Export: All available materials

addons/io_scene_gltf2/__init__.py

@@ -203,6 +203,12 @@ def __init__(self):
         default=True
     )
 
+    export_all_materials: BoolProperty(
+        name='All materials',
+        description='Export all avalaible materials',
+        default=False
+    )
+
     export_colors: BoolProperty(
         name='Vertex Colors',
         description='Export vertex colors with meshes',
@@ -432,6 +438,7 @@ def execute(self, context):
             export_settings['gltf_draco_mesh_compression'] = False
 
         export_settings['gltf_materials'] = self.export_materials
+        export_settings['gltf_all_materials'] = self.export_all_materials
         export_settings['gltf_colors'] = self.export_colors
         export_settings['gltf_cameras'] = self.export_cameras
 
@@ -567,6 +574,7 @@ def draw(self, context):
         col.prop(operator, 'export_extras')
         col.prop(operator, 'export_cameras')
         col.prop(operator, 'export_lights')
+        col.prop(operator, 'export_all_materials')
 
 
 class GLTF_PT_export_transform(bpy.types.Panel):

addons/io_scene_gltf2/blender/exp/gltf2_blender_export.py

@@ -61,7 +61,7 @@ def __export(export_settings):
 
 
 def __gather_gltf(exporter, export_settings):
-    active_scene_idx, scenes, animations = gltf2_blender_gather.gather_gltf2(export_settings)
+    active_scene_idx, scenes, animations, materials = gltf2_blender_gather.gather_gltf2(export_settings)
 
     plan = {'active_scene_idx': active_scene_idx, 'scenes': scenes, 'animations': animations}
     export_user_extensions('gather_gltf_hook', export_settings, plan)
@@ -75,7 +75,8 @@ def __gather_gltf(exporter, export_settings):
         exporter.add_scene(scene, idx==active_scene_idx)
     for animation in animations:
         exporter.add_animation(animation)
-
+    for material in materials:
+        exporter.add_material(material)
 
 def __create_buffer(exporter, export_settings):
     buffer = bytes()

addons/io_scene_gltf2/blender/exp/gltf2_blender_export_keys.py

@@ -46,6 +46,7 @@
 MORPH_TANGENT = 'gltf_morph_tangent'
 MORPH_NORMAL = 'gltf_morph_normal'
 MATERIALS = 'gltf_materials'
+ALL_MATERIALS = 'gltf_all_materials'
 EXTRAS = 'gltf_extras'
 CAMERAS = 'gltf_cameras'
 LIGHTS = 'gltf_lights'

addons/io_scene_gltf2/blender/exp/gltf2_blender_gather.py

@@ -18,6 +18,7 @@
 from io_scene_gltf2.io.com.gltf2_io_debug import print_console
 from io_scene_gltf2.blender.exp import gltf2_blender_gather_nodes
 from io_scene_gltf2.blender.exp import gltf2_blender_gather_animations
+from io_scene_gltf2.blender.exp import gltf2_blender_gather_materials
 from io_scene_gltf2.blender.exp.gltf2_blender_gather_cache import cached
 from ..com.gltf2_blender_extras import generate_extras
 from io_scene_gltf2.blender.exp import gltf2_blender_export_keys
@@ -32,14 +33,18 @@ def gather_gltf2(export_settings):
     """
     scenes = []
     animations = []  # unfortunately animations in gltf2 are just as 'root' as scenes.
+    materials = []
     active_scene = None
     for blender_scene in bpy.data.scenes:
         scenes.append(__gather_scene(blender_scene, export_settings))
         if export_settings[gltf2_blender_export_keys.ANIMATIONS]:
             animations += __gather_animations(blender_scene, export_settings)
+        if export_settings[gltf2_blender_export_keys.ALL_MATERIALS]:
+            materials += __gather_materials(blender_scene, export_settings)
         if bpy.context.scene.name == blender_scene.name:
             active_scene = len(scenes) -1
-    return active_scene, scenes, animations
+
+    return active_scene, scenes, animations, materials
 
 
 @cached
@@ -147,6 +152,30 @@ def __gather_animations(blender_scene, export_settings):
 
     return new_animations
 
+def __gather_materials(blender_scene, export_settings):
+    materials = []
+
+    for _blender_object in blender_scene.objects:
+        blender_object = _blender_object.proxy if _blender_object.proxy else _blender_object
+
+        # Check if this object is exclude from view layer
+        node = gltf2_blender_gather_nodes.gather_node(
+                blender_object,
+                blender_object.library.name if blender_object.library else None,
+                blender_scene, None, export_settings)
+        if node is None:
+            continue
+
+        for slot in blender_object.material_slots:
+            # Check if this slot as assigned material
+            if slot.material is None:
+                continue
+
+            double_sided = not slot.material.use_backface_culling
+            materials.append(gltf2_blender_gather_materials.gather_material(slot.material, double_sided, export_settings))
+
+    return materials
+
 
 def __gather_extras(blender_object, export_settings):
     if export_settings[gltf2_blender_export_keys.EXTRAS]:

addons/io_scene_gltf2/blender/exp/gltf2_blender_gltf2_exporter.py

@@ -192,6 +192,18 @@ def add_animation(self, animation: gltf2_io.Animation):
 
         self.__traverse(animation)
 
+    def add_material(self, material: gltf2_io.Material):
+        """
+        Add an material to the glTF.
+
+        :param material: glTF material, with python style references (names)
+        :return: nothing
+        """
+        if self.__finalized:
+            raise RuntimeError("Tried to add material to finalized glTF file")
+
+        self.__traverse(material)
+
     def __to_reference(self, property):
         """
         Append a child of root property to its respective list and return a reference into said list.