Table 6.140—DRM_Image_Mapping_Function

Property

Description

Superclass

· <DRM SEDRIS Abstract Base>

Class

· <DRM Image Mapping Function>

Subclass

· none

Definition

The function that specifies how images are mapped onto a textured object, including the mapping method, the projection, and how <DRM Texture Coordinate> instances (if present) are to be treated if they fall outside the image space bounded by (0, 0), (1, 1).

Example(s)

· A <DRM Image> is mapped to a <DRM Polygon>. The <DRM Polygon> has <DRM Texture Coordinate>s at three or more <DRM Vertex>s, the <DRM Image> is mapped the <DRM Polygon> using the <DRM Texture Coordinate>s. The <DRM Texture Coordinate> represents the location within the <DRM Image> that lies on top of the <DRM Vertex>.

· A <DRM Polygon> could have two <DRM Image>s mapped to a single polygon. One <DRM Image> could be the <DRM Image> displayed for most cases. The second <DRM Image>, if detail texture mapping is true, would then be the imagery that is added to polygon when the eyepoint is so close to the polygon that the main image texels are no longer useful for texturing the polygon.

Inherited field elements

field_name	range	Field_Data_Type
none

Field elements

field_name	range	Field_Data_Type
image_mapping_method^1		Image_Mapping_Method
image_wrap_s^2		Image_Wrap
image_wrap_t^3		Image_Wrap
image_projection_type^4		Image_Projection_Type
intensity_level^5		Long_Float
gain^6		Long_Float
image_detail_mapping^7		Boolean

Associated to (one-way) (inherited)

· none

Associated to (one-way)

· one <DRM Image>

Associated by (one-way) (inherited)

· none

Associated by (one-way)

· none

Associated with (two-way) (inherited)

· none

Associated with (two-way)

· none

Composed of (two-way) (inherited)

· none

Composed of (two-way)

· zero or one <DRM Image Anchor>

· zero or more <DRM Image Lookup>s

· zero or one <DRM Presentation Domain>⁸

Composed of (two-way metadata) (inherited)

· none

Composed of (two-way metadata)

· none

Component of (two-way) (inherited)

· none

Component of (two-way)

· zero or more <DRM Aggregate Feature>s

· zero or more <DRM Aggregate Geometry>s

· zero or more <DRM Attribute Set>s

· zero or more <DRM Data Table>s

· zero or more <DRM Primitive Feature>s

· zero or more <DRM Primitive Geometry>s

Constraints

· Image Mapping Functions and Texture Coordinates

Notes

¹ For details on these methods, see the Image_Mapping_Method data type.

² Clamp or repeat the image in s.

³ Clamp or repeat the image in t.

⁴ Type of projection used when applying image to polygons.

a) If planar projection is specified, the following cases may apply:

1) The object may have <DRM Texture Coordinate> or <DRM Tack Point>s, in which case the “Image Mapping Functions and Texture Coordinates” constraint will apply.

2) The <DRM Image Mapping Function> may have a <DRM Image Anchor>.

3) The <DRM Image> may have a <DRM Image Anchor>.

b) If cylindrical or spherical projection is specified, the object shall not have <DRM Texture Coordinate>s or <DRM Tack Point>s. Instead, either the <DRM Image Mapping Function> or its <DRM Image> shall have a <DRM Image Anchor>.

⁵ Value between zero and one that indicates the proportional contribution of this mapping to the total effect on the polygon (normal value is 1.0 meaning the entire effect) (multiply the color data values within the <DRM Image> by this value).

⁶ Value to add to the colour data values within the Image.

⁷ Boolean that indicates that this mapping function is used to describe mapping of "detail" image on the polygon.

⁸ <DRM Presentation Domain> is optional only when the aggregating object(s) have one and only one <DRM Image Mapping Function> component. If multiple <DRM Image Mapping Function>s are present, each shall have a distinct <DRM Presentation Domain> component.

Class diagram

<DRM Image Mapping Function>