I want to ask a question about Shadow Volumes. I found the silhoutte edges and i extend the shadow volume but when i do the gl... things (glStencilOp,glStencilFunc....) the result is a black window ( Nothing Rendered). Why is that? When i draw normally (without the Stencil) the shadow volume and the silhoutte edges they appear in the right way, but when i put it on the stencil none of the objects appear on the screen. I Use the same code on stencilling with the Nehe tutorial. Is there a problem with the opengl Lights? Where i can find a simple tutorial on stencil shadow volumes,becides Nvidia. The Nvidia stencil Shadow Volume code is hard to follow because the code is little ugly. PS. I render the black window that cover the entire screen and i want to ask a question. Why this black window need it? To optimize the code because you don''t render the third pass of the Scene? Please Answer...!!!!! Thanks in advance.

If your scene is completely black, that is certainly because the stencil buffer contains bad values or that you use the wrong stencil functions.

If you started from the NeHe tutorial, I can hardly see where you made a mistake. The NeHe stencil shadow tutorial is very good.