Function loop

source/src/world.cpp:681–691

bool worldbordercheck(int x1, int x2, int y1, int y2, int z1, int z2)  // check for solid world border
{
    loop(x, ssize) loop(y, ssize)
    {
        if(x >= x1 && x < ssize - x2 && y >= y1 && y < ssize - y2)
        {
            if(S(x,y)->type != SOLID && (S(x,y)->ceil > 126 - z1 || S(x,y)->floor < -127 + z2)) return false;
        }
        else
        {
            if(S(x,y)->type != SOLID) return false;
        }
    }
    return true;
}