dlleigh@mit-amt.MEDIA.MIT.EDU (Darren L. Leigh) (05/10/88)
I am trying to create a hi-res, interlaced horizontally scrolling display for use in my heart monitor project. I have been having some weird problems with wide bitmaps and with the ScrollVPort function. When the bitmap I am using is 1024 or fewer pixels wide, the display is fine and I just get some hashing when I call ScrollVPort (I know the docs said there would be some hashing, but that much?!?). When the bitmap is 1025 or more pixels wide, I get junk on the screen (even after clearing the associated rastport, and without doing any scrolling). The junk seems to scroll OK, but jumps around a lot. I don't seem to be able to draw onto the junk either. The bitmap in question is attached to the second rasinfo structure of a dual playfield display (many thanks to those who helped me get that working), but I get the same problem with single playfield displays. Am I doing something wrong? Is there a bug? Or am I just going crazy? ============================================================================= Darren Leigh dlleigh@media-lab.mit.edu 362 Memorial Dr. mit-amt!dlleigh Cambridge, MA 02139
papa@pollux.usc.edu (Marco Papa) (05/10/88)
In article <2465@mit-amt.MEDIA.MIT.EDU> dlleigh@media-lab.media.mit.edu.UUCP (Darren L. Leigh) writes: >I am trying to create a hi-res, interlaced horizontally scrolling |display for use in my heart monitor project. I have been having some |weird problems with wide bitmaps and with the ScrollVPort function. | |When the bitmap I am using is 1024 or fewer pixels wide, the display ^^^^^^^^^^^^^ |is fine and I just get some hashing when I call ScrollVPort (I know |the docs said there would be some hashing, but that much?!?). When |the bitmap is 1025 or more pixels wide, I get junk on the screen (even ^^^^^^^^^^^^ |after clearing the associated rastport, and without doing any |scrolling). The junk seems to scroll OK, but jumps around a lot. I |don't seem to be able to draw onto the junk either. |The bitmap in question is attached to the second rasinfo structure of |a dual playfield display (many thanks to those who helped me get that |working), but I get the same problem with single playfield displays. |Am I doing something wrong? Is there a bug? Or am I just going crazy? According to the RKM manual (page 2-20 of Vol. 1 of the CBM edition) : "The big picture (called a raster and represented by the BitMap structure) can have a maximum size of 1024 by 1024. " -- Marco Papa 'Doc' -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= uucp:...!pollux!papa BIX:papa ARPAnet:pollux!papa@oberon.usc.edu "There's Alpha, Beta, Gamma and Diga!" -- Leo Schwab [quoting Rick Unland] -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
cmcmanis%pepper@Sun.COM (Chuck McManis) (05/10/88)
In article <2465@mit-amt.MEDIA.MIT.EDU> (Darren L. Leigh) writes: > I am trying to create a hi-res, interlaced horizontally scrolling > display ... When the bitmap I am using is 1024 or fewer pixels wide, > the display is fine ... When the bitmap is 1025 or more pixels wide, > I get junk ... Darren, you can't scroll a bitmap that is more than (actually 1008 pixels wide) The reason being that the blitter cannot handle it. When the new blitter/Agnus becomes available this will be possible but it isn't yet. With custom blits you can play games with multiple bitmaps although I suspect you can do that now since you can't display a 1024 wide bitmap yet. Hashing occurs when you don't wait for the bottom of the frame before scrolling. --Chuck McManis uucp: {anywhere}!sun!cmcmanis BIX: cmcmanis ARPAnet: cmcmanis@sun.com These opinions are my own and no one elses, but you knew that didn't you.