> >a) explosions. Explosions for just about everything should be possible.
>
> I wouldn't be sure about explosions for invaders. That part of the kernel
> is rather busy.
I would know, I wrote the darn thing about fifteen times :) Don't try ti
figure it out... it works, don't mess with it :) Exploding invaders is
out of the question. About the only thing you could do is set the missile
to 8 clocks wide off the screen, then display it on alternating frames
with cycling colors. This doesn't involve changing the kernel during
invader display - all it involves is setting the missile X and Y
coordinates, and changing the color register, all of which can be done
offscreen.
> >b) better score. By advice would be to go with (if this is possible) an
> >interlaced 6-char so you can get a nice tight font on either side.
>
> I agree, I don't like the "combat" text anymore..
Especially since the last number is hardcoded as a zero :) I didn't want
to fight with a multiple-copy-player display routine just yet, so I did
the combat playfield text thing.
> >Something approximating the Taito text look would be nice, plus the "100"
> >when you blow up the saucer.
>
> The saucer score wouldn't be a problem, if.. (see below)
I thought I already put in the sprites for the 50, 100, 150, 300 for the
saucer, and had a mechanism to display different frames (so that a score
can be displayed instead of the saucer by changing one variable)... guess
I didn't?
> As I was saying, it depends on what can still be added to the
> invaders-block part of the kernel.
Nothing. Don't try. :) On the scanlines where invaders are actually
displayed, I didn't even check the missiles at all... I check to turn it
on or off on the first scanline before and last scanline after each row of
invaders. I need *all* the cycles to display the invaders - I don't even
WSYNC on three of the six scanlines for each row.
> ..there's almost no free RAM! More features, like variations, or things
> like animated explosions, sound effects, need RAM locations for their
> counters and flags.
> (Here's why the original Atari Space Invaders has only 3 shields... they
> hadn't enough RAM for the 4th shield, IMO) Think that I had some troubles
> to find the ram just for the few features I've added.
Are you still storing the shields as four blocks of eight bytes each?
That could easily be changed to four bytes per shield, displaying each
byte on two scanlines. And it'd be closer to the arcade because it'd take
four shots to break through theshield instead of eight. This gets you
sixteen bytes of RAM ifyou haven't done it already.
> Someone else should take care of the score, and write an interlaced,
> hi-res, twin scores display routine...
I currently score the scores as two bytes of BCD (four digits) if that
helps...
> The rest wouldn't be so hard, if there are enough processor cycles left in
> the kernel lines.
But there aren't :) Flickering a missile is the only way to add
*anything* to the invaders kernel without rewriting it for the sixteenth
time.
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