HAM-8 problem
2 messages in this thread
I have a program that converts windows bitmaps into ham-8 images. The results
display fine in Dpaint, but when I try to display them using my own Amiga
software, I just get a big mess on the screen. This software worked fine with
ham-6 images.
(I am definitely drawing all 8 bitplanes to the correct locations)
Am I correct in thinking that the way to set Ham-8 mode is the same as a normal
8 bitplane mode with the addition of the ham bit in bplcon0? I set bplcon0 to
0a11h to try to set ham-8. Are there some other bits I need to set?
Also, does anyone know how to switch between PAL and NTSC? I want to do this
within my program, so the 'holding down the mouse buttons at boot time' or
using one of the mode switching programs from the libs is out. It must be
possible, because Dpaint does it!
TIA
Mal
Ok. I'm replying to myself in case anyone else has had the same problems I
have. The answers can be found in a superb file called howto.lha in one of the
libraries around here. Thankyou Comrade J! It describes all the features of
AGA, the fmode register, PAL/NTSC etc, copper lists, sprites, blitter, in a
USEFULL non-beginner sort of way.
HAM8 appears to work back to front compared to HAM6 – ie the bitplanes
controlling whether to select from the palette or change the r/g/b components
come first – not last as in HAM6. For some reason though, these two bitplanes
must come last when creating a HAM8 ilbm file for dpaint. Looks like those
guys were caught out too!
Mal