1. A method for rendering an image for display, the method comprising: a computer system executing the following steps: computing a squash value representing a desired amount of anisotropy for an anisotropic texture sample; identifying a desired texture map using the squash value, wherein the desired texture map is a ripmap included in a set of potential ripmaps associated with a base texture and having the desired amount of anisotropy; determining whether the desired texture map is included in a set of available ripmaps; in response to a determination that the desired texture map is included in the set of available ripmaps, selecting the desired texture map as a selected texture map; in response to a determination that the desired texture map is not included in the set of available ripmaps, selecting an alternate texture map as the selected texture map, wherein the alternate texture map is an alternate ripmap included in the set of available ripmaps; modifying a texture state value to match an attribute of the selected texture map; sampling the selected texture map to determine an anisotropic texture sample value; using the anisotropic texture sample value to generate a pixel of an image to be displayed; updating a set of ripmap usage statistics associated with the set of potential ripmaps based on the desired texture map, wherein the set of ripmap usage statistics reflects a frequency of identification of a potential ripmap from the set of potential ripmaps as the desired texture map; and adding a new ripmap to the set of available ripmaps based on the ripmap usage statistics.