Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site terak.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!genrad!teddy!panda!talcott!harvard!seismo!hao!noao!terak!doug From: doug@terak.UUCP (Doug Pardee) Newsgroups: net.micro.atari Subject: Re: Atari 800XL superior to c64? Message-ID: <260@terak.UUCP> Date: Thu, 10-Jan-85 19:09:47 EST Article-I.D.: terak.260 Posted: Thu Jan 10 19:09:47 1985 Date-Received: Mon, 14-Jan-85 02:47:33 EST References: <212@eneevax.UUCP> <340@cadovax.UUCP> Organization: Terak Corporation, Scottsdale, AZ, USA Lines: 84 Since nobody else jumped in... > the Commodore '16 colors in hi res' obviously has limitations, > (only 2 in any 8x8 etc.) The Atari features are different and > may also have limitations. True, the Atari technically only has > 2 colors in hi-res, but with proper use of the display list, you > can have 128 colors (or is it 256?), limited to two different > shades on any raster line. In the max-resolution mode (320X200 bit-mapped) the C-64 is as noted. Since the color data is picked up by the video chip only once every 8 raster lines, there is no way to change it on a per-raster-line basis. Also, the bit-map is NOT in a logical order. > With the display list, you can mix > graphics and text modes on the screen like crazy, ie: a screen > with 1. four raster lines of hi-res, then 2. a text line, then > 3. 20 pixel lines at medium res, etc. ad infinitum (or at least > until the bottom of the screen) Ditto on the C-64. > The display list will also > facilitate scrolling of all or part of the screen either > horizontally or vertically without moving any of the actual > data. The C-64 can do this without display lists. It does require that the screen be "shrunk" -- 24 lines for vertical smooth scroll, 38 columns for horizontal smooth scroll. > Display list interrupts can be used to divide the 4 (actually > 5) players into seperate entities, provided they only move horizontally. > (actually you might even be able to do vertical movement like this with > some cute tricks). In this way, each of the 5 players could be divided > into up to 192 individual horizontal moving 'sprites'. Of course at > 192, each sprite is 8 horizontal by 1 vertical. The C-64 has 8 sprites which can be moved vertically as well as horizontally, each sprite being up to 24 pixels wide by 21 high, with the ability to "double" pixels in either or both dimensions. "High res" sprites have only one color each, (the "second" color being "transparent"), medium-res sprites (where the 24 pixels are made into 12 double-width pixels) can have 3 colors, one for each sprite plus two "common" colors shared by all sprites. All of the things that an Atari display list can do are also applicable to the C-64. > Collision detection > is built in for player-player, player-background, etc. but I suppose > the Commodore may have this feature. It does. Also priority -- what is seen when sprites overlap each other. Sprite 0 always covers sprite 1 ... sprite 6 covers sprite 7. Normally any sprite covers background, but this can be changed for any and all sprites. > I've heard nothing about any > display-list type features in the C64. If there are any, I'd like to > hear about them. The C-64 has a "raster line interrupt" which will produce an interrupt at any selected raster line. This gives essentially the same facility as Atari display lists. While this all sounds very impressive on the C-64 side, I feel obliged to point out that "features" and "quality" don't necessarily go together. The quality of the video that the C-64 presents is terrible. The only way to get a watchable picture is to use the Commodore monitor. > I don't know much about the C64 except it has 32 sprites. I guess it > just uses the T.I. 9918? (no display list or associated interrupts). Only 8 sprites. It uses the MOS Techonology (a division of Commodore) 6567 VIC-II video chip. > All I know about the sound generators is what was said in the above > referenced article. The sound synthesizers in the C-64 really are the best there is. If sound is what matters to you, you needn't look farther. Doug Pardee -- Terak Corp. -- !{hao,ihnp4,decvax}!noao!terak!doug