shadow volumes and portals.. anyone ?

How can I render proper shadows using shadow volumes inside a portal? If the stencil buffer is used to clip a portal, I can’t use it while rendering the portal itself…

Any suggestion?

Have you considered using the stencil bit-masks (glStencilMask

I haven’t tried this, but you should be able to use one bit for the portal and the remaining 7 for the stencilled shadows…

What exactly are you trying to do?

Good luck,

It is quite simple to use recursive stencil masks. Just render your portal stencil e.g. with ref number x and then reder your shadows in your portal with ref values >x.