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 01:48:25 GMT
>I just spent some time playing it.  It works fine on a Supercharger
>attached to my (NTSC) 2600 Jr., but that's no surprise.  My first
>suggestion was going to be give the invaders a little more shape, but
>if you're using playfield graphics, I guess you can't do much of that.

Nope, can't =)  I could vary the colors between lines more.. would that

>The screen also looks a little more crowded than the coin-op space
>invaders, but they do seem to have enough room to move back and forth,
>so I guess it's okay.

To be honest, I've never actually played a coin-op Space Invaders.. I was
basing the game mostly on TI Invaders, for the TI-99.  The invader
formation is a larger fraction of the screen width than TI Invaders, but it
moves a little slower, so it kinda works out.

>>Known bugs/limitations:
>>I don't yet check for collisions between enemy bombs and players.. that's
>>cause playing the game would be just too hard in its current setup..
>>suggestions welcome
>No kidding!  Slow those bombs down a little!

My draw-screen kernel as written can only draw them at four-scanline
intervals (especially within the invader formation, where I'm rewriting the
playfield 6x per line), so if I only advanced them every two or four
frames, I'd lose some of the smoothness of motion that we all love the 2600
for.  I'll probably have to do that, though.

>I wouldn't complain if you have to remove the score to display the
>saucer, if that's necessary.

Oh no, I won't need that (unlike 2600 Space Invaders =).. the invader
formation is significantly thinner vertically in my game, so there's plenty
of room up top to display a saucer.

>>to the playfield registers six times.  This is hardly noticeable, though.
>I didn't notice it, if I understand correctly.

That's the general idea =)  It doesn't happen too often either.. it happens
on 1/3 of the frames during which a bomb begins its display between the top
and bottom lines of the formation.  And this only happens when an invader
not in the bottom row of the formation shoots.

>I was trying to get to this point, but I let the invaders land
>accidentally before I got there.  I didn't feel like doing it all
>over to try again.

I haven't gotten there without the invaders landing either.  Also, my game
as set up requires at least a 4-line gap (and sometimes more) between the
invaders and players, so the invaders often land earlier than the graphics
would indicate.  I'll fix this if I can (should be able to.)

>>There are no "shields" above the players, nor will there be.. they would =
>>extremely difficult to implement with the setup of my screen kernel.
>Understood, but I kind of miss them.

Yeah, I'd like to do them.. the drawscreen kernel makes it difficult;
mostly because it needs a full scanline to reposition the ball for bombs,
and partially because I'd need to use player graphics for them, and it'd be
difficult to find time to reposition the players before it comes time to
draw them.  I do have enough RAM left available to store four 8x8 element
shields, which could be expanded to 16 high by only updating every other
scanline (which I'd definitely have to do).  I may be able to do it if I
kill the shields as soon as the invaders get to shield level, like 2600
Space Invaders does.. I'll work on it.

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.

Archives available at
E-mail UNSUBSCRIBE in the body to stella-request@xxxxxxxxxxx to be removed.

Current Thread