Re: Wall Defence game for Apple II

[drHirudo <drhirudo@gmail.com>]

On 24 Апр, 08:58, eriknoc <erik...@yahoo.com> wrote:
> I like the idea of porting games to the Apple II series.  Nice work,
> except it's very difficult to aim & control because he keeps moving,
> and fast, and having to press another direction or key to make him
> stop takes some of the fun away from playing the game IMHO.

I know about this issue, but as mentioned on other posts, on the Apple
II you can read single keypress, but you can not check if the key is
released or not. I think this is an issue in the keyboard controller
of the Apple II.You can not read more keypresses from the same key, or
not until the repeat process starts, where you receive keypresses even
if you clear the strobe. But this introduces keyboard response lag,
which in fast games like Wall Defence it is unacceptable. That's why
there is the joystick control implemented, where you can read the
joystick position anytime, and even different position for the
directions - half and full right for example. I believe this keyboard
problems were the reason some Apple II games where joystick only.
These games were the reason I had Joystick with my Apple 2 clone. On
the other hand I saw some Joystick only games hacked to work with
keyboard, but this was rare.

>  Is this
> how it works on ports to all the other systems?  I would have made it
> to where letting go of a key or direction would make you stop and
> holding it down would make you go.

It is this way on the Vic-20. When I port some game, I don't just do
straight port. I take into account the pecularities of the machine and
take advantage of the them. Unfortunally, with different machines,
some features had to go, or other new features are added. For example
I will not make graphics for CPM game, because there is no standard
graphic output there. Only texts with some control characters, despite
the different terminals available.

> That would make more sense to me
> anyways.

I remember the game Montezuma's Revenge on the Apple II was kind of
able to read exact keypress and keyreleases. When I asked an assembler
guru some twenty years ago, how it was done for this particular game,
his answer was: Because the game is slow, you can not see the
difference when the key-repeat had started, so you beleive that it can
detect keyrelease.