PBR Final Project - Weisheng Li

See the PDF report for more details about implementation and correctness validation. Check the release for images and test scenes in the report.

Code I wrote and stuffs I added

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Anisotropic volume rendering using SGGX:

• medium.h, medium.cpp - Add a HomogeneousAnisotropicMedium medium class and a SGGXPhase phase function class. These two needs to work together.
• parser - Parse the new medium class
• vec.h - Add a few functions that end with 3x3. They still take 4x4 matrices as input and output, but only process the top-left 3x3 submatrix. Other entries are all set to 0.

Layered material with statistical operator:

• material.h, material.cpp - Create new material class called Layered. Add a few functions for sampling and evaluating surface normal from Beckmann distribution
• layered.h - Implement FGD class that reads precomputed FGD texture from data/FGD.bin and supports interpolated texture lookup
• parser.cpp - Parse the new material class
• onb.h - Now allows converting from world coordinate to local coordinate using ONB