3 files changed, 53 insertions, 0 deletions
diff --git a/platform/linuxbsd/display_server_x11.cpp b/platform/linuxbsd/display_server_x11.cpp
index dc70e7c0c7..ee26abab86 100644
--- a/platform/linuxbsd/display_server_x11.cpp
+++ b/platform/linuxbsd/display_server_x11.cpp
@@ -1819,6 +1819,52 @@ bool DisplayServerX11::_window_maximize_check(WindowID p_window, const char *p_a
 	return retval;
 }
 
+bool DisplayServerX11::_window_fullscreen_check(WindowID p_window) const {
+	ERR_FAIL_COND_V(!windows.has(p_window), false);
+	const WindowData &wd = windows[p_window];
+
+	// Using EWMH -- Extended Window Manager Hints
+	Atom property = XInternAtom(x11_display, "_NET_WM_STATE", False);
+	Atom type;
+	int format;
+	unsigned long len;
+	unsigned long remaining;
+	unsigned char *data = nullptr;
+	bool retval = false;
+
+	if (property == None) {
+		return retval;
+	}
+
+	int result = XGetWindowProperty(
+			x11_display,
+			wd.x11_window,
+			property,
+			0,
+			1024,
+			False,
+			XA_ATOM,
+			&type,
+			&format,
+			&len,
+			&remaining,
+			&data);
+
+	if (result == Success) {
+		Atom *atoms = (Atom *)data;
+		Atom wm_fullscreen = XInternAtom(x11_display, "_NET_WM_STATE_FULLSCREEN", False);
+		for (uint64_t i = 0; i < len; i++) {
+			if (atoms[i] == wm_fullscreen) {
+				retval = true;
+				break;
+			}
+		}
+		XFree(data);
+	}
+
+	return retval;
+}
+
 bool DisplayServerX11::window_is_maximize_allowed(WindowID p_window) const {
 	_THREAD_SAFE_METHOD_
 	return _window_maximize_check(p_window, "_NET_WM_ALLOWED_ACTIONS");
@@ -3611,6 +3657,8 @@ void DisplayServerX11::process_events() {
 			case Expose: {
 				DEBUG_LOG_X11("[%u] Expose window=%lu (%u), count='%u' \n", frame, event.xexpose.window, window_id, event.xexpose.count);
 
+				windows[window_id].fullscreen = _window_fullscreen_check(window_id);
+
 				Main::force_redraw();
 			} break;
 
diff --git a/platform/linuxbsd/display_server_x11.h b/platform/linuxbsd/display_server_x11.h
index 57f6fe80da..9ce6a557db 100644
--- a/platform/linuxbsd/display_server_x11.h
+++ b/platform/linuxbsd/display_server_x11.h
@@ -267,6 +267,7 @@ class DisplayServerX11 : public DisplayServer {
 
 	void _update_real_mouse_position(const WindowData &wd);
 	bool _window_maximize_check(WindowID p_window, const char *p_atom_name) const;
+	bool _window_fullscreen_check(WindowID p_window) const;
 	void _update_size_hints(WindowID p_window);
 	void _set_wm_fullscreen(WindowID p_window, bool p_enabled);
 	void _set_wm_maximized(WindowID p_window, bool p_enabled);
diff --git a/platform/linuxbsd/godot_linuxbsd.cpp b/platform/linuxbsd/godot_linuxbsd.cpp
index 9fe00568fb..91a260182e 100644
--- a/platform/linuxbsd/godot_linuxbsd.cpp
+++ b/platform/linuxbsd/godot_linuxbsd.cpp
@@ -61,6 +61,10 @@ int main(int argc, char *argv[]) {
 	Error err = Main::setup(argv[0], argc - 1, &argv[1]);
 	if (err != OK) {
 		free(cwd);
+
+		if (err == ERR_HELP) { // Returned by --help and --version, so success.
+			return 0;
+		}
 		return 255;
 	}