🚀 go-pugleaf

In article <C0IEow.326@bcstec.ca.boeing.com> mce5921@bcstec.ca.boeing.com (Martin Emde) writes:

>Can anyone out there be more specific as to how those games work
>that sense screen position?  How does it compensate for different
>sized images and varying distances from the TV?

The idea is that the video controller chip always knows where _it_ is
scanning, so it doesn't matter what the output device is.  That is: When
the photo-sensor in the gun detects light (caused by the raster scan of the
TV), the video controller latches what position it's currently displaying.

The TV is scanning through the display with a very bright beam -- much
brighter than the average picture intensity (i.e., if the beam weren't
moving, it'd be a lot brighter than when your TV is displaying the beam
being moved all around the screen).

The Nintendo games I've seen also change all the colors of things you
should be able to hit vs. those you shouldn't be able to hit to either
black or white, which makes the jobs of the photosensor in the gun easier
still.

					---Joel Kolstad