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6.19.3 3D Textures as Multidimensional Functions

Instead of thinking of a 3D texture as a 3D volume of data, it can be thought of as a 2D texture map that varies as a function of the $r$ coordinate value. Since the 3D texture filters in three dimensions, changing the $r$ value smoothly blends from one 2D texture image to the next.


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An obvious application is animated 2D textures. A 3D texture can animate a sequence of images by using the $r$ value as time. Since the images are interpolated, temporal aliasing is reduced.

Another application is generalized billboards. A normal billboard is a 2D texture applied to a polygon that always faces the viewer. Billboards of objects such as trees behave poorly when the viewer views the object from above. A 3D texture billboard can change the textured image as a function of viewer elevation angle, blending a sequence of images between side view and top view, depending on the viewer's position.

next up previous contents
Next: 6.20 Detail Textures Up: 6.19 3D Textures Previous: 6.19.2 3D Textures to   Contents
2001-01-10