Table 6.288—DRM_Texture_Coordinate
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Property |
Description |
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Superclass |
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Class |
· <DRM Text Coordinate> |
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Subclass |
· none |
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Definition |
An object of this DRM class specifies a {s, t} tuple in image space (also known as texture space) used to specify how a texel from the image space is to be mapped to a location in “object” space. Each MIP level of a 2D <DRM Image> defines an image that has a width and height specified in texels. Regardless of the actual size of the image, the image space is defined by treating the two-dimensional image as a square, defined by the lower-left coordinate of (0.0, 0.0) and the upper-right coordinate of (1.0, 1.0). A <DRM Texture Coordinate> is a coordinate within this image space. A <DRM Texture Coordinate> specifies an exact location within a given image space, and this location is mapped to the "object space" location associated with the <DRM Vertex>, <DRM Point>, or <DRM Tack Point> of which the <DRM Texture Coordinate> is a component. A textured geometric object generally has a <DRM Texture Coordinate> for each vertex of the object, and the surface of the geometric object is “painted” or “covered” with the given <DRM Image>, interpolating what part of the <DRM Image> should be displayed where based on the <DRM Texture Coordinate> of the object's vertices. Whether a specified <DRM Texture Coordinate> corresponds to exactly one texel in the texture definition, or to a blending of many texel values from the definition, is a decision made by the texture interpolation algorithm used to display the texture. The methods for calculating the interpolated texture values and for blending the texture onto the object are determined by an <DRM Image Mapping Function>. (Note that by the Image Mapping Functions and Texture Coordinates constraint, <DRM Texture Coordinate> will only appear within the scope of some <DRM Image Mapping Function>s.) |
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Example(s) |
· The (s,t) coordinates to map to the lower left corner of a <DRM Polygon> |
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Inherited field elements |
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Field elements |
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Associated to (one-way) (inherited) |
· none |
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Associated to (one-way) |
· none |
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Associated by (one-way) (inherited) |
· none |
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Associated by (one-way) |
· none |
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Associated with (two-way) (inherited) |
· none |
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Associated with (two-way) |
· none |
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Composed of (two-way) (inherited) |
· none |
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Composed of (two-way) |
· zero or one <DRM Texture Coordinate Control Link> |
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Composed of (two-way metadata) (inherited) |
· none |
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Composed of (two-way metadata) |
· none |
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Component of (two-way) (inherited) |
· zero or one <DRM Texture Coordinate Table> |
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Component of (two-way) |
· zero or more <DRM Base Vertex>s · zero or more <DRM Point>s · zero or more <DRM Tack Point>s · zero or more <DRM Texture Coordinate Set>s |
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Constraints |
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Notes |
1 The s value of the (s,t) coordinate. 2 The t value of the (s,t) coordinate. |
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Class diagram |