Motion paths: Use minimal possible dependency graph

This change makes it so motion paths are using minimal possible
dependency graph which is sufficient to evaluate required motion
path targets.

Disclaimer: granularity is done on ID level, but it is possible
to go more granular if really needed.

Brings time down to 0.5 sec when updating motion path for the
Rain animation file used for benchmarks in the previous commits.

Reviewers: brecht

Differential Revision: https://developer.blender.org/D5874

1 files changed, 18 insertions, 5 deletions

diff --git a/source/blender/editors/armature/pose_edit.c b/source/blender/editors/armature/pose_edit.c
index e2c9828c20f..ad115896a43 100644
--- a/source/blender/editors/armature/pose_edit.c
+++ b/source/blender/editors/armature/pose_edit.c
@@ -208,12 +208,12 @@ void ED_pose_recalculate_paths(bContext *C, Scene *scene, Object *ob, ePosePathC
   }
 
   Main *bmain = CTX_data_main(C);
-  /* NOTE: Dependency graph will be evaluated at all the frames, but we first need to access some
-   * nested pointers, like animation data. */
-  Depsgraph *depsgraph = CTX_data_ensure_evaluated_depsgraph(C);
-  ListBase targets = {NULL, NULL};
+  ViewLayer *view_layer = CTX_data_view_layer(C);
+
+  Depsgraph *depsgraph;
   bool free_depsgraph = false;
 
+  ListBase targets = {NULL, NULL};
   /* set flag to force recalc, then grab the relevant bones to target */
   ob->pose->avs.recalc |= ANIMVIZ_RECALC_PATHS;
   animviz_get_object_motionpaths(ob, &targets);
@@ -223,6 +223,19 @@ void ED_pose_recalculate_paths(bContext *C, Scene *scene, Object *ob, ePosePathC
   TIMEIT_START(pose_path_calc);
 #endif
 
+  /* For a single frame update it's faster to re-use existing dependency graph and avoid overhead
+   * of building all the relations and so on for a temporary one.  */
+  if (range == POSE_PATH_CALC_RANGE_CURRENT_FRAME) {
+    /* NOTE: Dependency graph will be evaluated at all the frames, but we first need to access some
+     * nested pointers, like animation data. */
+    depsgraph = CTX_data_ensure_evaluated_depsgraph(C);
+    free_depsgraph = false;
+  }
+  else {
+    depsgraph = animviz_depsgraph_build(bmain, scene, view_layer, &targets);
+    free_depsgraph = true;
+  }
+
   animviz_calc_motionpaths(
       depsgraph, bmain, scene, &targets, pose_path_convert_range(range), !free_depsgraph);
 
@@ -238,7 +251,7 @@ void ED_pose_recalculate_paths(bContext *C, Scene *scene, Object *ob, ePosePathC
     DEG_id_tag_update(&ob->id, ID_RECALC_COPY_ON_WRITE);
   }
 
-  /* Free temporary depsgraph instance */
+  /* Free temporary depsgraph. */
   if (free_depsgraph) {
     DEG_graph_free(depsgraph);
   }