Visibility with One Reeection
نویسندگان
چکیده
We extend the concept of the polygon visible from a source point S in a simple polygon by considering visibility with two types of reeection, specular and diiuse. In specular reeection a light ray reeects from an edge of the polygon according to the rule: the angle of incidence equals the angle of reeection. In diiuse reeection a light ray reeects from an edge of the polygon in all inward directions. Several geometric and combinatorial properties of visibility polygons under these two types of reeection are described, when at most one reeection is permitted. We show that the visibility polygon Vs(S) under specular reeection may be non-simple, while the visibility polygon Vd(S) under diiuse reeection is always simple. We present a (n 2) worst-case bound on the combinatorial complexity of both Vs(S) and Vd(S) and describe simple O(n 2 log 2 n) time algorithms for constructing the sets.
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