dlleigh@mit-amt.MEDIA.MIT.EDU (Darren Leigh) (11/10/89)
I'm looking for various ways to do fast and smooth vertical scrolling of text. Both up and down scrolling are necessary. Prefereably the scrolling should take as little CPU time as possible. I also need to have the sprites usable over the entire screen. I recall some discussion here a while back about making each text line be a different viewport and then reconstructing the view 60 times a second (or so). That would be great, but how well do the sprites work across viewport boundaries? I know the Intuition pointer goes blank on the scan line between two different screens. Any other schemes for scrolling (even if they are not quite what I'm looking for) are welcomed. Please mail replies. I'll summarize to the net. Darren Leigh dlleigh@media-lab.media.mit.edu mit-amt!dlleigh
33014-18@sjsumcs.sjsu.edu (Eduardo Horvath) (11/13/89)
In article <993@mit-amt.MEDIA.MIT.EDU> dlleigh@media-lab.media.mit.edu.UUCP (Darren Leigh) writes: >I'm looking for various ways to do fast and smooth vertical scrolling >of text. Both up and down scrolling are necessary. Prefereably the >scrolling should take as little CPU time as possible. I also need to >have the sprites usable over the entire screen. > You could consider creating a really big bitmap, and changing the modulo for the start of the bitmap. This takes almost zero cpu time. If the bitmap is 3x the height (width) of the screen, you can do a quick blit to copy the bottom of the screen to the top, change the modulo to the top of the screen, and then continue. =============================================================================== //x = "When things are blackest, /// \ Try: 33014-18@sjsumcs.SJSU.EDU = I just tell myself `cheer /// \ = up, things could be worse!' /// \ Eduardo Horvath = And sure enough, \\\ ///=======\ = they get worse!" \\\/// \ = -The Great Skeeve \xxx \miga. The computer for the corruptive mind. ===============================================================================