add on_chunk_present and on_chunk_remove events

src/world/Level.cpp

@@ -52,13 +52,14 @@ Level::Level(
         entities->setNextID(worldInfo.nextEntityId);
     }
 
-    events->listen(LevelEventType::EVT_CHUNK_SHOWN, [this](LevelEventType, Chunk* chunk) {
+    events->listen(LevelEventType::CHUNK_SHOWN, [this](LevelEventType, Chunk* chunk) {
         chunks->incref(chunk);
     });
-    events->listen(LevelEventType::EVT_CHUNK_HIDDEN, [this](LevelEventType, Chunk* chunk) {
+    events->listen(LevelEventType::CHUNK_HIDDEN, [this](LevelEventType, Chunk* chunk) {
         chunks->decref(chunk);
     });
-    chunks->setOnUnload([this](const Chunk& chunk) {
+    chunks->setOnUnload([this](Chunk& chunk) {
+        events->trigger(LevelEventType::CHUNK_UNLOAD, &chunk);
         AABB aabb = chunk.getAABB();
         entities->despawn(entities->getAllInside(aabb));
     });

src/world/LevelEvents.hpp

@@ -6,9 +6,11 @@
 
 class Chunk;
 
-enum LevelEventType {
-    EVT_CHUNK_SHOWN,
-    EVT_CHUNK_HIDDEN,
+enum class LevelEventType {
+    CHUNK_SHOWN,
+    CHUNK_HIDDEN,
+    CHUNK_PRESENT,
+    CHUNK_UNLOAD,
 };
 
 using ChunkEventFunc = std::function<void(LevelEventType, Chunk*)>;