thank your for your responses.
You're the first to address to my be my last name only
And I've been in these forums since 2006 ;)
Yey, im the first one : )
You seem to think that if one of the vertices has z > 1 then the triangle can't be rasterized on screen, it doesn't work like that.
Yes i realy thought this way, thanks for making this clear.
The shadow volume covers everything except what you've shaded.
But wouldn't this be false either. The shadow volume would enclose more objects then it should (Ok, in my sketch there is only one object, but if there would be more, then the shadow volume would enclose objects which were originally not shadowed)
The situation gets even worse, when you think about a shadow volume perpendicular to the z axis in eye space.
I wonder, why this behaviour is never mentioned in texts describing stencil shadows. Sketches i saw are just extruding the shadow volumes in eyespace where everything looks fine, but in clipspace i got this mess, where everything goes to the far plane.