Mitsuba 0.x with additional BSDFs and phase functions

This is my fork of the 0.x mitsuba repo: http://mitsuba-renderer.org/

BRDFs

A batch script in scenes/lambert_sphere/Figure8 tests a variety of diffuse BRDFs, which can be compared using the provided Mathematica notebook.

Lambert-sphere BRDF

This models the reflectance from a half space comprised of sparsely distributed spherical Lambertian particles from the EGSR 2021 paper. Three versions implemented: `lambert_sphere`, `lambert_sphere_fast` and `lambert_sphere_hapke81`.

Shader toy implementation: https://www.shadertoy.com/view/ftlXWl

Chandrasekhar's BRDF

This BRDF is for a half space with isotropic scattering. Albedo inversion and importance sampling implemented. Implemented as: chandra. For more information see A Hitchhiker's guide to multiple scattering

Diffusion-transport BDRF

This models the reflectance from a non-exponential half space with isotropic scattering where the distances between collisions are drawn from a Gamma/Erlang-2 distribution. Implemented as: diffusion_transport. Presented at ICTT and SIGGRAPH:

• ICTT_abstract
• SIGGRAPH course