Implement universal translation of touch to mouse

Now generating mouse events from touch is optional (on by default) and it's performed by `InputDefault` instead of having each OS abstraction doing it. (*)

The translation algorithm waits for a touch index to be pressed and tracks it translating its events to mouse events until it is raised, while ignoring other pointers.

Furthermore, to avoid an stuck "touch mouse", since not all platforms may report touches raised when the window is unfocused, it checks if touches are still down by the time it's focused again and if so it resets the state of the emulated mouse.

*: In the case of Windows, since it already provides touch-to-mouse translation by itself, "echo" mouse events are filtered out to have it working like the rest.

On X11 a little hack has been needed to avoid a case of a spurious mouse motion event that is generated during touch interaction.

Plus: Improve/fix tracking of current mouse position.

** Summary of changes to settings: **

- `display/window/handheld/emulate_touchscreen` becomes `input/pointing_devices/emulate_touch_from_mouse`
- New setting: `input/pointing_devices/emulate_mouse_from_touch`

3 files changed, 13 insertions, 47 deletions

diff --git a/platform/iphone/gl_view.mm b/platform/iphone/gl_view.mm
index ff95cf6e5f..478a3125af 100644
--- a/platform/iphone/gl_view.mm
+++ b/platform/iphone/gl_view.mm
@@ -497,7 +497,7 @@ static void clear_touches() {
 			int tid = get_touch_id(touch);
 			ERR_FAIL_COND(tid == -1);
 			CGPoint touchPoint = [touch locationInView:self];
-			OSIPhone::get_singleton()->mouse_button(tid, touchPoint.x * self.contentScaleFactor, touchPoint.y * self.contentScaleFactor, true, touch.tapCount > 1, tid == 0);
+			OSIPhone::get_singleton()->touch_press(tid, touchPoint.x * self.contentScaleFactor, touchPoint.y * self.contentScaleFactor, true, touch.tapCount > 1);
 		};
 	};
 }
@@ -514,10 +514,9 @@ static void clear_touches() {
 				continue;
 			int tid = get_touch_id(touch);
 			ERR_FAIL_COND(tid == -1);
-			int first = get_first_id(touch);
 			CGPoint touchPoint = [touch locationInView:self];
 			CGPoint prev_point = [touch previousLocationInView:self];
-			OSIPhone::get_singleton()->mouse_move(tid, prev_point.x * self.contentScaleFactor, prev_point.y * self.contentScaleFactor, touchPoint.x * self.contentScaleFactor, touchPoint.y * self.contentScaleFactor, first == tid);
+			OSIPhone::get_singleton()->touch_drag(tid, prev_point.x * self.contentScaleFactor, prev_point.y * self.contentScaleFactor, touchPoint.x * self.contentScaleFactor, touchPoint.y * self.contentScaleFactor);
 		};
 	};
 }
@@ -533,9 +532,9 @@ static void clear_touches() {
 				continue;
 			int tid = get_touch_id(touch);
 			ERR_FAIL_COND(tid == -1);
-			int rem = remove_touch(touch);
+			remove_touch(touch);
 			CGPoint touchPoint = [touch locationInView:self];
-			OSIPhone::get_singleton()->mouse_button(tid, touchPoint.x * self.contentScaleFactor, touchPoint.y * self.contentScaleFactor, false, false, rem == 0);
+			OSIPhone::get_singleton()->touch_press(tid, touchPoint.x * self.contentScaleFactor, touchPoint.y * self.contentScaleFactor, false, false);
 		};
 	};
 }
diff --git a/platform/iphone/os_iphone.cpp b/platform/iphone/os_iphone.cpp
index 97ebc19335..f618c80a77 100644
--- a/platform/iphone/os_iphone.cpp
+++ b/platform/iphone/os_iphone.cpp
@@ -190,7 +190,7 @@ void OSIPhone::key(uint32_t p_key, bool p_pressed) {
 	queue_event(ev);
 };
 
-void OSIPhone::mouse_button(int p_idx, int p_x, int p_y, bool p_pressed, bool p_doubleclick, bool p_use_as_mouse) {
+void OSIPhone::touch_press(int p_idx, int p_x, int p_y, bool p_pressed, bool p_doubleclick) {
 
 	if (!GLOBAL_DEF("debug/disable_touch", false)) {
 		Ref<InputEventScreenTouch> ev;
@@ -202,28 +202,10 @@ void OSIPhone::mouse_button(int p_idx, int p_x, int p_y, bool p_pressed, bool p_
 		queue_event(ev);
 	};
 
-	mouse_list.pressed[p_idx] = p_pressed;
-
-	if (p_use_as_mouse) {
-
-		Ref<InputEventMouseButton> ev;
-		ev.instance();
-
-		ev->set_position(Vector2(p_x, p_y));
-		ev->set_global_position(Vector2(p_x, p_y));
-
-		//mouse_list.pressed[p_idx] = p_pressed;
-
-		input->set_mouse_position(ev->get_position());
-		ev->set_button_index(BUTTON_LEFT);
-		ev->set_doubleclick(p_doubleclick);
-		ev->set_pressed(p_pressed);
-
-		queue_event(ev);
-	};
+	touch_list.pressed[p_idx] = p_pressed;
 };
 
-void OSIPhone::mouse_move(int p_idx, int p_prev_x, int p_prev_y, int p_x, int p_y, bool p_use_as_mouse) {
+void OSIPhone::touch_drag(int p_idx, int p_prev_x, int p_prev_y, int p_x, int p_y) {
 
 	if (!GLOBAL_DEF("debug/disable_touch", false)) {
 
@@ -234,21 +216,6 @@ void OSIPhone::mouse_move(int p_idx, int p_prev_x, int p_prev_y, int p_x, int p_
 		ev->set_relative(Vector2(p_x - p_prev_x, p_y - p_prev_y));
 		queue_event(ev);
 	};
-
-	if (p_use_as_mouse) {
-		Ref<InputEventMouseMotion> ev;
-		ev.instance();
-
-		ev->set_position(Vector2(p_x, p_y));
-		ev->set_global_position(Vector2(p_x, p_y));
-		ev->set_relative(Vector2(p_x - p_prev_x, p_y - p_prev_y));
-
-		input->set_mouse_position(ev->get_position());
-		ev->set_speed(input->get_last_mouse_speed());
-		ev->set_button_mask(BUTTON_LEFT); // pressed
-
-		queue_event(ev);
-	};
 };
 
 void OSIPhone::queue_event(const Ref<InputEvent> &p_event) {
@@ -262,10 +229,10 @@ void OSIPhone::touches_cancelled() {
 
 	for (int i = 0; i < MAX_MOUSE_COUNT; i++) {
 
-		if (mouse_list.pressed[i]) {
+		if (touch_list.pressed[i]) {
 
 			// send a mouse_up outside the screen
-			mouse_button(i, -1, -1, false, false, false);
+			touch_press(i, -1, -1, false, false);
 		};
 	};
 };
@@ -376,7 +343,7 @@ Point2 OSIPhone::get_mouse_position() const {
 
 int OSIPhone::get_mouse_button_state() const {
 
-	return mouse_list.pressed[0];
+	return 0;
 };
 
 void OSIPhone::set_window_title(const String &p_title){};
diff --git a/platform/iphone/os_iphone.h b/platform/iphone/os_iphone.h
index 00d9efb01a..7d73a6fe5c 100644
--- a/platform/iphone/os_iphone.h
+++ b/platform/iphone/os_iphone.h
@@ -106,7 +106,7 @@ private:
 		};
 	};
 
-	MouseList mouse_list;
+	MouseList touch_list;
 
 	Vector3 last_accel;
 
@@ -127,8 +127,8 @@ public:
 
 	uint8_t get_orientations() const;
 
-	void mouse_button(int p_idx, int p_x, int p_y, bool p_pressed, bool p_doubleclick, bool p_use_as_mouse);
-	void mouse_move(int p_idx, int p_prev_x, int p_prev_y, int p_x, int p_y, bool p_use_as_mouse);
+	void touch_press(int p_idx, int p_x, int p_y, bool p_pressed, bool p_doubleclick);
+	void touch_drag(int p_idx, int p_prev_x, int p_prev_y, int p_x, int p_y);
 	void touches_cancelled();
 	void key(uint32_t p_key, bool p_pressed);
 	void set_virtual_keyboard_height(int p_height);