glTF exporter: remove some channel animation if bone is not animated

Check is done after sampling: if animated is constant and bone has no fcurve, we remove the channel

4 files changed, 71 insertions, 11 deletions

diff --git a/io_scene_gltf2/__init__.py b/io_scene_gltf2/__init__.py
index 33af1111..0abcb811 100755
--- a/io_scene_gltf2/__init__.py
+++ b/io_scene_gltf2/__init__.py
@@ -15,7 +15,7 @@
 bl_info = {
     'name': 'glTF 2.0 format',
     'author': 'Julien Duroure, Scurest, Norbert Nopper, Urs Hanselmann, Moritz Becher, Benjamin Schmithüsen, Jim Eckerlein, and many external contributors',
-    "version": (1, 7, 21),
+    "version": (1, 7, 22),
     'blender': (2, 91, 0),
     'location': 'File > Import-Export',
     'description': 'Import-Export as glTF 2.0',
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_channels.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_channels.py
index 114ff901..6c184198 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_channels.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_channels.py
@@ -69,6 +69,11 @@ def gather_animation_channels(blender_action: bpy.types.Action,
             bones_to_be_animated, _, _ = gltf2_blender_gather_skins.get_bone_tree(None, blender_object)
             bones_to_be_animated = [blender_object.pose.bones[b.name] for b in bones_to_be_animated]
 
+        list_of_animated_bone_channels = []
+        for channel_group in __get_channel_groups(blender_action, blender_object, export_settings):
+            channel_group_sorted = __get_channel_group_sorted(channel_group, blender_object)
+            list_of_animated_bone_channels.extend([(gltf2_blender_get.get_object_from_datapath(blender_object, get_target_object_path(i.data_path)).name, get_target_property_name(i.data_path)) for i in channel_group])
+
         for bone in bones_to_be_animated:
             for p in ["location", "rotation_quaternion", "scale"]:
                 channel = __gather_animation_channel(
@@ -80,8 +85,10 @@ def gather_animation_channels(blender_action: bpy.types.Action,
                     bake_range_start,
                     bake_range_end,
                     blender_action.name,
-                    None)
-                channels.append(channel)
+                    None,
+                    (bone.name, p) in list_of_animated_bone_channels)
+                if channel is not None:
+                    channels.append(channel)
 
 
         # Retrieve animation on armature object itself, if any
@@ -91,7 +98,7 @@ def gather_animation_channels(blender_action: bpy.types.Action,
             if len(channel_group) == 0:
                 # Only errors on channels, ignoring
                 continue
-            channel = __gather_animation_channel(channel_group, blender_object, export_settings, None, None, bake_range_start, bake_range_end, blender_action.name, None)
+            channel = __gather_animation_channel(channel_group, blender_object, export_settings, None, None, bake_range_start, bake_range_end, blender_action.name, None, False)
             if channel is not None:
                 channels.append(channel)
 
@@ -109,7 +116,8 @@ def gather_animation_channels(blender_action: bpy.types.Action,
                 bake_range_start,
                 bake_range_end,
                 blender_action.name,
-                obj)
+                obj,
+                False)
             channels.append(channel)
 
     else:
@@ -118,7 +126,17 @@ def gather_animation_channels(blender_action: bpy.types.Action,
             if len(channel_group_sorted) == 0:
                 # Only errors on channels, ignoring
                 continue
-            channel = __gather_animation_channel(channel_group_sorted, blender_object, export_settings, None, None, bake_range_start, bake_range_end, blender_action.name, None)
+            channel = __gather_animation_channel(
+                        channel_group_sorted,
+                        blender_object,
+                        export_settings,
+                        None,
+                        None,
+                        bake_range_start,
+                        bake_range_end,
+                        blender_action.name,
+                        None,
+                        False)
             if channel is not None:
                 channels.append(channel)
 
@@ -189,17 +207,25 @@ def __gather_animation_channel(channels: typing.Tuple[bpy.types.FCurve],
                                bake_range_start,
                                bake_range_end,
                                action_name: str,
-                               driver_obj
+                               driver_obj,
+                               node_channel_is_animated: bool
                                ) -> typing.Union[gltf2_io.AnimationChannel, None]:
     if not __filter_animation_channel(channels, blender_object, export_settings):
         return None
 
     __target= __gather_target(channels, blender_object, export_settings, bake_bone, bake_channel, driver_obj)
     if __target.path is not None:
+        sampler = __gather_sampler(channels, blender_object, export_settings, bake_bone, bake_channel, bake_range_start, bake_range_end, action_name, driver_obj, node_channel_is_animated)
+
+        if sampler is None:
+            # After check, no need to animate this node for this channel
+            return None
+
+
         animation_channel = gltf2_io.AnimationChannel(
             extensions=__gather_extensions(channels, blender_object, export_settings, bake_bone),
             extras=__gather_extras(channels, blender_object, export_settings, bake_bone),
-            sampler=__gather_sampler(channels, blender_object, export_settings, bake_bone, bake_channel, bake_range_start, bake_range_end, action_name, driver_obj),
+            sampler=sampler,
             target=__target
         )
 
@@ -249,7 +275,8 @@ def __gather_sampler(channels: typing.Tuple[bpy.types.FCurve],
                      bake_range_start,
                      bake_range_end,
                      action_name,
-                     driver_obj
+                     driver_obj,
+                     node_channel_is_animated: bool
                      ) -> gltf2_io.AnimationSampler:
     return gltf2_blender_gather_animation_samplers.gather_animation_sampler(
         channels,
@@ -260,6 +287,7 @@ def __gather_sampler(channels: typing.Tuple[bpy.types.FCurve],
         bake_range_end,
         action_name,
         driver_obj,
+        node_channel_is_animated,
         export_settings
     )
 
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_sampler_keyframes.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_sampler_keyframes.py
index 3bf5b97c..932ea25e 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_sampler_keyframes.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_sampler_keyframes.py
@@ -22,6 +22,7 @@ from io_scene_gltf2.blender.exp import gltf2_blender_get
 from io_scene_gltf2.blender.exp.gltf2_blender_gather_drivers import get_sk_drivers, get_sk_driver_values
 from . import gltf2_blender_export_keys
 from io_scene_gltf2.io.com import gltf2_io_debug
+import numpy as np
 
 
 class Keyframe:
@@ -193,6 +194,7 @@ def gather_keyframes(blender_object_if_armature: typing.Optional[bpy.types.Objec
                      bake_range_end,
                      action_name: str,
                      driver_obj,
+                     node_channel_is_animated: bool,
                      export_settings
                      ) -> typing.List[Keyframe]:
     """Convert the blender action groups' fcurves to keyframes for use in glTF."""
@@ -309,6 +311,21 @@ def gather_keyframes(blender_object_if_armature: typing.Optional[bpy.types.Objec
 
             keyframes.append(key)
 
+    # For armature only
+    # Check if all values are the same
+    # In that case, if there is no real keyframe on this channel for this given bone,
+    # We can ignore this keyframes
+    # if there are some fcurve, we can keep only 2 keyframes, first and last
+    if blender_object_if_armature is not None:
+        std = np.ptp(np.ptp([[k.value[i] for i in range(len(keyframes[0].value))] for k in keyframes], axis=0))
+
+        if node_channel_is_animated is True: # fcurve on this bone for this property
+             # Keep animation, but keep only 2 keyframes if data are not changing
+             return [keyframes[0], keyframes[-1]] if std < 0.0001 and len(keyframes) >= 2 else keyframes
+        else: # bone is not animated (no fcurve)
+            # Not keeping if not changing property
+            return None if std < 0.0001 else keyframes
+
     return keyframes
 
 
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_samplers.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_samplers.py
index d555bcb9..d3b9e022 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_samplers.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_samplers.py
@@ -39,6 +39,7 @@ def gather_animation_sampler(channels: typing.Tuple[bpy.types.FCurve],
                              bake_range_end,
                              action_name: str,
                              driver_obj,
+                             node_channel_is_animated: bool,
                              export_settings
                              ) -> gltf2_io.AnimationSampler:
 
@@ -61,11 +62,17 @@ def gather_animation_sampler(channels: typing.Tuple[bpy.types.FCurve],
     else:
         matrix_parent_inverse = mathutils.Matrix.Identity(4).freeze()
 
+    input = __gather_input(channels, blender_object_if_armature, non_keyed_values,
+                         bake_bone, bake_channel, bake_range_start, bake_range_end, action_name, driver_obj, node_channel_is_animated, export_settings)
+
+    if input is None:
+        # After check, no need to animate this node for this channel
+        return None
+
     sampler = gltf2_io.AnimationSampler(
         extensions=__gather_extensions(channels, blender_object_if_armature, export_settings, bake_bone, bake_channel),
         extras=__gather_extras(channels, blender_object_if_armature, export_settings, bake_bone, bake_channel),
-        input=__gather_input(channels, blender_object_if_armature, non_keyed_values,
-                             bake_bone, bake_channel, bake_range_start, bake_range_end, action_name, driver_obj, export_settings),
+        input=input,
         interpolation=__gather_interpolation(channels, blender_object_if_armature, export_settings, bake_bone, bake_channel),
         output=__gather_output(channels,
                                matrix_parent_inverse,
@@ -77,6 +84,7 @@ def gather_animation_sampler(channels: typing.Tuple[bpy.types.FCurve],
                                bake_range_end,
                                action_name,
                                driver_obj,
+                               node_channel_is_animated,
                                export_settings)
     )
 
@@ -229,6 +237,7 @@ def __gather_input(channels: typing.Tuple[bpy.types.FCurve],
                    bake_range_end,
                    action_name,
                    driver_obj,
+                   node_channel_is_animated: bool,
                    export_settings
                    ) -> gltf2_io.Accessor:
     """Gather the key time codes."""
@@ -241,7 +250,11 @@ def __gather_input(channels: typing.Tuple[bpy.types.FCurve],
                                                                                   bake_range_end,
                                                                                   action_name,
                                                                                   driver_obj,
+                                                                                  node_channel_is_animated,
                                                                                   export_settings)
+    if keyframes is None:
+        # After check, no need to animation this node
+        return None
     times = [k.seconds for k in keyframes]
 
     return gltf2_blender_gather_accessors.gather_accessor(
@@ -306,6 +319,7 @@ def __gather_output(channels: typing.Tuple[bpy.types.FCurve],
                     bake_range_end,
                     action_name,
                     driver_obj,
+                    node_channel_is_animated: bool,
                     export_settings
                     ) -> gltf2_io.Accessor:
     """Gather the data of the keyframes."""
@@ -318,6 +332,7 @@ def __gather_output(channels: typing.Tuple[bpy.types.FCurve],
                                                                                   bake_range_end,
                                                                                   action_name,
                                                                                   driver_obj,
+                                                                                  node_channel_is_animated,
                                                                                   export_settings)
     if bake_bone is not None:
         target_datapath = "pose.bones['" + bake_bone + "']." + bake_channel