What are texture coordinates? Well, texture coordinates are used to specify a point on a texture. Because a texture is 2D we only need two values to specify any point: U and V. U is the number of units across (columns) and V is the number of units down (rows). The values of U and V should be between 0 and 1 (you can specify other values to create special effects, more on this later). The top left corner of the texture is (0, 0) and the bottom right corner is (1, 1) in the form (U, V). Fig 6.1 below shows the texture coordinates of nine points of a texture.