are not visible for BSDFs. */
-  if (!(object->get_visibility() & (PATH_RAY_DIFFUSE | PATH_RAY_GLOSSY | PATH_RAY_TRANSMIT))) {
-    return false;
-  }
-  /* Skip if we have no emission shaders. */
-  /* TODO(sergey): Ideally we want to avoid such duplicated loop, since it'll
-   * iterate all geometry shaders twice (when counting and when calculating
-   * triangle area.
-   */
-  foreach (Node *node, geom->get_used_shaders()) {
-    Shader *shader = static_cast<Shader *>(node);
-    if (shader->emission_sampling != EMISSION_SAMPLING_NONE) {
-      return true;
-    }
-  }
-  return false;
-}
-
 void LightManager::device_update_distribution(Device *,
                                               DeviceScene *dscene,
                                               Scene *scene,
@@ -284,7 +256,7 @@ void LightManager::device_update_distribution(Device *,
     if (progress.get_cancel())
       return;
 
-    if (!object_usable_as_light(object)) {
+    if (!object->usable_as_light()) {
       continue;
     }
 
@@ -329,7 +301,7 @@ void LightManager::device_update_distribution(Device *,
     if (progress.get_cancel())
       return;
 
-    if (!object_usable_as_light(object)) {
+    if (!object->usable_as_light()) {
       j++;
       continue;
     }
@@ -510,7 +482,7 @@ void LightManager::device_update_tree(Device *,
     if (progress.get_cancel())
       return;
 
-    if (!object_usable_as_light(object)) {
+    if (!object->usable_as_light()) {
       object_id++;
       continue;
     }

intern/cycles/scene/light.h

@@ -21,7 +21,6 @@ CCL_NAMESPACE_BEGIN
 
 class Device;
 class DeviceScene;
-class Object;
 class Progress;
 class Scene;
 class Shader;
@@ -140,9 +139,6 @@ class LightManager {
                                 Progress &progress);
   void device_update_ies(DeviceScene *dscene);
 
-  /* Check whether light manager can use the object as a light-emissive. */
-  bool object_usable_as_light(Object *object);
-
   struct IESSlot {
     IESFile ies;
     uint hash;

intern/cycles/scene/object.cpp

@@ -370,6 +370,34 @@ int Object::get_device_index() const
   return index;
 }
 
+bool Object::usable_as_light() const
+{
+  Geometry *geom = get_geometry();
+  if (!geom->is_mesh() && !geom->is_volume()) {
+    return false;
+  }
+  /* Skip non-traceable objects. */
+  if (!is_traceable()) {
+    return false;
+  }
+  /* Skip if we are not visible for BSDFs. */
+  if (!(get_visibility() & (PATH_RAY_DIFFUSE | PATH_RAY_GLOSSY | PATH_RAY_TRANSMIT))) {
+    return false;
+  }
+  /* Skip if we have no emission shaders. */
+  /* TODO(sergey): Ideally we want to avoid such duplicated loop, since it'll
+   * iterate all geometry shaders twice (when counting and when calculating
+   * triangle area.
+   */
+  foreach (Node *node, geom->get_used_shaders()) {
+    Shader *shader = static_cast<Shader *>(node);
+    if (shader->emission_sampling != EMISSION_SAMPLING_NONE) {
+      return true;
+    }
+  }
+  return false;
+}
+
 /* Object Manager */
 
 ObjectManager::ObjectManager()

intern/cycles/scene/object.h

@@ -105,6 +105,9 @@ class Object : public Node {
   /* Compute step size from attributes, shaders, transforms. */
   float compute_volume_step_size() const;
 
+  /* Check whether this object can be used as light-emissive. */
+  bool usable_as_light() const;
+
  protected:
   /* Specifies the position of the object in scene->objects and
    * in the device vectors. Gets set in device_update. */