feat(facades): 0.1.5 — hero detail, scene audit, material orphaning fixed (#32)

Merged PR #32: 0.1.5 — hero detail, scene audit, material orphaning fixed

Co-authored-by: Zwitschi <zwitschi82@gmail.com>

Tools/ue_build_demo_map.py

@@ -23,6 +23,8 @@ import unreal
 MAP = "/Game/Hollywood/DemoMap"
 # Repository root, so the texture generator can be invoked by path.
 ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
+sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
+import ue_placement  # noqa: E402
 RESULT = "/tmp/gigline/demo-map.txt"
 lines = []
 
@@ -116,14 +118,23 @@ def ensure_material(mat_name, spec, textures=None):
     does not read as one flat specular value.
     """
     path = f"/Game/Hollywood/Site/{mat_name}"
-    if unreal.EditorAssetLibrary.does_asset_exist(path):
-        # Rebuilt every run so a look change cannot be masked by a stale asset.
-        unreal.EditorAssetLibrary.delete_asset(path)
-
-    mat = unreal.AssetToolsHelpers.get_asset_tools().create_asset(
-        mat_name, "/Game/Hollywood/Site", unreal.Material, unreal.MaterialFactoryNew())
     lib = unreal.MaterialEditingLibrary
 
+    # Update the existing material IN PLACE rather than deleting and recreating it.
+    # Deleting the asset to force a look rebuild silently orphaned every reference:
+    # after one demo-builder run, all 598 kit actors and the theatre trim pointed at
+    # deleted materials and rendered with the default one (604 actors with no
+    # material), while the map itself looked merely "a bit flat".
+    mat = unreal.EditorAssetLibrary.load_asset(path)
+    if mat is None:
+        mat = unreal.AssetToolsHelpers.get_asset_tools().create_asset(
+            mat_name, "/Game/Hollywood/Site", unreal.Material, unreal.MaterialFactoryNew())
+    else:
+        # Clear the old graph so a removed node cannot survive a look change.
+        # `Material.expressions` is protected from Python, so use the editing
+        # library's own deleter rather than reading the array.
+        lib.delete_all_material_expressions(mat)
+
     def node(cls):
         return lib.create_material_expression(mat, cls)
 
@@ -401,7 +412,7 @@ def build():
     # the NORTH side of the street, which only looked right while it stood alone.
     hero = unreal.EditorAssetLibrary.load_asset("/Game/Hollywood/ElCapitan/SM_HeroFacade")
     if hero:
-        actor = spawn(unreal.StaticMeshActor, unreal.Vector(-13336.0, 1307.0, 0.0), "Hero_Facade")
+        actor = spawn(unreal.StaticMeshActor, unreal.Vector(*ue_placement.HERO_LOCATION_CM), ue_placement.HERO_ACTOR)
         if actor:
             actor.static_mesh_component.set_static_mesh(hero)
             actor.static_mesh_component.set_mobility(unreal.ComponentMobility.STATIC)