On 08/14/2011 09:50 PM, Hársfalvi Levente wrote: > On 2011-08-14 21:14, Gerrit Heitsch wrote: > >> Do you have a link giving some background on how that is done? I have >> seen full screen images on the C16, but so far was unable to find >> documentation that explains how to do this. Since TED doesn't have >> sprites you can't do things as you'd do with a VIC when you want to put >> graphics in the border area. > > Border removal doesn't need making use of the NTSC-bit ie. the above > trick of enhancing horizontal resolution. > > Either way, I don't know where they're documented. > > In short, removing the vertical border is done by $ff1d tricks (setting > the raster register back and forth at certain positions, so that screen > redraw would be started earlier / stopped later than usual (taking care > of the number of lines per frame that should be kept unaffected), with > the additional work of switching screen memory at some position where > the screen memory page would normally run "out" ie. wrap around). On the > VIC, the possibility of using that trick is prevented by the absence of > a writeable rasterline counter. Here it's fully possible to "enlarge" > the screen area (without the chip stopping screen redraw after 25 rows), > so no sprites are needed either. Hm, yes, almost forgot that all relevant counters on TED can be written to. I can see how one can do neat tricks by using more than one bitmap area and adjusting the counters on the fly. Getting the timing right must be a pain with the double clocking unless one decides to go with single speed at all times. Gerrit Message was sent through the cbm-hackers mailing listReceived on 2011-08-14 21:00:10
Archive generated by hypermail 2.2.0.