USD: add USD importer

This is an initial implementation of a USD importer.

This work is comprised of Tangent Animation's open source USD importer,
combined with features @makowalski had implemented.

The design is very similar to the approach taken in the Alembic
importer. The core functionality resides in a collection of "reader"
classes, each of which is responsible for converting an instance of a
USD prim to the corresponding Blender Object representation.

The flow of control for the conversion can be followed in the
`import_startjob()` and `import_endjob()` functions in `usd_capi.cc`.
The `USDStageReader` class is responsible for traversing the USD stage
and instantiating the appropriate readers.

Reviewed By: sybren, HooglyBoogly

Differential Revision: https://developer.blender.org/D10700

1 files changed, 16 insertions, 19 deletions

diff --git a/source/blender/io/alembic/intern/alembic_capi.cc b/source/blender/io/alembic/intern/alembic_capi.cc
index e8d70bf3edb..b94b75b2216 100644
--- a/source/blender/io/alembic/intern/alembic_capi.cc
+++ b/source/blender/io/alembic/intern/alembic_capi.cc
@@ -19,6 +19,7 @@
  */
 
 #include "../ABC_alembic.h"
+#include "IO_types.h"
 
 #include <Alembic/AbcMaterial/IMaterial.h>
 
@@ -89,18 +90,14 @@ using Alembic::AbcMaterial::IMaterial;
 
 using namespace blender::io::alembic;
 
-struct AbcArchiveHandle {
-  int unused;
-};
-
-BLI_INLINE ArchiveReader *archive_from_handle(AbcArchiveHandle *handle)
+BLI_INLINE ArchiveReader *archive_from_handle(CacheArchiveHandle *handle)
 {
   return reinterpret_cast<ArchiveReader *>(handle);
 }
 
-BLI_INLINE AbcArchiveHandle *handle_from_archive(ArchiveReader *archive)
+BLI_INLINE CacheArchiveHandle *handle_from_archive(ArchiveReader *archive)
 {
-  return reinterpret_cast<AbcArchiveHandle *>(archive);
+  return reinterpret_cast<CacheArchiveHandle *>(archive);
 }
 
 //#define USE_NURBS
@@ -150,8 +147,8 @@ static bool gather_objects_paths(const IObject &object, ListBase *object_paths)
   }
 
   if (get_path) {
-    void *abc_path_void = MEM_callocN(sizeof(AlembicObjectPath), "AlembicObjectPath");
-    AlembicObjectPath *abc_path = static_cast<AlembicObjectPath *>(abc_path_void);
+    void *abc_path_void = MEM_callocN(sizeof(CacheObjectPath), "CacheObjectPath");
+    CacheObjectPath *abc_path = static_cast<CacheObjectPath *>(abc_path_void);
 
     BLI_strncpy(abc_path->path, object.getFullName().c_str(), sizeof(abc_path->path));
     BLI_addtail(object_paths, abc_path);
@@ -160,9 +157,9 @@ static bool gather_objects_paths(const IObject &object, ListBase *object_paths)
   return parent_is_part_of_this_object;
 }
 
-AbcArchiveHandle *ABC_create_handle(struct Main *bmain,
-                                    const char *filename,
-                                    ListBase *object_paths)
+CacheArchiveHandle *ABC_create_handle(struct Main *bmain,
+                                      const char *filename,
+                                      ListBase *object_paths)
 {
   ArchiveReader *archive = new ArchiveReader(bmain, filename);
 
@@ -178,7 +175,7 @@ AbcArchiveHandle *ABC_create_handle(struct Main *bmain,
   return handle_from_archive(archive);
 }
 
-void ABC_free_handle(AbcArchiveHandle *handle)
+void ABC_free_handle(CacheArchiveHandle *handle)
 {
   delete archive_from_handle(handle);
 }
@@ -359,8 +356,8 @@ static std::pair<bool, AbcObjectReader *> visit_object(
     readers.push_back(reader);
     reader->incref();
 
-    AlembicObjectPath *abc_path = static_cast<AlembicObjectPath *>(
-        MEM_callocN(sizeof(AlembicObjectPath), "AlembicObjectPath"));
+    CacheObjectPath *abc_path = static_cast<CacheObjectPath *>(
+        MEM_callocN(sizeof(CacheObjectPath), "CacheObjectPath"));
     BLI_strncpy(abc_path->path, full_name.c_str(), sizeof(abc_path->path));
     BLI_addtail(&settings.cache_file->object_paths, abc_path);
 
@@ -812,7 +809,7 @@ bool ABC_mesh_topology_changed(
 
 /* ************************************************************************** */
 
-void CacheReader_free(CacheReader *reader)
+void ABC_CacheReader_free(CacheReader *reader)
 {
   AbcObjectReader *abc_reader = reinterpret_cast<AbcObjectReader *>(reader);
   abc_reader->decref();
@@ -822,13 +819,13 @@ void CacheReader_free(CacheReader *reader)
   }
 }
 
-void CacheReader_incref(CacheReader *reader)
+void ABC_CacheReader_incref(CacheReader *reader)
 {
   AbcObjectReader *abc_reader = reinterpret_cast<AbcObjectReader *>(reader);
   abc_reader->incref();
 }
 
-CacheReader *CacheReader_open_alembic_object(AbcArchiveHandle *handle,
+CacheReader *CacheReader_open_alembic_object(CacheArchiveHandle *handle,
                                              CacheReader *reader,
                                              Object *object,
                                              const char *object_path)
@@ -847,7 +844,7 @@ CacheReader *CacheReader_open_alembic_object(AbcArchiveHandle *handle,
   find_iobject(archive->getTop(), iobject, object_path);
 
   if (reader) {
-    CacheReader_free(reader);
+    ABC_CacheReader_free(reader);
   }
 
   ImportSettings settings;