Advance Path Tracing with NVIDIA RTX

This project was the result of my master thesis at the University of Tübingen, which is included in this repository as MasterThesis.pdf.

The master thesis contains the theoretical background, as well as a more in-depth description of the capabilities of the project.

Abstract

Hardware accelerated ray tracing is now possible with the NVIDIA RTX and the newly released AMD RDNA 2 GPUs. This master thesis implements common and advanced path tracing techniques while utilizing the new ray tracing hardware acceleration, and evaluating their performance and quality. The evaluated techniques are Next Event Estimation, Multiple Importance Sampling, Irradiance Caching, Adjoint-drive Russian Roulette and Splitting, and Parallax-aware Path Guiding. Also included is a wide range of visualization modes that can be enabled interactively to better understand the inner workings of the implemented techniques. This, in combination with the way higher performance than CPU based path tracer and resulting fast convergence rate, allows for interactive comparisons between the different methods.

Images

Path tracing of a dielectric element in a Cornell box

Irradiance Cache enabled

Visualization of Irradiance Cache values

UI of the path tracer, where most settings can be changed at runtime to switch between different methods

Visualization of the generated guiding information as spherical distributions in the scene

Requirements

• A graphics card with ray tracing support
• Vulkan SDK 1.2.154 https://vulkan.lunarg.com/sdk/home as well as compatible drivers
• SDL2 sudo apt-get install libsdl2-dev
• OpenEXR (recommended to install from source, so that CMake can easily find OpenEXR)
• CMake sudo apt-get install cmake
• GLM

sudo apt-get install libsdl2-dev libopenexr-dev cmake build-essential libglm-dev

Build steps

cmake -DCMAKE_BUILD_TYPE=Debug -S . -B cmake-build-debug

cmake -DCMAKE_BUILD_TYPE=Release -S . -B cmake-build-release

cd cmake-build-release

make -j8

Compile the shaders with ./shaders/compile.sh

Running the application

./rtx_raytracer WIDTH HEIGHT IC_SIZE GUIDING_SPLITS Scenes ... IC_SIZE is the maximum number of Irradiance Cache entries. GUIDING_SPLITS is the initial number of bounding box splits for the path-guiding regions Scenes are paths to scene definitions, relative to the scenes folder

For example: ./rtx_raytracer 1280 720 10000 8 cornell-dielectric/cornell-dielectric.xml veachMIS/veachMIS.xml

Vulkan Version

This project was created prior to the finalization of the Vulkan Ray Tracing extension and therefore depends on the beta version of the extension, i.e. Vulkan SDK 1.2.154 or earlier.