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. Removal of the horizontal border is rather tricky. $ff1e tricks are used line-by-line (in a similar fashion to the removal of the vertical border - tricking the TED so that checkpoints are triggered sooner, others later than normal). Line sync (number of cycles per line) needs to be kept unaffected. The resulting places are slightly hard to fill up with valid screen data; it's either the idle-byte ($ffff) that is used, or bitmap mode, which is displayed on the borders (if the effect is done right), and it also does keep count of the number of displayed positions. Either case, the ability to set colors for the newly inserted places is limited. Message was sent through the cbm-hackers mailing listReceived on 2011-08-14 20:00:32
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