libbsdf

Overview

libbsdf is a C++ library for BSDF, BRDF, and BTDF. libbsdf provides basic functions: file IO, interpolation, data structure and so on. Eigen 3 is used for arrays, vectors, and matrices. libbsdf is licensed under the terms of the Mozilla Public License, version 2.0. See the LICENSE file.

Building libbsdf

C++ compiler that supports C++17 is required. CMake is used as the build system. The search path for Eigen 3 is set through CMake variables: Eigen3_DIR. To enable the fitting function to reflectance models, enable LIBBSDF_ENABLE_FITTING and set the Ceres Solver path to the Ceres_DIR variable.

Data structure

• Scatter and specular data
  • BRDF
  • BTDF
  • Specular reflectance
  • Specular transmittance
• Color
  • Monochrome
  • RGB
  • XYZ
  • Spectrum
• Parameterization
  • Spherical coordinate system
  • Specular coordinate system
  • Half-difference coordinate system

File reader

Format	Extension	Measured Data
Surface Scattering Distribution Data	.ssdd
Integra Diffuse Distribution	.ddr, .ddt
Integra Specular Distribution	.sdr, .sdt
Zemax BSDF	.bsdf	RPC Photonics
LightTools BSDF	.bsdf
ASTM E1392-96(2002)	.astm	Cornell University
MERL BRDF	.binary	MERL

File writer

Format	Extension
Surface Scattering Distribution Data	.ssdd
Integra Diffuse Distribution	.ddr, .ddt