Fix Determining Window for Touchscreen

DisplayServer::screen_is_touchscreen will likely never utilize its
parameter p_screen.
This PR replaces this function by DisplayServer::is_touchscreen_available()
with the same functionality.
This solves the problem, that a SubViewport was used for determining
the screen, which resulted in error messages.

doc/classes/DisplayServer.xml

@@ -719,6 +719,12 @@
 				[b]Note:[/b] This method is implemented on macOS, Windows and Linux (X11).
 			</description>
 		</method>
+		<method name="is_touchscreen_available" qualifiers="const">
+			<return type="bool" />
+			<description>
+				Returns [code]true[/code] if touch events are available (Android or iOS), the capability is detected on the Webplatform or if [member ProjectSettings.input_devices/pointing/emulate_touch_from_mouse] is [code]true[/code].
+			</description>
+		</method>
 		<method name="keyboard_get_current_layout" qualifiers="const">
 			<return type="int" />
 			<description>
@@ -889,13 +895,6 @@
 				Returns [code]true[/code] if the screen should never be turned off by the operating system's power-saving measures. See also [method screen_set_keep_on].
 			</description>
 		</method>
-		<method name="screen_is_touchscreen" qualifiers="const">
-			<return type="bool" />
-			<param index="0" name="screen" type="int" default="-1" />
-			<description>
-				Returns [code]true[/code] if the screen can send touch events or if [member ProjectSettings.input_devices/pointing/emulate_touch_from_mouse] is [code]true[/code].
-			</description>
-		</method>
 		<method name="screen_set_keep_on">
 			<return type="void" />
 			<param index="0" name="enable" type="bool" />

editor/editor_node.cpp

@@ -6038,14 +6038,7 @@ EditorNode::EditorNode() {
 	Input *id = Input::get_singleton();
 
 	if (id) {
-		bool found_touchscreen = false;
-		for (int i = 0; i < DisplayServer::get_singleton()->get_screen_count(); i++) {
-			if (DisplayServer::get_singleton()->screen_is_touchscreen(i)) {
-				found_touchscreen = true;
-			}
-		}
-
-		if (!found_touchscreen && Input::get_singleton()) {
+		if (!DisplayServer::get_singleton()->is_touchscreen_available() && Input::get_singleton()) {
 			// Only if no touchscreen ui hint, disable emulation just in case.
 			id->set_emulate_touch_from_mouse(false);
 		}

editor/plugins/node_3d_editor_plugin.cpp

@@ -8420,7 +8420,7 @@ Node3DEditor::Node3DEditor() {
 	EDITOR_DEF("editors/3d/manipulator_gizmo_opacity", 0.9);
 	EditorSettings::get_singleton()->add_property_hint(PropertyInfo(Variant::FLOAT, "editors/3d/manipulator_gizmo_opacity", PROPERTY_HINT_RANGE, "0,1,0.01"));
 	EDITOR_DEF_RST("editors/3d/navigation/show_viewport_rotation_gizmo", true);
-	EDITOR_DEF_RST("editors/3d/navigation/show_viewport_navigation_gizmo", DisplayServer::get_singleton()->screen_is_touchscreen());
+	EDITOR_DEF_RST("editors/3d/navigation/show_viewport_navigation_gizmo", DisplayServer::get_singleton()->is_touchscreen_available());
 
 	current_hover_gizmo_handle = -1;
 	current_hover_gizmo_handle_secondary = false;

main/main.cpp

@@ -2233,13 +2233,7 @@ Error Main::setup2(Thread::ID p_main_tid_override) {
 
 		if (bool(GLOBAL_DEF("input_devices/pointing/emulate_touch_from_mouse", false)) &&
 				!(editor || project_manager)) {
-			bool found_touchscreen = false;
-			for (int i = 0; i < DisplayServer::get_singleton()->get_screen_count(); i++) {
-				if (DisplayServer::get_singleton()->screen_is_touchscreen(i)) {
-					found_touchscreen = true;
-				}
-			}
-			if (!found_touchscreen) {
+			if (!DisplayServer::get_singleton()->is_touchscreen_available()) {
 				//only if no touchscreen ui hint, set emulation
 				id->set_emulate_touch_from_mouse(true);
 			}

platform/android/display_server_android.cpp

@@ -221,7 +221,7 @@ float DisplayServerAndroid::screen_get_refresh_rate(int p_screen) const {
 	return godot_io_java->get_screen_refresh_rate(SCREEN_REFRESH_RATE_FALLBACK);
 }
 
-bool DisplayServerAndroid::screen_is_touchscreen(int p_screen) const {
+bool DisplayServerAndroid::is_touchscreen_available() const {
 	return true;
 }
 

platform/android/display_server_android.h

@@ -121,7 +121,7 @@ public:
 	virtual int screen_get_dpi(int p_screen = SCREEN_OF_MAIN_WINDOW) const override;
 	virtual float screen_get_scale(int p_screen = SCREEN_OF_MAIN_WINDOW) const override;
 	virtual float screen_get_refresh_rate(int p_screen = SCREEN_OF_MAIN_WINDOW) const override;
-	virtual bool screen_is_touchscreen(int p_screen = SCREEN_OF_MAIN_WINDOW) const override;
+	virtual bool is_touchscreen_available() const override;
 
 	virtual void virtual_keyboard_show(const String &p_existing_text, const Rect2 &p_screen_rect = Rect2(), VirtualKeyboardType p_type = KEYBOARD_TYPE_DEFAULT, int p_max_length = -1, int p_cursor_start = -1, int p_cursor_end = -1) override;
 	virtual void virtual_keyboard_hide() override;

platform/ios/display_server_ios.h

@@ -199,7 +199,7 @@ public:
 	virtual void window_set_vsync_mode(DisplayServer::VSyncMode p_vsync_mode, WindowID p_window = MAIN_WINDOW_ID) override;
 	virtual DisplayServer::VSyncMode window_get_vsync_mode(WindowID p_vsync_mode) const override;
 
-	virtual bool screen_is_touchscreen(int p_screen) const override;
+	virtual bool is_touchscreen_available() const override;
 
 	virtual void virtual_keyboard_show(const String &p_existing_text, const Rect2 &p_screen_rect, VirtualKeyboardType p_type, int p_max_length, int p_cursor_start, int p_cursor_end) override;
 	virtual void virtual_keyboard_hide() override;

platform/ios/display_server_ios.mm

@@ -581,7 +581,7 @@ bool DisplayServerIOS::can_any_window_draw() const {
 	return true;
 }
 
-bool DisplayServerIOS::screen_is_touchscreen(int p_screen) const {
+bool DisplayServerIOS::is_touchscreen_available() const {
 	return true;
 }
 

platform/web/display_server_web.cpp

@@ -579,8 +579,8 @@ void DisplayServerWeb::touch_callback(int p_type, int p_count) {
 	}
 }
 
-bool DisplayServerWeb::screen_is_touchscreen(int p_screen) const {
-	return godot_js_display_touchscreen_is_available();
+bool DisplayServerWeb::is_touchscreen_available() const {
+	return godot_js_display_touchscreen_is_available() || (Input::get_singleton() && Input::get_singleton()->is_emulating_touch_from_mouse());
 }
 
 // Virtual Keyboard

platform/web/display_server_web.h

@@ -143,7 +143,7 @@ public:
 	virtual Point2i mouse_get_position() const override;
 
 	// touch
-	virtual bool screen_is_touchscreen(int p_screen = SCREEN_OF_MAIN_WINDOW) const override;
+	virtual bool is_touchscreen_available() const override;
 
 	// clipboard
 	virtual void clipboard_set(const String &p_text) override;

scene/2d/touch_screen_button.cpp

@@ -100,7 +100,7 @@ void TouchScreenButton::_notification(int p_what) {
 			if (!is_inside_tree()) {
 				return;
 			}
-			if (!Engine::get_singleton()->is_editor_hint() && !!DisplayServer::get_singleton()->screen_is_touchscreen(DisplayServer::get_singleton()->window_get_current_screen(get_viewport()->get_window_id())) && visibility == VISIBILITY_TOUCHSCREEN_ONLY) {
+			if (!Engine::get_singleton()->is_editor_hint() && !!DisplayServer::get_singleton()->is_touchscreen_available() && visibility == VISIBILITY_TOUCHSCREEN_ONLY) {
 				return;
 			}
 
@@ -137,7 +137,7 @@ void TouchScreenButton::_notification(int p_what) {
 		} break;
 
 		case NOTIFICATION_ENTER_TREE: {
-			if (!Engine::get_singleton()->is_editor_hint() && !!DisplayServer::get_singleton()->screen_is_touchscreen(DisplayServer::get_singleton()->window_get_current_screen(get_viewport()->get_window_id())) && visibility == VISIBILITY_TOUCHSCREEN_ONLY) {
+			if (!Engine::get_singleton()->is_editor_hint() && !!DisplayServer::get_singleton()->is_touchscreen_available() && visibility == VISIBILITY_TOUCHSCREEN_ONLY) {
 				return;
 			}
 			queue_redraw();

scene/gui/scroll_bar.cpp

@@ -550,7 +550,7 @@ void ScrollBar::_drag_node_input(const Ref<InputEvent> &p_input) {
 			drag_node_accum = Vector2();
 			last_drag_node_accum = Vector2();
 			drag_node_from = Vector2(orientation == HORIZONTAL ? get_value() : 0, orientation == VERTICAL ? get_value() : 0);
-			drag_node_touching = DisplayServer::get_singleton()->screen_is_touchscreen(DisplayServer::get_singleton()->window_get_current_screen(get_viewport()->get_window_id()));
+			drag_node_touching = DisplayServer::get_singleton()->is_touchscreen_available();
 			drag_node_touching_deaccel = false;
 			time_since_motion = 0;
 

scene/gui/scroll_container.cpp

@@ -164,8 +164,8 @@ void ScrollContainer::gui_input(const Ref<InputEvent> &p_gui_input) {
 			}
 		}
 
-		bool screen_is_touchscreen = DisplayServer::get_singleton()->screen_is_touchscreen(DisplayServer::get_singleton()->window_get_current_screen(get_viewport()->get_window_id()));
-		if (!screen_is_touchscreen) {
+		bool is_touchscreen_available = DisplayServer::get_singleton()->is_touchscreen_available();
+		if (!is_touchscreen_available) {
 			return;
 		}
 

scene/gui/tree.cpp

@@ -3671,7 +3671,7 @@ void Tree::gui_input(const Ref<InputEvent> &p_event) {
 					drag_accum = 0;
 					//last_drag_accum=0;
 					drag_from = v_scroll->get_value();
-					drag_touching = DisplayServer::get_singleton()->screen_is_touchscreen(DisplayServer::get_singleton()->window_get_current_screen(get_viewport()->get_window_id()));
+					drag_touching = DisplayServer::get_singleton()->is_touchscreen_available();
 					drag_touching_deaccel = false;
 					if (drag_touching) {
 						set_physics_process_internal(true);

servers/display_server.cpp

@@ -367,8 +367,7 @@ float DisplayServer::screen_get_scale(int p_screen) const {
 	return 1.0f;
 };
 
-bool DisplayServer::screen_is_touchscreen(int p_screen) const {
-	//return false;
+bool DisplayServer::is_touchscreen_available() const {
 	return Input::get_singleton() && Input::get_singleton()->is_emulating_touch_from_mouse();
 }
 
@@ -618,7 +617,7 @@ void DisplayServer::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("screen_get_usable_rect", "screen"), &DisplayServer::screen_get_usable_rect, DEFVAL(SCREEN_OF_MAIN_WINDOW));
 	ClassDB::bind_method(D_METHOD("screen_get_dpi", "screen"), &DisplayServer::screen_get_dpi, DEFVAL(SCREEN_OF_MAIN_WINDOW));
 	ClassDB::bind_method(D_METHOD("screen_get_scale", "screen"), &DisplayServer::screen_get_scale, DEFVAL(SCREEN_OF_MAIN_WINDOW));
-	ClassDB::bind_method(D_METHOD("screen_is_touchscreen", "screen"), &DisplayServer::screen_is_touchscreen, DEFVAL(SCREEN_OF_MAIN_WINDOW));
+	ClassDB::bind_method(D_METHOD("is_touchscreen_available"), &DisplayServer::is_touchscreen_available, DEFVAL(SCREEN_OF_MAIN_WINDOW));
 	ClassDB::bind_method(D_METHOD("screen_get_max_scale"), &DisplayServer::screen_get_max_scale);
 	ClassDB::bind_method(D_METHOD("screen_get_refresh_rate", "screen"), &DisplayServer::screen_get_refresh_rate, DEFVAL(SCREEN_OF_MAIN_WINDOW));
 

servers/display_server.h

@@ -262,7 +262,7 @@ public:
 		return scale;
 	}
 	virtual float screen_get_refresh_rate(int p_screen = SCREEN_OF_MAIN_WINDOW) const = 0;
-	virtual bool screen_is_touchscreen(int p_screen = SCREEN_OF_MAIN_WINDOW) const;
+	virtual bool is_touchscreen_available() const;
 
 	// Keep the ScreenOrientation enum values in sync with the `display/window/handheld/orientation`
 	// project setting hint.