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Post by mkarcz on May 14, 2016 23:16:48 GMT
Hello,
I am new here, so let me introduce myself before I post my problem:
I am 46, programmer at work, electronics and retro-computing hobbyist at home. Wife, kids, mortgage, problems, yada, yada... So the hobby is my venting outlet. Nice to meet you all.
Now to more interesting stuff:
I started to explore VDC graphics programming on C128. I am reading Compute's C128 Programmer's Guide and researching online while learning VDC programming.
I have been able to draw hi-res pixel by pixel graphics using 80-col chip, but after I return from graphics to text, my leftmost column in text mode is invisible. I must hit RUNSTOP/RESTORE to recover proper 80-col display. My C128's VDC has 16 kB of RAM.
This BASIC program reproduces the issue:
10 fast:ad=dec("cdcc") 20 sys ad,128,25:rem turn on graphics, turn off attributes 30 rem do something here, clean the screen, draw pixels etc. 70 getkey a$:sys ad,64,25:sys 65378:end:rem turn off graph., turn on attr., restore characters from rom
Do any of you guys have any idea what am I doing wrong?
Thanks!
--- Marek
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