Re: New Apple II blog

[heuser.marcus@freenet.de]

On Oct 22, 9:09 pm, JJ Sonick <jj.lawre...@gmail.com> wrote:
>
> Oh, and I forgot to say: comments very much welcome here and
> on the blog!

Your first few entries make up for an interesting read!

While learning assembly I found it best to NOT rely too much in typing
in printed example programs. You not only may find errors but they
also
tend to be rather extensive for what they do - and often you don't
have
a real need for these programs or routines. Short assembly programs
can
be as demonstrative and don't take too much of your time.

If the book you currently use doesn't handle hi-res graphics very well
you should look for another one (there are enough out there).
A good read for the budding Apple II graphics programmer is the book
"Graphically Speaking" by Mark Pelczarski (co-programmed "The
Graphics Magician" which was the basis for many graphics adventures)
which not only describes the workings of the hi-res mode but
introduces
you to use assembly with this mode, using simple examples at first
which
slowly get more elaborate in later chapters.

I can't help you much with sound routines but your goal #2 (tile-based
graphics scrolling) is similar to a goal I had three years ago (damn,
you time flies!): A fast enough routine for the Apple hi-res screen.
And yes, "quirky" is a word often attached to the Apple screen modes
because of their funny memory locations and bitmap interpretation.
The hi-res mode also is quite powerful which games like Ultima
exploited
very well: Six colors including a hi-res white while other systems had
their own constraints or needed bigger screen buffers etc.

There are lots of possible solutions for this problem but it
ultimately
(bad pun!) comes down to a memory copy routine - which, obviously,
copies bytes from the tile memory area to the screen buffer.
Of course it's up to the game design how complicated it will be but
for
a space RPG where you don't want to restrict the field of vision like
in Ultima IV it may be rather simple.

I can supply you with an example of a really fast routine but you
should be able to handle it as it needs an infrastructure to operate
- your call, really.

bye
Marcus