Subject: Re: [stella] 2600 rpg|
From: emooney@xxxxxxxxxxxxxxxx (Erik Mooney)
Date: Sat, 22 Mar 1997 19:44:11 GMT
>from the Rat Shack (aka Radio Shack) Color Computer 3. Basically, you have >a set number of equally sized memory slots visible to the processor, each >with its own dedicated control location. (Just like VSYNC, or WSYNC in the >2600 console.) Your physical memory is divided into blocks of the same size. >When you want to switch banks, you write the address of the desired block >into a given memory slot. Voila! New block of memory! Note that using >this system, I could put any physical block of memory into any desired slot. >This is pretty powerful, but also could be a problem during power up. To >get aournd this, one slot (highest order) is a dedicated boot block. Simply >make your RESET vector point to the beginning of this slot, and you can >always power up under known conditions. I assume either RAM or ROM could be mapped to any of your blocks.. I suppose you could execute code in RAM, then. Anyone wanna use self-modifying code on the 2600? =) >I hope this reads something like English...ugh! :P Except for the "voila", it did ;) >I don't think this would be too bad. Simply store the font in ROM once. >Store any text as ASCII or make up your own code, or whatever. Your display >code would take in x,y coordinates and an ASCII code and go for it. This is >simplified of course, as you would have to draw one scanline of several >characters, then come back for the next scan line, same characters, etc. >But I don't think it would be terribly difficult. The score-displaying routines posted here recently do that, though they're limited to 6 characters. It isn't that hard to expand that to 12 characters drawn on alternating frames, and if you use a 4-pixel wide font, you can stuff 24 characters in there. It'd be a little harder to calculate, but all that can be done during VBLANK so the timing of the drawing code stays the same. >Anybody wanna write some demo code?? >I might give it a try, but be warned...it'll be UGLY! Anyone ever seen pretty 6502 assembler? =) >> one myself) and Galaga ported to the 2600. > >OOH!!! YEAH!!! YEAH!!! Galaga!!!! > >Mmmmm....Galaga.... It'll be a while if ever until someone writes this.. I looked at Galaxian, one of the few 2600 games to display more than six sprites on one line, and it uses some routines that PC Atari doesn't yet implement perfectly, so it'll be a while till anyone understands the 2600 enough to do Galaga. At least it's a vertically oriented game, unlike such beasts as Scramble that would be just about impossible on the 2600. Also, there would definitely be a large demand for Galaga on the 2600, so that might be an incentive to do it =) Or, with lots of RAM (32k would probably be enough with efficient storage methods) and a true save-game, one could do a SimCity or Civilization-like strategy game on the 2600... code speed doesn't matter too much in a non-realtime game (except maybe for Video Chess =) ), and PAL conversion would be easy. -- Archives available at http://www.biglist.com/lists/stella/archives/ E-mail UNSUBSCRIBE in the body to stella-request@xxxxxxxxxxx to be removed.