Space/query-time tradeoff for computing the visibility polygon
نویسندگان
چکیده
منابع مشابه
Space-Query-Time Tradeoff for Computing the Visibility Polygon
Computing the visibility polygon, VP, of a point in a polygonal scene, is a classical problem that has been studied extensively. In this paper, we consider the problem of computing VP for any query point efficiently, with some additional preprocessing phase. The scene consists of a set of obstacles, of total complexity O(n). We show for a query point q, V P (q) can be computed in logarithmic ti...
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We present several algorithms for computing the visibility polygon of a simple polygon P from a viewpoint inside the polygon, when the polygon resides in read-only memory and only few working variables can be used. The first algorithm uses a constant number of variables, and outputs the vertices of the visibility polygon in O(nr̄) time, where r̄ denotes the number of reflex vertices of P that are...
متن کاملComputing a visibility polygon using few variables
We present several algorithms for computing the visibility polygon of a simple polygon P from a viewpoint inside the polygon, when the polygon resides in read-only memory and only few working variables can be used. The first algorithm uses a constant number of variables, and outputs the vertices of the visibility polygon in O(nr̄) time, where r̄ denotes the number of reflex vertices of P that are...
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Visibility computation is a classical problem in computer graphics. A wide variety of algorithms provides solutions with a different accuracy. However, the four dimensional nature of the 3D visibility has prevented for a long time from leading to exact from-polygon visibility algorithms. Recently, the two first tractable solutions were presented by Nirenstein, then Bittner. Their works give the...
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A deflated polygon is a polygon with no visibility crossings. We answer a question posed by Devadoss et al. () by presenting a polygon that cannot be deformed via continuous visibility-decreasing motion into a deflated polygon. We show that the least n for which there exists such an n-gon is seven. In order to demonstrate non-deflatability, we use a new combinatorial structure for polygons,...
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ژورنال
عنوان ژورنال: Computational Geometry
سال: 2013
ISSN: 0925-7721
DOI: 10.1016/j.comgeo.2012.10.004