Create triangle shadow

Using the stencil buffer, you render your geometry once to generate the shadow volume, and again to the scene. I see no reason that a single triangle will not work.

I cannot understand u exactly, I use stenciled shadow volumes in my application for a model that contains triangles and quads as well, and it doesn't matter what kind of primitive you project your volumes from. Obviously the side of the extruded volume will be a quad. But here is a very useful document about the topic:

http://www.gamedev.net/columns/hardcore/shadowvolume

Oh ok thanks, I asked a simular question to this in another forum (but more on the imlimentation)... not gamedev and they said you could only do it with quads, not triangle. This will make life a whole lot easier! Thanks for your replies.

For the stencil technique to work the shadow volume doesn't have to be build by quads! It can be build by triangles and every polygon you like...