iOS: don't update frames in the background

src/drawscene.cpp

@@ -595,6 +595,11 @@ void draw_load_screen(const std::wstring &text, IrrlichtDevice* device,
 		gui::IGUIEnvironment* guienv, ITextureSource *tsrc,
 		float dtime, int percent, bool clouds)
 {
+#ifdef __IOS__
+	if (device->isWindowMinimized())
+		return;
+#endif
+
 	video::IVideoDriver* driver    = device->getVideoDriver();
 	v2u32 screensize               = porting::getWindowSize();
 

src/game.cpp

@@ -4171,6 +4171,11 @@ void Game::updateFrame(ProfilerGraph *graph, RunStats *stats, f32 dtime,
 		time_of_day_smooth = time_of_day_smooth * (1.0 - todsm)
 				+ time_of_day * todsm;
 
+#ifdef __IOS__
+	if (device->isWindowMinimized())
+		return;
+#endif
+
 	runData.time_of_day = time_of_day;
 	runData.time_of_day_smooth = time_of_day_smooth;
 

src/guiEngine.cpp

@@ -268,6 +268,11 @@ bool GUIEngine::loadMainMenuScript()
 /******************************************************************************/
 void GUIEngine::run()
 {
+#ifdef __IOS__
+	if (m_device->isWindowMinimized())
+		return;
+#endif
+
 	// Always create clouds because they may or may not be
 	// needed based on the game selected
 	// NO!!!