Improve multiple drag and drop

editor/limbo_ai_editor_plugin.cpp

@@ -848,19 +848,10 @@ void LimboAIEditor::_on_tasks_dragged(const TypedArray<BTTask> &p_tasks, Ref<BTT
 		return;
 	}
 
-	// Filter tasks
+	// Remove descendants of selected.
 	Vector<Ref<BTTask>> tasks_list;
-	int no_effect = 0;
 	for (int i = 0; i < p_tasks.size(); i++) {
 		Ref<BTTask> task = p_tasks[i];
-		// Count tasks that don't change position
-		if (task == p_to_task) {
-			if (Math::abs(task->get_index() - p_to_pos) <= 1) {
-				++no_effect;
-			}
-		}
-		
-		// Remove descendants of selected
 		bool remove = false;
 		for (int s_idx = 0; s_idx < p_tasks.size(); s_idx++) {
 			Ref<BTTask> selected = p_tasks[s_idx];
@@ -873,48 +864,27 @@ void LimboAIEditor::_on_tasks_dragged(const TypedArray<BTTask> &p_tasks, Ref<BTT
 			tasks_list.push_back(task);
 		}
 	}
-	if (tasks_list.is_empty() || p_tasks.size() == no_effect) {
-		return;
-	}
 
 	EditorUndoRedoManager *undo_redo = _new_undo_redo_action(TTR("Drag BT Task"));
 
-	// Apply changes in the task hierarchy.
+	// Remove all tasks first so adding ordering is stable.
-	int drop_idx = p_to_pos;
+	int before_pos = 0;
-	for (const Ref<BTTask> &task : tasks_list) {
+	for (const Ref<BTTask> task : tasks_list) {
-		if (task->get_parent() == p_to_task && drop_idx > task->get_index()) {
+		if (task->get_parent() == p_to_task && p_to_pos > task->get_index()) {
-			drop_idx -= 1;
+			before_pos += 1;
 		}
-		if (task == p_to_task) {
-			if (Math::abs(task->get_index() - p_to_pos) <= 1) {
-				++drop_idx;
-				continue;
-			}
-		}
-		
 		undo_redo->add_do_method(task->get_parent().ptr(), LW_NAME(remove_child), task);
+	}
 
-		undo_redo->add_do_method(p_to_task.ptr(), LW_NAME(add_child_at_index), task, drop_idx);
+	for (int i = 0; i < tasks_list.size(); i++) {
+		Ref<BTTask> task = tasks_list[i];
+		undo_redo->add_do_method(p_to_task.ptr(), LW_NAME(add_child_at_index), task, p_to_pos + i - before_pos);
 		undo_redo->add_undo_method(p_to_task.ptr(), LW_NAME(remove_child), task);
-
-		++drop_idx;
 	}
 
 	// Re-add tasks in later undo action so indexes match the old order.
-	drop_idx = p_to_pos;
+	for (const Ref<BTTask> task : tasks_list) {
-	for (const Ref<BTTask> &task : tasks_list) {
-		if (task->get_parent() == p_to_task && drop_idx > task->get_index()) {
-			drop_idx -= 1;
-		}
-		if (task == p_to_task) {
-			if (Math::abs(task->get_index() - p_to_pos) <= 1) {
-				++drop_idx;
-				continue;
-			}
-		}
-
 		undo_redo->add_undo_method(task->get_parent().ptr(), LW_NAME(add_child_at_index), task, task->get_index());
-		++drop_idx;
 	}
 
 	_commit_action_with_update(undo_redo);

editor/task_tree.cpp

@@ -266,15 +266,7 @@ Vector<Ref<BTTask>> TaskTree::get_selected_tasks() const {
 }
 
 void TaskTree::clear_selection() {
-	Vector<TreeItem*> selected_tasks;
+	tree->deselect_all();
-	TreeItem *next = tree->get_next_selected(nullptr);
-	while (next) {
-		Ref<BTTask> task = next->get_metadata(0);
-		if (task.is_valid()) {
-			remove_selection(task);
-		}
-		next = tree->get_next_selected(next);
-	}
 }
 
 Rect2 TaskTree::get_selected_probability_rect() const {
@@ -384,7 +376,7 @@ bool TaskTree::_can_drop_data_fw(const Point2 &p_point, const Variant &p_data) c
 		return false;
 	}
 
-	if (!item->get_parent() && section != 0) { // Before/after root item.
+	if (!item->get_parent() && section < 0) { // Before root item.
 		return false;
 	}
 
@@ -393,12 +385,18 @@ bool TaskTree::_can_drop_data_fw(const Point2 &p_point, const Variant &p_data) c
 		if (tasks.is_empty()) {
 			return false; // No tasks.
 		}
+
+		Ref<BTTask> to_task = item->get_metadata(0);
+		int to_pos = -1;
+		int type = tree->get_drop_section_at_position(p_point);
+		_normalize_drop(item, type, to_pos, to_task);
+		if (to_task.is_null()) {
+			return false; // Outside root.
+		}
 		for (int i = 0; i < tasks.size(); i++) {
 			Ref<BTTask> task = tasks[i];
-			const Ref<BTTask> to_task = item->get_metadata(0);
+			if (to_task->is_descendant_of(task) || task == to_task) {
-			if (to_task->is_descendant_of(task) || task == to_task ||
+				return false; // Don't drop as child of selected tasks.
-					(task == to_task && task->get_index() + section >= to_task->get_index() && !item->is_collapsed() && item->get_child_count() > 0)) {
-				return false; // Don't drop as child of itself.
 			}
 		}
 	}
@@ -408,31 +406,46 @@ bool TaskTree::_can_drop_data_fw(const Point2 &p_point, const Variant &p_data) c
 
 void TaskTree::_drop_data_fw(const Point2 &p_point, const Variant &p_data) {
 	Dictionary d = p_data;
+	if (!d.has("tasks")) {
+		return;
+	}
+
 	TreeItem *item = tree->get_item_at_position(p_point);
 	int type = tree->get_drop_section_at_position(p_point);
 	ERR_FAIL_NULL(item);
 	ERR_FAIL_COND(type < -1 || type > 1);
 
-	if (item && d.has("tasks")) {
+	// The drop behavior depends on the TreeItem's state.
-		TypedArray<BTTask> tasks = d["tasks"];
+	// Normalize and emit the parent task and position instead of exposing TreeItem.
 	int to_pos = -1;
 	Ref<BTTask> to_task = item->get_metadata(0);
 	ERR_FAIL_COND(to_task.is_null());
+	_normalize_drop(item, type, to_pos, to_task);
+	emit_signal(LW_NAME(tasks_dragged), d["tasks"], to_task, to_pos);
+}
 
-		// The drop behavior depends on the TreeItem's state.
+void TaskTree::_normalize_drop(TreeItem *item, int type, int &to_pos, Ref<BTTask> &to_task) const {
-		// Normalize and emit the parent task and position instead of exposing TreeItem.
 	switch (type) {
 		case 0: // Drop as last child of target.
 			to_pos = to_task->get_child_count();
 			break;
 		case -1: // Drop above target.
 			ERR_FAIL_COND_MSG(to_task->get_parent().is_null(), "Cannot perform drop above the root task!");
-				to_pos = MAX(0, to_task->get_index());
+			to_pos = MAX(0, to_task->get_index() - 1);
+			{
+				Vector<Ref<BTTask>> selected = get_selected_tasks();
+				if (to_task == selected[selected.size()-1]) {
+					to_pos += 1;
+				}
+			}
 			to_task = to_task->get_parent();
 			break;
 		case 1: // Drop below target.
 			if (item->get_child_count() == 0) {
 				to_pos = to_task->get_index() + 1;
+				if (to_task == tree->get_next_selected(nullptr)->get_metadata(0)) {
+					to_pos -= 1;
+				}
 				to_task = to_task->get_parent();
 				break;
 			}
@@ -456,8 +469,6 @@ void TaskTree::_drop_data_fw(const Point2 &p_point, const Variant &p_data) {
 			}
 			break;
 	}
-		emit_signal(LW_NAME(tasks_dragged), tasks, to_task, to_pos);
-	}
 }
 
 void TaskTree::_draw_probability(Object *item_obj, Rect2 rect) {

editor/task_tree.h

@@ -75,6 +75,7 @@ private:
 	Variant _get_drag_data_fw(const Point2 &p_point);
 	bool _can_drop_data_fw(const Point2 &p_point, const Variant &p_data) const;
 	void _drop_data_fw(const Point2 &p_point, const Variant &p_data);
+	void _normalize_drop(TreeItem *item, int type, int &to_pos, Ref<BTTask> &to_task) const;
 
 	void _draw_probability(Object *item_obj, Rect2 rect);