Re: [stella] Asymmetrical Reflected Playfield
Subject: Re: [stella] Asymmetrical Reflected Playfield|
From: Glenn Saunders <cybpunks2@xxxxxxxxxxxxx>
Date: Fri, 21 Sep 2001 22:34:51 -0700
At 10:33 PM 9/21/2001 -0400, you wrote:
Have you given thought to stealing from Centipede?
If someone posts a disassembly I'll take a look at it.
What I don't like about that approach is that it forces spaces between the
bricks. Sure, the spaces wind up being small enough that you couldn't
drive a car through them, but it would result in a different play pattern
having them alternated like that.
Also, the tombstones are taller than the mushrooms so the alternating
pattern will be more obvious.
Even if the tombstones are striped I might need two scanlines between rows,
one to increment the PF Ram pointers and the other to keep up with what's
going on with the sprites.
I don't think striping the tombstones will look too bad. It could be
considered a form of dithering to make them more grey. Congo Bongo
attempts something like that for dithering. I might even try doing a
closed venetian blind flicker, or would that drive people insane?
If I need to do a proper PF write on the same scanlines I'm doing the
sprite logic I don't see myself having enough cycles.
As I outlined in an earlier email, I need to perform quite a bit of
conditional evaluation on the sprite scanlines:
1) Do I display P0? If so, how far into the table do I index? Do I need
to turn VDELP0 on?
2) Do I display P1? If so, how far into the table do I index? Do I need
to turn VDELP1 on?
3) Do I display M0? If so, how far into the M0 width/fine-control table do
3) Do I display M1? If so, how far into the M1 width/fine-control table do
THEN I get to write the registers and I need to issue an HMOVE as well for
the missile fine control adjustments to take.
Also, if I want full vertical res for the pedestrian motion I'm going to
have to do have enough time to do the missile routines in the playfield
scanline since there is no VDEL for the missiles.
(Centipede and Millipede compromise vertical motion. Smooth movement is
more important than cosmetics to me.)
Or I could do something even wackier. If I do flicker the venitian blind,
though, I can intelligently determine whether to do odd or even scanlines
to avoid having to change the missiles on a playfield scanline. That would
be pretty sneaky. Or I could just not do the playfield on that one
scanline, have it drop out.
It's too early to tell how it's going to wind up in the end, I guess.
I'll just tackle features one at a time.
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