Screenlock

The original game used an interesting technique to screenlock() screens. All enemies on a screen would have a screenlock(1); command in their main(), and this in their die() procedure:

if (get_sprite_with_this_brain(9, &current_sprite) == 0)
{
    // no more brain 9 monsters here, lets unlock the screen
    screenlock(0);
    playsound(43, 22050,0,0,0);
}

So, once all of the monsters on the screen were dead, the screenlock() would be removed.

This worked well enough... but it is rather annoying to make special screenlock()-versions of existing enemies scripts.

There is a better way to do this. In the map editor, attach the following script to a normal sprite in the scene. Note that the sprite will be made invisible, so you don't just attach it to an existing tree or something.

// scrnlk.c
void main(void)
{
    // Make this sprite invisible
    sp_nodraw(&current_sprite,1);

    // Screenlock the screen
    screenlock(1);

    // Loop forever, until there aren't any sprites with brains 9 and 10 on the screen
    loop:

    wait(250);
    if (get_sprite_with_this_brain(9, 0) == 0)
    {
        if (get_sprite_with_this_brain(10, 0) == 0)
        {
            // Remove the screenlock
            screenlock(0);
            playsound(43, 22050,0,0,0);
            kill_this_task();
        }
    }

    goto loop;
}

Then, if you have a screen with monsters on it, it will automatically perform a screenlock() and remove the screenlock() if all of the monsters are killed. That's as good as we can get, right?

In fact, we can do this a little better. Screenlocks can be a little bit annoying, so what if we had a screenlock() that only appeared the first time the player entered the screen? Thanks to editor_type(), we can do this easily.

// scrnlk1.c
void main(void)
{
    // Make this sprite invisible
    sp_nodraw(&current_sprite,1);
    // Screenlock the screen
    screenlock(1);

    // Loop forever, until there aren't any sprites with brains 9 and 10 on the screen
    loop:
    wait(250);
    if (get_sprite_with_this_brain(9, 0) == 0)
    {
        if (get_sprite_with_this_brain(10, 0) == 0)
        {
            // Remove the screenlock
            screenlock(0);
            playsound(43, 22050,0,0,0);
            // Kill this sprite forever, so there aren't any more screenlocks!
            int &editor_sprite = sp_editor_num(&current_sprite);
            if (&editor_sprite != 0)
            {
                editor_type(&editor_sprite, 1);
            }
            kill_this_task();
        }
    }
    goto loop;
}

Screenlock ​

Screenlock