Function MainLoop

source/core/mainloop.cpp:727–791

//==========================================================================

void MainLoop ()
{
	int lasttic = 0;

	// Clamp the timer to TICRATE until the playloop has been entered.
	r_NoInterpolate = true;

	if (userConfig.CommandMap.IsNotEmpty())
	{
		auto maprecord = FindMapByName(userConfig.CommandMap.GetChars());
		if (maprecord == nullptr)
		{
			maprecord = SetupUserMap(userConfig.CommandMap.GetChars(), g_gameType & GAMEFLAG_DUKE? "dethtoll.mid" : nullptr);
		}
		userConfig.CommandMap = "";
		if (maprecord)
		{
			DeferredStartGame(maprecord, g_nextskill);
		}
	}

	for (;;)
	{
		try
		{
			// frame syncronous IO operations
			if (gametic > lasttic)
			{
				lasttic = gametic;
				I_StartFrame ();
			}
			I_SetFrameTime();

			// update the scale factor for unsynchronised input here.
			gameInput.UpdateInputScale();

			TryRunTics (); // will run at least one tic
			// Update display, next frame, with current state.
			I_StartTic();

			Display();
			Mus_UpdateMusic();		// must be at the end.
		}
		catch (CRecoverableError &error)
		{
			if (error.GetMessage ())
			{
				Printf (PRINT_BOLD, "\n%s\n", error.GetMessage());
			}
			gi->ErrorCleanup();
			M_ClearMenus();
			C_FullConsole();
			gameaction = ga_nothing;
		}
		catch (CVMAbortException &error)
		{
			error.MaybePrintMessage();
			Printf("%s", error.stacktrace.GetChars());