Class

• <DRM Image Mapping Function>

Superclass

• <DRM SEDRIS Abstract Base>

Subclass

• None.

Definition

An instance of this DRM class specifies how the given <DRM Image> is to be mapped onto a given 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).

The image_mapping_method field specifies how to combine the referenced texture map with any <DRM Colour> instances on the textured object.

The image_wrap_s field specifies whether to clamp or repeat the given <DRM Image> instance in s.

The image_wrap_t field specifies whether to clamp or repeat the given <DRM Image> instance in t.

The image_projection_type field specifies the type of projection to be used when applying the given <DRM Image> instance to textured objects.

1. If planar projection is specified, the following cases may apply.

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

   2. The <DRM Image Mapping Function> instance may have an <DRM Image Anchor> instance.

   3. The <DRM Image> instance may have an <DRM Image Anchor> instance.

2. If cylindrical or spherical projection is specified, the object shall not have <DRM Texture Coordinate> or <DRM Tack Point> instances. Instead, either the <DRM Image Mapping Function> instance or its <DRM Image> instance shall have an <DRM Image Anchor> instance.

The intensity_level field specifies the percent contribution of the given <DRM Image Mapping Function> instance to the total effect on the textured object. For an <DRM Image> instance with a colour coordinate component specified by its signature, multiply first, second, and third colour coordinate values within the <DRM Image> instance’s texels by this value.

The value of the gain field is to be added to each colour data value from the texel data of the given <DRM Image> instance to obtain the displayed image.

The image_detail_mapping field specifies whether the given <DRM Image Mapping Function> instance is used to describe mapping of a detail image on the textured object.

Class diagram

Figure 6.135 — DRM_Image_Mapping_Function

Constraints

• Image Anchor spatial reference frame
• Image Mapping Functions and Texture Coordinates
• Publishable Object

Example(s)

• An <DRM Image> is mapped to a <DRM Polygon>. The <DRM Polygon> has <DRM Texture Coordinate> instances at three or more of its <DRM Vertex> components, the <DRM Image> is mapped the <DRM Polygon> using the <DRM Texture Coordinate> instances. Each <DRM Texture Coordinate> instance represents the location within the <DRM Image> instance that lies on top of the <DRM Vertex> instance corresponding to the given <DRM Texture Coordinate> instance.

• Consider a <DRM Polygon> instance with two <DRM Image> instances mapped to it. One <DRM Image> could be the <DRM Image> displayed for most cases. The second <DRM Image>, if image_detail_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.