glTF exporter: Manage basic color when shader tree is not used

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, 4, 23),
+    "version": (1, 4, 24),
     'blender': (2, 90, 0),
     'location': 'File > Import-Export',
     'description': 'Import-Export as glTF 2.0',

io_scene_gltf2/blender/exp/gltf2_blender_gather_materials_pbr_metallic_roughness.py

@@ -47,6 +47,9 @@ def __filter_pbr_material(blender_material, export_settings):
 
 
 def __gather_base_color_factor(blender_material, export_settings):
+    if not blender_material.use_nodes:
+        return [*blender_material.diffuse_color[:3], 1.0]
+
     rgb, alpha = None, None
 
     alpha_socket = gltf2_blender_get.get_socket(blender_material, "Alpha")
@@ -99,6 +102,9 @@ def __gather_extras(blender_material, export_settings):
 
 
 def __gather_metallic_factor(blender_material, export_settings):
+    if not blender_material.use_nodes:
+        return blender_material.metallic
+
     metallic_socket = gltf2_blender_get.get_socket(blender_material, "Metallic")
     if metallic_socket is None:
         metallic_socket = gltf2_blender_get.get_socket_old(blender_material, "MetallicFactor")
@@ -134,6 +140,9 @@ def __gather_metallic_roughness_texture(blender_material, orm_texture, export_se
 
 
 def __gather_roughness_factor(blender_material, export_settings):
+    if not blender_material.use_nodes:
+        return blender_material.roughness
+
     roughness_socket = gltf2_blender_get.get_socket(blender_material, "Roughness")
     if roughness_socket is None:
         roughness_socket = gltf2_blender_get.get_socket_old(blender_material, "RoughnessFactor")