PYC121@URIACC.BITNET (Andy Kress) (06/24/91)
Ok....we can now change the pallet for everline on the screen. But can we change the pallet of a line while the beam is scanning across that line in order to get more than 16 colors on the line? +--------------+-------------------------+----------------------------+ | Andy Kress | Univ. of Rhode Island | PYC121 AT URIACC.URI.EDU | +--------------+--------+----------------+----------------------------+ | No, it's not a Mac. | Apple II: The power to rule the world!!! | +-----------------------+---------------------------------------------+
cmm@en.ecn.purdue.edu (Chris M McKinsey) (06/24/91)
In article <9106241405.AA21887@apple.com> PYC121@URIACC.BITNET (Andy Kress) writes: > > Ok....we can now change the pallet for everline on the screen. But > can we change the pallet of a line while the beam is scanning across > that line in order to get more than 16 colors on the line? > > +--------------+-------------------------+----------------------------+ > | Andy Kress | Univ. of Rhode Island | PYC121 AT URIACC.URI.EDU | > +--------------+--------+----------------+----------------------------+ > | No, it's not a Mac. | Apple II: The power to rule the world!!! | > +-----------------------+---------------------------------------------+ To: PYC121@URIACC.BITNET Subject: Re: 3200+ colors Newsgroups: comp.sys.apple2 In-Reply-To: <9106241405.AA21887@apple.com> Organization: Purdue University Engineering Computer Network Cc: Bcc: > > Ok....we can now change the pallet for everline on the screen. But > can we change the pallet of a line while the beam is scanning across > that line in order to get more than 16 colors on the line? > Yes, it's possible. Anything is possible, though. You can monitor the softswitch at $E0C03E/3F to read the horizontal beam location. Now whether or not you can get the GS to read this beam fast enough as to change the palette at the exact same pixel everytime around is another story. I would have to say: no. But I think only experimentation will yield the truth. So to answer your question, yes, it is possible to change the palette while the beam is in mid-line. But, it may not look all that well. On another side, a friend of mine claims to be working on a 4096 color viewer for the IIgs. He mentioned it had 3 unfolded code segements each 64k in size to do the palette/color switches. I'm anxious to see if he can pull it off. Chris M. McKinsey AOL: McKinsey GEnie: A2pro.Chris
jmueller@umaxc.weeg.uiowa.edu (Jim Mueller) (06/25/91)
In article <1991Jun24.143726.10040@en.ecn.purdue.edu> cmm@en.ecn.purdue.edu (Chris M McKinsey) writes: >In article <9106241405.AA21887@apple.com> PYC121@URIACC.BITNET (Andy Kress) writes: >> >> Ok....we can now change the pallet for everline on the screen. But >> can we change the pallet of a line while the beam is scanning across >> that line in order to get more than 16 colors on the line? >> > >Yes, it's possible. Anything is possible, though. You can monitor the >softswitch at $E0C03E/3F to read the horizontal beam location. Now whether >or not you can get the GS to read this beam fast enough as to change the >palette at the exact same pixel everytime around is another story. I would >have to say: no. But I think only experimentation will yield the truth. So >to answer your question, yes, it is possible to change the palette while the >beam is in mid-line. But, it may not look all that well. Well, I think that would work a little bit better if you were reading $E0C02E/2F. But at any rate that won't help you. The VGC in the IIgs doesn't check to see what colors are stored in the video ram for a particular palette more than once per scan line, in short, it is *>NOT<* possible to change colors Mid-Scan, because the video hardware doesn't allow it. In the Tool Box reference #2, it says that you may change colors in between scan lines (hinting at 3200 capabilities), at any rate, I tested to see if its possible, and determined that it's not. >On another side, a friend of mine claims to be working on a 4096 color viewer >for the IIgs. He mentioned it had 3 unfolded code segements each 64k in size >to do the palette/color switches. I'm anxious to see if he can pull it off. There is not a way to show more than 3200 TRUE colors on the SHR screen in a given screen refresh. >Chris M. McKinsey >AOL: McKinsey >GEnie: A2pro.Chris Jason Andersen AOL: DWS Jason InterNet: jgandersen@icaen.uiowa.edu -- |Jim Mueller | |Internet: jmueller@umaxc.weeg.uiowa.edu | |The University of Iowa | |"Many truths we cling to...greatly to our own point of view do they depend."|
cmm@en.ecn.purdue.edu (Chris M McKinsey) (06/25/91)
> In the Tool Box reference #2, it says that you may change colors >in between scan lines (hinting at 3200 capabilities), at any rate, I >tested to see if its possible, and determined that it's not. > Jason, you say you've tried to switch palettes mid line? Or are you quoting another source as to how the VGC handles scan line color palettes? > There is not a way to show more than 3200 TRUE colors on the SHR >screen in a given screen refresh. > I agree totally on this one, but he keeps insisting it is possible -- and that he can generate 4096 distinct colors. FYI, he also isn't using midline palette changes. I normally wouldn't pay any heed, accept he is a very intelligent programmer. Chris M. McKinsey Genie: A2pro.Chris AOL: McKinsey
jake@labpca.mscs.mu.edu (Jake Buchholz) (06/26/91)
Andy, from what I've gathered, the horizontal beam goes by significantly faster than the vertical counter... But... We wouldn't need to switch it ever single pixel, would we? I mean, even if we could catch the counter at the middle of the screen, we'd have 32 colors instead of 16... -- /\/\/\/\/\/\/\/\/\/\/\ /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ \ Jacob S. Buchholz \ \ / / jake@sc.mscs.mu.edu / / \ \/\/\/\/\/\/\/\/\/\/\/ \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
stc7@cunixb.cc.columbia.edu (Steven T Chiang) (06/26/91)
In article <1991Jun25.142310.3887@en.ecn.purdue.edu> cmm@en.ecn.purdue.edu (Chris M McKinsey) writes: > >Jason, you say you've tried to switch palettes mid line? Or are you quoting >another source as to how the VGC handles scan line color palettes? Yeah, I have. I tried switching just the scb, and the actual color data on a line during mid scan, with a technique used to produce text on the border. (horizontal synchronizing) >I agree totally on this one, but he keeps insisting it is possible -- and that >he can generate 4096 distinct colors. FYI, he also isn't using midline palette >changes. I normally wouldn't pay any heed, accept he is a very intelligent >programmer. Well, there are ways of generating more colors... but not true colors, and it will require a lot of processor time... Jason Andersen don't mind the account.. :P Steven Chiang Coming Soon: DreamGrafix 3200 color power stc7@cunixb.cc.columbia.edu America On_Line: DWS Steve Apple IIgs Forever!