This project started as a playground and implementation of light transport theory and concepts in the form of a unidirectional pathtracer. It is currently a Work In Progress, with a lot of features to work on still.

• Physically based BRDFs (Lambertian, Oren-Nayar, Specular (GGX))
• Naive BRDF sampling
• NEE (Next Event Estimation / Direct light sampling)
• MIS (Multiple Importance Sampling between Naive and NEE)
• OpenGL Compute Shader implementation (OpenGL 4.6 Core, GLSL)
• Custom-made BVH implementations using Sweep SAH split
• (WIP) glTF model loading and material creation
• CMake build that supports Windows (MSVC, Clang for Windows) and Linux (GCC, Clang)

Very early result using a purely Lambertian BRDF and naive hemisphere sampling

First tests of MIS between Naive and NEE

MIS (Naive+NEE), Modified Blinn-Phong, Sweep SAH BVH

Specular BRDF (GGX NDF with Smith geometry func.), using GGX importance sampling - Metallic Gold material

(WIP) glTF Model support

• cgltf (GitHub)
• PCG Random Number Generation Library (Minimal C Edition) (GitHub)
• GLAD - Multi-Language OpenGL Loader-Generator (GitHub)
• Simple DirectMedia Layer 2 - SDL2 (GitHub)
• stb libraries (GitHub)
• glm (GitHub)

• Shader includes (Preprocess shaders and copy/paste included shaders)
• Optimize BVH traversal
• Multiscattering approximation for Oren-Nayar BRDF
• Separate different estimators (BRDF-only, NEE-only, MIS) into different compute shaders
• Implement more variance reduction techniques (stratified sampling, BRDF sampling, low discrepancy sequences).
• Russian Roulette
• Measuring different radiometric quantities (for example intensity, to get an orthographic projection)