Reconstruction filters for bump mapping

Abstract

Textures that are magnified appears jagged, and therefore reconstruction filters using linear or cubic interpolation polynomials are often used to reduce aliasing. The same aliasing problem is noticed for bump mapping, where it is often solved by bilinear interpolation of the height map, in order to obtain intermediate values. Low-pass filtering of the height map is not suitable for the magnification problem since it will suppress the bumps. It will be shown that reconstruction filters can be used to interpolate gradients, rather than height values directly. The goal is to produce non jagged bumps, without removing high frequency details by low-pass filtering.