Initial commit of glTF 2.0 importer/exporter

Official Khronos Group Blender glTF 2.0 importer and exporter.

glTF specification: https://github.com/KhronosGroup/glTF
The upstream repository can be found here:
https://github.com/KhronosGroup/glTF-Blender-IO

Reviewed By: Bastien, Campbell

Differential Revision: https://developer.blender.org/D3929

1 files changed, 169 insertions, 0 deletions

diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_animations.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_animations.py
new file mode 100755
index 00000000..3740fefa
--- /dev/null
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_animations.py
@@ -0,0 +1,169 @@
+# Copyright 2018 The glTF-Blender-IO authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import bpy
+import typing
+
+from io_scene_gltf2.io.com import gltf2_io
+from io_scene_gltf2.blender.exp import gltf2_blender_gather_animation_channels
+
+
+def gather_animations(blender_object: bpy.types.Object, export_settings) -> typing.List[gltf2_io.Animation]:
+    """
+    Gather all animations which contribute to the objects property.
+
+    :param blender_object: The blender object which is animated
+    :param export_settings:
+    :return: A list of glTF2 animations
+    """
+    animations = []
+
+    # Collect all 'actions' affecting this object. There is a direct mapping between blender actions and glTF animations
+    blender_actions = __get_blender_actions(blender_object)
+
+    # Export all collected actions.
+    for blender_action in blender_actions:
+        animation = __gather_animation(blender_action, blender_object, export_settings)
+        if animation is not None:
+            animations.append(animation)
+
+    return animations
+
+
+def __gather_animation(blender_action: bpy.types.Action,
+                       blender_object: bpy.types.Object,
+                       export_settings
+                       ) -> typing.Optional[gltf2_io.Animation]:
+    if not __filter_animation(blender_action, blender_object, export_settings):
+        return None
+
+    animation = gltf2_io.Animation(
+        channels=__gather_channels(blender_action, blender_object, export_settings),
+        extensions=__gather_extensions(blender_action, blender_object, export_settings),
+        extras=__gather_extras(blender_action, blender_object, export_settings),
+        name=__gather_name(blender_action, blender_object, export_settings),
+        samplers=__gather_samplers(blender_action, blender_object, export_settings)
+    )
+
+    # To allow reuse of samplers in one animation,
+    __link_samplers(animation, export_settings)
+
+    if not animation.channels:
+        return None
+
+    return animation
+
+
+def __filter_animation(blender_action: bpy.types.Action,
+                       blender_object: bpy.types.Object,
+                       export_settings
+                       ) -> bool:
+    if blender_action.users == 0:
+        return False
+
+    return True
+
+
+def __gather_channels(blender_action: bpy.types.Action,
+                      blender_object: bpy.types.Object,
+                      export_settings
+                      ) -> typing.List[gltf2_io.AnimationChannel]:
+    return gltf2_blender_gather_animation_channels.gather_animation_channels(
+        blender_action, blender_object, export_settings)
+
+
+def __gather_extensions(blender_action: bpy.types.Action,
+                        blender_object: bpy.types.Object,
+                        export_settings
+                        ) -> typing.Any:
+    return None
+
+
+def __gather_extras(blender_action: bpy.types.Action,
+                    blender_object: bpy.types.Object,
+                    export_settings
+                    ) -> typing.Any:
+    return None
+
+
+def __gather_name(blender_action: bpy.types.Action,
+                  blender_object: bpy.types.Object,
+                  export_settings
+                  ) -> typing.Optional[str]:
+    return blender_action.name
+
+
+def __gather_samplers(blender_action: bpy.types.Action,
+                      blender_object: bpy.types.Object,
+                      export_settings
+                      ) -> typing.List[gltf2_io.AnimationSampler]:
+    # We need to gather the samplers after gathering all channels --> populate this list in __link_samplers
+    return []
+
+
+def __link_samplers(animation: gltf2_io.Animation, export_settings):
+    """
+    Move animation samplers to their own list and store their indices at their previous locations.
+
+    After gathering, samplers are stored in the channels properties of the animation and need to be moved
+    to their own list while storing an index into this list at the position where they previously were.
+    This behaviour is similar to that of the glTFExporter that traverses all nodes
+    :param animation:
+    :param export_settings:
+    :return:
+    """
+    # TODO: move this to some util module and update gltf2 exporter also
+    T = typing.TypeVar('T')
+
+    def __append_unique_and_get_index(l: typing.List[T], item: T):
+        if item in l:
+            return l.index(item)
+        else:
+            index = len(l)
+            l.append(item)
+            return index
+
+    for i, channel in enumerate(animation.channels):
+        animation.channels[i].sampler = __append_unique_and_get_index(animation.samplers, channel.sampler)
+
+
+def __get_blender_actions(blender_object: bpy.types.Object
+                          ) -> typing.List[bpy.types.Action]:
+    blender_actions = []
+
+    if blender_object.animation_data is not None:
+        # Collect active action.
+        if blender_object.animation_data.action is not None:
+            blender_actions.append(blender_object.animation_data.action)
+
+        # Collect associated strips from NLA tracks.
+        for track in blender_object.animation_data.nla_tracks:
+            # Multi-strip tracks do not export correctly yet (they need to be baked),
+            # so skip them for now and only write single-strip tracks.
+            if track.strips is None or len(track.strips) != 1:
+                continue
+            for strip in track.strips:
+                blender_actions.append(strip.action)
+
+    if blender_object.type == "MESH"\
+            and blender_object.data is not None \
+            and blender_object.data.shape_keys is not None \
+            and blender_object.data.shape_keys.animation_data is not None:
+        blender_actions.append(blender_object.data.shape_keys.animation_data.action)
+
+    # Remove duplicate actions.
+    blender_actions = list(set(blender_actions))
+
+    return blender_actions
+