Calculate the mouse focus inverse transform only when needed

Revival of #49158

Co-authored-by: Marcel Admiraal <madmiraal@users.noreply.github.com>

2 files changed, 10 insertions, 32 deletions

diff --git a/scene/main/viewport.cpp b/scene/main/viewport.cpp
index 7ca1f9d3ec..15225ca490 100644
--- a/scene/main/viewport.cpp
+++ b/scene/main/viewport.cpp
@@ -1401,7 +1401,7 @@ Control *Viewport::gui_find_control(const Point2 &p_global) {
 			xform = sw->get_canvas_transform();
 		}
 
-		Control *ret = _gui_find_control_at_pos(sw, p_global, xform, gui.focus_inv_xform);
+		Control *ret = _gui_find_control_at_pos(sw, p_global, xform);
 		if (ret) {
 			return ret;
 		}
@@ -1410,7 +1410,7 @@ Control *Viewport::gui_find_control(const Point2 &p_global) {
 	return nullptr;
 }
 
-Control *Viewport::_gui_find_control_at_pos(CanvasItem *p_node, const Point2 &p_global, const Transform2D &p_xform, Transform2D &r_inv_xform) {
+Control *Viewport::_gui_find_control_at_pos(CanvasItem *p_node, const Point2 &p_global, const Transform2D &p_xform) {
 	if (!p_node->is_visible()) {
 		return nullptr; // Canvas item hidden, discard.
 	}
@@ -1430,7 +1430,7 @@ Control *Viewport::_gui_find_control_at_pos(CanvasItem *p_node, const Point2 &p_
 				continue;
 			}
 
-			Control *ret = _gui_find_control_at_pos(ci, p_global, matrix, r_inv_xform);
+			Control *ret = _gui_find_control_at_pos(ci, p_global, matrix);
 			if (ret) {
 				return ret;
 			}
@@ -1448,7 +1448,6 @@ Control *Viewport::_gui_find_control_at_pos(CanvasItem *p_node, const Point2 &p_
 
 	Control *drag_preview = _gui_get_drag_preview();
 	if (!drag_preview || (c != drag_preview && !drag_preview->is_ancestor_of(c))) {
-		r_inv_xform = matrix;
 		return c;
 	}
 
@@ -1495,12 +1494,11 @@ void Viewport::_gui_input_event(Ref<InputEvent> p_event) {
 
 		Point2 mpos = mb->get_position();
 		if (mb->is_pressed()) {
-			Size2 pos = mpos;
 			if (!gui.mouse_focus_mask.is_empty()) {
 				// Do not steal mouse focus and stuff while a focus mask exists.
 				gui.mouse_focus_mask.set_flag(mouse_button_to_mask(mb->get_button_index()));
 			} else {
-				gui.mouse_focus = gui_find_control(pos);
+				gui.mouse_focus = gui_find_control(mpos);
 				gui.last_mouse_focus = gui.mouse_focus;
 
 				if (!gui.mouse_focus) {
@@ -1519,10 +1517,7 @@ void Viewport::_gui_input_event(Ref<InputEvent> p_event) {
 
 			mb = mb->xformed_by(Transform2D()); // Make a copy of the event.
 
-			mb->set_global_position(pos);
-
-			pos = gui.focus_inv_xform.xform(pos);
-
+			Point2 pos = gui.mouse_focus->get_global_transform_with_canvas().affine_inverse().xform(mpos);
 			mb->set_position(pos);
 
 #ifdef DEBUG_ENABLED
@@ -1586,11 +1581,8 @@ void Viewport::_gui_input_event(Ref<InputEvent> p_event) {
 				return;
 			}
 
-			Size2 pos = mpos;
-
 			mb = mb->xformed_by(Transform2D()); // Make a copy.
-			mb->set_global_position(pos);
-			pos = gui.focus_inv_xform.xform(pos);
+			Point2 pos = gui.mouse_focus->get_global_transform_with_canvas().affine_inverse().xform(mpos);
 			mb->set_position(pos);
 
 			Control *mouse_focus = gui.mouse_focus;
@@ -1893,11 +1885,7 @@ void Viewport::_gui_input_event(Ref<InputEvent> p_event) {
 				bool stopped = false;
 				if (over->can_process()) {
 					touch_event = touch_event->xformed_by(Transform2D()); // Make a copy.
-					if (over == gui.mouse_focus) {
-						pos = gui.focus_inv_xform.xform(pos);
-					} else {
-						pos = over->get_global_transform_with_canvas().affine_inverse().xform(pos);
-					}
+					pos = over->get_global_transform_with_canvas().affine_inverse().xform(pos);
 					touch_event->set_position(pos);
 					stopped = _gui_call_input(over, touch_event);
 				}
@@ -1912,11 +1900,7 @@ void Viewport::_gui_input_event(Ref<InputEvent> p_event) {
 			Control *over = control_id.is_valid() ? Object::cast_to<Control>(ObjectDB::get_instance(control_id)) : nullptr;
 			if (over && over->can_process()) {
 				touch_event = touch_event->xformed_by(Transform2D()); // Make a copy.
-				if (over == gui.last_mouse_focus) {
-					pos = gui.focus_inv_xform.xform(pos);
-				} else {
-					pos = over->get_global_transform_with_canvas().affine_inverse().xform(pos);
-				}
+				pos = gui.last_mouse_focus->get_global_transform_with_canvas().affine_inverse().xform(pos);
 				touch_event->set_position(pos);
 
 				stopped = _gui_call_input(over, touch_event);
@@ -1942,11 +1926,7 @@ void Viewport::_gui_input_event(Ref<InputEvent> p_event) {
 			bool stopped = false;
 			if (over->can_process()) {
 				gesture_event = gesture_event->xformed_by(Transform2D()); // Make a copy.
-				if (over == gui.mouse_focus) {
-					pos = gui.focus_inv_xform.xform(pos);
-				} else {
-					pos = over->get_global_transform_with_canvas().affine_inverse().xform(pos);
-				}
+				pos = over->get_global_transform_with_canvas().affine_inverse().xform(pos);
 				gesture_event->set_position(pos);
 				stopped = _gui_call_input(over, gesture_event);
 			}
@@ -2393,7 +2373,6 @@ void Viewport::_post_gui_grab_click_focus() {
 		}
 
 		gui.mouse_focus = focus_grabber;
-		gui.focus_inv_xform = gui.mouse_focus->get_global_transform_with_canvas().affine_inverse();
 		click = gui.mouse_focus->get_global_transform_with_canvas().affine_inverse().xform(gui.last_mouse_pos);
 
 		for (int i = 0; i < 3; i++) {
diff --git a/scene/main/viewport.h b/scene/main/viewport.h
index 9f182682d7..603e92b071 100644
--- a/scene/main/viewport.h
+++ b/scene/main/viewport.h
@@ -374,7 +374,6 @@ private:
 		ObjectID drag_preview_id;
 		Ref<SceneTreeTimer> tooltip_timer;
 		double tooltip_delay = 0.0;
-		Transform2D focus_inv_xform;
 		bool roots_order_dirty = false;
 		List<Control *> roots;
 		int canvas_sort_index = 0; //for sorting items with canvas as root
@@ -403,7 +402,7 @@ private:
 	void _gui_call_notification(Control *p_control, int p_what);
 
 	void _gui_sort_roots();
-	Control *_gui_find_control_at_pos(CanvasItem *p_node, const Point2 &p_global, const Transform2D &p_xform, Transform2D &r_inv_xform);
+	Control *_gui_find_control_at_pos(CanvasItem *p_node, const Point2 &p_global, const Transform2D &p_xform);
 
 	void _gui_input_event(Ref<InputEvent> p_event);
 	void _perform_drop(Control *p_control = nullptr, Point2 p_pos = Point2());