Teaching Texture Mapping Visually

Rosalee Wolfe
DePaul University

15: The objects have a map shape of a sphere, and the poles of the sphere are parallel to the y-axis. At the object’s "North Pole" and "South Pole", the squares of the texture map become squeezed into pie-wedge shapes. Compare this slide to slide 12 which has a map shape of a cylinder. Both map shapes have the pie-wedge shapes at the poles, but there is a subtle difference at the object’s "equator". The spherical mapping stretches the squares in the texture map near the equator, and squeezes the squares as the longitude reaches a pole. slide15.jpg (20694 bytes)
16: These objects have a spherical map shape. slide16.jpg (17142 bytes)
17: Using a box as the map shape is similar to planar mapping. Instead of using one texture map, box mapping uses six -- one each for the left, right, front, back, top and bottom sides of the object. To texture map the front and back sides, we eliminate the z-component of an object’s point and use the remaining x- and y-components to locate the color in the corresponding texture maps. slide17.jpg (13362 bytes)
18: Here are six textures that we will use in our next example. slide18.jpg (13085 bytes)
19: The objects in the slide have a box as the map shape. slide19.jpg (21454 bytes)
20: Here’s another six textures. This scene was modeled by Steve van der Burg. slide20.jpg (15175 bytes)
21: Here’s the result. slide21.jpg (13884 bytes)

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Last changed May 30, 1999, G. Scott Owen, owen@siggraph.org