Improve/fix picking

Acknowledge mouse button events as position tellers (to make picking more solid; for instance, the touch mouse is raised with a mouse unpressed event that may have a more current position)
Forget mouse position for physics if touch mouse raised (because the position known as last is no longer meaningful)
Remove needless check for mouse over/exit (now there's code to inject an spurious move for cases where camera/objects have moved)
Restrict 2D mouse over/exit to mouse events (including emulated from touch; true touches shouldn't trigger the signals)

Fixes #26460.

3 files changed, 63 insertions, 76 deletions

diff --git a/main/input_default.cpp b/main/input_default.cpp
index e8133f9eba..65910b34bc 100644
--- a/main/input_default.cpp
+++ b/main/input_default.cpp
@@ -355,6 +355,7 @@ void InputDefault::_parse_input_event_impl(const Ref<InputEvent> &p_event, bool
 				Ref<InputEventMouseButton> button_event;
 				button_event.instance();
 
+				button_event->set_device(-1);
 				button_event->set_position(st->get_position());
 				button_event->set_global_position(st->get_position());
 				button_event->set_pressed(st->is_pressed());
@@ -383,6 +384,7 @@ void InputDefault::_parse_input_event_impl(const Ref<InputEvent> &p_event, bool
 			Ref<InputEventMouseMotion> motion_event;
 			motion_event.instance();
 
+			motion_event->set_device(-1);
 			motion_event->set_position(sd->get_position());
 			motion_event->set_global_position(sd->get_position());
 			motion_event->set_relative(sd->get_relative());
@@ -600,6 +602,7 @@ void InputDefault::ensure_touch_mouse_raised() {
 		Ref<InputEventMouseButton> button_event;
 		button_event.instance();
 
+		button_event->set_device(-1);
 		button_event->set_position(mouse_pos);
 		button_event->set_global_position(mouse_pos);
 		button_event->set_pressed(false);
diff --git a/scene/main/viewport.cpp b/scene/main/viewport.cpp
index d86c241ec6..4f1330ee36 100644
--- a/scene/main/viewport.cpp
+++ b/scene/main/viewport.cpp
@@ -251,31 +251,6 @@ void Viewport::_collision_object_input_event(CollisionObject *p_object, Camera *
 	physics_last_id = id;
 }
 
-void Viewport::_test_new_mouseover(ObjectID new_collider) {
-#ifndef _3D_DISABLED
-	if (new_collider != physics_object_over) {
-
-		if (physics_object_over) {
-
-			CollisionObject *co = Object::cast_to<CollisionObject>(ObjectDB::get_instance(physics_object_over));
-			if (co) {
-				co->_mouse_exit();
-			}
-		}
-
-		if (new_collider) {
-
-			CollisionObject *co = Object::cast_to<CollisionObject>(ObjectDB::get_instance(new_collider));
-			if (co) {
-				co->_mouse_enter();
-			}
-		}
-
-		physics_object_over = new_collider;
-	}
-#endif
-}
-
 void Viewport::_notification(int p_what) {
 
 	switch (p_what) {
@@ -424,18 +399,19 @@ void Viewport::_notification(int p_what) {
 
 				bool discard_empty_motion = false;
 
-				{ // if no motion event exists, create a new one. This is necessary because objects or camera may have moved.
+				if (physics_has_last_mousepos) {
+					// if no mouse event exists, create a motion one. This is necessary because objects or camera may have moved.
 					// while this extra event is sent, it is checked if both camera and last object and last ID did not move. If nothing changed, the event is discarded to avoid flooding with unnecessary motion events every frame
-					bool has_mouse_motion = false;
+					bool has_mouse_event = false;
 					for (List<Ref<InputEvent> >::Element *E = physics_picking_events.front(); E; E = E->next()) {
-						Ref<InputEventMouseMotion> mm = E->get();
-						if (mm.is_valid()) {
-							has_mouse_motion = true;
+						Ref<InputEventMouse> m = E->get();
+						if (m.is_valid()) {
+							has_mouse_event = true;
 							break;
 						}
 					}
 
-					if (!has_mouse_motion && physics_has_last_mousepos) {
+					if (!has_mouse_event) {
 						Ref<InputEventMouseMotion> mm;
 						mm.instance();
 						mm->set_global_position(physics_last_mousepos);
@@ -450,21 +426,21 @@ void Viewport::_notification(int p_what) {
 					}
 				}
 
-				bool motion_tested = false;
-
 				while (physics_picking_events.size()) {
 
 					Ref<InputEvent> ev = physics_picking_events.front()->get();
 					physics_picking_events.pop_front();
 
 					Vector2 pos;
+					bool is_mouse = false;
 
 					Ref<InputEventMouseMotion> mm = ev;
 
 					if (mm.is_valid()) {
 
 						pos = mm->get_position();
-						motion_tested = true;
+						is_mouse = true;
+
 						physics_has_last_mousepos = true;
 						physics_last_mousepos = pos;
 						physics_last_mouse_state.alt = mm->get_alt();
@@ -477,7 +453,12 @@ void Viewport::_notification(int p_what) {
 					Ref<InputEventMouseButton> mb = ev;
 
 					if (mb.is_valid()) {
+
 						pos = mb->get_position();
+						is_mouse = true;
+
+						physics_has_last_mousepos = true;
+						physics_last_mousepos = pos;
 						physics_last_mouse_state.alt = mb->get_alt();
 						physics_last_mouse_state.shift = mb->get_shift();
 						physics_last_mouse_state.control = mb->get_control();
@@ -487,6 +468,11 @@ void Viewport::_notification(int p_what) {
 							physics_last_mouse_state.mouse_mask |= (1 << (mb->get_button_index() - 1));
 						} else {
 							physics_last_mouse_state.mouse_mask &= ~(1 << (mb->get_button_index() - 1));
+
+							// If touch mouse raised, assume we don't know last mouse pos until new events come
+							if (mb->get_device() == -1) {
+								physics_has_last_mousepos = false;
+							}
 						}
 					}
 
@@ -540,12 +526,14 @@ void Viewport::_notification(int p_what) {
 									CollisionObject2D *co = Object::cast_to<CollisionObject2D>(res[i].collider);
 									if (co) {
 
-										Map<ObjectID, uint64_t>::Element *F = physics_2d_mouseover.find(res[i].collider_id);
-										if (!F) {
-											F = physics_2d_mouseover.insert(res[i].collider_id, frame);
-											co->_mouse_enter();
-										} else {
-											F->get() = frame;
+										if (is_mouse) {
+											Map<ObjectID, uint64_t>::Element *F = physics_2d_mouseover.find(res[i].collider_id);
+											if (!F) {
+												F = physics_2d_mouseover.insert(res[i].collider_id, frame);
+												co->_mouse_enter();
+											} else {
+												F->get() = frame;
+											}
 										}
 
 										co->_input_event(this, ev, res[i].shape);
@@ -554,25 +542,27 @@ void Viewport::_notification(int p_what) {
 							}
 						}
 
-						List<Map<ObjectID, uint64_t>::Element *> to_erase;
+						if (is_mouse) {
+							List<Map<ObjectID, uint64_t>::Element *> to_erase;
 
-						for (Map<ObjectID, uint64_t>::Element *E = physics_2d_mouseover.front(); E; E = E->next()) {
-							if (E->get() != frame) {
-								Object *o = ObjectDB::get_instance(E->key());
-								if (o) {
+							for (Map<ObjectID, uint64_t>::Element *E = physics_2d_mouseover.front(); E; E = E->next()) {
+								if (E->get() != frame) {
+									Object *o = ObjectDB::get_instance(E->key());
+									if (o) {
 
-									CollisionObject2D *co = Object::cast_to<CollisionObject2D>(o);
-									if (co) {
-										co->_mouse_exit();
+										CollisionObject2D *co = Object::cast_to<CollisionObject2D>(o);
+										if (co) {
+											co->_mouse_exit();
+										}
 									}
+									to_erase.push_back(E);
 								}
-								to_erase.push_back(E);
 							}
-						}
 
-						while (to_erase.size()) {
-							physics_2d_mouseover.erase(to_erase.front()->get());
-							to_erase.pop_front();
+							while (to_erase.size()) {
+								physics_2d_mouseover.erase(to_erase.front()->get());
+								to_erase.pop_front();
+							}
 						}
 					}
 
@@ -634,35 +624,30 @@ void Viewport::_notification(int p_what) {
 									}
 								}
 
-								if (mm.is_valid()) {
-									_test_new_mouseover(new_collider);
-								}
-							}
+								if (is_mouse && new_collider != physics_object_over) {
 
-							last_pos = pos;
-						}
-					}
-				}
+									if (physics_object_over) {
 
-				if (!motion_tested && camera && physics_has_last_mousepos) {
+										CollisionObject *co = Object::cast_to<CollisionObject>(ObjectDB::get_instance(physics_object_over));
+										if (co) {
+											co->_mouse_exit();
+										}
+									}
 
-					//test anyway for mouseenter/exit because objects might move
-					Vector3 from = camera->project_ray_origin(physics_last_mousepos);
-					Vector3 dir = camera->project_ray_normal(physics_last_mousepos);
+									if (new_collider) {
 
-					PhysicsDirectSpaceState *space = PhysicsServer::get_singleton()->space_get_direct_state(find_world()->get_space());
-					if (space) {
+										CollisionObject *co = Object::cast_to<CollisionObject>(ObjectDB::get_instance(new_collider));
+										if (co) {
+											co->_mouse_enter();
+										}
+									}
 
-						bool col = space->intersect_ray(from, from + dir * 10000, result, Set<RID>(), 0xFFFFFFFF, true, true, true);
-						ObjectID new_collider = 0;
-						if (col) {
-							CollisionObject *co = Object::cast_to<CollisionObject>(result.collider);
-							if (co) {
-								new_collider = result.collider_id;
+									physics_object_over = new_collider;
+								}
 							}
-						}
 
-						_test_new_mouseover(new_collider);
+							last_pos = pos;
+						}
 					}
 #endif
 				}
diff --git a/scene/main/viewport.h b/scene/main/viewport.h
index b8b5bf07a7..28a52ac4b6 100644
--- a/scene/main/viewport.h
+++ b/scene/main/viewport.h
@@ -226,7 +226,6 @@ private:
 	bool handle_input_locally;
 	bool local_input_handled;
 
-	void _test_new_mouseover(ObjectID new_collider);
 	Map<ObjectID, uint64_t> physics_2d_mouseover;
 
 	Ref<World2D> world_2d;