Add an `OS.is_window_focused()` getter

This makes it possible to know whether the window is focused
at a given time, without having to track the focus state manually
using `NOTIFICATION_WM_FOCUS_IN` and `NOTIFICATION_WM_FOCUS_OUT`.

This partially addresses #33928.

core/bind/core_bind.cpp

@@ -400,6 +400,10 @@ bool _OS::is_window_always_on_top() const {
 	return OS::get_singleton()->is_window_always_on_top();
 }
 
+bool _OS::is_window_focused() const {
+	return OS::get_singleton()->is_window_focused();
+}
+
 void _OS::set_borderless_window(bool p_borderless) {
 	OS::get_singleton()->set_borderless_window(p_borderless);
 }
@@ -1213,6 +1217,7 @@ void _OS::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("is_window_maximized"), &_OS::is_window_maximized);
 	ClassDB::bind_method(D_METHOD("set_window_always_on_top", "enabled"), &_OS::set_window_always_on_top);
 	ClassDB::bind_method(D_METHOD("is_window_always_on_top"), &_OS::is_window_always_on_top);
+	ClassDB::bind_method(D_METHOD("is_window_focused"), &_OS::is_window_focused);
 	ClassDB::bind_method(D_METHOD("request_attention"), &_OS::request_attention);
 	ClassDB::bind_method(D_METHOD("get_real_window_size"), &_OS::get_real_window_size);
 	ClassDB::bind_method(D_METHOD("center_window"), &_OS::center_window);

core/bind/core_bind.h

@@ -198,6 +198,7 @@ public:
 	virtual bool is_window_maximized() const;
 	virtual void set_window_always_on_top(bool p_enabled);
 	virtual bool is_window_always_on_top() const;
+	virtual bool is_window_focused() const;
 	virtual void request_attention();
 	virtual void center_window();
 	virtual void move_window_to_foreground();

core/os/os.h

@@ -217,6 +217,7 @@ public:
 	virtual bool is_window_maximized() const { return true; }
 	virtual void set_window_always_on_top(bool p_enabled) {}
 	virtual bool is_window_always_on_top() const { return false; }
+	virtual bool is_window_focused() const { return true; }
 	virtual void set_console_visible(bool p_enabled) {}
 	virtual bool is_console_visible() const { return false; }
 	virtual void request_attention() {}

doc/classes/OS.xml

@@ -636,6 +636,14 @@
 				Returns [code]true[/code] if the window should always be on top of other windows.
 			</description>
 		</method>
+		<method name="is_window_focused" qualifiers="const">
+			<return type="bool">
+			</return>
+			<description>
+				Returns [code]true[/code] if the window is currently focused.
+				[b]Note:[/b] Only implemented on desktop platforms. On other platforms, it will always return [code]true[/code].
+			</description>
+		</method>
 		<method name="kill">
 			<return type="int" enum="Error">
 			</return>

platform/osx/os_osx.h

@@ -124,6 +124,7 @@ public:
 	bool maximized;
 	bool zoomed;
 	bool resizable;
+	bool window_focused;
 
 	Size2 window_size;
 	Rect2 restore_rect;
@@ -277,6 +278,7 @@ public:
 	virtual bool is_window_maximized() const;
 	virtual void set_window_always_on_top(bool p_enabled);
 	virtual bool is_window_always_on_top() const;
+	virtual bool is_window_focused() const;
 	virtual void request_attention();
 	virtual String get_joy_guid(int p_device) const;
 

platform/osx/os_osx.mm

@@ -397,9 +397,6 @@ static Vector2 get_mouse_pos(NSPoint locationInWindow, CGFloat backingScaleFacto
 }
 
 - (void)windowDidBecomeKey:(NSNotification *)notification {
-	//_GodotInputWindowFocus(window, GL_TRUE);
-	//_GodotPlatformSetCursorMode(window, window->cursorMode);
-
 	if (OS_OSX::singleton->get_main_loop()) {
 		get_mouse_pos(
 				[OS_OSX::singleton->window_object mouseLocationOutsideOfEventStream],
@@ -408,25 +405,31 @@ static Vector2 get_mouse_pos(NSPoint locationInWindow, CGFloat backingScaleFacto
 
 		OS_OSX::singleton->get_main_loop()->notification(MainLoop::NOTIFICATION_WM_FOCUS_IN);
 	}
+
+	OS_OSX::singleton->window_focused = true;
 }
 
 - (void)windowDidResignKey:(NSNotification *)notification {
-	//_GodotInputWindowFocus(window, GL_FALSE);
-	//_GodotPlatformSetCursorMode(window, Godot_CURSOR_NORMAL);
 	if (OS_OSX::singleton->get_main_loop())
 		OS_OSX::singleton->get_main_loop()->notification(MainLoop::NOTIFICATION_WM_FOCUS_OUT);
+
+	OS_OSX::singleton->window_focused = false;
 }
 
 - (void)windowDidMiniaturize:(NSNotification *)notification {
 	OS_OSX::singleton->wm_minimized(true);
 	if (OS_OSX::singleton->get_main_loop())
 		OS_OSX::singleton->get_main_loop()->notification(MainLoop::NOTIFICATION_WM_FOCUS_OUT);
+
+	OS_OSX::singleton->window_focused = false;
 };
 
 - (void)windowDidDeminiaturize:(NSNotification *)notification {
 	OS_OSX::singleton->wm_minimized(false);
 	if (OS_OSX::singleton->get_main_loop())
 		OS_OSX::singleton->get_main_loop()->notification(MainLoop::NOTIFICATION_WM_FOCUS_IN);
+
+	OS_OSX::singleton->window_focused = true;
 };
 
 @end
@@ -2618,6 +2621,10 @@ bool OS_OSX::is_window_always_on_top() const {
 	return [window_object level] == NSFloatingWindowLevel;
 }
 
+bool OS_OSX::is_window_focused() const {
+	return window_focused;
+}
+
 void OS_OSX::request_attention() {
 
 	[NSApp requestUserAttention:NSCriticalRequest];
@@ -3070,6 +3077,7 @@ OS_OSX::OS_OSX() {
 	window_size = Vector2(1024, 600);
 	zoomed = false;
 	resizable = false;
+	window_focused = true;
 
 	Vector<Logger *> loggers;
 	loggers.push_back(memnew(OSXTerminalLogger));

platform/windows/os_windows.cpp

@@ -352,12 +352,14 @@ LRESULT OS_Windows::WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 			if (LOWORD(wParam) == WA_ACTIVE || LOWORD(wParam) == WA_CLICKACTIVE) {
 
 				main_loop->notification(MainLoop::NOTIFICATION_WM_FOCUS_IN);
+				window_focused = true;
 				alt_mem = false;
 				control_mem = false;
 				shift_mem = false;
 			} else { // WM_INACTIVE
 				input->release_pressed_events();
 				main_loop->notification(MainLoop::NOTIFICATION_WM_FOCUS_OUT);
+				window_focused = false;
 				alt_mem = false;
 			};
 
@@ -2097,6 +2099,11 @@ bool OS_Windows::is_window_always_on_top() const {
 	return video_mode.always_on_top;
 }
 
+bool OS_Windows::is_window_focused() const {
+
+	return window_focused;
+}
+
 void OS_Windows::set_console_visible(bool p_enabled) {
 	if (console_visible == p_enabled)
 		return;
@@ -3374,6 +3381,7 @@ OS_Windows::OS_Windows(HINSTANCE _hInstance) {
 	meta_mem = false;
 	minimized = false;
 	was_maximized = false;
+	window_focused = true;
 	console_visible = IsWindowVisible(GetConsoleWindow());
 
 	//Note: Functions for pen input, available on Windows 8+

platform/windows/os_windows.h

@@ -276,6 +276,7 @@ protected:
 	bool maximized;
 	bool minimized;
 	bool borderless;
+	bool window_focused;
 	bool console_visible;
 	bool was_maximized;
 
@@ -324,6 +325,7 @@ public:
 	virtual bool is_window_maximized() const;
 	virtual void set_window_always_on_top(bool p_enabled);
 	virtual bool is_window_always_on_top() const;
+	virtual bool is_window_focused() const;
 	virtual void set_console_visible(bool p_enabled);
 	virtual bool is_console_visible() const;
 	virtual void request_attention();

platform/x11/os_x11.cpp

@@ -1689,6 +1689,10 @@ bool OS_X11::is_window_always_on_top() const {
 	return current_videomode.always_on_top;
 }
 
+bool OS_X11::is_window_focused() const {
+	return window_focused;
+}
+
 void OS_X11::set_borderless_window(bool p_borderless) {
 
 	if (get_borderless_window() == p_borderless)
@@ -2281,6 +2285,8 @@ void OS_X11::process_xevents() {
 				minimized = false;
 				window_has_focus = true;
 				main_loop->notification(MainLoop::NOTIFICATION_WM_FOCUS_IN);
+				window_focused = true;
+
 				if (mouse_mode_grab) {
 					// Show and update the cursor if confined and the window regained focus.
 					if (mouse_mode == MOUSE_MODE_CONFINED)
@@ -2308,6 +2314,7 @@ void OS_X11::process_xevents() {
 				window_has_focus = false;
 				input->release_pressed_events();
 				main_loop->notification(MainLoop::NOTIFICATION_WM_FOCUS_OUT);
+				window_focused = false;
 
 				if (mouse_mode_grab) {
 					//dear X11, I try, I really try, but you never work, you do whathever you want.
@@ -3502,6 +3509,7 @@ OS_X11::OS_X11() {
 	xi.last_relative_time = 0;
 	layered_window = false;
 	minimized = false;
+	window_focused = true;
 	xim_style = 0L;
 	mouse_mode = MOUSE_MODE_VISIBLE;
 }

platform/x11/os_x11.h

@@ -198,6 +198,7 @@ class OS_X11 : public OS_Unix {
 
 	int video_driver_index;
 	bool maximized;
+	bool window_focused;
 	//void set_wm_border(bool p_enabled);
 	void set_wm_fullscreen(bool p_enabled);
 	void set_wm_above(bool p_enabled);
@@ -287,6 +288,7 @@ public:
 	virtual bool is_window_maximized() const;
 	virtual void set_window_always_on_top(bool p_enabled);
 	virtual bool is_window_always_on_top() const;
+	virtual bool is_window_focused() const;
 	virtual void request_attention();
 
 	virtual void set_borderless_window(bool p_borderless);