Texture Coordinate

Class Name: Texture Coordinate

Superclass - Texture Coordinate Entry

Definition

An ST tuple (also known as XY, UV, or AB coordinates) in image space that maps a texel from the texture image to a Vertex, Point, or Tack-Point. Each level of a texture definition defines an image that has a width and a height in texels. Common sizes are 64 by 64 or 256 by 256. Regardless of the actual size of the image, each two-dimensional texture image is treated as square defined by the lower-left coordinate of (0.0, 0.0) and the upper-right coordinate of (1.0, 1.0). This is the definition of the image space. A Texture Coordinate is a coordinate within that image space (a value within that square). Whether or not a specified 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. A Texture Coordinate specifies an exact location within a texture definition, and this location is mapped to the Vertex, Point, or Tack Point of which the Texture Coordinate is a component. A textured geometric object generally has a Texture Coordinate for each vertex of the object, and the surface of the geometric object is 'painted' or 'covered' with the given Image, interpolating what part of the Image should be displayed where based on the Texture Coordinates of the object's vertices. The methods for calculating the interpolated texture values and for blending the texture onto the object are determined by an Image Mapping Function.