Hi,
On Sun, Dec 14, 2008 at 6:12 PM, Heiko Schulz <aeitsch...@yahoo.de> wrote:
>
> My last cloudset has fewer but larger sprites. I did this because I noticed
> that it saves a lot of fps. On the forum Gijs noticed the same with my
> cloudset.
>
> Mores sprites means more alpha and more textures which is always a
> fps-killer.
> I'm pretty sure that there is another solution looking to X-plane which
> seems to use the same technic for their clouds.
>
Fewer bigger sprites with few parts of the sprite with 0 < alpha < 1. One
opaque pre-pass drawing front to back with
alpha culling != 1 and blending off to fill up z-buffer then a second pass
back to front with alpha culling < 1 and blending on.
Second pass gets massively z-culled, saving on rop blending bandwidth. First
pass gets also z-culled by itself.
It's a tradeoff between cpu and gpu fill and blend rate, whatever is your
bottleneck.
Sadly, that changes between machines, so the opaque pre-pass should be a
configurable.
>
> Regards
> HHS
>
greetings,
yon
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