Re: PIC/SCR Compression (Was:Re: [ql-users] DISP_COLOUR)

[Dave]

On Tue, 19 Feb 2002, Marcel Kilgus wrote:

> Well, there is just no way to avoid flickering. On fast machines the
> possibility that flicker appears gets smaller but it's never zero.

I slightly disagree. Not much, just a little bit.

If you know how long it takes to carry out task X, and that you can carry
out task X a certain amount of times between each frame being read out for
display, simply make the program aware of that interrupt, and carry out
the task right after the frame has been drawn, confident of finishing it
before the next interrupt. If there's too much activity to redraw in the
time available, drop the lower priority redraws.

On other architectures it's easy to have two video buffers, and alternate
between them - I don't know how easy it is to move the start of screen
memory on the QL and derivitives (on the vanilla QL it's prolly
impossible) but hey, no problem - we'll find a way ;)

Dave
ql.spodmail.com