function scr_become_dark()
{
    global.darkzone = 1;
    global.hp[1] = ceil((global.lhp / global.lmaxhp) * global.maxhp[1]);
    if (global.hp[1] < 1)
        global.hp[1] = 1;
    if (global.hp[1] > global.maxhp[1])
        global.hp[1] = global.maxhp[1];
}