I was playing around with double sided alpha testing, i.e. alpha tests of
the form min<a<max, and this is the result. Of course most video cards
(all?) do not directly support this kind of alpha test. By using the stencil
buffer to hold the results of one portion of the test, the complete test can
be effectively emulated with 2 passes on not only current hardware, but also
older video cards. I have this singular effect demo with source code
available at http://bellsouthpwp.net/d/f/dfrey69/DoubleSidedAlphaTest.zip.
The demo uses both GLUT and DevIL and are not included. I believe I was
using version 1.6.5 of DevIL, and I have no idea which version of GLUT I
used since the glut32.dll properties doesn't show a version tab, I assume
its 3 something.
I should have another IOTD in the near future of a game I am about to
a.k.a Mastaba on the flipcode boards