Fix T63865: Animated Influence slider of NLA Strip doesn't update

Add special case to construct PointerRNA from evaluated NLA strip
to an original one when flushing animation back to the original ID.

Reviewers: brecht

Maniphest Tasks: T63865

Differential Revision: https://developer.blender.org/D4762

1 files changed, 28 insertions, 11 deletions

diff --git a/source/blender/blenkernel/intern/anim_sys.c b/source/blender/blenkernel/intern/anim_sys.c
index 2beacbcd254..5bc22197021 100644
--- a/source/blender/blenkernel/intern/anim_sys.c
+++ b/source/blender/blenkernel/intern/anim_sys.c
@@ -1832,25 +1832,42 @@ bool BKE_animsys_execute_fcurve(PointerRNA *ptr, FCurve *fcu, float curval)
   return ok;
 }
 
+static bool animsys_construct_orig_pointer_rna(const PointerRNA *ptr, PointerRNA *ptr_orig)
+{
+  *ptr_orig = *ptr;
+  /* NOTE: nlastrip_evaluate_controls() creates PointerRNA with ID of NULL. Technically, this is
+   * not a valid pointer, but there are exceptions in various places of this file which handles
+   * such pointers.
+   * We do special trickery here as well, to quickly go from evaluated to original NlaStrip. */
+  if (ptr->id.data == NULL) {
+    if (ptr->type != &RNA_NlaStrip) {
+      return false;
+    }
+    NlaStrip *strip = ((NlaStrip *)ptr_orig->data);
+    if (strip->orig_strip == NULL) {
+      return false;
+    }
+    ptr_orig->data = strip->orig_strip;
+  }
+  else {
+    ptr_orig->id.data = ((ID *)ptr_orig->id.data)->orig_id;
+    ptr_orig->data = ptr_orig->id.data;
+  }
+  return true;
+}
+
 static void animsys_write_orig_anim_rna(PointerRNA *ptr,
                                         const char *rna_path,
                                         int array_index,
                                         float value)
 {
-  /* Pointer is expected to be an ID pointer, if it's not -- we are doomed.
-   *
-   * NOTE: It is possible to have animation data on NLA strip, see T57360.
-   * TODO(sergey): Find solution for those cases.
-   */
-  if (ptr->id.data == NULL) {
+  PointerRNA ptr_orig;
+  if (!animsys_construct_orig_pointer_rna(ptr, &ptr_orig)) {
     return;
   }
-  PointerRNA orig_ptr = *ptr;
-  orig_ptr.id.data = ((ID *)orig_ptr.id.data)->orig_id;
-  orig_ptr.data = orig_ptr.id.data;
   PathResolvedRNA orig_anim_rna;
-  /* TODO(sergey): Is there a faster way to get anim_rna of original ID? */
-  if (animsys_store_rna_setting(&orig_ptr, rna_path, array_index, &orig_anim_rna)) {
+  /* TODO(sergey): Should be possible to cache resolved path in dependency graph somehow. */
+  if (animsys_store_rna_setting(&ptr_orig, rna_path, array_index, &orig_anim_rna)) {
     animsys_write_rna_setting(&orig_anim_rna, value);
   }
 }