[Freeciv-Dev] Re: different iso drawing algorithms

[Raimar Falke <rf13@xxxxxxxxxxxxxxxxx>]

On Sat, Dec 14, 2002 at 02:20:14AM -0500, Jason Short wrote:
> On Fri, 2002-12-13 at 23:52, Rafa³ Bursig wrote:
> 
> > Flush/refresh/update ( what name you want ) "copy" this buffer to 
> > screen.( this take some time )
> 
> x11perf -copypixwin100
> x11perf -copypixpix100
> 
> On my system, there was about a 15% slowdown writing to the screen
> versus writing to another pixmap.  This is far less than I had thought. 
> On Raimar's system there was about a 50% slowdown.
> 
> I also found that in iso mode about 35% of the drawing time was spent
> drawing terrain and 35% was spent drawing roads/rails (in a high-tech
> society).  I suspect using a two- or a three-layered system could cut
> down hugely on the drawing time in most cases.  The "bad" case is where
> the screen is recentered - in which case we have to redraw everything
> unless we do something clever.

IMHO we have to consider two scenarios here:
 1) updates of certain tiles and/or the city descriptions at the end
 of the turn. Your patch decouples the in a nice way. While the patch
 is ok the idea we follow is different: I see the first backing store
 tile-based with easy update rules and the second backing store is for
 all the objects which aren't tile-based (city descriptions, goto
 lines, ...). So there is IMHO no need for any other layer.

 2) recenter (other by mouse click or via packets): I see two
 solutions:
   a) make the backing store bigger (as large as the map) -> a lot of
   memory for large tilesets
   b) prepare tiles or more general lists of sprites: see
   http://lists.complete.org/freeciv-dev@xxxxxxxxxxx/2001/08/msg00194.html.gz
   and
   http://lists.complete.org/freeciv-dev@xxxxxxxxxxx/2001/10/msg01036.html.gz.

        Raimar

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