by Kate » Wed Apr 30, 2008 12:42 pm
This is a GL-specific effect that's been around since the days of the original ZDoomGL; more specifically this is
environment mapping. The way GL does this particular environment map is that the specified image is cast into an inward cubical or spherical shape, then the player's viewpoint is traced against the plane to see how light would reflect off of it. The direction that the reflected beams would travel off of the plane indicate what part of the inverted outer image is rendered onto the surface in question at that specific point.
As I see it, this would likely take a massive effort to make work in software and would generally be too slow to be useful.
This is a GL-specific effect that's been around since the days of the original ZDoomGL; more specifically this is [url=http://en.wikipedia.org/wiki/Reflection_mapping]environment mapping[/url]. The way GL does this particular environment map is that the specified image is cast into an inward cubical or spherical shape, then the player's viewpoint is traced against the plane to see how light would reflect off of it. The direction that the reflected beams would travel off of the plane indicate what part of the inverted outer image is rendered onto the surface in question at that specific point.
As I see it, this would likely take a massive effort to make work in software and would generally be too slow to be useful.