python: expose scene-related APIs in AbstractSceneConverter.

doc/python/magnum.trade.rst

@@ -612,6 +612,9 @@
 .. py:property:: magnum.trade.AbstractSceneConverter.mesh_count
     :raise AssertionError: If no conversion is in progress
 
+.. py:property:: magnum.trade.AbstractSceneConverter.scene_count
+    :raise AssertionError: If no conversion is in progress
+
 .. py:function:: magnum.trade.AbstractSceneConverter.add
     :raise AssertionError: If no conversion is in progress
     :raise RuntimeError: If adding the data fails
@@ -620,6 +623,15 @@
     :raise AssertionError: If no conversion is in progress
     :raise AssertionError: If :p:`attribute` is not custom
 
+.. py:function:: magnum.trade.AbstractSceneConverter.set_default_scene
+    :raise AssertionError: If no conversion is in progress
+    :raise AssertionError: If :p:`id` is negative or not less than
+        :ref:`scene_count`
+
+.. py:function:: magnum.trade.AbstractSceneConverter.set_scene_field_name
+    :raise AssertionError: If no conversion is in progress
+    :raise AssertionError: If :p:`field` is not custom
+
 .. py:function:: magnum.trade.AbstractSceneConverter.add_importer_contents
     :raise AssertionError: If no conversion is in progress
     :raise RuntimeError: If adding the importer contents fails

src/python/magnum/test/test_trade.py

@@ -31,7 +31,7 @@ import unittest
 
 from corrade import containers, pluginmanager
 from magnum import *
-from magnum import primitives, trade
+from magnum import primitives, scenetools, trade
 import magnum
 
 class ImageData(unittest.TestCase):
@@ -1840,6 +1840,87 @@ class SceneConverter(unittest.TestCase):
             with self.assertRaisesRegex(AssertionError, "not a custom attribute"):
                 converter.set_mesh_attribute_name(trade.MeshAttribute.POSITION, 'foo')
 
+    def test_batch_add_scene(self):
+        importer = trade.ImporterManager().load_and_instantiate('GltfImporter')
+        importer.open_file(os.path.join(os.path.dirname(__file__), 'scene.gltf'))
+
+        scene = importer.scene("A default scene that's empty")
+
+        converter = trade.SceneConverterManager().load_and_instantiate('GltfSceneConverter')
+
+        with tempfile.TemporaryDirectory() as tmp:
+            filename = os.path.join(tmp, "scene.gltf")
+            converter.begin_file(filename)
+            converter.add(scene, "A default scene that's empty")
+            converter.end_file()
+
+            with open(filename, 'r') as f:
+                self.assertIn("A default scene that's empty", f.read())
+
+    def test_batch_set_default_scene(self):
+        importer = trade.ImporterManager().load_and_instantiate('GltfImporter')
+        importer.open_file(os.path.join(os.path.dirname(__file__), 'scene.gltf'))
+
+        scene = importer.scene("A default scene that's empty")
+
+        converter = trade.SceneConverterManager().load_and_instantiate('GltfSceneConverter')
+
+        with tempfile.TemporaryDirectory() as tmp:
+            filename = os.path.join(tmp, "scene.gltf")
+            converter.begin_file(filename)
+            converter.add(scene, "A default scene that's empty")
+            converter.set_default_scene(0)
+            converter.end_file()
+
+            with open(filename, 'r') as f:
+                self.assertIn('"scene": 0', f.read())
+
+    def test_batch_set_default_scene_out_of_range(self):
+        converter = trade.SceneConverterManager().load_and_instantiate('GltfSceneConverter')
+
+        with tempfile.TemporaryDirectory() as tmp:
+            filename = os.path.join(tmp, "scene.gltf")
+            converter.begin_file(filename)
+
+            with self.assertRaisesRegex(AssertionError, "index 1 out of range for 0 scenes"):
+                converter.set_default_scene(1)
+
+    def test_batch_set_scene_field_name(self):
+        importer = trade.ImporterManager().load_and_instantiate('GltfImporter')
+        importer.open_file(os.path.join(os.path.dirname(__file__), 'scene.gltf'))
+
+        # Keep only the single custom numeric attribute in the scene (plus
+        # hierarchy and transformation that's required by glTF)
+        # TODO clean up once there's a possibility to create scenes from
+        # scratch
+        scene = scenetools.filter_only_fields(importer.scene("A scene"),             [
+            trade.SceneField.PARENT,
+            trade.SceneField.TRANSLATION,
+            importer.scene_field_for_name('aNumber'),
+        ])
+
+        converter = trade.SceneConverterManager().load_and_instantiate('GltfSceneConverter')
+
+        with tempfile.TemporaryDirectory() as tmp:
+            filename = os.path.join(tmp, "scene.gltf")
+            converter.begin_file(filename)
+            converter.set_scene_field_name(importer.scene_field_for_name('aNumber'), 'aNumber')
+            converter.add(scene)
+            converter.end_file()
+
+            with open(filename, 'r') as f:
+                self.assertIn('"aNumber":', f.read())
+
+    def test_batch_set_scene_field_name_not_custom(self):
+        converter = trade.SceneConverterManager().load_and_instantiate('GltfSceneConverter')
+
+        with tempfile.TemporaryDirectory() as tmp:
+            filename = os.path.join(tmp, "scene.gltf")
+            converter.begin_file(filename)
+
+            with self.assertRaisesRegex(AssertionError, "not a custom field"):
+                converter.set_scene_field_name(trade.SceneField.SCALING, 'foo')
+
     def test_batch_add_importer_contents(self):
         importer = trade.ImporterManager().load_and_instantiate('GltfImporter')
         importer.open_file(os.path.join(os.path.dirname(__file__), 'two-meshes.gltf'))
@@ -1908,6 +1989,8 @@ class SceneConverter(unittest.TestCase):
         importer = trade.ImporterManager().load_and_instantiate('GltfImporter')
         importer.open_file(os.path.join(os.path.dirname(__file__), 'mesh.gltf'))
         mesh = importer.mesh('Custom mesh attribute')
+        importer.open_file(os.path.join(os.path.dirname(__file__), 'scene.gltf'))
+        scene = importer.scene("A default scene that's empty")
 
         converter = trade.SceneConverterManager().load_and_instantiate('GltfSceneConverter')
         self.assertFalse(converter.is_converting)
@@ -1920,6 +2003,14 @@ class SceneConverter(unittest.TestCase):
             converter.add(mesh)
         with self.assertRaisesRegex(AssertionError, "no conversion in progress"):
             converter.set_mesh_attribute_name(trade.MeshAttribute.CUSTOM(1), 'foobar')
+        with self.assertRaisesRegex(AssertionError, "no conversion in progress"):
+            converter.scene_count
+        with self.assertRaisesRegex(AssertionError, "no conversion in progress"):
+            converter.add(scene)
+        with self.assertRaisesRegex(AssertionError, "no conversion in progress"):
+            converter.set_default_scene(0)
+        with self.assertRaisesRegex(AssertionError, "no conversion in progress"):
+            converter.set_scene_field_name(trade.SceneField.CUSTOM(1), 'foobar')
         with self.assertRaisesRegex(AssertionError, "no conversion in progress"):
             converter.add_importer_contents(importer)
         with self.assertRaisesRegex(AssertionError, "no conversion in progress"):

src/python/magnum/trade.cpp

@@ -1826,6 +1826,48 @@ void trade(py::module_& m) {
                 throw py::error_already_set{};
             }
         }, "End converting a scene to a file")
+        .def("set_default_scene", [](Trade::AbstractSceneConverter& self, const UnsignedInt id) {
+            if(!self.isConverting()) {
+                PyErr_SetString(PyExc_AssertionError, "no conversion in progress");
+                throw py::error_already_set{};
+            }
+            if(id >= self.sceneCount()) {
+                PyErr_Format(PyExc_AssertionError, "index %u out of range for %u scenes", id, self.sceneCount());
+                throw py::error_already_set{};
+            }
+
+            self.setDefaultScene(id);
+        }, "Set default scene", py::arg("id"))
+        .def_property_readonly("scene_count", [](Trade::AbstractSceneConverter& self) {
+            if(!self.isConverting()) {
+                PyErr_SetString(PyExc_AssertionError, "no conversion in progress");
+                throw py::error_already_set{};
+            }
+            return self.sceneCount();
+        }, "Count of added scenes")
+        /** @todo drop std::string in favor of our own string caster */
+        .def("add", [](Trade::AbstractSceneConverter& self, const Trade::SceneData& scene, const std::string& name) {
+            if(!self.isConverting()) {
+                PyErr_SetString(PyExc_AssertionError, "no conversion in progress");
+                throw py::error_already_set{};
+            }
+            if(const Containers::Optional<UnsignedInt> out = self.add(scene, name))
+                return *out;
+
+            PyErr_SetString(PyExc_RuntimeError, "adding the scene failed");
+            throw py::error_already_set{};
+        }, "Add a scene", py::arg("scene"), py::arg("name") = std::string{})
+        .def("set_scene_field_name", [](Trade::AbstractSceneConverter& self, const Trade::SceneField field, const std::string& name) {
+            if(!Trade::isSceneFieldCustom(field)) {
+                PyErr_SetString(PyExc_AssertionError, "not a custom field");
+                throw py::error_already_set{};
+            }
+            if(!self.isConverting()) {
+                PyErr_SetString(PyExc_AssertionError, "no conversion in progress");
+                throw py::error_already_set{};
+            }
+            self.setSceneFieldName(field, name);
+        }, "Set name of a custom scene field", py::arg("field"), py::arg("name"))
         .def_property_readonly("mesh_count", [](Trade::AbstractSceneConverter& self) {
             if(!self.isConverting()) {
                 PyErr_SetString(PyExc_AssertionError, "no conversion in progress");