GLSL-PathTracer

A physically based Path Tracer that runs in a GLSL Fragment shader.

Recreation of a scene from Greyscalegorilla. Render time: 2 minutes on a GTX 750 Ti. 3 bounces

Features

• Unidirectional PathTracer
• RadeonRays for building BVHs (Traversal is performed in a shader)
• Metallic-Roughness Material Model
• Texture Mapping (Albedo, Metallic, Roughness, Normal maps)
• Spherical and Rectangular Area Lights
• IBL with importance sampling
• Progressive + Tiled Rendering (Reduces GPU usage and timeout when depth/scene complexity is high)

Build Instructions

Please see INSTALL-WIN.txt for the build instructions for Windows and INSTALL-LINUX.txt for Linux

Sample Scenes

A couple of sample scenes are provided in the repository. Additional scenes can be downloaded from here: https://drive.google.com/file/d/1UFMMoVb5uB7WIvCeHOfQ2dCQSxNMXluB/view

TODO

• IBL importance sampling
• Emissive geometry
• Two-level BVH for instances and transforms
• Support for different texture sizes
• Performance improvements
• Support for rendering out animation sequences

Additional Screenshots

References/Credits

• A huge shout-out to Cedric Guillemet (https://github.com/CedricGuillemet) for cleaning up the code, adding the UI, integrating ImGuizmo, cmake and quite a lot of fixes.
• Ray Tracing in One Weekend (https://github.com/petershirley/raytracinginoneweekend) Peter Shirley's excellent book introductory book on raytracing which helped me get started on this project
• Mitsuba Renderer (https://github.com/mitsuba-renderer/mitsuba) Main reference for validation of the code.
• Tinsel Renderer (https://github.com/mmacklin/tinsel) A really amazing renderer which has several features. A modified version of the scene description & loader are taken from here. Reference for MIS, light sampling
• Sam Lapere's path tracing tutorial ((https://github.com/straaljager/GPU-path-tracing-tutorial-4) Source for the Nvidia's SBVH used here. Traversal isn't the same as this code though. No Woop triangles either
• Erich Loftis's THREE.js PathTracer (https://github.com/erichlof/THREE.js-PathTracing-Renderer) Several amazing webgl examples including bidirectional path tracing all running in a web browser.
• Optix Advanced Samples, especially OptiX Introduction Samples (https://github.com/nvpro-samples/optix_advanced_samples/tree/master/src/optixIntroduction) Source for several tutorials