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Next: 11.1.3.2 Arbitrary Curved Reflectors Up: 11.1.3 Curved Reflectors Previous: 11.1.3 Curved Reflectors

11.1.3.1 Implicit and Extruded Reflectors

Since the objective with accelerated reflection is to find ``virtual'' vertices that appear to the viewer in the same place as an actual reflection, we can extend the planar technique to other reflection objects whose surface definitions are well-known.

For example, if our object is a sphere, the point on the sphere where a ray of light from vertex in our scene would reflect in order to reach the viewpoint can be computed directly [71]. Using the plane defined by that point and the normal to the sphere at that point, the real vertex can be reflected into a virtual vertex, as shown in Figure59 This reflection takes the place of the planar reflection transformation presented above, and is calculated for each reflected vertex rather than once per reflector.

 

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...hefigure . Virtual Reflected Vertices from a Curved Reflector}\\
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The clip plane technique discussed for planar reflectors cannot be used directly for curved reflectors, although it may be acceptable to approximate the reflector surface for a single reflected face. The stencil masking and texture techniques, however, work well for this case.


next up previous contents
Next: 11.1.3.2 Arbitrary Curved Reflectors Up: 11.1.3 Curved Reflectors Previous: 11.1.3 Curved Reflectors
David Blythe
1999-08-06