IO: Allow exporting a subset of the writers

This is in order to prepare for compatibility with the Alembic exporter.
That exporter is capable of writing object transforms and object data at
different (sub)frames.

The rename from `created_writers` to `used_writers` is necessary, as not
all created writers will be actually used in each iteration.

The Universal Scene Description (USD) exporter does not make use of
this.

Reviewed By: mont29

Differential Revision: https://developer.blender.org/D7670

1 files changed, 125 insertions, 11 deletions

diff --git a/tests/gtests/usd/abstract_hierarchy_iterator_test.cc b/tests/gtests/usd/abstract_hierarchy_iterator_test.cc
index f2e8b09b8d3..1ca0ad93470 100644
--- a/tests/gtests/usd/abstract_hierarchy_iterator_test.cc
+++ b/tests/gtests/usd/abstract_hierarchy_iterator_test.cc
@@ -30,16 +30,16 @@ extern "C" {
 
 /* Mapping from ID.name to set of export hierarchy path. Duplicated objects can be exported
  * multiple times with different export paths, hence the set. */
-typedef std::map<std::string, std::set<std::string>> created_writers;
+typedef std::map<std::string, std::set<std::string>> used_writers;
 
 using namespace blender::io;
 
 class TestHierarchyWriter : public AbstractHierarchyWriter {
  public:
   std::string writer_type;
-  created_writers &writers_map;
+  used_writers &writers_map;
 
-  TestHierarchyWriter(const std::string &writer_type, created_writers &writers_map)
+  TestHierarchyWriter(const std::string &writer_type, used_writers &writers_map)
       : writer_type(writer_type), writers_map(writers_map)
   {
   }
@@ -47,7 +47,7 @@ class TestHierarchyWriter : public AbstractHierarchyWriter {
   void write(HierarchyContext &context) override
   {
     const char *id_name = context.object->id.name;
-    created_writers::mapped_type &writers = writers_map[id_name];
+    used_writers::mapped_type &writers = writers_map[id_name];
 
     if (writers.find(context.export_path) != writers.end()) {
       ADD_FAILURE() << "Unexpectedly found another " << writer_type << " writer for " << id_name
@@ -57,7 +57,7 @@ class TestHierarchyWriter : public AbstractHierarchyWriter {
   }
 };
 
-void debug_print_writers(const char *label, const created_writers &writers_map)
+void debug_print_writers(const char *label, const used_writers &writers_map)
 {
   printf("%s:\n", label);
   for (auto idname_writers : writers_map) {
@@ -70,10 +70,10 @@ void debug_print_writers(const char *label, const created_writers &writers_map)
 
 class TestingHierarchyIterator : public AbstractHierarchyIterator {
  public: /* Public so that the test cases can directly inspect the created writers. */
-  created_writers transform_writers;
-  created_writers data_writers;
-  created_writers hair_writers;
-  created_writers particle_writers;
+  used_writers transform_writers;
+  used_writers data_writers;
+  used_writers hair_writers;
+  used_writers particle_writers;
 
  public:
   explicit TestingHierarchyIterator(Depsgraph *depsgraph) : AbstractHierarchyIterator(depsgraph)
@@ -151,7 +151,7 @@ TEST_F(USDHierarchyIteratorTest, ExportHierarchyTest)
   iterator->iterate_and_write();
 
   // Mapping from object name to set of export paths.
-  created_writers expected_transforms = {
+  used_writers expected_transforms = {
       {"OBCamera", {"/Camera"}},
       {"OBDupli1", {"/Dupli1"}},
       {"OBDupli2", {"/ParentOfDupli2/Dupli2"}},
@@ -177,7 +177,7 @@ TEST_F(USDHierarchyIteratorTest, ExportHierarchyTest)
       {"OBParentOfDupli2", {"/ParentOfDupli2"}}};
   EXPECT_EQ(expected_transforms, iterator->transform_writers);
 
-  created_writers expected_data = {
+  used_writers expected_data = {
       {"OBCamera", {"/Camera/Camera"}},
       {"OBGEO_Ear_L",
        {"/Dupli1/GEO_Head-0/GEO_Ear_L-1/Ear",
@@ -204,4 +204,118 @@ TEST_F(USDHierarchyIteratorTest, ExportHierarchyTest)
   // The scene has no hair or particle systems.
   EXPECT_EQ(0, iterator->hair_writers.size());
   EXPECT_EQ(0, iterator->particle_writers.size());
+
+  // On the second iteration, everything should be written as well.
+  // This tests the default value of iterator->export_subset_.
+  iterator->transform_writers.clear();
+  iterator->data_writers.clear();
+  iterator->iterate_and_write();
+  EXPECT_EQ(expected_transforms, iterator->transform_writers);
+  EXPECT_EQ(expected_data, iterator->data_writers);
+}
+
+TEST_F(USDHierarchyIteratorTest, ExportSubsetTest)
+{
+  // The scene has no hair or particle systems, and this is already covered by ExportHierarchyTest,
+  // so not included here. Update this test when hair & particle systems are included.
+
+  /* Load the test blend file. */
+  if (!blendfile_load("usd/usd_hierarchy_export_test.blend")) {
+    return;
+  }
+  depsgraph_create(DAG_EVAL_RENDER);
+  iterator_create();
+
+  // Mapping from object name to set of export paths.
+  used_writers expected_transforms = {
+      {"OBCamera", {"/Camera"}},
+      {"OBDupli1", {"/Dupli1"}},
+      {"OBDupli2", {"/ParentOfDupli2/Dupli2"}},
+      {"OBGEO_Ear_L",
+       {"/Dupli1/GEO_Head-0/GEO_Ear_L-1",
+        "/Ground plane/OutsideDupliGrandParent/OutsideDupliParent/GEO_Head/GEO_Ear_L",
+        "/ParentOfDupli2/Dupli2/GEO_Head-0/GEO_Ear_L-1"}},
+      {"OBGEO_Ear_R",
+       {"/Dupli1/GEO_Head-0/GEO_Ear_R-2",
+        "/Ground plane/OutsideDupliGrandParent/OutsideDupliParent/GEO_Head/GEO_Ear_R",
+        "/ParentOfDupli2/Dupli2/GEO_Head-0/GEO_Ear_R-2"}},
+      {"OBGEO_Head",
+       {"/Dupli1/GEO_Head-0",
+        "/Ground plane/OutsideDupliGrandParent/OutsideDupliParent/GEO_Head",
+        "/ParentOfDupli2/Dupli2/GEO_Head-0"}},
+      {"OBGEO_Nose",
+       {"/Dupli1/GEO_Head-0/GEO_Nose-3",
+        "/Ground plane/OutsideDupliGrandParent/OutsideDupliParent/GEO_Head/GEO_Nose",
+        "/ParentOfDupli2/Dupli2/GEO_Head-0/GEO_Nose-3"}},
+      {"OBGround plane", {"/Ground plane"}},
+      {"OBOutsideDupliGrandParent", {"/Ground plane/OutsideDupliGrandParent"}},
+      {"OBOutsideDupliParent", {"/Ground plane/OutsideDupliGrandParent/OutsideDupliParent"}},
+      {"OBParentOfDupli2", {"/ParentOfDupli2"}}};
+
+  used_writers expected_data = {
+      {"OBCamera", {"/Camera/Camera"}},
+      {"OBGEO_Ear_L",
+       {"/Dupli1/GEO_Head-0/GEO_Ear_L-1/Ear",
+        "/Ground plane/OutsideDupliGrandParent/OutsideDupliParent/GEO_Head/GEO_Ear_L/Ear",
+        "/ParentOfDupli2/Dupli2/GEO_Head-0/GEO_Ear_L-1/Ear"}},
+      {"OBGEO_Ear_R",
+       {"/Dupli1/GEO_Head-0/GEO_Ear_R-2/Ear",
+        "/Ground plane/OutsideDupliGrandParent/OutsideDupliParent/GEO_Head/GEO_Ear_R/Ear",
+        "/ParentOfDupli2/Dupli2/GEO_Head-0/GEO_Ear_R-2/Ear"}},
+      {"OBGEO_Head",
+       {"/Dupli1/GEO_Head-0/Face",
+        "/Ground plane/OutsideDupliGrandParent/OutsideDupliParent/GEO_Head/Face",
+        "/ParentOfDupli2/Dupli2/GEO_Head-0/Face"}},
+      {"OBGEO_Nose",
+       {"/Dupli1/GEO_Head-0/GEO_Nose-3/Nose",
+        "/Ground plane/OutsideDupliGrandParent/OutsideDupliParent/GEO_Head/GEO_Nose/Nose",
+        "/ParentOfDupli2/Dupli2/GEO_Head-0/GEO_Nose-3/Nose"}},
+      {"OBGround plane", {"/Ground plane/Plane"}},
+      {"OBParentOfDupli2", {"/ParentOfDupli2/Icosphere"}},
+  };
+
+  // Even when only asking an export of transforms, on the first frame everything should be
+  // exported.
+  iterator->set_export_subset({
+      .transforms = true,
+      .shapes = false,
+  });
+  iterator->iterate_and_write();
+  EXPECT_EQ(expected_transforms, iterator->transform_writers);
+  EXPECT_EQ(expected_data, iterator->data_writers);
+
+  // Clear data to prepare for the next iteration.
+  iterator->transform_writers.clear();
+  iterator->data_writers.clear();
+
+  // Second iteration, should only write transforms now.
+  iterator->iterate_and_write();
+  EXPECT_EQ(expected_transforms, iterator->transform_writers);
+  EXPECT_EQ(0, iterator->data_writers.size());
+
+  // Clear data to prepare for the next iteration.
+  iterator->transform_writers.clear();
+  iterator->data_writers.clear();
+
+  // Third iteration, should only write data now.
+  iterator->set_export_subset({
+      .transforms = false,
+      .shapes = true,
+  });
+  iterator->iterate_and_write();
+  EXPECT_EQ(0, iterator->transform_writers.size());
+  EXPECT_EQ(expected_data, iterator->data_writers);
+
+  // Clear data to prepare for the next iteration.
+  iterator->transform_writers.clear();
+  iterator->data_writers.clear();
+
+  // Fourth iteration, should export everything now.
+  iterator->set_export_subset({
+      .transforms = true,
+      .shapes = true,
+  });
+  iterator->iterate_and_write();
+  EXPECT_EQ(expected_transforms, iterator->transform_writers);
+  EXPECT_EQ(expected_data, iterator->data_writers);
 }