RE: [stella] Space Instigators - Final Version (?)

Subject: RE: [stella] Space Instigators - Final Version (?)
From: Christopher Tumber <christophertumber@xxxxxxxxxx>
Date: Thu, 17 Oct 2002 14:50:16 -0400
Thanks everyone!

I'm going to tackle all this in one post since otherwise I'd be posting a half dozen emails and there's a fair bit of bit of overlap. Plus I'm lazy and have to get back to code....

Manuel wrote:

>I'm really interested in what you're doing inbetween the 
>rows. Really no chance at all to reduce that? Already a 
>single line would be a great improvement I think.

Well, never say never - I managed to salvage a total of 13 scanlines, about 2 per row! (Course that's mitigated slightly by moving the screen down 4 scanlines, but there ya go...)

(Getting a stable kernal wound being quite frustrating given the calcs/branching/etc (Kept getting "phantom" scanlines) and it looks like I was a little conservative....)

>I think this'd be better. I never got past the first 

I've halved the shot speed (one scanline per frame instead of two) but it seems really... wussy to me. Maybe if I improved their shooting accuracy - Shooting is not random, they're supposed to shoot right at you but it's an approximation because divide by 8 is a lot nicer than divide by 9. It looks a lot better if it appears a little random and they're not always just shooting right at you. But maybe I can increase the percentage of shots that ARE right at you...

However, I have made the shots switch over to fast again near the end of a level. That works out quite well...

>Another thing would be working on a little break 
>inbetween shots. At the moment, there's always an enemy 
>shot onscreen. Especially invaders at the bottom can 
>have sucha high fire frequency that you've almost no 
>chance to kill them.

Yeah, I should probably turn off shots once they're below a certain level. (Done!)

>What about your own shot, it seems like it is normally 
>hiding underneath the player sprite? 

Both the player and the Instigators shots are the ball.

>This is producing a little flaw, since I've experienced 
>"Game Over" situations with the shot still visible at 
>the bottom.

Should be fixed (but hard to verify) - This was occuring if you pressed fire on the exact frame that you got killed as the collision detection occured before firing and dying didn't reset the player's shot.

>- Neither RESET nor SELECT seem to do anything. While 
>RESET is definately necessary, a few gameplay variants 
>wouldn't hurt either. Maybe there's some variants the 
>Atari SI port has implemented, which could easily be 
>adopted into your game?

Neither do anything. I suppose I could add a reset (Done!).

I have 1 byte RAM and 3 bytes ROM free so I don't thik there are going to be any variants.

Adam wrote:

>Instead of displaying credits, you could just stuff your name in (in
>ASCII) at the end of the ROM, like Greg Troutman did in Dark Mage.
>That'd let you maintain only one version.

But I want people to be able to find me (ie: to get a cart) if they've downloaded it off some obscure web site or Usenet or what have you...

Nicolás wrote:

>    I´ve noticed that too. The score starts getting displayed three lines
>before the usual. I mean three WSYNC, then 37 VBLANK lines.

Um, yeah, vertical blank is 37 lines, right? Or have I misread something? Anyway, I've put it at 41.

>    Also, when you press fire to start the game, the screen seems do some
>nasty effect, but I didn´t tested it on the real thing. Maybe the screen get
>displayed a little earlier for that frame.

Hrm, I thought I'd fixed that. But then my "tv" is notoriously stable wrt roll. But z26 does show any variance in the scanlines...

>    I haven´t been following the thread very carefully, so maybe this has
>been said, but I really think the game needs some animation when you 

Maybe possible, but implys some bitmaps and extra code. Dunno if I have room (mind you I've been able to go in a rescue a half dozen bytes every time I've needed too so far. So maybe...)

>or the invaders get hit. 

Not possible.

Manuel wrote:

>I noticed that to. When starting the game, either more 
>or less than 262 lines are generated at least for one 
>frame. You can clearly see that in Z26 Mode 9. I'd 
>expect a noticable *jump* on the real thing.

Hrm, I don't see anything but 262 on z26. I wonder if I accidentally posted an earlier version.

At any rate, somebody please confirm or deny if this problem still exists in the version attached!

Erik wrote:

>I haven't been following the thread much either, but maybe you could take
>a page from Piero's additions to INV long long ago.  Can you set the player's
>missile to 4-wide or 8-wide?  Use the player's missile to flicker an explosion in
>the place of the invader for a few frames when an invader gets hit.

Umm, I don't think so. On scanlines where Instigators are drawn, I'm lucky if I have 1 cycle available (usually none). So this effect would need to be setup at the top of the screen and the explosion would be limited to being a rectangle (since I can't change the size/position on the scanlines on which it will be drawn). In addition, the player's shot and the Instigator's shot are sharing the ball so it'd have to take into consideration the multiplexing.

To do:

- Fix restart "roll" (if it exists?)
- Make Instigators shots more accurate
- Explosion when you die (maybe)

I really, really need to get this done soon in order to get carts manufactured in time, so expect another post later today...


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