The Virtual Reality Modeling Language

7 Conformance

7.1 Introduction

7.1.1 Table of contents

Table 7.1: Table of contents

7.1.2 Objectives

This clause addresses conformance of VRML UTF-8 encoded files and conformance of VRML generators and VRML browsers that support the VRML UTF-8 encoding.

The primary objectives of the specifications in this clause are:

1. to promote interoperability by eliminating arbitrary subsets of, or extensions to, ISO/IEC 14772;
2. to promote uniformity in the development of conformance tests;
3. to promote consistent results across VRML browsers;
4. to facilitate automated test generation.

7.1.3 Scope

Conformance is defined for VRML UTF-8 encoded files and for VRML browsers which support UTF-8 encoded files. For VRML generators, conformance guidelines are presented for enhancing the likelihood of successful interoperability.

A concept of conformance to a VRML profile is introduced along with the rules which apply to this encoding.

This clause addresses the VRML data stream and implementation requirements. Implementation requirements include the latitude allowed for VRML generators and VRML browsers. This clause does not directly address the environmental, performance, or resource requirements of the generator or browser.

This clause does not define the application requirements or dictate application functional content within a VRML file.

The scope of this clause is limited to rules for the open interchange of VRML content using the UTF-8 encoding.

7.2 Conformance

7.2.1 Conformance of VRML UTF-8 encoded files

A VRML file is syntactically correct according to ISO/IEC 14772 if the following conditions are met:

1. The VRML file contains as its first element a VRML header comment (see 4.2.2, Header).
2. All entities contained therein match the functional specification of the corresponding entities of ISO/IEC 14772-3. The VRML file shall obey the relationships defined in the formal grammar and all other syntactic requirements.
3. The sequence of entities in the VRML UTF-8 encoded file obeys the relationships specified in ISO/IEC 14772-1 producing the structure specified in ISO/IEC 14772-1.
4. All field values in the VRML UTF-8 encoded file obey the relationships specified in ISO/IEC 14772-1 producing the structure specified in ISO/IEC 14772-1.
5. No nodes appear in the VRML file other than those allowed by ISO/IEC 14772-1 unless required for the encoding technique or those defined by the PROTO or EXTERNPROTO entities.
6. The VRML file is encoded according to the rules of ISO/IEC 14772-3.
7. It does not contain behaviour described as undefined elsewhere in this specification.

A VRML UTF-8 encoded file conforms to the core profile if:

8. It is syntactically correct.
9. It meets the restrictions of the profile as defined in ISO/IEC 14772-1--8. Core profile.

A VRML UTF-8 encoded file conforms to the base profile if:

10. It is syntactically correct.
11. It meets the restrictions of the profile as defined in ISO/IEC 14772-1--9. Base profile.

A VRML UTF-8 encoded file conforms to other profiles if:

12. It is syntactically correct.
13. It meets the restrictions of the profile as defined in the specification for that profile.

7.2.2 Conformance of VRML UTF-8 encoding generators

A VRML UTF-8 encoding generator conforms to this part of ISO/IEC 14772 if all VRML files that are generated are syntactically correct.

A VRML UTF-8 encoding generator conforms to a particular profile if it can be configured such that all VRML files generated conform to that particular profile.

7.2.3 Conformance of VRML UTF-8 encoding browsers

A VRML browser that supports the UTF-8 encoding conforms to a particular profile if:

1. It is able to read any VRML UTF-8 encoded file that conforms to that particular profile.
2. It presents the graphical and audio characteristics of the VRML nodes in any VRML UTF-8 encoded file that conforms to the that particular profile, within the latitude defined the specification for that particular profile.
3. It correctly handles user interaction and generation of events as specified in ISO/IEC 14772-1, within the latitude defined in the specification for that particular profile.
4. It satisfies the requirements of that particular profile in regard to minimum support requirements as defined in the specification for that particular profile.
5. It satisfies the general conformance requirements for browsers as stated in ISO/IEC 14772-1--7. Conformance.