feat: flexible LOD loading

Author: laurentsenta

src/terrain_3d_mesh_asset.cpp

@@ -306,8 +306,46 @@ void Terrain3DMeshAsset::set_scene_file(const Ref<PackedScene> &p_scene_file) {
 			_height_offset = 0.0f;
 		}
 		LOG(DEBUG, "Loaded scene with parent node: ", node);
-		TypedArray<Node> mesh_instances = node->find_children("*", "MeshInstance3D");
 		_meshes.clear();
+
+		// Look for MeshInstance3D nodes
+		TypedArray<Node> mesh_instances;
+		bool meshes_found = false;
+
+		// First look for XXXXLOD# meshes
+		mesh_instances = node->find_children("*LOD?", "MeshInstance3D");
+		if (mesh_instances.size() > 0) {
+			LOG(INFO, "Found ", mesh_instances.size(), " meshes using LOD# naming convention, using the first ", MAX_LOD_COUNT);
+			meshes_found = true;
+			// mesh_instances.sort_custom(callable_mp_static(&Terrain3DMeshAsset::sort_lod_nodes));
+		}
+
+		// Fallback to all the meshes
+		if (!meshes_found) {
+			mesh_instances = node->find_children("*", "MeshInstance3D");
+
+			if (mesh_instances.size() > 0) {
+				LOG(INFO, "No LOD# meshes found, assuming the first ", MAX_LOD_COUNT, " are LOD0-LOD3");
+				meshes_found = true;
+				mesh_instances.sort();
+			}
+		}
+
+		// Fallback to the root mesh
+		if (!meshes_found) {
+			if (node->is_class("MeshInstance3D")) {
+				LOG(INFO, "No LOD# meshes found, assuming the root mesh is LOD0");
+				mesh_instances.push_back(node);
+				meshes_found = true;
+			}
+		}
+
+		// Give up finding meshes
+		if (!meshes_found) {
+			LOG(ERROR, "No MeshInstance3D found in scene file");
+		}
+
+		// Now process the meshes
 		for (int i = 0; i < mesh_instances.size(); i++) {
 			MeshInstance3D *mi = cast_to<MeshInstance3D>(mesh_instances[i]);
 			LOG(DEBUG, "Found mesh: ", mi->get_name());
@@ -351,6 +389,10 @@ void Terrain3DMeshAsset::set_scene_file(const Ref<PackedScene> &p_scene_file) {
 	emit_signal("instancer_setting_changed");
 }
 
+bool Terrain3DMeshAsset::sort_lod_nodes(const Node &a, const Node &b) {
+	return a.get_name().right(1) < b.get_name().right(1);
+}
+
 void Terrain3DMeshAsset::set_material_override(const Ref<Material> &p_material) {
 	_set_material_override(p_material);
 	LOG(DEBUG, "Emitting setting_changed");

src/terrain_3d_mesh_asset.h

@@ -125,6 +125,8 @@ class Terrain3DMeshAsset : public Terrain3DAssetResource {
 	void set_mesh_count(const int p_count) {} // no-op, used to expose the property in the editor
 	Ref<Texture2D> get_thumbnail() const { return _thumbnail; }
 
+	static bool sort_lod_nodes(const Node &a, const Node &b);
+
 protected:
 	void _validate_property(PropertyInfo &p_property) const;
 	static void _bind_methods();