Re: Relocatable vector games available

On Thu, 16 Mar 2000, Clay Cowgill wrote:
> >
> > And, of course, we all anxiously await the new game that you'll
> > include, Asteroids Lander Deluxe.
> ...
> >Either that, or vector Pong. :)
>
> :-) Ohhhh, see, I already started an exciting new game called "hit a button
> when the little box appears on the screen". The suspense is mind-bending.
> As a matter of fact, the neighbor's kid has been anxiously awaiting the
> little box to appear since Tuesday. Of course, I told him the machine pays
> him $5 if he does it at *exactly* the time the box appears... If he lasts
> through Friday I'll plug the machine in and let him play asteroids for a
> while...

ROFL. (Hmm, actually, Space Zap - even if it's raster - is basically "hit
a button when the little box appears on the screen").

Now that I think about it, it wouldn't be too hard to implement in vector.
(Chalks it in on his "list of cool hacks to develop".)

Asteroids Lander Deluxe would take a bit more work, but wasn't there a
huge thread about implementing gravity a while back? I always wanted to
play Asteroids with an approximation of gravity on the rocks.

There's a finite number of rocks to draw, a finite number of distance-
from-ship comparisons that has to be done. Sorting that list shouldn't be
too bad. Run the gravity algorithm on the five nearest rocks within a
distance of "x" and sum the vectors. Add the vectors onto the ship's
velocity.

For bonus style points, increase the "speed limit" of the ship to allow
the ship to slingshot itself fast enough that it can run into its own
bullets, and get rid of the "friction" effect that slows your ship down
when you release the thrust button. The latter is a one-byte hack (RTS
out the friction routine), the former involves changing the values in a
couple of CMP instructions.

Silly idea: If this becomes too computationally intensive, you have two
options. Cut down on the number of rocks, or speed up the CPU.

The easiest is to limit the number of "big rocks" that can show up on the
screen and thereby limit the number of "little rocks" in the worst-case
scenario.

So here's the really silly idea.

But if the hack involves replacing the CPU and ROM and RAM, it's possible
that the new parts will work fine at higher speeds than originally
designed. (Assuming ROM/RAM is the bottleneck, and not the TTL on the
rest of the board.) Has anyone tried overclocking or underclocking their
6502-based vector games by swapping the crystal? This can't work for
*raster* games because the sync signal is generated from the same clock,
but for vector games, it just might work.

I'm gonna try plugging a 6 MHz crystal into my Asteroids tonight and see
what happens. If the vectors display normally but the game runs slower,
it just might work. (IIRC Asteroids runs at 1 MHz or 1.5 MHz, and the
6502 is rated for 2 MHz. So there just might be some headroom to work
with.)

Later,
Doug.

-- 
 dougj   |
   @     |
hwcn.org |
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