-Fix crash opening and closing the scene, closes #3491

scene/3d/camera.cpp

@@ -213,8 +213,7 @@ void Camera::_notification(int p_what) {
 		case NOTIFICATION_ENTER_WORLD: {
 
 
-			bool first_camera = get_viewport()->cameras.size()==0;
-			get_viewport()->cameras.insert(this);
+			bool first_camera = get_viewport()->_camera_add(this);
 			if (!get_tree()->is_node_being_edited(this) && (current || first_camera))
 				make_current();
 
@@ -236,7 +235,7 @@ void Camera::_notification(int p_what) {
 				}
 			}
 
-			get_viewport()->cameras.erase(this);
+			get_viewport()->_camera_remove(this);
 
 
 		} break;
@@ -304,7 +303,7 @@ void Camera::make_current() {
 	if (!is_inside_tree())
 		return;
 
-	get_viewport()->_set_camera(this);
+	get_viewport()->_camera_set(this);
 
 	//get_scene()->call_group(SceneMainLoop::GROUP_CALL_REALTIME,camera_group,"_camera_make_current",this);
 }
@@ -319,20 +318,8 @@ void Camera::clear_current() {
 		return;
 
 	if (get_viewport()->get_camera()==this) {
-		get_viewport()->_set_camera(NULL);
-		//a group is used beause this needs to be in order to be deterministic
-
-		for (Set<Camera*>::Element *E=get_viewport()->cameras.front();E;E=E->next()) {
-
-			if (this==E->get())
-				continue;
-			if (!E->get()->is_inside_tree())
-				continue;
-			if (get_viewport()->get_camera()!=NULL)
-				return;
-
-			E->get()->make_current();
-		}
+		get_viewport()->_camera_set(NULL);
+		get_viewport()->_camera_make_next_current(this);
 	}
 
 }

scene/main/viewport.cpp

@@ -855,7 +855,7 @@ void Viewport::_camera_transform_changed_notify() {
 #endif
 }
 
-void Viewport::_set_camera(Camera* p_camera) {
+void Viewport::_camera_set(Camera* p_camera) {
 
 #ifndef _3D_DISABLED
 
@@ -880,6 +880,36 @@ void Viewport::_set_camera(Camera* p_camera) {
 #endif
 }
 
+bool Viewport::_camera_add(Camera* p_camera) {
+
+	cameras.insert(p_camera);
+	return cameras.size()==1;
+}
+
+void Viewport::_camera_remove(Camera* p_camera) {
+
+	cameras.erase(p_camera);
+	if (camera==p_camera) {
+		camera=NULL;
+	}
+}
+
+void Viewport::_camera_make_next_current(Camera* p_exclude) {
+
+	for(Set<Camera*>::Element *E=cameras.front();E;E=E->next()) {
+
+		if (p_exclude==E->get())
+			continue;
+		if (!E->get()->is_inside_tree())
+			continue;
+		if (camera!=NULL)
+			return;
+
+		E->get()->make_current();
+
+	}
+}
+
 
 void Viewport::set_transparent_background(bool p_enable) {
 

scene/main/viewport.h

@@ -264,7 +264,11 @@ friend class Control;
 
 friend class Camera;
 	void _camera_transform_changed_notify();
-	void _set_camera(Camera* p_camera);
+	void _camera_set(Camera* p_camera);
+	bool _camera_add(Camera* p_camera); //true if first
+	void _camera_remove(Camera* p_camera);
+	void _camera_make_next_current(Camera* p_exclude);
+
 
 protected:	
 	void _notification(int p_what);