glTF exporter: avoid exporting rotation twice when both euler and quaternion are animated

Keeping only the current rotation mode of the object or bone

io_scene_gltf2/__init__.py

@@ -15,7 +15,7 @@
 bl_info = {
     'name': 'glTF 2.0 format',
     'author': 'Julien Duroure, Norbert Nopper, Urs Hanselmann, Moritz Becher, Benjamin Schmithüsen, Jim Eckerlein, and many external contributors',
-    "version": (1, 1, 8),
+    "version": (1, 1, 9),
     'blender': (2, 81, 6),
     'location': 'File > Import-Export',
     'description': 'Import-Export as glTF 2.0',

io_scene_gltf2/blender/com/gltf2_blender_data_path.py

@@ -26,3 +26,14 @@ def get_target_object_path(data_path: str) -> str:
         return ""
     return path_split[0]
 
+def get_rotation_modes(target_property: str) -> str:
+    """Retrieve rotation modes based on target_property"""
+    if target_property in ["rotation_euler", "delta_rotation_euler"]:
+        return True, ["XYZ", "XZY", "YXZ", "YZX", "ZXY", "ZYX"]
+    elif target_property in ["rotation_quaternion", "delta_rotation_quaternion"]:
+        return True, ["QUATERNION"]
+    elif target_property in ["rotation_axis_angle"]:
+        return True, ["AXIS_ANGLE"]
+    else:
+        return False, []
+

io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_channels.py

@@ -15,7 +15,7 @@
 import bpy
 import typing
 
-from ..com.gltf2_blender_data_path import get_target_object_path, get_target_property_name
+from ..com.gltf2_blender_data_path import get_target_object_path, get_target_property_name, get_rotation_modes
 from io_scene_gltf2.io.com import gltf2_io
 from io_scene_gltf2.io.com import gltf2_io_debug
 from io_scene_gltf2.blender.exp.gltf2_blender_gather_cache import cached
@@ -200,6 +200,7 @@ def __gather_target(channels: typing.Tuple[bpy.types.FCurve],
 
 def __get_channel_groups(blender_action: bpy.types.Action, blender_object: bpy.types.Object, export_settings):
     targets = {}
+    multiple_rotation_mode_detected = False
     for fcurve in blender_action.fcurves:
         # In some invalid files, channel hasn't any keyframes ... this channel need to be ignored
         if len(fcurve.keyframe_points) == 0:
@@ -239,6 +240,13 @@ def __get_channel_groups(blender_action: bpy.types.Action, blender_object: bpy.t
                     gltf2_io_debug.print_console("WARNING", "Animation target {} not found".format(object_path))
                     continue
 
+        # Detect that object or bone are not multiple keyed for euler and quaternion
+        # Keep only the current rotation mode used by object / bone
+        rotation, rotation_modes = get_rotation_modes(target_property)
+        if rotation and target.rotation_mode not in rotation_modes:
+            multiple_rotation_mode_detected = True
+            continue
+
         # group channels by target object and affected property of the target
         target_properties = targets.get(target, {})
         channels = target_properties.get(target_property, [])
@@ -250,5 +258,9 @@ def __get_channel_groups(blender_action: bpy.types.Action, blender_object: bpy.t
     for p in targets.values():
         groups += list(p.values())
 
+    if multiple_rotation_mode_detected is True:
+        gltf2_io_debug.print_console("WARNING", "Multiple rotation mode detected for {}".format(blender_object.name))
+
+
     return map(tuple, groups)