Add check to pause game on lost window focus

builtin/settingtypes.txt

@@ -536,6 +536,9 @@ fps_max (Maximum FPS) int 60
 #    Maximum FPS when game is paused.
 pause_fps_max (FPS in pause menu) int 20
 
+#    Open the pause menu when the window's focus is lost. Does not pause if a formspec is open.
+pause_on_lost_focus (Pause on lost window focus) bool false
+
 #    View distance in nodes.
 viewing_range (Viewing range) int 100 20 4000
 

minetest.conf.example

@@ -994,6 +994,10 @@
 #    type: int
 # max_out_chat_queue_size = 20
 
+#    Open the pause menu when the window's focus is lost. Does not pause if a formspec is open.
+#    type: bool
+# pause_on_lost_focus = false
+
 ## Advanced
 
 #    Timeout for client to remove unused map data from memory.

src/defaultsettings.cpp

@@ -58,6 +58,7 @@ void set_default_settings(Settings *settings)
 	settings->setDefault("enable_remote_media_server", "true");
 	settings->setDefault("enable_client_modding", "false");
 	settings->setDefault("max_out_chat_queue_size", "20");
+	settings->setDefault("pause_on_lost_focus", "false");
 
 	// Keymap
 	settings->setDefault("remote_port", "30000");

src/game.cpp

@@ -1487,6 +1487,8 @@ class Game {
 	bool m_first_loop_after_window_activation = false;
 	bool m_camera_offset_changed = false;
 
+	bool m_does_lost_focus_pause_game = false;
+
 #ifdef __ANDROID__
 	bool m_cache_hold_aux1;
 	bool m_android_chat_open;
@@ -1741,6 +1743,10 @@ void Game::run()
 
 		// Update if minimap has been disabled by the server
 		flags.show_minimap &= client->shouldShowMinimap();
+
+		if (m_does_lost_focus_pause_game && !device->isWindowFocused() && !isMenuActive()) {
+			showPauseMenu();
+		}
 	}
 }
 
@@ -4638,6 +4644,7 @@ void Game::readSettings()
 	m_cache_cam_smoothing = rangelim(m_cache_cam_smoothing, 0.01f, 1.0f);
 	m_cache_mouse_sensitivity = rangelim(m_cache_mouse_sensitivity, 0.001, 100.0);
 
+	m_does_lost_focus_pause_game = g_settings->getBool("pause_on_lost_focus");
 }
 
 /****************************************************************************/