feat: threads only run while needed

modules/terrain/TODO.org

@@ -1,9 +1,13 @@
 - [x] Cache chunk meshes
 - [ ] Noise modifier
 - [ ] Min/Max modifier
-- [ ] Only load Defined chunks
+- [ ] Only load defined chunks
+- [ ] More accurate modifier bounds
 - [ ] Separate terrain module into it's own repository
 - [ ] Texturing step
 - [ ] Use Semaphores in mesh gen multi-threading
-- [ ] Separate files for terrain modifiers
-- [ ] Stop threads when generation finishes
+- [ ] Separate source files for terrain modifiers
+- [x] Stop threads when generation finishes
+- [ ] Regenerate chunks when deleting/reordering modifiers
+- [ ] Stop processing terrain after generation is complete
+- [ ] Don't start generation threads if all meshes are cached

modules/terrain/terrain.cpp

@@ -108,6 +108,7 @@ void Terrain::_notification(int what) {
 				construct_chunk_grid();
 				synchronous_generate_terrain();
 			}
+			set_process(true);
 			return;
 		}
 		case NOTIFICATION_PROCESS: