Subject: Re: [stella] Repository|
From: Nick S Bensema <nickb@xxxxxxxxxxxx>
Date: Mon, 23 Feb 1998 13:37:37 -0700 (MST)
> > At 06.11 23/02/98 -0800, Greg Troutman wrote: > > >Nick S Bensema wrote: > >> > >> > 1- learn the basic concepts from the programmer's guide. And I mean > >> > "basic": don't waste time on VDEL, for example! What's the use of VDEL, > >> > anyway? ;-) > >> > >> It's my understanding that when VDEL is enabled, a player's graphics don't > >> change immediately when its data register changes; it waits until the > >> next write to player data before it makes the change. This was intended > >> to allow single-scanline positioning in double-scanline kernels, but > >> its most common use is in six-digit scoring routines. > > I was almost joking, VDEL is very important, thought maybe it's not a clear > issue at all - and I did't use it in Oystron. > Exercise: take a simple kernel, let's say Adventure, remove the VDEL (just > change the STA VDELPx to two NOPs with PCAE) and see what happens. Harder exercise: modify Adventure or Combat to a single-scanline kernel. Whether this yields more detailed shapes or ahalf-height screen, you decide. With Adventure, you might need to either use bankswitching or crowd out the Warren Robinett message. -- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/stella.html Don't post pirate BINs to Stellalist. Be a programmer, not a pirate. Write the best game, win framed autographs of famous Atari alumni!!