   Really big shadow volume problem
  I''m implementing real time shadow rendering with shadow volumes and stencil buffer on my game engine but I got a really big trouble that I dont even no if it haves a "cure".When I''m looking the light from this ( http://www.unidev.com.br/imagem/prob1.jpg ) angle the shadow looks nice, but when I am inside the volume a problem apears, the illuminated part becomes dark ( http://www.unidev.com.br/imagem/prob2.jpg ) and the shadowed part becomes illuminated.I see some FPS engines using this kind of shadowing but I think those games dont have this problem... what is the solution? 
  I think you should either be able to find it in here or in the pages it lnks to:http://developer.nvidia.com/object/fast_shadow_volumes.htmltj963 ;  Well I guess you are using the ZPass technique. Try Carmacks Reverse or ZFail. It will successfully handle cases where the viewport is shadowed. 