Aw: Re: [stella] Player data loading...semi newbie

Subject: Aw: Re: [stella] Player data loading...semi newbie
From: cybergoth@xxxxxxxx
Date: Thu, 18 Oct 2001 09:35:00 +0200 (CEST)
Hi Brian!

> > >.skipDraw:              ;  = 19/12 (or 17/10)

> > But how do you handle skipdraw?
> > Am I correct in assuming that all sprite frames require a zero line at the
> > top in order to make sure the last write to the sprite clears it out?  If
> > .skipDraw doesn't contain an LDA #0, STA GRP0 then it will continue to
> hold 
> > the last line of graphics until the end of the screen otherwise.

> Easiest way of doing this is to make sure the last byte of your player is a
> zero... you waste one byte of ROM that way, 

Depends. Gunfight would only have to waste that one byte in the RAM, 
but that is unacceptable to me.

> but you'd waste a lot more bytes

Instead of wasting a byte _per_ shape, you'd only lose two 
bytes _once_ in each skipdraw.

> (and cycles) trying to decide whether or not to put a 0 in your kernel.

You don't waste a cycle at all, since the skipdraw branch 
is way faster than the drawing branch. In fact you'll 
probably even have to add NOPs or .Ws in there, to match the 
running times of both branches.
> You can always define them as macros... though that won't handle different
> addressing modes. When I get home, if I have time, I'll look at the source
> for DASM to see how hard it looks like it would be, to add opcodes. This
> would be a nice feature to have...

Thomas already did that long ago...

Oh... I wish people would start browsing the archive instead of
reinventing the wheel every half a year :-)


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