This is probably a trite problem for most people, so here I am asking…
First, I uploaded a youtube video of my problem so you can laugh at me 
http://www.youtube.com/watch_private?v=sOFtIXdRljI&sharing_token=gvQhB6lDPXopldLItmSoRQ
I want to add texture from pictures to a human head model. I’m using glTexGen() to map textures to automatically assign texture coordinates. The results are alright, but the back side is horrifying as you can see. Textures also get mapped to the back of the head. This will get worse if i’m using a picture taken from a different angle, wrong texture will be more clearly visible as, for example, cheeks will have eyes.
Is there a way to somehow clip/stop the texturing at a certain plane? (i.e. texturing only the front half of the head)