Method and apparatus for effective level of detail selection

摘要

Method and apparatus for rendering texture to an object to be displayed on a pixel screen display. This technique makes use of linear interpolation between perspectively correct texture address to calculate rates of change of individual texture addresses components to determine a selection of the correct LOD map to use and intermediate texture addresses for pixels of the object between the perspectively correct addresses. The method first determines perspectively correct texture address values associated with four corners of a predefined span or grid of pixels. Then, a linear interpolation technique is implemented to calculate a rate of change of texture address components in the screen x and y directions for pixels between the perspectively bound span corners. This linear interpolation technique is performed in both screen directions to thereby create a potentially unique level of detail value for each pixel, which is then used as an index to select the correct pre-filtered LOD texture map. When mapping an individually determined LOD value per pixel, the effect of producing undesirable artifacts that may appear if a single LOD for an entire span or polygon is used, is obviated.