dos33fsprogs/ootw/FAQ
2019-01-27 21:44:47 -05:00

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Q. Are you implementing the game just like the original (i.e. vector
drawing)?
A. No, this is just a quick hack using all sprites.
I'm not doing something amazing like writing a 6502 optimized
vector drawing library.
Q. Is there anything impressive going on here, like with your other demos?
A. No, it's pretty much straight up "sprite" drawing.
One unusual thing is I am using grey2 (color 10) as the transparent
color rather than black, as there is black in the sprites.
It's actually refreshing not having to cycle count.
Q. How are you making the graphics?
A. Using the original for reference (currently a Windows/EGA version
for some reason?) Size down to 80x40. Manually map colors to
Apple II Lo-res palette. Then manually adjust to 40x40.
Finally fine tune in a bit while using original for reference.
Q. Why lores graphics? It's so *horribly* blocky.
A. Yes, but I like it anyway. So many colors!
I spent a lot of time as an ANSI artist so I am used to blocky
16-color graphics, and to be honest with you my art skills sort
of peak at that resolution.
Also Apple II graphics programming is painful and LORES is the
easiest of them all.
Partly nostalgia too, but my family only had a monochrome monitor
so I never got to experience full-color lores back in the day.
Unfortunately this game doesn't really play well in monochrome.
Q. Are you going to make a version using Hi-res or Double Hi-res graphics?
A. No, there's an official version for the Apple IIgs if you want something
like that. Apple II hires graphics with sprites are a huge pain
to program, would probably be slower, and would take up a lot more
RAM.
Q. How about double-lores graphics (80x48)? It would give you almost
square pixels?
A. While not as bad as Hires, double-lores is also a pain. It only
works on the IIe with 128k or newer. Also you now have to copy
things to aux memory, and your sprites have to worry about the
colors being shifted (I think) on the AUX page. It will take
twice the ram and probably run 1/2 the speed.
Also the current code uses page-flipping to avoid flicker/tearing,
but doing page-flipping in double-lores is really tricky.
Q. Why are you targeting such an old machine, an original Apple II or II+?
A. Well, I own one. Also there's something about programming on a machine
from 1977, whose graphics hardware is a glorified shift register,
and is implemented entirely out of 7400 series logic and 555 timers.