Re: [stella] Qb: v0.05

Subject: Re: [stella] Qb: v0.05
From: "Thomas Jentzsch" <tjentzsch@xxxxxx>
Date: Mon, 19 Feb 2001 13:34:17 +0100
Andrew Davie wrote:
> Another day, another version.

Getting better and better!

> I am now very very very short of ROM.  I doubt there will be many (any?)
> sounds in this game, primarily because I can't DO sound, and as I have
> little ROM, I can't do MUCH sound.  Remember, I still have a few creature
> frames and additional AI to do.  SOME AI is already in there, but disabled
> (bugs!).  So, ROM space isn't incredibly desperate... just very desperate :)
> Things will be very tight, but I'm close to having the game there now,
> anyway.... so I have little doubt I'll have something to release soon.  I
> have one or two bytes of RAM free, and about 400 bytes of ROM.  Not much!
> Even if I do say so myself... its now looking/playing pretty good.
> As usual, any feedback/comments most welcome.

I've tried to understand your SpriteRedirect thing. If I understand anything correct, I'd say you can get the same result with much less ROM and even less cycles by redesigning it the way I did explain Manuel some days ago.

At the moment you need about 240 bytes for your SpriteRedirect table and 22 cycles do draw a sprite line:
  inc SpriteLine
  ldy SpriteLine
  lda SpriteRedirect
  lda (Sprite),y
  sta GRP0

If you change this to:
  tya                   ; only one global linecounter which you should try to keep in the y register
  sec                   ; if you know the state of the CF you can eliminate this
  sbc SpriteEnd     
  bcc .skipDraw         ; waste some time there (or load 0 into a if you need that)
  lda (Sprite),y        ; to calculate the sprite pointers is a bit more complicated now ;-)  
  sta GRP0

...then you'll save 3 to 5 cycles and a LOT of ROM space.

BTW: Try not to start with (or avoid at all) the gray PF color, it doesn't look very nice. And the first impression sometimes counts...

I just played up to level 20 (W2K makes this a bit easier ;-). You don't have any predefined level, right? That means, you think every setup is solvable. Are you sure?
If yes, your game would have up to about 2^16 (or so) possible levels. Cool! 

Have fun!
Thomas Jentzsch         | *** Every bit is sacred ! ***
tjentzsch at web dot de |

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