RE: [stella] FlipDraw...

Subject: RE: [stella] FlipDraw...
From: "Fred Quimby" <c9r@xxxxxxxxxxx>
Date: Thu, 11 Aug 2005 21:22:27 -0400
FWIW, the Alpha 0.1 and 0.2 bB kernel uses this too, mostly because of the 
pointer setup thing.  However, I will probably use a kernel rewritten with 
skip/switchdraw to get more on the screen, but I'm not looking forward to 
the pointer setup stuff.  Actually, I haven't figured out how to setup the 
pointers at all yet...

>Hi there!
>
>How about...
>
>      LDA #SPRITEHEIGHT
>      DCP spriteOffset
>      BCC FlipDraw
>      LDY spriteOffset
>      LDA (spritePtr),Y
>Continue
>      STA GRP0
>
>That's 2/3 cycles more than skip/switchdraw, but it neither requires a
>line counter (save lotsa cycles here!) nor occupies a register.
>
>I'm currently working on a 4LK with 2LK sprites, and this seems to be by
>far the most elegant way to do that :-)
>
>Also instead of the nightmarrish sprite/pointer setup for skip/switchdraw
>it only requires a setup as simple as:
>
>      LDA spriteY
>      STA spriteOffset
>      SET_POINTER spritePtr, spritedata
>
>Greetings,
>Manuel
>Archives (includes files) at http://www.biglist.com/lists/stella/archives/
>Unsub & more at http://stella.biglist.com
>


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