ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1989.tb00483.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1989.tb00484.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractA concise, complete and reliable algorithm for triangulating an arbitrary polygon is presented as a powerful core processor of PLAN‐I (Production Layout Automation Nucleus) system1. A polygon with inner loops is converted into a non‐self‐intersecting polygon (NIP) through adding‘Bridge Edges'. A triangular splitting algorithm for NIP is described in detail and successfully implemented. The program is about 300 lines in FORTRAN‐77. Sweeping and local operations with respect to the triangular‐faceted boundary representation are designed with the algorithm to improve functions of solid modeling in PLAN‐I. The algorithm of triangulation can also be applied to Boolean operations and

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1989.tb00485.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractA processing pipeline solution to the generation and display of octree encoded 3‐D objects is described. Particular emphasis is given to an algorithm which removes that part a of linear octree code which describes parts of the object which are invisible from a prescribed viewing position. The scope of the algorithm is restricted to viewing directions which are parallel to the Cartesian axes and to orthogonal projections. The algorithm is specifically designed to operate as a single stage within a pipeline of processe

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1989.tb00486.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe increasing importance of the User Interface Management System THESEUS stimulated the development of a formalized graphics input model that is based on the THESEUS input concepts. This paper presents cooperative work by the Zentrum fur Gra‐phische Datenverarbeitung (ZGDV), West Germany and IST/INESC, Portugal which aims to formalize, generalize and enhance the THESEUS input model and transfer it to a clean object‐oriented approach. The main goal was to establish concepts for specifying and managing user interfaces tailored to the requirements of graphics dialogues; among these concepts are the diversity of input devices, many different kinds of interaction techniques, higher complexity in dialogue structures, dynamic control over dialogue specification, a strong coupling of input and output instead of ping‐pong sequencing, powerful output capabilities, support of continuous input operations and a close interlocking between user interface component and applic

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1989.tb00487.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractIt is well known that homogeneous linear matrix transformations of the projective space may be efficiently used for the representation and the execution of common geometrical transformations but the general class of such transformations include also matrices which may cause numerical problems by transforming certain finite geometrical objects to infinity Different methods have been developed for handling such cases and this paper presents a new one called‘UW clipping’which is based on some interesting properties of projective transformations. Furthermore the paper introduces die concept of ‘conic sectors’ as a generalisation to half‐planes and halfspaces respectively, with the invariance property that such sectors are mapped onto other such sectors by projective transformations, and thus enable the transformation of clipping halfplanes and halfspaces. Finally the possibility of transforming die rectangular clipping box into the object space is inv

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1989.tb00488.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractIn designing graphical workstations for high‐level performance presentations of graphical models, the main goal nowadays is to perform some effective real‐time traversal and rendering of data. In this paper we present a reference model of parallel processing for graphics, taking into account the main aspects of colour rendering of solid hierarchical shapes; i.e., traversal of structures, hidden surfaces removal, shadow identification and light models. In particular, a parallel design of the main graphical algorithms is presented. Three abstract machines are proposed, designed respectively for data structure traversing, for depth ordering and shadows computation and finally for shape merging and screen processing. Such abstract machines, internally parallel, may be combined in various ways to define different physical architectures.CR Categories and Subject Descriptors: C.1.2 [Multiple Data Stream Architectures] MIMD Processors, Parallel Processors; 1.3.2 [Computer Graphics]Graphics Systems; 1.3.3 [Computer Graphics] Picture Generation ‐Display Algorithms, Viewing Algorithms; 1.3.7 [Computer Graphics]Three Dimensional Graphics and Realism ‐ Colour, Shading, Shadowing, Visible Line/Surface I Alg

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1989.tb00489.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1989.tb00490.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1989.tb00491.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe Migration Problem of GKS‐3D and PHIGS is discussed in this report under the view of the graphics reference model's description technique: the component and framework concept. Therefore the components of GKS‐3D and PHIGS are defined. The common and different concepts are indicated and the mapping from PHIGS to GKS‐3D and from GKS‐3D to PHIGS is done. This mapping is performed only on the components which have been proved as a description technique suited for such purposes. The migration has two different aspects. One is the theoretical approach to prove that such a migration is possible. The other one is more practical. It gives guide‐lines for the use of PHIGS and GKS‐3D and shows under which circumstances both can be us

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1989.tb00492.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY