Adaptive tri-linear interpolation for use when switching to a new level-of-detail map

An intermittent tri-linear interpolator for a graphics engine comprising:

• a texel memory for storing texels indicating texture attributes of pixels for display on a display screen, the texels being arranged into a plurality of level-of-detail LOD maps, the LOD maps for applying different levels of detail of texture onto pixels;
• a bi-linear interpolator, coupled to receive four texels from a current LOD map in the texel memory, the four texels being four closest approximations to a pixel, the bi-linear interpolator generating a first average texel from the four texels, the first average texel being a closer approximation for the pixel than any of the four texels;
• an LOD-map selector, coupled to the texel memory, for selecting the current LOD map for the pixel from the plurality of LOD maps;
• a second bi-linear interpolator, coupled to receive another four texels from a next LOD map in the texel memory, the another four texels being four closest approximations to the pixel, the second bi-linear interpolator generating a second average texel from the another four texels, the second average texel being a closer approximation for the pixel than any of the another four texels;
• a tri-linear interpolator, receiving the first average texel from the bi-linear interpolator and receiving the second average texel from the second bi-linear interpolator, for generating a dual-map-averaged texel, the dual-map-averaged texel being a better approximation for the pixel than either the first or second average texels;
• an LOD-transition detector, coupled to the LOD-map selector, for determining when the pixel is near a LOD transition from the current LOD map to the next LOD map, the LOD-transition detector generating an enable signal when the pixel is near the LOD transition;
• and
• a texel output, coupled to output the dual-map-averaged texel from the tri-linear interpolator when the enable signal is active, but for outputting the first average texel from the bi-linear interpolator when the enable signal is not active,
• whereby tri-linear interpolation generates the texel outputted near the LOD transition, but bi-linear interpolation generates the texel outputted when not near the LOD transition.