[Freeciv-Dev] Re: different iso drawing algorithms

[Jason Short <jdorje@xxxxxxxxxxxxxxxxxxxxx>]

On Sun, 2002-12-08 at 16:20, Rafa³ Bursig wrote:
> Map screen has 800x600 pixels
> RLE :
> Redraw time = 93, 103, 91, 92, 98, 87 ms
> Flush_fullscreen time :  ~ 24 ms
> 
> P233MMX
> 
> I think that there could be thirt metod.
> For now all basic terrain tile are normall store in memory and 
> gtk/gtk2/mui draw them partial to screen but when we can break each 
> tile into 4 rectangular parts (a,b,c,d) and store those parts in memory 
> insted one terrain tille. Drawing will be take normaly with little 
> change that parts will be separate sprites ( we don't make direct acces 
> to pixels or use mask ). SDLClient can use RLE on this parts.

Problems:

- To draw a tile requires redrawing of all 8 triangles.

- Since the areas are triangles, it is very difficult to break the
sprites into their constituent parts.

- Some sprites don't easily correspond to these 8 areas - for instance
coastal tiles, civ3-style terrain tiles, or civ3-style (rail)road tiles.

I realize that problem#3 is an issue for any drawing system, but if the
drawing is confined to within a single rectangular area (which both
systems provide) there are workarounds for all of them.  But this system
increases the complexity without directly addressing that.

jason