carter@Neon.Stanford.EDU (Thomas J. Carter) (03/13/90)
I'm trying to speed up some graphics where I've previously used CopyBits(). I want to use the alternate screen buffer and simply switch back and forth between them. On the SE I know the location of both screens in memory given by ScrnBase and ScrnBase - 0x8000 but I'm having trouble finding the alternate screen buffer on a Mac II with a combination of monitors. Can this be done? How? Also, on the SE I just switch the vPage2 bit in the VIA register back and forth. Can I do the same thing on a Mac II? I read somewhere that that bit is reserved but I don't what it is reserved for. Can someone shed a little light here? Thanks in advance. Tom Carter carter@neon.stanford.edu
brecher@well.sf.ca.us (Steve Brecher) (03/15/90)
In article <1990Mar13.040203.6874@Neon.Stanford.EDU>, carter@Neon.Stanford.EDU (Thomas J. Carter) writes: > ...I'm having trouble finding the alternate screen buffer on a Mac II > with a combination of monitors. Can this be done? No. An alternate screen buffer is not a feature of Mac II video. -- brecher@well.sf.ca.us (Steve Brecher)
rsfinn@athena.mit.edu (Russell S. Finn) (03/16/90)
In article <16691@well.sf.ca.us>, brecher@well.sf.ca.us (Steve Brecher) writes: > > In article <1990Mar13.040203.6874@Neon.Stanford.EDU>, > carter@Neon.Stanford.EDU (Thomas J. Carter) writes: > > > ...I'm having trouble finding the alternate screen buffer on a Mac II > > with a combination of monitors. Can this be done? > > No. An alternate screen buffer is not a feature of Mac II video. Now, far be it for me to contradict one of the Big Names of the Macintosh Community, but it *is* possible to do page flipping on (at least) a standard Apple Video Card. The problems are that it's not documented very clearly; it's a function of the video card, not the main hardware; you have to make calls directly to the video driver (i.e., you can't just flip a bit in the VIA); and it's not recommended by Apple. However, if you're really game, it's possible. You have to go digging in the Apple "Designing Cards and Drivers for the SE and II" book, and look in the chapter on video drivers; the information is there. (Sorry I can't be more specific, as I don't own this book, or a Mac II; but I *have* seen it done. It should work on any third-party video card that supports *all* the standard video driver calls; apparently, few of them do.) -- Russ
russotto@eng.umd.edu (Matthew T. Russotto) (03/16/90)
In article <1990Mar15.222250.7763@athena.mit.edu> rsfinn@athena.mit.edu (Russell S. Finn) writes: >In article <16691@well.sf.ca.us>, brecher@well.sf.ca.us (Steve Brecher) writes: >> >> In article <1990Mar13.040203.6874@Neon.Stanford.EDU>, >> carter@Neon.Stanford.EDU (Thomas J. Carter) writes: >> >> > ...I'm having trouble finding the alternate screen buffer on a Mac II >> > with a combination of monitors. Can this be done? >> >> No. An alternate screen buffer is not a feature of Mac II video. > >Now, far be it for me to contradict one of the Big Names of the >Macintosh Community, but it *is* possible to do page flipping on (at >least) a standard Apple Video Card. The problems are that it's not >documented very clearly; it's a function of the video card, not the main >hardware; you have to make calls directly to the video driver (i.e., you >can't just flip a bit in the VIA); and it's not recommended by Apple. >However, if you're really game, it's possible. You have to go digging >in the Apple "Designing Cards and Drivers for the SE and II" book, and >look in the chapter on video drivers; the information is there. (Sorry >I can't be more specific, as I don't own this book, or a Mac II; but I >*have* seen it done. It should work on any third-party video card that >supports *all* the standard video driver calls; apparently, few of them do.) > >-- Russ As far as I can tell, you cannot actually do page flipping. What you can do is change the area of video card memory that you are actually displaying It doesn't seem to be possible through the driver calls-- they return controlErr. -- Matthew T. Russotto russotto@eng.umd.edu russotto@wam.umd.edu ][, ][+, ///, ///+, //e, //c, IIGS, //c+ --- Any questions?
gabler@oakhill.UUCP (Christopher Gabler) (03/20/90)
I am in the process of writing a device driver for a General Purpose Interface Bus card in a Mac II. The operating system used is A/UX 1.0. I have purchased the APDA A/UX Device Drivers Kit and several supportive documents on Apple hardware and Unix programming. I have had many difficulties using the present resources and I am interested in getting help in programming the driver and correctly installing it in the A/UX kernel. I would like to hire someone on a contract basis to do some programming on this project. This person should have considerable experience in writing and testing device drivers in the A/UX environment (UNIX experience is NOT enough). ctg +++++++++++++++++++++++++++++++++++++++++ Christopher Gabler + Motorola Inc. + MS OE28 + 6501 Wm. Cannon Drive West + Austin, Texas 78735-8598 + (512) 891-3313 + FAX (512) 891-3354 + + gabler@sol1.UUCP (Christopher Gabler) + +++++++++++++++++++++++++++++++++++++++++