VIEW* camera1= //camera player1
{
layer=15;
arc=110;
}

VIEW* camera2= //camera player2
{
layer=15;
arc=110;
}

.......

//call that in your main-function

//define new views (splitted like in HALO)
camera1.pos_x=0;
camera1.pos_y=0;
camera1.size_x=screen_size.x;
camera1.size_y=screen_size.y/2;
camera2.pos_x=0;
camera2.pos_y=screen_size.y/2;
camera2.size_x=screen_size.x;
camera2.size_y=screen_size.y/2;

//activate new views and deactivate the old camera

reset(camera,SHOW|AUDIBLE);
set(camera1,SHOW);
set(camera2,SHOW);