Polynomial Texture Maps -- an Implementation
Alex Mohr
Abstract
Abstract:
This work implements Polynomial Texture Maps as presented by Malzbender
et al. at SIGGRAPH 2001. Polynomial Texture Maps (PTMs) are a space and
time efficient method for encoding an object's diffuse lighting response
as the light position varies with respect to the surface. A traditional
texture map encodes a different color C for each point (u,v) on a
surface. In contrast, a PTM encodes a set of coefficients Cf for each
point on a surface. These coefficients are parameters to a polynomial
model that approximates the surface point's color change as the lighting
position changes. The object is sampled from a number of different
lighting directions, and coefficients are obtained by a least-squares
fit of the model to the data. During rendering, the pixel-processing
hardware of modern graphics processors is used to evaluate the
polynomial model very quickly. Because each point on a surface can vary
with the lighting direction, PTMs can capture interesting surface
reflectance properties that normal texture maps cannot. These include
approximately correct diffuse lighting for small-scale features and
global effects like self-shadowing.
Download the Report
PTM.doc
My apologies for only having .doc format and for the large file size
(images too big). I will fix this soon.