Support setting up mesh LODs from a scene with name `LODx` suffixes

doc/source/changelog.md

@@ -22,6 +22,7 @@ Godot 4 is required from this version.
     - `VoxelToolLodTerrain`: added *experimental* `do_sphere_async`, an alternative version of `do_sphere` which defers the task on threads to reduce stutter if the affected area is big.
     - `VoxelInstancer`: Allow to dump VoxelInstancer as scene for debug inspection
     - `VoxelInstancer`: Editor: instance chunks are shown when the node is selected
+    - `VoxelInstanceLibraryMultiMeshItem`: Support setting up mesh LODs from a scene with name `LODx` suffixes
 
 - Fixes
     - `VoxelBuffer`: frequently creating buffers with always different sizes no longer wastes memory
@@ -41,6 +42,8 @@ Godot 4 is required from this version.
     - `Voxel` was renamed `VoxelBlockyModel`
     - `VoxelLibrary` was renamed `VoxelBlockyLibrary`
     - `VoxelVoxImporter` was renamed `VoxelVoxSceneImporter`
+    - `VoxelInstanceLibraryItem` was renamed `VoxelInstanceLibraryMultiMeshItem`
+    - `VoxelInstanceLibraryItemBase` was renamed `VoxelInstanceLibraryItem`
 
 - Known issues
     - Some nodes and resources no longer start with predefined properties due to a warning introduced in Godot4 when properties are resources.

doc/source/instancing.md

@@ -104,7 +104,10 @@ This conversion process expects your scene to follow a specific structure:
 
 ```
 - PhysicsBody (StaticBody, RigidBody...)
-	- MeshInstance
+	- MeshInstance_LOD0 <-- "LOD" suffixes are optional but allow to specify the 4 LODs if needed
+	- MeshInstance_LOD1
+	- MeshInstance_LOD2
+	- MeshInstance_LOD3
 	- CollisionShape1
 	- CollisionShape2
 	- ...

terrain/instancing/voxel_instance_library_multimesh_item.cpp

@@ -98,6 +98,24 @@ static RenderingServer::ShadowCastingSetting node_to_visual_server_enum(Geometry
 }
 
 void VoxelInstanceLibraryMultiMeshItem::setup_from_template(Node *root) {
+	struct L {
+		static unsigned int get_lod_index_from_name(const String &name) {
+			if (name.ends_with("LOD0")) {
+				return 0;
+			}
+			if (name.ends_with("LOD1")) {
+				return 1;
+			}
+			if (name.ends_with("LOD2")) {
+				return 2;
+			}
+			if (name.ends_with("LOD3")) {
+				return 3;
+			}
+			return 0;
+		}
+	};
+
 	ERR_FAIL_COND(root == nullptr);
 
 	_collision_shapes.clear();
@@ -111,9 +129,9 @@ void VoxelInstanceLibraryMultiMeshItem::setup_from_template(Node *root) {
 	for (int i = 0; i < root->get_child_count(); ++i) {
 		MeshInstance3D *mi = Object::cast_to<MeshInstance3D>(root->get_child(i));
 		if (mi != nullptr) {
-			// TODO Support LODs
-			_mesh_lods[0] = mi->get_mesh();
-			_mesh_lod_count = 1;
+			const unsigned int lod_index = L::get_lod_index_from_name(mi->get_name());
+			_mesh_lods[lod_index] = mi->get_mesh();
+			_mesh_lod_count = math::max(lod_index + 1, _mesh_lod_count);
 			_material_override = mi->get_material_override();
 			_shadow_casting_setting = node_to_visual_server_enum(mi->get_cast_shadows_setting());
 		}