[Bf-blender-cvs] [0f84fbd6fdb] usd-importer-T81257-merge: USD import: xform cache constraint parenting bug.

[makowalski]

Commit: 0f84fbd6fdb490efe70aadaadb41c6d7ef72b2a7
Author: makowalski
Date:   Thu Feb 11 16:47:28 2021 -0500
Branches: usd-importer-T81257-merge
https://developer.blender.org/rB0f84fbd6fdb490efe70aadaadb41c6d7ef72b2a7

USD import: xform cache constraint parenting bug.

USD_get_transform() was not taking the object's parent
transform into account.  Now following the same logic
as in the corresponding Alembic implementation,
ABC_get_transform(), to fix this.

===================================================================

M	source/blender/io/usd/intern/usd_capi.cc

===================================================================

diff --git a/source/blender/io/usd/intern/usd_capi.cc b/source/blender/io/usd/intern/usd_capi.cc
index 1afe89681e3..ad2adac2e40 100644
--- a/source/blender/io/usd/intern/usd_capi.cc
+++ b/source/blender/io/usd/intern/usd_capi.cc
@@ -57,11 +57,13 @@
 #include "BKE_library.h"
 #include "BKE_main.h"
 #include "BKE_node.h"
+#include "BKE_object.h"
 #include "BKE_scene.h"
 #include "BKE_world.h"
 
 #include "BLI_fileops.h"
 #include "BLI_listbase.h"
+#include "BLI_math_matrix.h"
 #include "BLI_path_util.h"
 #include "BLI_string.h"
 
@@ -747,7 +749,7 @@ void USD_free_handle(USDStageHandle *handle)
   delete archive;
 }
 
-void USD_get_transform(struct CacheReader *reader, float r_mat[4][4], float time, float scale)
+void USD_get_transform(struct CacheReader *reader, float r_mat_world[4][4], float time, float scale)
 {
   if (!reader) {
     return;
@@ -755,5 +757,23 @@ void USD_get_transform(struct CacheReader *reader, float r_mat[4][4], float time
   USDXformReader *usd_reader = reinterpret_cast<USDXformReader *>(reader);
 
   bool is_constant = false;
-  usd_reader->read_matrix(r_mat, time, scale, is_constant);
+
+  /* Convert from the local matrix we obtain from USD to world coordinates
+   * for Blender. This conversion is done here rather than by Blender due to
+   * work around the non-standard interpretation of CONSTRAINT_SPACE_LOCAL in
+   * BKE_constraint_mat_convertspace(). */
+  Object *object = usd_reader->object();
+  if (object->parent == nullptr) {
+    /* No parent, so local space is the same as world space. */
+    usd_reader->read_matrix(r_mat_world, time, scale, is_constant);
+    return;
+  }
+
+  float mat_parent[4][4];
+  BKE_object_get_parent_matrix(object, object->parent, mat_parent);
+
+  float mat_local[4][4];
+  usd_reader->read_matrix(mat_local, time, scale, is_constant);
+  mul_m4_m4m4(r_mat_world, mat_parent, object->parentinv);
+  mul_m4_m4m4(r_mat_world, r_mat_world, mat_local);
 }