primitives.diff

diff --git a/blender/exp/gltf2_blender_extract.py b/blender/exp/gltf2_blender_extract.py
index b5c09de..c65a9fc 100644
--- a/blender/exp/gltf2_blender_extract.py
+++ b/blender/exp/gltf2_blender_extract.py
@@ -32,6 +32,7 @@ from io_scene_gltf2.blender.exp import gltf2_blender_gather_skins
 INDICES_ID = 'indices'
 MATERIAL_ID = 'material'
 ATTRIBUTES_ID = 'attributes'
+MODE_ID = 'mode'
 
 COLOR_PREFIX = 'COLOR_'
 MORPH_TANGENT_PREFIX = 'MORPH_TANGENT_'
@@ -383,6 +384,40 @@ def extract_primitive_pack(a, indices, use_tangents):
     return result_primitive
 
 
+def extract_line_primitives(blender_mesh, vertices_in_polygons, export_settings):
+    range_indices = 65535
+    valid_edges = []
+    for blender_edge in blender_mesh.edges:
+        if blender_edge.vertices[0] not in vertices_in_polygons or blender_edge.vertices[1] not in vertices_in_polygons:
+            # edge has at least one edge not in a polygon, add to primitive
+            valid_edges.append(blender_edge)
+    
+    if len(valid_edges) == 0:
+        return []
+    
+    else:
+        attributes = {
+            POSITION_ATTRIBUTE: [],
+            NORMAL_ATTRIBUTE: []
+        }
+        
+        primitive = {
+            MODE_ID: 1, # LINES
+            INDICES_ID: [],
+            MATERIAL_ID: 0,
+            ATTRIBUTES_ID: attributes
+        }
+        
+        for edge in valid_edges:
+            attributes[POSITION_ATTRIBUTE].extend([v for i in edge.vertices for v in convert_swizzle_location(blender_mesh.vertices[i].co, export_settings)])
+            attributes[NORMAL_ATTRIBUTE].extend([v for i in edge.vertices for v in blender_mesh.vertices[i].normal])
+            primitive[INDICES_ID].append(len(primitive[INDICES_ID]))
+            primitive[INDICES_ID].append(len(primitive[INDICES_ID]))
+        
+        edge_primitives = [primitive]
+        
+        return edge_primitives
+
 def extract_primitives(glTF, blender_mesh, blender_vertex_groups, modifiers, export_settings):
     """
     Extract primitives from a mesh. Polygons are triangulated and sorted by material.
@@ -1108,6 +1143,14 @@ def extract_primitives(glTF, blender_mesh, blender_vertex_groups, modifiers, exp
             print_console('DEBUG', 'Adding primitive without splitting. Indices: ' + str(
                 len(primitive[INDICES_ID])) + ' Vertices: ' + str(
                 len(primitive[ATTRIBUTES_ID][POSITION_ATTRIBUTE]) // 3))
+    #
+    # Add edges and points not associated with a polygon
+    #
+    
+    # compute this once, might get expensive for big meshes
+    vertices_in_polygons = frozenset([v for p in blender_mesh.polygons for v in p.vertices])
+    line_primitives = extract_line_primitives(blender_mesh, vertices_in_polygons, export_settings)    
+    result_primitives.extend(line_primitives)
 
     print_console('INFO', 'Primitives created: ' + str(len(result_primitives)))
 
diff --git a/blender/exp/gltf2_blender_gather_primitives.py b/blender/exp/gltf2_blender_gather_primitives.py
index 2c4ee91..e1b4d8c 100644
--- a/blender/exp/gltf2_blender_gather_primitives.py
+++ b/blender/exp/gltf2_blender_gather_primitives.py
@@ -69,7 +69,7 @@ def gather_primitives(
             extras=None,
             indices=internal_primitive['indices'],
             material=material,
-            mode=None,
+            mode=internal_primitive.get('mode', None),
             targets=internal_primitive['targets']
         )
         primitives.append(primitive)
@@ -96,6 +96,7 @@ def __gather_cache_primitives(
             "attributes": __gather_attributes(internal_primitive, blender_mesh, modifiers, export_settings),
             "indices": __gather_indices(internal_primitive, blender_mesh, modifiers, export_settings),
             "material": internal_primitive['material'],
+            "mode": internal_primitive.get('mode', None),
             "targets": __gather_targets(internal_primitive, blender_mesh, modifiers, export_settings)
         }
         primitives.append(primitive)