glTF export: Fix T78754: export alpha scalar value (not coming from texture)

1 files changed, 5 insertions, 2 deletions

diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_materials_pbr_metallic_roughness.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_materials_pbr_metallic_roughness.py
index 54493799..7913d175 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_materials_pbr_metallic_roughness.py
+++ b/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):
+    alpha_socket = gltf2_blender_get.get_socket(blender_material, "Alpha")
+    alpha = alpha_socket.default_value if alpha_socket is not None and not alpha_socket.is_linked else 1.0
+
     base_color_socket = gltf2_blender_get.get_socket(blender_material, "Base Color")
     if base_color_socket is None:
         base_color_socket = gltf2_blender_get.get_socket(blender_material, "BaseColor")
@@ -57,7 +60,7 @@ def __gather_base_color_factor(blender_material, export_settings):
     if not isinstance(base_color_socket, bpy.types.NodeSocket):
         return None
     if not base_color_socket.is_linked:
-        return list(base_color_socket.default_value)
+        return list(base_color_socket.default_value)[:3] + [alpha]
 
     texture_node = __get_tex_from_socket(base_color_socket)
     if texture_node is None:
@@ -85,7 +88,7 @@ def __gather_base_color_factor(blender_material, export_settings):
                       .format(multiply_node.name))
         return None
 
-    return list(factor_socket.default_value)
+    return list(factor_socket.default_value)[:3] + [alpha]
 
 
 def __gather_base_color_texture(blender_material, export_settings):