glTF exporter: various fixes/enhancements:

* enhancement for vertex weights export
* export animation only if checkbox is ticked
* use unsigned short or unsigned int for indices
* Fix T60012 metallic and roughness image export (channels not in same image)

5 files changed, 52 insertions, 29 deletions

diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_extract.py b/io_scene_gltf2/blender/exp/gltf2_blender_extract.py
index 87c9d426..0add794a 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_extract.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_extract.py
@@ -662,12 +662,16 @@ def extract_primitives(glTF, blender_mesh, blender_vertex_groups, modifiers, exp
 
                     #
 
-                    vertex_group_index = group_element.group
-                    vertex_group_name = blender_vertex_groups[vertex_group_index].name
+                    joint_weight = group_element.weight
+                    if joint_weight <= 0.0:
+                        continue
 
                     #
 
-                    joint_index = 0
+                    vertex_group_index = group_element.group
+                    vertex_group_name = blender_vertex_groups[vertex_group_index].name
+
+                    joint_index = None
 
                     if modifiers is not None:
                         modifiers_dict = {m.type: m for m in modifiers}
@@ -677,12 +681,12 @@ def extract_primitives(glTF, blender_mesh, blender_vertex_groups, modifiers, exp
                             for index, j in enumerate(skin.joints):
                                 if j.name == vertex_group_name:
                                     joint_index = index
-
-                    joint_weight = group_element.weight
+                                    break
 
                     #
-                    joint.append(joint_index)
-                    weight.append(joint_weight)
+                    if joint_index is not None:
+                        joint.append(joint_index)
+                        weight.append(joint_weight)
 
                 if len(joint) > 0:
                     bone_count += 1
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather.py
index 217930e1..6a5a9947 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather.py
@@ -32,7 +32,8 @@ def gather_gltf2(export_settings):
     animations = []  # unfortunately animations in gltf2 are just as 'root' as scenes.
     for blender_scene in bpy.data.scenes:
         scenes.append(__gather_scene(blender_scene, export_settings))
-        animations += __gather_animations(blender_scene, export_settings)
+        if export_settings[gltf2_blender_export_keys.ANIMATIONS]:
+            animations += __gather_animations(blender_scene, export_settings)
 
     return scenes, animations
 
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_image.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_image.py
index b6131a59..a694cac3 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_image.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_image.py
@@ -115,20 +115,35 @@ def __get_image_data(sockets_or_slots, export_settings):
         image = None
         for result, socket in zip(results, sockets_or_slots):
             # rudimentarily try follow the node tree to find the correct image data.
-            channel = None
+            source_channel = None
+            target_channel = None
+            source_channels_length = None
             for elem in result.path:
                 if isinstance(elem.from_node, bpy.types.ShaderNodeSeparateRGB):
-                    channel = {
+                    source_channel = {
                         'R': 0,
                         'G': 1,
                         'B': 2
                     }[elem.from_socket.name]
 
-            if channel is not None:
-                pixels = [split_pixels_by_channels(result.shader_node.image, export_settings)[channel]]
+            if source_channel is not None:
+                pixels = [split_pixels_by_channels(result.shader_node.image, export_settings)[source_channel]]
+                target_channel = source_channel
+                source_channel = 0
+                source_channels_length = 1
             else:
                 pixels = split_pixels_by_channels(result.shader_node.image, export_settings)
-                channel = 0
+                target_channel = 0
+                source_channel = 0
+                source_channels_length = len(pixels)
+
+            # Change target channel for metallic and roughness.
+            if elem.to_socket.name == 'Metallic':
+                target_channel = 2
+                source_channels_length = 1
+            elif elem.to_socket.name == 'Roughness':
+                target_channel = 1
+                source_channels_length = 1
 
             file_name = os.path.splitext(result.shader_node.image.name)[0]
 
@@ -137,13 +152,15 @@ def __get_image_data(sockets_or_slots, export_settings):
                 result.shader_node.image.filepath,
                 result.shader_node.image.size[0],
                 result.shader_node.image.size[1],
-                channel,
+                source_channel,
+                target_channel,
+                source_channels_length,
                 pixels)
 
             if image is None:
                 image = image_data
             else:
-                image.add_to_image(channel, image_data)
+                image.add_to_image(target_channel, image_data)
 
         return image
     elif __is_slot(sockets_or_slots):
@@ -156,6 +173,8 @@ def __get_image_data(sockets_or_slots, export_settings):
             texture.image.size[0],
             texture.image.size[1],
             0,
+            0,
+            len(pixels),
             pixels)
         return image_data
     else:
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_primitives.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_primitives.py
index 4fa025b2..23d51fa6 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_primitives.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_primitives.py
@@ -73,9 +73,7 @@ def __gather_indices(blender_primitive, blender_mesh, modifiers, export_settings
     indices = blender_primitive['indices']
 
     max_index = max(indices)
-    if max_index < (1 << 8):
-        component_type = gltf2_io_constants.ComponentType.UnsignedByte
-    elif max_index < (1 << 16):
+    if max_index < (1 << 16):
         component_type = gltf2_io_constants.ComponentType.UnsignedShort
     elif max_index < (1 << 32):
         component_type = gltf2_io_constants.ComponentType.UnsignedInt
diff --git a/io_scene_gltf2/io/exp/gltf2_io_image_data.py b/io_scene_gltf2/io/exp/gltf2_io_image_data.py
index 92bdd09f..fb6ecb2a 100755
--- a/io_scene_gltf2/io/exp/gltf2_io_image_data.py
+++ b/io_scene_gltf2/io/exp/gltf2_io_image_data.py
@@ -24,34 +24,35 @@ class ImageData:
     # FUTURE_WORK: as a method to allow the node graph to be better supported, we could model some of
     # the node graph elements with numpy functions
 
-    def __init__(self, name: str, filepath: str, width: int, height: int, offset: int, channels: typing.Optional[typing.List[np.ndarray]] = []):
+    def __init__(self, name: str, filepath: str, width: int, height: int, source: int, target: int, source_length: int, channels: typing.Optional[typing.List[np.ndarray]] = []):
         if width <= 0 or height <= 0:
             raise ValueError("Image data can not have zero width or height")
-        if offset + len(channels) > 4:
-            raise ValueError("Image data can not have more than 4 channels")
+        if source + source_length > 4:
+            raise ValueError("Source image data can not have more than 4 channels")
+        if target + source_length > 4:
+            raise ValueError("Target image data can not have more than 4 channels")
         self.channels = [None, None, None, None]
-        channels_length = len(channels)
-        for index in range(offset, offset + channels_length):
-            self.channels[index] = channels[index - offset]
+        for index in range(source, source + source_length):
+            self.channels[target + index - source] = channels[index]
         self.name = name
         self.filepath = filepath
         self.width = width
         self.height = height
 
-    def add_to_image(self, channel, image_data):
+    def add_to_image(self, target: int, image_data):
         if self.width != image_data.width or self.height != image_data.height:
             raise ValueError("Image dimensions do not match")
-        if channel < 0 or channel > 3:
-            raise ValueError("Can't append image: channels out of bounds")
+        if target < 0 or target > 3:
+            raise ValueError("Can't insert image: channels out of bounds")
         if len(image_data.channels) != 4:
-            raise ValueError("Can't append image: incomplete image")
+            raise ValueError("Can't insert image: incomplete image")
 
         if self.name != image_data.name:
             self.name += image_data.name
             self.filepath = ""
 
         # Replace channel.
-        self.channels[channel] = image_data.channels[channel]
+        self.channels[target] = image_data.channels[target]
 
     @property
     def r(self):