VDC "Extended Background Color Mode"?
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From: Vanessa Ezekowitz on 1 Oct 2009 22:35 On Thu, 1 Oct 2009 18:24:01 -0500 Vanessa Ezekowitz <vanessaezekowitz(a)gmail.com> wrote: > 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. Replying to myself... I solved the problem I was having, so the aforementioned test program has been imported and is available on my website now: http://starbase.globalpc.net/~vanessa/binaries/vdcdemo1.zip -- "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)
From: adric22 on 1 Oct 2009 22:53 > Replying to myself... I solved the problem I was having, so the > aforementioned test program has been imported and is available on my > website now: > > http://starbase.globalpc.net/~vanessa/binaries/vdcdemo1.zip Well, I can't view your program yet until they get VICE working on Snow Leopard.. But, if I understood what you wanted to do, then I did something like that once before. I filled the screen with a character that was half-a-block so to speak. That way I could manipulate the background color to change the top "pixel" and the foreground color to change the "bottom" pixel. In doing so, I created an 80x50 graphics mode. I made a little drawing program that could use it. The graphics looked pretty much like what you could do with the PETSCII block characters on the VIC screen (which also creates an 80x50 environment) except that you would have more freedom of colors. I also created a program that put the VDC into a mode where the color cells were 8x2 in size. Then I filled the left 4 pixels of each cell and created a 160x100 graphics mode that allowed any of the 16 colors to be used and placed next to each other. I had theorized that it might even be possible to create a 160x200 graphics mode with some tweaking which would allow importing of C64's multi-color bitmaps (such as koala) but I never got that far.
From: Vanessa Ezekowitz on 2 Oct 2009 05:23 On Thu, 1 Oct 2009 19:53:37 -0700 (PDT) adric22 <adric22(a)yahoo.com> wrote: > > Replying to myself... Â I solved the problem I was having, so the > > aforementioned test program has been imported and is available on my > > website now: > > > > http://starbase.globalpc.net/~vanessa/binaries/vdcdemo1.zip > > Well, I can't view your program yet until they get VICE working on > Snow Leopard.. But, if I understood what you wanted to do, then I > did something like that once before. I filled the screen with a > character that was half-a-block so to speak. [...] I've played around with similar "modes" before, but in this case, the original poster was looking for 80x50 *text* with at least as much background color control as a VIC-II can get in Extended Background Color mode. The only way to achieve that on the VDC is by drawing the text onto a 640x400 bitmap, using 8x8 pixel character images (and 8x8 color cells), or 640x200 with 8x4 characters (and 8x4 color cells). The former would be slow but reasonably easy to read, while the latter would be fast but hard to read. -- "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)
From: saehn on 2 Oct 2009 09:13 Sorry, I see now that I may have been a bit unclear. The "text" part of EBGM was only to achieve a blocky 80x50 pixel mode, with each cell being capable of two colors. So, in 640x200 mode, each 8x8 color cell would contain two "software" pixels, each being comprised of 8x4 real pixels. Does that make more sense? What Vanessa is describing seems like it might work. I'm a graphics guy, this would be for low-res 80col graphics on the 128, preferably without requiring the extra 64k VDC RAM (which I have, I just would want the widest possible audience of course). Thanks Vanessa for the information and your download, looking forward to trying it out! Dave, I've heard you mention your 160x100 mode before and it still sounds interesting. I would be happy to do a pic or two for you if you ever release a PC-based converter or a CBM-based editor.
From: Errol Smith on 2 Oct 2009 21:08
adric22 wrote: > I also created a program that put the VDC into a mode where the color > cells were 8x2 in size. Then I filled the left 4 pixels of each cell > and created a 160x100 graphics mode that allowed any of the 16 colors > to be used and placed next to each other. I had theorized that it > might even be possible to create a 160x200 graphics mode with some > tweaking which would allow importing of C64's multi-color bitmaps > (such as koala) but I never got that far. I've heard of this, a similar mode was used on IBM CGA adapters as well to make a 160x100 16 colour mode. (Actually, the VDC and CGA have a lot in common, the modes are produced in an identical fashion). 160x200 is theoretically possible but would require some timing tricks. A mode like this is used in the RFO VDC demo to display an FLI like image, although it is not full screen height. Errol |