Re: [Plib-devel] Sorting transparent polygons front to back?

[Steve B. <sjb...@ai...>]

Sam Stickland wrote:

> Are transparent or translucsant polygons sorted front to back in SSG?

No.

The only thing I do is to render all translucent polygons after all opaque
ones.

The problem is that there is no way to sort polygons front-to-back without
potentially having to chop them into pieces:

               /\    /\
              /  \  /  \
              \   \/   /
               \   \  /
                \   \/
                /\   \
               /  \   \
              /   /\   \
          ___/   /__\___\___
         |  /   /           |
         |_/   /____________|
          /___/       \___\

Ha!!  Sort *that*!

It's really even deeper than that.  Sorting by depth tends to cause
much more ssgState switching - which does bad things to performance.
It may also require me to split triangle strips and fans into triangles,
do multiple calls to the same Draw callbacks...it's gets VERY ugly.

So, since I can't do a great job, I decided to do nothing...sorry.

There are a number of things that simple games can do to eliminate
transparency ordering issues...but I'm afraid PLIB doesn't do much
to help.

On the bright side, look at my Tux_AQFH game - you almost never notice
hidden surface errors - despite numerous shadows, trees, herring,
lightning bolts, translucent ocean, translucent flippers on Tux, etc.

-- 
Steve Baker                  http://web2.airmail.net/sjbaker1
sjb...@ai... (home)  http://www.woodsoup.org/~sbaker
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