The SEDRIS Data Representation Model
APPENDIX A - Classes
Reference Vector Control Link

Class Name: Reference Vector Control Link

Superclass - <Control Link>

Subclasses

This DRM class is concrete and has no subclasses.

Definition

The specialized <Control Link> used to provide the connection between an ordered aggregation of <Expressions> and the target fields of a <Reference Vector>.

The v0_expr_index field is a 1-based index into the ordered aggregation of <Expressions>, and is used to select the specific <Expression> that controls the unit_vector.vector[0] field of the <Reference Vector>.

The v1_expr_index field is a 1-based index into the ordered aggregation of <Expressions>, and is used to select the specific <Expression> that controls the unit_vector.vector[1] field of the <Reference Vector>.

The v2_expr_index field is a 1-based index into the ordered aggregation of <Expressions>, and is used to select the specific <Expression> that controls the unit_vector.vector[2] field of the <Reference Vector>.

Primary Page in DRM Diagram:

Secondary Pages in DRM Diagram:

Example

  1. For the <Reference Vector> component of a <Polygon> the <Reference Vector> is its normal, so the <Expressions> would compute the 3 fields of the normal of a <Polygon>.

  2. A <Model> of a lighthouse has a <Geometry Model> with a <Union Of Geometry Hierarchy>, to which is attached a <Spot Light> representing the lighthouse's light. The <Spot Light> has a <Lobe Data> describing the shape of the light code, in which a <Reference Vector> specifies the light direction. The SE_LIGHT_DIRECTION <Reference Vector> has a <Reference Vector Control Link> to change the direction vector of the light so that the lighthouse light sweeps over an area rather than holding stationary.

FAQs

No FAQs supplied.

Constraints

None.

Composed of (two-way)(inherited)

Component of (two-way)

Inherited Field Elements

SE_String description; (notes)

Field Elements

SE_Integer_Unsigned expr_index_v0; (notes)
SE_Integer_Unsigned expr_index_v1; (notes)
SE_Integer_Unsigned expr_index_v2; (notes)

Notes

Fields Notes


description

 A text description of what the <Control Link> is for

expr_index_v0

 index of the expression whose value controls
 the unit_vector.vector[0] field of the affected <Reference_Vector>.
 If 0, this field is not controlled.

expr_index_v1

 index of the expression whose value controls
 the unit_vector.vector[1] field of the affected <Reference_Vector>.
 If 0, this field is not controlled.

expr_index_v2

 index of the expression whose value controls
 the unit_vector.vector[2] field of the affected <Reference_Vector>.
 If 0, this field is not controlled.
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Last updated: October 1, 2002 Copyright © 2002 SEDRIS™