Hydra: add support for legacy hair modifier

Fixed case when Hair is in edit mode

@@ -36,3 +37,3 @@
   void insert() override;
   void remove() override;
-  void update() override;
+  virtual void update() override;

@@ -254,6 +257,12 @@ pxr::SdfPath HydraSceneDelegate::material_prim_id(const Material *mat) const
   return prim_id((ID *)mat, "M");
 }
 
+pxr::SdfPath HydraSceneDelegate::hair_prim_id(const pxr::SdfPath parent_obj,

@@ -257,0 +260,4 @@
+pxr::SdfPath HydraSceneDelegate::hair_prim_id(const pxr::SdfPath parent_obj,
+                                              const ParticleSystem *psys) const
+{
+  return parent_obj.AppendPath(pxr::SdfPath(prim_id((ID *)psys, "H").GetName()));

@@ -520,6 +517,49 @@ void HydraSceneDelegate::update_collection()
   });
 }
 
+void HydraSceneDelegate::update_object(Set<std::string> &available_objects, Object *object)

@@ -523,0 +524,4 @@
+      continue;
+    }
+    if (HairData::is_supported(psys) && HairData::is_visible(this, object, psys)) {
+      pxr::SdfPath psys_path = hair_prim_id(object_prim_id(object), psys);

@@ -523,0 +525,4 @@
+    }
+    if (HairData::is_supported(psys) && HairData::is_visible(this, object, psys)) {
+      pxr::SdfPath psys_path = hair_prim_id(object_prim_id(object), psys);
+      ObjectData *psys_data = object_data(psys_path);

@@ -182,0 +194,4 @@
+
+bool HairData::is_supported(const ParticleSystem *particle_system)
+{
+  if (particle_system->part && particle_system->part->type == PART_HAIR) {

@@ -182,0 +213,4 @@
+  ID_LOGN(1, "");
+
+  if (psys_in_edit_mode(scene_delegate_->depsgraph, particle_system_)) {
+    return;

@@ -182,0 +227,4 @@
+  if (particle_system_->part->type != PART_HAIR) {
+    CLOG_WARN(LOG_HYDRA_SCENE, "Unsupported particle type: %d", particle_system_->part->type);
+    if (scene_delegate_->GetRenderIndex().HasRprim(prim_id)) {
+      remove();

@@ -94,6 +94,7 @@ class HydraSceneDelegate : public pxr::HdSceneDelegate {
   pxr::SdfPath prim_id(const ID *id, const char *prefix) const;
   pxr::SdfPath object_prim_id(const Object *object) const;
   pxr::SdfPath material_prim_id(const Material *mat) const;
+  pxr::SdfPath psys_prim_id(Object *parent_obj, const ParticleSystem *mat) const;