I didn't do much rasters, but a few plasmas. The idea is basically the same. First and foremost you should go in Supervisor mode and switch off the interuptions:super%=GEMDOS(32,L:0)
BYTE{&Hfffffa09}=0Then, in your main loop, "stabilize" your code with the beam:REPEAT
b|=BYTE{&HFFFF8209}
UNTIL b|
VOID SHL(1,-b|)Then set the background color ( one scanline = 128 NOP @ 50Hz, so you might need to wait until the next scanline )CARD{&HFFFF8240}=value;And finally on exit, reset the interuptions and switch back to User mode:BYTE{&HFFFA09}=100
~GEMDOS(32,L:super%)