EN ISO/IEC 9592-4:1996

SLOVENSKI STANDARD
SIST EN ISO/IEC 9592-4:1998
01-januar-1998
Information processing systems - Computer graphics - Programmer's Hierarchical
Interactive Graphics System (PHIGS) - Part 4: Plus Lumiere und Surfaces, PHIGS
PLUS (ISO/IEC 9592-4:1992, including Technical Corrigendum 1:1994)
Information processing systems - Computer graphics - Programmer's Hierarchical
Interactive Graphics System (PHIGS) - Part 4: Plus Lumiere und Surfaces, PHIGS PLUS
(ISO/IEC 9592-4:1992, including Technical Corrigendum 1:1994)
Systemes de traitement de l'information - Infographie - Interface de programmation du
systeme graphique hiérarchisé (PHIGS) - Partie 4: Plus Lumiere und Surfaces, PHIGS
PLUS (ISO/IEC 9592-4:1992, Rectificatif Technique 1:1994 inclus)
Ta slovenski standard je istoveten z: EN ISO/IEC 9592-4:1996
ICS:
35.140 5DþXQDOQLãNDJUDILND Computer graphics
SIST EN ISO/IEC 9592-4:1998 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO/IEC 9592-4:1998

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SIST EN ISO/IEC 9592-4:1998

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SIST EN ISO/IEC 9592-4:1998

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SIST EN ISO/IEC 9592-4:1998
ISO/IEC
I N TE R NAT1 O NA L
9592-4
STANDARD
First edition
1992-09-01
Information processing systems - Computer
graphics - Programmer% Hierarchical
Interactive Graphics System (PHIGS) --
Part 4:
Plus Lumière und Surfaces, PHIGS PLUS
Syst&mes de traitement de l’information -- lnfographie - lnterface de
programmation dlJ système graphique hiérûrchis4 (PH/GS) -
Partie 4: Plils Lumiére und Surfaces, PHlGS PLUS
Reference number
ISQ/IEC 9592-4: 1992( E)

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SIST EN ISO/IEC 9592-4:1998
ISO/IEC 9592-4:1992(E)
Contents Page
1 scope . 1
2 Normative references . 2
3 Definitions . 3
4 The PHIGS PLUS system . 7
4.1 About this part of ISO/IEC 9592 . 7
4.1.1 Specification and conformance . 7
4.1.2 Regismtion . 7
4.1.3 Notational conventions . 7
4.2 Overview and concepts . 8
4.2.1 Overview . 8
4.2.2 Concepts . .8
4.3 PHIGS PLUS structure elements . 10
4.3.1 Output primitive structure elements . 10
4.3.2 Attribute specification structure elements . 10
4.3.3 Structure element archive . 11
4.4 Output primitives . 12
4.4.1 General . 12
4.4.2 Polyline set with colour . 12
4.4.3 Fill area set with data . 12
4.4.4 Cell array PLUS . 13
4.4.5 Set of fill area set with data . 13
4.4.6 Triangle set with data . 13
4.4.7 Triangle strip with data . 13
4.4.8 Quadrilateral mesh with data . 14
4.4.9 Non-uniform B-spline curve . 14
4.4.10 Non-uniform B-spline curve with colour . 16
4.4.11 Non-uniform B-spline surface . 16
4.4.12 Surface trimming . 17
4.4.13 Non-uniform B-spline surface with data . 18
4.4.14 Area primitives and facets . 20
4.4.15 Modelling clip . 20
4.5 Output primitive attributes . 21
4.5.1 General colour specification . 21
4.5.2 Extended workstation state and description tables . . 22
4.5.3 PHIGS PLUS attributes applied to PHIGS output primitives . 23
4.5.3.1 General . 23
4.5.3.2 Polyline attributes . 25
4.5.3.3 Polymarker attributes . 25
4.5.3.4 Text attributes . 25
4.5.3.5 Annotation text attributes . 25
4.5.3.6 Fill area attributes . 26
4.5.3.7 Fill area set attributes . 26
Q ISOllEC 1992
All rights reserved . No part of this publication may be reproduced or utilized in any form
or by any means. electronic or mechanical. including photocopying and tnicrofilrn. without
permission in writing from the publisher .
ISOllEC Copyright Office Case Postale 56 * CH-1211 Genève 20 Switzerland
Printed in Switzerland
ii

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SIST EN ISO/IEC 9592-4:1998
ISO/IEC 9592-4:1992(E)
4.5.3.8 Cell array attributes . 26
4.5.3.9 Generalized drawing primitive attributes . 26
4.5.4 Attributes applied to PHIGS PLUS output primitives . 27
4.5.4.1 General . 27
4.5.4.2 Polyline set with colour attributes . 27
4.5.4.3 Fill area set with data attributes . 27
4.5.4.4 Cell array PLUS attributes . 27
4.5.4.5 Set of fill area set with data attributes . 27
4.5.4.6 Triangle set with data attributes . 27
4.5.4.7 Triangle strip with data attributes . 27
4.5.4.8 Quadrilateral mesh with data attributes . 27
4.5.4.9 Non-uniform B-spline curve attributes . 31
4.5.4.10 Non-uniform B-spline curve with colour attributes . 32
4.5.4.11 Non-uniform B-spline surface attributes . 33
4.5.4.12 Non-uniform B-spline surface with data attributes . 36
4.5.4.13 Individual edge control for PHIGS PLUS area primitives . 36
4.5.4.14 Reflectance properties . 36
4.5.5 Implicitly specified attributes . 37
4.5.5.1 General . 37
4.5.5.2 Facet normal . 37
4.5.5.3 Facet orientation . 38
4.5.5.4 Reflectance normal . 38
4.5.5.5 Intrinsic colour . 39
4.5.6 Facet culling . 40
4.5.7 Distinguishing facets by orientation . 40
4.5.8 Hidden line and hidden surface removal . 40
4.5.9 Stability . 40
4.6 The PHIGS PLUS rendering pipeline . 41
4.6.1 General . 41
4.6.1.1 Primitives affected by the rendering pipeline . 41
4.6.1.2 The effect of the interior style on lighting and shading . 41
4.6.1.3 Aspects and attributes used in the rendering pipeline . 42
4.6.2 Data mapping . 42
4.6.3 Lighting . 47
4.6.3.1 Reflectance calculation . 47
4.6.3.2 Light sources . 48
4.6.3.3 Workstation light sources . 48
4.6.4 Shading . 49
4.6.4.1 General . 49
4.6.4.2 Interpolation . 49
4.6.4.3 Colour interpolation . 49
4.6.4.4 Data interpolation . 50
4.6.4.5 Normal-vector interpolation . 50
4.6.4.6 Polyline shading . 50
4.6.4.7 Interior shading . 50
4.6.5 The rendering colour modcl . 53
4.6.6 Depth cueing . 54
4.6.7 Colour mapping . 55
4.7 Workstations . 57
iii

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SIST EN ISO/IEC 9592-4:1998
ISO/IEC 9592-4: 1992(E)
4.8 Graphical input . 58
4.9 Limitations . 59
4.9.1 General . 59
4.9.2 Non-planar geometry and data . 59
4.9.3 Relationship of shading method to geometry . 59
4.9.4 Normal-vector interpolation . 59
4.9.5 Effects of transformations . 59
4.9.6 Approximation criteria and data splines . 60
4.10 Minimum support criteria . 61
5 PHIGS PLUS Functional Specification . 65
5.1 Notational Conventions . 65
5.2 Output primitive functions . 65
5.3 Attribute specification functions . 82
5.3.1 Bundled attribute selection . 82
5.3.2 Individual attribute selection . 84
5.3.3 Aspect source flag setting . 99
5.3.4 Workstation attribute table definition . 100
5.4 inquiry functions . 112
5.4.1 Introduction . 112
5.4.2 Inquiry functions for workstation state list . 113
5.4.3 Inquiry functions for workstation description table . 123
5.4.4 Inquiry functions for structure content . 138
6 PHIGS PLUS data structures . 143
6.1 General . 143
6.2 Notation and Data Types . 143
6.3 PHIGS PLUS additions and replacements to the PHIGS description table . 144
6.4 PHIGS PLUS additions and replacements to the PHIGS traversa1 state list . 146
6.5 PHIGS PLUS additions and replacements to the PHIGS workstation state list . 148
6.6 PHIGS PLUS additions and replacements to the PHIGS workstation descriplion table . 151
Annex A Function lists . 155
A.l Alphabetic . 155
A.2 Order of appearance . 157
Annex B Error list . 161
B.l Implementation dependent . 161
B.2 Output attributes . 161
B.3 Output primitives . 161
Annex C Suggested reflectance formulae . 163
C.1 Variable definitions and their sources . 163
C.2 Reflectance formulae . 164
Annex D Allowable differences in PHIGS PLUS implementalions . 167
D.1 Introduction . 167
D.2 Workstation dependent differences . 167
Annex E Suggested depth cueing formulae . 169
E.l Linear colour interpolation . 169
E.2 Definitions . 169
E.3 Formulae . 169
Annex F Attribute table . 171
iv

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SIST EN ISO/IEC 9592-4:1998
ISOhEC 9592-4:1992(E)
r
%4
Foreword
IS0 (the International Organization for Standardization) and IEC (the
International Electrotechnical Commission) form the specialized system
for worldwide standardization. National bodies that are members of IS0
or IEC participate in the development of International Standards through
technical cornmittees established by the respective organization to deal
with particular fields of technical activity. IS0 and IEC technical com-
mittees collaborate in fields of mutual interest. Other international or-
ganizations, governmental and non-governmental, in liaison with IS0
and IEC, also take part in the work.
In the field of information technology, IS0 and IEC have established a
joint technical committee, ISO/IEC JTC 1. Drafi International Standards
adopted by the joint technical committee are circulated to national bod-
ies for voting.
Publication as an International Standard requires ap-
proval by at least 75 Oh of the national bodies casting a vote.
International Standard ISO/IEC 9592-4 was prepared by Joint Technical
Committee IÇOAEC JTC 1, lnformation technology.
ISO/IEC 9592 consists of the following parts, under the general title ln-
formation processing systems - Computer graphics - Programmer's
Hierarchical Interactive Graphics System (PHIGS):
-- Part 1: Filnctional description
-- Part 2: Archive file format
- Pari 3: Clear-fexf encoding of archive file
- Pari 4: Plus Lumière und Surfaces, PHlGS PLUS
Annex D forms an integral part of this part of iSO/IEC 9592. Annexes A,
B, C, E and F are for information only.

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SIST EN ISO/IEC 9592-4:1998
ISO/IEC 9592-4:1992(E)
In t reduction
ISO/IEC 9592-1 provides a set of functions for the definition, display and modification of 2D or 3D graphical data. It does
not provide support for simulating the effects of lighting, shading, and other properties that are important for the display
data. This part of ISODEC 9592 specifies a basic set of such functionality for use in conjunction with
of multi-dimensional
the functionality defined in ISODEC 9592-1 and its amendment 1.
To provide this support, PHIGS PLUS defines
a) output primitives specified by rational and non-rational B-spline curves and surfaces;
b) output primitives containing both geometric and non-geometric data in their definition;
c) attributes that control the application of lighting and shading to both the new primitives and the primitives specified
in ISO/IEC 9592-1;
d) a generalized mechanism for colour specification to allow non-indexed colour specification.

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SIST EN ISO/IEC 9592-4:1998
INTERNATIONAL STANDARD ISO/IEC 9592-4:1992(E)
Information processing systems-
Computer graphics-
Programmer’s Hierarchical Interactive Graphics System
(PH1GS)-
Part 4-Plus Lumière und Surfaces, PHIGS PLUS
1 Scope
This part of ISO/IEC 9592 specifies an additional set of functionality of the Programmer’s Hierarchical Interactive
Graphics System. This additional functionality is intended to satisfy basic application requirements in the areas of
lighting and shading and defines additional primitives and functionality for controlling the rendering of 3D objects. It
relies on the coexistence of the functions and functionality specified in ISO/IEC 9592-1, and is meant to extend that func-
tionality in the above areas.
It is the intent of this part of ISO/IEC 9592 to be compatible with ISODEC 9592-1 and its Amendment 1. That is, in a stan-
dard conforming PHIGS PLUS implementation all functions defined in ISO/IEC 9592-1 and not altered by ISO/IEC 9592-4
shall perform as specified in ISODEC 9592-1, and all functions defined in ISO/IEC 9592-1 but altered in ISO/IEC 9592-4
shall perform as specified in ISO/IEC 9592-1 and ISODEC 9592-4, and, an application functionally conforming to
ISO/IEC 9592-1 produces the same effect running on a standard conforming PHIGS PLUS implementation as it would
pmduce running on a standard conforming PI-IJGS ISOiIEC 9592-1 impleineiitation, cxcepiing such differences among
implementations as are allowed in ISODEC9592-1. If PHIGS PLUS functions are used, they should only cause the
extended effects specified in this part of ISO/IEC 9592.
This part of ISODEC 9592 defines a language indcpcndcnt extension to a graphics system for integration into a program-
ming language. PHIGS PLUS is embedded in a language layer obeying the particular conventions of the language. Such
language bindings are specified for IS0 or ISO/IEC languages in ISOflEC 9593.
1

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SIST EN ISO/IEC 9592-4:1998
ISOhEC 9592-4: 1992(E)
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this part of
ISOAEC 9592. At the time of publication, the editions indicated were valid. All standards are subject to revision, and
parties to agreements based on this part of ISOAEC 9592 are encouraged to investigate the possibility of applying the
most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid
International Standards.
ISODEC 646: 1991, Information technology - IS0 7-bit coded character setfor information exchange.
ISOAEC 7942: 1985, Information processing systems - Computer graphics - Graphical Kernel System (GKS)
functional description.
ISO/IEC 863211987, Information processing systems - Computer graphics - Metafile for storage and transfer
...