Re: [stella] Alpha version of my game

Subject: Re: [stella] Alpha version of my game
From: emooney@xxxxxxxxxxxxxxxx (Erik Mooney)
Date: Fri, 11 Apr 1997 21:03:54 GMT
>Hmmm.  It might.  At least make them a little more distinctive than
>the two shades of red.  (Of course, I don't know how it will look on
>PAL systems.)
>>To be honest, I've never actually played a coin-op Space Invaders.. I was
>What?!?  How old are you?  Might I suggest grabbing an emulator like
>Sparcade or MAME and the ROMs and taking a look?

*smack* why do I never think of these things?  I already have MAME, too.. I
think the only ROMs I have are Millipede, though.  (I'm 19, btw... my .edu
address should've been a clue I couldn't be too old)

Picked up the Space Invaders ROMs (yeah yeah sue me for piracy) and the
game is more different from TI Invaders than I had thought.  Is the
emulator running really lousy on my system (in Windows), or do the invaders
actually advance one line at a time instead of the whole formation at once?

Looking at this, I can definitely make my game closer to the arcade..
expanding my invaders to twice their current width and raising their height
slightly should make it a lot closer.  I'll also implement collisions
between the player's missile and the bombs.. I wasn't sure if that was in
the arcade or not.

Also, should I attempt to give every game player Atari Thumb all over again
by making the ship only fire when the button is pressed instead of holding
it down? =)  (I've always wondered if I'd do better on Millipede if the
fire button worked this way..)

>Yes, it does.  I haven't seen TI Invaders myself.  Don't be offended
>by the age question.  I just thought it's quite odd that someone who's
>never played Space Invaders is trying to create a more pure 2600
>version of it.

Gotta start somewhere.. I started with a playfield kernel and just worked
from there, and Space Invaders was the first thing I thought of where I
could use the playfield extensively.

>You'l have to do something.  I hate to say it, but you might have to
>rewrite your kernel for two-scanline intervals or something.

I *think* I can rewrite it for three-scanline intervals (raising the
invaders to six lines each with a six-line gap between instead of 4 and 8.)
If I do that and advance the bombs only every other frame, that should work
out, I think.

Yeah, I can rewrite it for 3-line intervals, but I still can't reposition
bombs on the same line as an invader row, or on the same line as the
shields.  Without repositioning, I can only do one bomb at a time, or two
on alternating frames (I think this is what 2600 Invaders does.)  I
couldn't tell if the arcade went past two bombs at once, though.  Also,
without repositioning, I could easily get my kernel down to two scanlines,
even during the invader formation and shields.

>That should be okay.  If you've let the invades get that low, you're
>in trouble any way. 8)  You could also use John Dondzilla's cheat of
>keeping each shield intact until it takes so many hits.  Then it

I'll rewrite my screen kernel for 3-line intervals and then see what
happens.  As it stands, my players begin on scanline 176 (counting from
zero).. 174 is a multiple of three, so my new kernel will end at 173,
letting me reposition the players during 174 and 175.

>>I could probably do them with the playfield graphics without too much
>>trouble, but I wouldn't have single-pixel control.. at best, I have 4-wide
>>by 1-high control.
>That sounds acceptable.  You've got square invaders, so why not square

I think I can do them with players, though not with the resolution of the
arcade (then again, what 2600 game does? =) )

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