[Freeciv-Dev] Re: different iso drawing algorithms

[Jason Short <jdorje@xxxxxxxxxxxxxxxxxxxxx>]

On Sun, 2002-12-15 at 07:19, Raimar Falke wrote:
> On Sun, Dec 15, 2002 at 07:04:04AM -0500, Jason Short wrote:
> > On Sun, 2002-12-15 at 06:54, Raimar Falke wrote:
> > > On Sat, Dec 14, 2002 at 06:06:27PM -0500, Jason Short wrote:
> > > > On Sat, 2002-12-14 at 17:49, Raimar Falke wrote:
> > > > > On Sat, Dec 14, 2002 at 05:14:46PM -0500, Jason Short wrote:
> > 
> > > > > > - Below-animation gfx versus above-animation gfx.  Since the city
> > > > > > descriptions are normally drawn above units, it makes sense that 
> > > > > > they
> > > > > > should be drawn above unit animations.  Extending this idea, we can 
> > > > > > put
> > > > > > all animation gfx (including nukes, combat, etc.) on the same layer,
> > > > > > with graphics below and above.
> > > > > 
> > > > > I don't see what this buys us.
> > > > 
> > > > This gives better drawing quality!
> > > 
> > > It is possible to draw the animation on the first backing store. It
> > > may cause some extra refreshes but these are local (4 tiles for a
> > > move), uncommon and you also don't get flicker with this. Advantage is
> > > that you don't need a third layer which is most of the time empty and
> > > increase the cost of the normal draws.
> > 
> > Here I am not talking about flicker but about having the texts not
> > disappear when single-tile updates and animations happen.  I do not know
> > of any other way to do this besides having a separate buffer.
> 
> So what is the problem? Current situation (drawn in this order):
>  1) tiles (from backing store)
>  2) city descriptions
>  3) animations

This is only the case for update_map_canvas_visible.  For
refresh_tile_mapcanvas() or any of the animation functions the order is:

1) Tiles (from backing store)
2) Animation

and there is no possibility for drawing city texts.

In principle we could draw the city graphics from nearby cities;
however, the code is not structured to support this.  Also, we don't
really know how nearby they can be.

> Proposed:
>  1) tiles and animation (from first backing store)
>  2) city descriptions (from second backing store)

I still feel this method is best.  But as I said, I value correctness
very highly.  I doubt it would be slower than the current method.

jason