[SDL] Scrolling?

Tim Oertel toertel at rpa.net
Sun Apr 16 08:36:20 PDT 2000



Clifford Benoist wrote:
> 
> I am trying to scroll as fast as possible in an RPG that a few friends of
> mine are working on.  The scroll version I have now seems to be very slow.
> Is there any general suggestions that might speed things up.  I have come
> up with two ideas so far that just take to much time to copy things around.
> 
> The overall idea that I have is for 3 layers.  One for the background, One
> for Player / Walls, and one for roofs and other things.  If there is a best
> way to do this I need it.

You don't give many details about the sort of engine you have written,
but I
assume it is just a normal 2d sprite engine.  The typical way to handle
this is
to redraw the entire display every frame (preferably using double
buffering).
  If you redraw the entire display, scrolling is easy.  If you are
already
doing this and it isn't fast enough, my recommendation is to make your
engine
faster (in other ways).
  If you generally aren't scrolling, but moving around within a screen
you can
do some fancy updates by keeping track of what areas have changed and
update
only those, but that is more difficult to implement, moreso if you
double
buffer.  Another difficulty would be doing the actual scrolling, which
will
slow down your updates, since you will have to update the entire screen
anyway.

I can give more ideas, but without more info, I'd be shooting in the
dark...

> Thanks
> 
> --
> Clifford Benoist
> Lead Engine Programmer
> ABOGWAG Entertainment

Hope that helps

Tim
-- 
"Though you die, La Resistance lives on" - SP:BL&U



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