Re: [Algorithms] Maximizing overdraw == Optimizing hair rendering?

[Madoc E. <tm...@ti...>]

This is something on my to do list, but in my case performance is not 
a big issue.

I've tried alpha to coverage but I didn't get acceptable 
results with less than ~15 levels of transparency and even that wasn't 
great.
I've been hoping to accomplish what John suggests but haven't 
made the attempt yet. If that doesn't work out I will probably use 
depth peeling which I hope will give good results with few layers. This 
is probably too demanding for your application but if you're interested 
there is an nvidia demo with source.


----Original Message----
From: 
BO...@vv...
Date: 29-Jan-2008 08:26 PM
To: "Game Development 
Algorithms"<gda...@li...>
Subj: [Algorithms] 
Maximizing overdraw == Optimizing hair rendering?

Hi,

I'm currently 
looking into some simple solution to the ordering problem
for complex 
transparent meshes, particularly hair. I've seen the older
work, but 
our ultimate use case is less demanding (and I don't think we
can 
justify multiple passes at run-time).

 

Obviously, in the simplest 
case, it makes sense to render something like
hair "inside-out". It 
seems (to me) like that is the exact opposite
criteria used when trying 
to minimize overdraw. Thus, it follows that
using any algorithm to 
minimize overdraw, but inverting the cost
function, should produce a 
"mostly correct" ordering for hair?

 

In particular, I'd like to use 
the tipsy algorithm from "Fast Triangle
Reordering for Vertex Locality 
and Reduced Overdraw" [Sander, Nehab,
Barczak], to instead increase 
overdraw. I've tried lots of searches to
unify transparency sorting (eg 
hair) and overdraw, but there don't seem
to be many papers that make 
the connection. Is there some flaw in my
logic, or is it just so 
obvious that everyone takes it for granted?

 

-Brian Osman

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Vicarious Visions