fix: Destroy and create bodies after step is done

spydon · spydon · commit f4ad2fe4ddef · 2025-09-07T17:23:19.000+02:00
diff --git a/packages/forge2d/lib/src/dynamics/world.dart b/packages/forge2d/lib/src/dynamics/world.dart
@@ -25,6 +25,8 @@ class World {
   late ContactManager contactManager;
   final List<Body> bodies = <Body>[];
   final List<Joint> joints = <Joint>[];
+  final List<Body> bodiesToCreate = <Body>[];
+  final List<Body> bodiesToDestroy = <Body>[];
 
   final Vector2 _gravity;
 
@@ -133,8 +135,11 @@ class World {
   ///
   /// Warning: This function is locked during callbacks.
   Body createBody(BodyDef def) {
-    assert(!isLocked);
     final body = Body(def, this);
+    if (isLocked) {
+      bodiesToCreate.add(body);
+      return body;
+    }
     bodies.add(body);
     return body;
   }
@@ -145,8 +150,10 @@ class World {
   /// Warning: This automatically deletes all associated shapes and joints.
   /// Warning: This function is locked during callbacks.
   void destroyBody(Body body) {
-    assert(bodies.isNotEmpty);
-    assert(!isLocked);
+    if (isLocked) {
+      bodiesToDestroy.add(body);
+      return;
+    }
 
     // Delete the attached joints.
     while (body.joints.isNotEmpty) {
@@ -297,6 +304,16 @@ class World {
 
     flags &= ~locked;
 
+    for (final body in bodiesToCreate) {
+      bodies.add(body);
+    }
+    bodiesToCreate.clear();
+
+    for (final body in bodiesToDestroy) {
+      destroyBody(body);
+    }
+    bodiesToDestroy.clear();
+
     _profile.step.record(_stepTimer.getMilliseconds());
   }
 
