Direct calculation of mip-map level for faster texture mapping

computer graphics, texture mapping, MIP mapping, trilinear filtering, floating-point arithmetic © Copyright Hewlett-Packard Company 1998 This paper describes a method applicable to texture mapping for calculating the MIP-map level directly from the IEEE-standard floating-point representation of the compression value. This calculation ordinarily requires execution of a base-2 logarithm, and it needs to be performed once per pixel. However, the full logarithm need not be evaluated because only the integer part of the result is required. The MIP-map level is essentially the base-2 exponent of the MIP map compression value, and this exponent is immediately available from the IEEEstandard floating-point representation. 1