Aminet 2/Aminet AMIGA CDROM (1994)(Walnut Creek)[Feb 1994][W.O. 44790-1].iso/Aminet/dev/amos/AMOSList0993.lzh/AMOSLIST/[e-mail]_Sun Sep 5 20:00:43 1993.msg

Internet Message Format | 1993-10-03 | 2KB

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Date: 5 Sep 93 16:56:00 EST
From: "Andrew Church" <[e-mail]>
Subject: Re: Flicker/stuttering
To: "amos-list" <[e-mail]>
Status: O

>>One other type of flickering I have noticed occured in the earlier
>>versions of my current project.  When the screen was scrolled I noticed
>>the darker colours left a bright "After image".  I have since managed to
>>fix this but I do wonder why this occurs.
>
>Hmmm. I saw mention in a FAQ file that this could come from blitter operations
>taking a bit to long (more than one frame). Bit planes are apparently copied
>one at a time, and the resulting combinations can look funny.

  As I think I mentioned before (if it reached the list), this is what happens.
You could wind up with 2 bitplanes from the old picture and 2 from the new one
(for example).  The following code demonstrates this more clearly:

Screen Open 0,768,512,64,Laced
Palette 0,$F,,$F0,,,,$F00,,,,,,,,$8F,,,,,,,,,,,,,,,,$FFF
Cls 63 : Cls 0

  --Andy Church