This paper reports on an interactive system for manipulating a tensor-product B-spline approximation to field data for applications in which contours are of interest. The features of the system are: an interpolation t...
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Several different adaptive subdivision algorithms are developed for a set of Bézier triangle surfaces which generate piecewise planar approximations to the surfaces. They are called adaptive because they use more...
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Several different adaptive subdivision algorithms are developed for a set of Bézier triangle surfaces which generate piecewise planar approximations to the surfaces. They are called adaptive because they use more triangles in areas of greater curvature of the surfaces and so adapt to the local geometry of the surfaces. The approximation is guaranteed not to deviate from the true surface more than an arbitrarily specified tolerance. Due to the many different ways of subdividing Bézier triangles, a number of adaptive subdivision algorithms are possible. This paper develops, categorizes, and compares some of the plausible ones. The chief distinctions between the algorithms are the number triangles that are generated and their degree of uniformity (eg ‘equilateralness’). Minimizing the number of triangles generated is important for efficient processing on the approximation. However, very nonuniform triangles, which can aid in this minimization, can also cause severe numerical problems.
Fast algorithms for pre-filtered anti-aliasing previously operated solely on straight line objects; this work extends the class of objects to include circles and ellipses. The new algorithms do not require floating po...
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Fast algorithms for pre-filtered anti-aliasing previously operated solely on straight line objects; this work extends the class of objects to include circles and ellipses. The new algorithms do not require floating point, square root, or division operations in the inner loops. When rendering against a constant background, a single inner loop multiapplication operation may also be eliminated. We describe in detail how the technique is applied to rendering an octant of a filled circle using a square area integration filter. We briefly describe the extensions necessary for different types of anti-aliased circles and ellipses. We show how pre-computed filters stored in a lookup table may be implemented.
A natural language based color naming system for color raster graphics, the Artist's Color Naming System (ACNS), is introduced. ACNS is an English-based nomenclature which is a high-level alternative to the numeri...
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This paper focuses on the problem of management of CAD data by investigating the use of the software engineering principles of data abstraction and object-oriented programming as means for managing the volume and comp...
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In order to make computer programs more readable, understandable, appealing, memorable, and maintainable, the presentation of program source text needs to be enhanced over its conventional treatment. Towards this end,...
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Standardization of a high performance blackplane bus, so that it can accommodate boards developed by different vendors, implies the need for a standardized cache consistency protocol. In this paper we define a class o...
ISBN:
(纸本)9780818607196
Standardization of a high performance blackplane bus, so that it can accommodate boards developed by different vendors, implies the need for a standardized cache consistency protocol. In this paper we define a class of compatible consistency protocols supported by the current IEEE Futurebus design. We refer to this class as the MOESI class of protocols; the term “MOESI” is derived from the names of the states. This class of protocols has the property that any system component can select (dynamically) any action permitted by any protocol in the class, and be assured that consistency is maintained throughout the system. Included in this class are actions suitable for copyback caches, write through caches and non-caching processors. We show that the Berkeley protocol and the Dragon protocol fall within this class, and can be extended to be compatible with other members of the class. The Illinois, Firefly and Write-Once protocols can be adapted to be compatible with this class; the facilities of he Futurebus currently do not support those protocols without adaptation. We discuss very briefly performance choices among protocols, and also other issues relating to a standard bus consistency protocol.
This paper reports on an interactive system for manipulating a tensor-product B-spline approximation to field data for applications in which contours are of interest. The features of the system are: an interpolation t...
ISBN:
(纸本)9780897912136
This paper reports on an interactive system for manipulating a tensor-product B-spline approximation to field data for applications in which contours are of interest. The features of the system are: an interpolation technique for approximating fields defined from scattered or gridded data by tensor-product B-splines, an interactive display providing control-vertex manipulation of the resulting B-spline approximation, and a contouring algorithm that is designed specifically for B-spline surfaces.
Five primary approaches to texture synthesis for computergraphics are surveyed: a syntactic approach, a statistical approach, a growth model approach, a computer drafting approach, and a stochastic modeling approach....
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Five primary approaches to texture synthesis for computergraphics are surveyed: a syntactic approach, a statistical approach, a growth model approach, a computer drafting approach, and a stochastic modeling approach. Most of these methods, derived from texture analysis techniques or from mathematical models of texture, have a relatively low-level, cumbersome way to define, manipulate, or input textures. As an alternative, a high-level language approach is proposed. It provides easy-to-use coding mechanisms to define, synthesize, and manipulate textures. The high-level approach is introduced by means of the Texture Synthesis Language (TSL).
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