wniren@pyrtech.pyramid.com (Walter "Crash" Nirenberg) (04/04/91)
Greetings, I'm planning on designing an application which will use scrolling. I would like to build it on a TT but since it will be a while until the TT's arrive, I would like to get a head start using an older system. As most of you know, the 1040STe and the TT have hardware scrolling while the other models don't. My question is what's the difference between scrolling routines written for an older system and a new system with hardware scrolling? Would I have to completely rewrite them to take advantage of the hardware or would it be a minor modification? If it's going to be difficult, I will either buy a 1040STe or wait for the TT to come out. Any help would be appreciated, thanks. Walter Nirenberg wniren@pyramid.com wniren@pyrtech.pyramid.com 415/335-8730w
vsnyder@jato.jpl.nasa.gov (Van Snyder) (04/04/91)
In article <150708@pyramid.pyramid.com> wniren@pyrtech.pyramid.com (Walter "Crash" Nirenberg) writes: >My question is what's the difference between scrolling routines written >for an older system and a new system with hardware scrolling? Would I have >to completely rewrite them to take advantage of the hardware or would it be >a minor modification? I've been using the raster operations in VDI and LineA, in the hope that the OS will automatically take advantage of the hardware when it's there. If I'm wrong, will somebody please post? -- vsnyder@jato.Jpl.Nasa.Gov ames!elroy!jato!vsnyder vsnyder@jato.uucp
apratt@atari.UUCP (Allan Pratt) (04/05/91)
>In article <150708@pyramid.pyramid.com> wniren@pyrtech.pyramid.com >(Walter "Crash" Nirenberg) writes: >>My question is what's the difference between scrolling routines written >>for an older system and a new system with hardware scrolling? Would I have >>to completely rewrite them to take advantage of the hardware or would it be >>a minor modification? vsnyder@jato.jpl.nasa.gov (Van Snyder) writes: >I've been using the raster operations in VDI and LineA, in the hope that the >OS will automatically take advantage of the hardware when it's there. If >I'm wrong, will somebody please post? You're wrong. The only hardware that can help raster operations is a blitter, and VDI/LineA automatically takes advantage of that when you do those operations. But "hardware scrolling" means something else. It operates on the entire display, not just pieces of memory. Hardware scrolling means that you have a "virtual display" which is larger than your physical screen. Imagine a large piece of paper with a smaller piece of glass on it. Your screen is a "window" onto the larger display. You can move the window around very quickly, in very fine increments, and this is hardware scrolling. The point is that you just bang a few registers rather than moving all 32K of screen memory to accomplish the move. (On the TT it can be 150K of screen memory!) (Of course, the piece of paper doesn't have to be as big as the world you're scrolling around in; it can be just a little bigger, and you can write the world in strips as it becomes visible.) Both the TT and the STe can move the window vertically on single-line boundaries, and the STe can move the window horizontally on single-pixel boundaries, but the TT can only move horizontally on 8-byte boundaries. This is eight pixels in the 256-color mode, but sixteen pixels in the 16-color modes, and sixty-four pixels in the monochrome modes. Hardware scrolling is only good for limited applications like paint programs where you want a canvas larger than your screen, or games where you want to scroll the player's view around in a larger world. Hardware scrolling CAN be used to make whole-screen scrolling faster. This is something you do in TOS programs when you're on the bottom line of the screen and you hit return. But that's another specialized operation, and it doesn't help such useful programs as Emacs, where some parts of the screen move and some don't. ============================================ Opinions expressed above do not necessarily -- Allan Pratt, Atari Corp. reflect those of Atari Corp. or anyone else. ...ames!atari!apratt
scale@abode.wciu.edu (Luis Outumuro) (04/05/91)
In article <150708@pyramid.pyramid.com> wniren@pyrtech.pyramid.com (Walter "Crash" Nirenberg) writes: > >Greetings, > >I'm planning on designing an application which will use scrolling. I >would like to build it on a TT but since it will be a while until the >TT's arrive, I would like to get a head start using an older system. >As most of you know, the 1040STe and the TT have hardware scrolling >while the other models don't. > >My question is what's the difference between scrolling routines written >for an older system and a new system with hardware scrolling? Would I have >to completely rewrite them to take advantage of the hardware or would it be >a minor modification? > >If it's going to be difficult, I will either buy a 1040STe or wait for >the TT to come out. > >Any help would be appreciated, thanks. > > >Walter Nirenberg >wniren@pyramid.com >wniren@pyrtech.pyramid.com >415/335-8730w Hi Walter, Well so you know, the TT's and Mega STe's are shipping now. Check with your local dealer as to when they will recieve them. Here is a buffered message from CodeHead Quarters BBS: Message : 12250 [Open] 4-03-91 6:19pm From : John King Tarpinian To : One And All Subject : They're Here... Sig(s) : 9 (Did Somebody Say Deal?) The Computer Network got its first shipment of TT030's and MEGA STe's with a second shipment on the way... The Computer Network 1605 W. Glenoaks Bl. Glendale, CA 91201 818-500-3900 [N]ext [J]ump [R]eply [A]gain [Q]uit -- """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" Luis Mark Outumuro III | "Well... you're damned if you do, Computer Office Products 818/813-1051 | and you're damned if you don't!" Infoline 818/813-1053 | - Bart Simpson, 1990...