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> > Thanks, man, you are very kind, but unfortunately this info is not enough... > > > > Character Map Mode > > Each character is 8x8. The screen is made of 40x25 characters > > > > Well, (8x8)*(40x25) is 320x200. Fine, that's the usable text area. But I guess > > that the backgroud surrounding it is not considered here... > > > > Bitmapped Graphics Mode > > HiRes Mode: 320x200 pixels, any one color per character-cell, and the > background > > color > > Multocolor Mode: 160x200 pixels, 3 pre-selected colors, any one color per > > character-cell, and the background color > > > > Again, this is the "work area". It would be enough, if the VIC-II wouldn't > allow > > to blit anything outside of it - which is not the case. > > Play some tricky-programmed games, like Creatures 1 & 2 or Turrican (if my > > memory serves me well), and you'll see sprites travelling right there, where > > there shouldn't be anything... > > > > I want to know the resolution of the WHOLE C64 screen, not just the "normally > > usable" part of it. > > Pixel-addressable space on the C-64 is 320x200 (in hires graphics/character > mode) and 160x200 (in multicolor hires/multicolor character mode). There was > also a VIC-II register that controlled "border" color (which was basically > anywhere outside the 320x200 or 160x200 area), and you could set up a scan-line > interrupt to change the register at certain scanlines, but pixels outside of the > 320x200 area could never be affected by anything outside the border color > register. The size of the border was actually a function of you monitor's > horizontal/vertical size/height adjustments, nothing could be done from within > the machine to change that. > > So what resolution you run your emulator at is all in personal preference. You > can run any game at 320x240 (and have the border only at the top and bottom), > and this is the resolution that I run at. You can run it at 400x300 (which will > give you left/right borders, as well). Your choice, makes no difference. > > There was a "trick" to display sprites in the border area (which involved > flipping the screen vertical height bit from 25 rows to 24 rows after the VIC > had started displaying the 24th row, thus tricking the VIC into never turning > off the sprites at the "bottom" (and top) of the screen), but this only allows > sprites to be seen outside the borders, it doesn't affect the display resolution > of the VIC chip at all, and you can't use vertical scrolling in 25-line mode > without artifacts showing up on the top/bottom of the screen. Few (if any) > games used this- AFAIK only demo coders used this "bug", because you could stick > a sprite out there but no background graphics. > > The C-64 programmers reference manual has a section on sprites (Commodore called > them "movable object blocks" or "MOBS")... if you read the section detailing > sprite X and Y coordinates, you'll get an insight into how the VIC internally > divvied up the screen coordinates, which is I believe what you are looking for. >
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