glTF exporter: fix bezier interpolation export

1 files changed, 8 insertions, 2 deletions

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 8c01a940..16346729 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
@@ -296,7 +296,10 @@ def __gather_output(channels: typing.Tuple[bpy.types.FCurve],
             if is_yup and blender_object_if_armature is None:
                 in_tangent = gltf2_blender_math.swizzle_yup(in_tangent, target_datapath)
             # the tangent in glTF is relative to the keyframe value
-            in_tangent = value - in_tangent if not isinstance(value, list) else [value[0] - in_tangent[0]]
+            if not isinstance(value, list):
+                in_tangent = value - in_tangent
+            else:
+                in_tangent = [value[i] - in_tangent[i] for i in range(len(value))]
             keyframe_value = gltf2_blender_math.mathutils_to_gltf(in_tangent) + keyframe_value  # append
 
         if keyframe.out_tangent is not None:
@@ -305,7 +308,10 @@ def __gather_output(channels: typing.Tuple[bpy.types.FCurve],
             if is_yup and blender_object_if_armature is None:
                 out_tangent = gltf2_blender_math.swizzle_yup(out_tangent, target_datapath)
             # the tangent in glTF is relative to the keyframe value
-            out_tangent = value - out_tangent if not isinstance(value, list) else [value[0] - out_tangent[0]]
+            if not isinstance(value, list):
+                out_tangent = value - out_tangent
+            else:
+                out_tangent = [value[i] - out_tangent[i] for i in range(len(value))]
             keyframe_value = keyframe_value + gltf2_blender_math.mathutils_to_gltf(out_tangent)  # append
 
         values += keyframe_value