Up to now 3D has been considered exclusively as giving different images to right and left lenses. Accordingly in this system the computer screen changes in a rapid cycle and the computer sends a signal to the spectacles which the viewer is wearing to alternately change from opaque to transparent in phase with the cycle on the computer screen. However there is one further component of 3D which has not up till now been considered, and that id movement of the viewer himself/herself. According in the spectacles there is a ultrasonic transmitter. With 3 microphones the computer can tell exactly where the viewer is, and thereby produce an appropriate image.
It is clear that some sophisticated graphics is required, although a multicored graphics chip should, according to Moore's law, be capable of doing this in the not too distant future. If we place an image (say) 1-3 m behind the front of the computer screen the solid illusion should be perfect and the computer screen will look exactly like a pane of glass with a real life solid object behind it.
Could more than one person view the screen? Not immediately, in general one person looks at a computer screen, although id we had n people looking at the computer we would need an extremely rapid cycling of images. 2n in our reaction cycle period. This would be possible with the 80 core processor of Moore's law. Our spectacles would then be opaque most of the time. The screen would have to be bright and most of the ambient light would be cut off.