glTF exporter: option to export placeholder of materials

* export all materials used by object exported
* not export materials at all (mesh will be exported as a single primitive)
* export placeholder: materials are not exported, but slots are still used to separate mesh into primitives

1 files changed, 11 insertions, 9 deletions

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 4fe498e1..fd325d48 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_primitives.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_primitives.py
@@ -54,15 +54,17 @@ def gather_primitives(
         material_idx = internal_primitive['material']
         double_sided = False
         material = None
-        try:
-            blender_material = bpy.data.materials[material_names[material_idx]]
-            double_sided = not blender_material.use_backface_culling
-            material = gltf2_blender_gather_materials.gather_material(blender_material,
-                                                                  double_sided,
-                                                                  export_settings)
-        except IndexError:
-            # no material at that index
-            pass
+
+        if export_settings['gltf_materials'] == "EXPORT":
+            try:
+                blender_material = bpy.data.materials[material_names[material_idx]]
+                double_sided = not blender_material.use_backface_culling
+                material = gltf2_blender_gather_materials.gather_material(blender_material,
+                                                                      double_sided,
+                                                                      export_settings)
+            except IndexError:
+                # no material at that index
+                pass
 
 
         primitive = gltf2_io.MeshPrimitive(