The SEDRIS Data Representation Model
APPENDIX B - Constraints
Image Anchor SRF

Definition

Consider an <Image Anchor> instance A.

  1. The <Location> components of A shall be valid or extended as allowed by the SRF specified by the srf_context_info field of A.

  2. The <Location> components of A shall specify distinct coordinate values that shall not be collinear.

  3. A shall be either a component of one or more <Image> instances or of one or more <Image Mapping Function> instances, but not both.

  4. If A is a component of an <Image Mapping Function> instance F, and if F appears within the context of some SRF S, the following shall apply.

    1. The srf_context_info field of A shall specify the same SRF as S.

    2. If A specifies a non-planar projection, the <Location> components of A shall specify the endpoints of orthogonal axes.

Rationale

Every <Location> instance is required to be valid within the context of the SRF in which it is defined. (In this sense, "valid" includes the SRM concept of "extended" coordinates.) To allow an <Image Mapping Function> instance specified with an <Image Anchor> component to be applied correctly to the textured objects, its SRF and theirs are required to be compatible.

Example

No example supplied.

FAQs

No FAQs supplied.

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Last updated: July 26, 2006 Copyright © 2006 SEDRIS™