VDC "Extended Background Color Mode"?
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From: saehn on 30 Sep 2009 09:15 I originally posted this to Lemon64, but this is probably the better place, with people like Vanessa and Dave Murray hanging around... Is there any way to have a text-based VDC Extended BG Color Mode in 80 columns, like on the C64? Ideally, I'd like to have each 8x8 cell have its own foreground and background colors. The goal here is an 80x50 fast graphics mode. Thanks for any help...
From: rusure on 30 Sep 2009 20:55 On Sep 30, 7:15 am, saehn <shanef...(a)gmail.com> wrote: > I originally posted this to Lemon64, but this is probably the better > place, with people like Vanessa and Dave Murray hanging around... > > Is there any way to have a text-based VDC Extended BG Color Mode in 80 > columns, like on the C64? Ideally, I'd like to have each 8x8 cell have > its own foreground and background colors. The goal here is an 80x50 > fast graphics mode. Thanks for any help.. Can you post a program that does what you describe on the 64 on a 40 column screen?
From: Errol Smith on 1 Oct 2009 07:43 saehn wrote: > I originally posted this to Lemon64, but this is probably the better > place, with people like Vanessa and Dave Murray hanging around... > > Is there any way to have a text-based VDC Extended BG Color Mode in 80 > columns, like on the C64? No. > Ideally, I'd like to have each 8x8 cell have > its own foreground and background colors. You would have to use bitmap mode to achieve independent fore/back colours. Plus you would need 64k vdc ram, unless you are prepared to lose some rows and/or columns. You could use a second attribute screen and switch between them every few frames to simulate blinking, but other text mode stuff would have to be emulated (underline, reverse etc). > The goal here is an 80x50 > fast graphics mode. Thanks for any help... Depends on your definition of "fast". At least the VDC has fill/copy things you can use to speed scrolling/clearing. I suspect it would be as painfully slow as soft80 on the 64, but at least you could read it. Errol
From: rusure on 1 Oct 2009 14:38 On Sep 30, 7:15 am, saehn <shanef...(a)gmail.com> wrote: > I originally posted this to Lemon64, but this is probably the better > place, with people like Vanessa and Dave Murray hanging around... > > Is there any way to have a text-based VDC Extended BG Color > Mode in 80 columns, like on the C64? Ideally, I'd like to have > each 8x8 cell have its own foreground and background colors. The > goal here is an 80x50 fast graphics mode. Thanks for any help... I don't think this is what you want but here goes. This works in both 128 and 64 mode on both 40 and 80 column text screens. The action is to print text in revere video. In a print statement, construct strings using an open quote followed by a control 9 character(chr$(18)) then a control or C= character of the numerals in the top row, and followed in turn by the text string. Finally terminate the string with a control 0 (chr$(146))and a close quote. One disadvantage to this is that the text can have only one color, that of the background.,
From: Vanessa Ezekowitz on 1 Oct 2009 19:24
saehn wrote: > I originally posted this to Lemon64, but this is probably the better > place, with people like Vanessa and Dave Murray hanging around... > > Is there any way to have a text-based VDC Extended BG Color Mode > in 80 columns, like on the C64? In answer to the original question - yes you can get this effect, but only if you use a bitmap. To do 80x25 text, you need a 640x200 bitmap, 8x8 color cells, and 64K video RAM. I wrote a simple program some time back to demonstrate this. If you only have 16K video RAM, you'd need to use fewer character lines, to make room for a color attribute map. The "driver" code does full foreground and background color control per character, flashing text using an interrupt-driven routine that periodically switches color attribute maps, and it has a simple windowing feature like that offered by the C128 screen editor. I seem to recall that it has underlining, and I remember trying to get italics into it also. I originally wrote it as a proof-of-concept, in hopes that someone would turn it into an ANSI-compatible terminal driver. The "demo" program wrapped around it just reads a sequential file from disk and displays it more or less raw, with incrementing colors (i.e. it isn't meant to be comfortable to read, just legible). >> The goal here is an 80x50 fast graphics mode. Thanks for any help... My little demo program only does 80x25. To get 80x50 you'd either need to interlace the screen to 640x400 and use 8x8 cells/characters, or you need to use 8x4 cells with the 640x200 mode. The former would be slow and the latter would be hard to read. Suffice it to say, I don't recommend 80x50 in anything but plain old text mode. :-) You'd be better off with 160x25 (two characters per color cell, like soft-80) if you need more text on the screen, but it'd still be hard to read. Errol Smith wrote: > Depends on your definition of "fast". At least the VDC has fill/copy > things you can use to speed scrolling/clearing. I suspect it would be as > painfully slow as soft80 on the 64, but at least you could read it. Actually, scrolling the screen with the Block-Copy function is fast enough that it's barely noticeable, at least it is in that little demo I mentioned above. As for the text plotter, yeah it'll be a lot slower than native text mode, but if you were to pre-render entire lines of text into the C128 memory before writing them to the VDC's memory, it would speed things up by a significant amount. Having a SuperCPU also helps a little bit, especially if you need a non-trivial amount of CPU time to pre-process your text before it is printed, but that's hardly an easy thing to get these days. Also note that the more bitmap and color attribute data you are able to get the VDC to display at one time, the slower the chip will operate (I think this is because of bandwidth issues with the VDC's own accesses to its video RAM). If I can get my PC to stop being stupid, I'll transfer that VDC program over and share it, if anyone wants it. Errol, I think I sent it your way some time back, so if you find it before I do, feel free to spread it. -- "There are some things in life worth obsessing over. Most things aren't, and when you learn that, life improves." http://starbase.globalpc.net/~vanessa/ Vanessa E. <vanDEesLEsaTEezTHekISowitz(a)gmail.com> (Delete the obvious to email me) |