Re: [stella] Invaders update! - inv-beta.bin

Subject: Re: [stella] Invaders update! - inv-beta.bin
From: emooney@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx (Erik Mooney)
Date: Fri, 25 Apr 1997 01:03:40 GMT
>>- Invaders now animated!  Each type of invader can cycle through 6 frames
>>of animation.  (must be 6 frames, though it can repeat a 2-frame sequence
>>three times.)  Thanks to all who helped with that concept.  Do the middle
>>two rows of invaders look silly?  If so, how should I change them?
>They don't look too silly.  You might have them change every frame
>instead of every other.  The top row looks a little silly until it
>gets fast.  (Just my opinion.)

I can't do that for the middle row.. the animation has to be a six-frame
cycle, so they can't have four pictures and change every frame.  As for the
top row, what could I do with them?

>>- Shields implemented!  They're on the small side, but I really can't
>>enlarge them any.
>I think they're fine.  Have you considered an extra game variation
>without shields?  It would provide another difficulty level for good

I could do that.  I'll start taking suggestions for game variations at any
time.. I don't plan to have quite 112 of them, though, but something in the
8-30 range is good (three to six variables, with various combinations of

>>Shields disappear when the invaders reach that level.
>And reappear when all the invaders on that level are shot.  (Until
>another row gets down that far.)  You might want to fix that. 

Oops, yeah, I noticed that after I posted the binary. =)

>>- Keeps score!  Well, it's a flat 10 points per invader at the moment, =
>>but it's a start =3D)
>Yes it is!
>>  Also, my score-displaying routine is hardcoded to =
>>display a zero as the ones digit (it's always that way in the game.)
>I think that's fine.  It beats the Pac-Man method of changing the
>scores to ones instead of tens.  You might want to fix it so that the
>player two score is only displayed in two-player mode, though.

That's on my list of things to do.  I have a slight problem in that the
score routine is hardcoded to display a zero, but I want to use the score
to display the game number when game selecting like most games do.  I'll
figure out a way around that somehow.

>>The rates of player fire and
>>invader fire are close to that of the arcade, though not exact.
>And I'd say it's an improvement.  The games a little harder now (which
>is good).

It's about as close as I'm going to get without disassembling the original
Space Invaders code and looking at the timings (which would require
learning Z80 assembler on top of 6502 assembler =) )

>>This worked on PC Atari and on a 4-switch system with Supercharger.. as
>>always, huge thanks to all that helped... comments welcome!
>This version works fine on my 2600 Jr.  No phantom lines!

Cool.  Anyone wanna try it on a 7800 or Coleco?

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