Work Log by Kevin Beason

Added Ashikhmin & Shirley’s Anisotropic Phong BRDF and Schlick’s BRDF (the ’94 paper) support for pure path tracing (implicit light paths only). My Schlick BRDF is probably broken. Adding these entailed abstracting a BRDF interface class, implementing importance sampling and computing BRDF/PDF. The daylight image is after sunset for a good reason. The sun would only contribute if a ray found it by chance… talk about noise.

Front row is Ashikhmin & Shirley Anisotropic Phong BRDF. 2nd row is Schlick’s anisotropic BRDF. Third row is my preexisting set of materials. Back row is A&S BRDF with measured reflectance values (in RGB. See previous post.) The floor is A&S BRDF and my fascimile of their texture.

Left image is Preetham daylight model. Right is Debevec’s Uffizi HDR environment probe.

2048 spp, 24-30 minutes each on a Q6600 2.4GHz Core 2 Quad.

This work is from May 2008.