how to change the day duration?

[Capaverde]

I changed this line in game.cpp

daycycle = 3600;

to

daycycle = 120;

but it doesnt seem to alter anything, I've already waited 120 seconds and its still day

- - - Updated - - -

okay I figure out something

I changed

		case LIGHT_STATE_SUNRISE:
		{
			newlightlevel += (LIGHT_LEVEL_DAY - LIGHT_LEVEL_NIGHT) / 30;
			lightChange = true;
			break;
		}
		case LIGHT_STATE_SUNSET:
		{
			newlightlevel -= (LIGHT_LEVEL_DAY - LIGHT_LEVEL_NIGHT)/30;
			lightChange = true;
			break;
		}

to

		case LIGHT_STATE_SUNRISE:
		{
			newlightlevel += (LIGHT_LEVEL_DAY - LIGHT_LEVEL_NIGHT) *light_hour_delta / 120;
			lightChange = true;
			break;
		}
		case LIGHT_STATE_SUNSET:
		{
			newlightlevel -= (LIGHT_LEVEL_DAY - LIGHT_LEVEL_NIGHT) *light_hour_delta / 120;
			lightChange = true;
			break;
		}

but its weird, I only see the changes if I logout and login again
and when I print getWorldLight() it keeps giving 215 no matter if its day or night