CUDA Ray Tracing

Learning about cuda with ray tracing

Update April 6th 2024: Now that I've taken a CSC367 Parallel Computing course, I realize there is a lot to improve here.

Disclaimer: This project is heavily inspired by contents learnt from UofT Computer Graphics Course, specifically A2, A3 and A4. It repurposes course assets like JSON config style and .stl files for scene and borrows some high level concepts from the course.

All implementation of the core data structure and algorithms are my own work.

4K Bunny!!! Ray Traced in lighting speed

(for real...😅 the CPU version for 360p took 90 seconds)

Requirements

• CMake $\geq$ 3.11
• CUDA Toolkit (Any modern version should work)
• Currently Targeting GPU with compute capability 86 (My GPU)

Note: If you are using a different GPU, you will need to change ARCH_CODE in CMakeLists.txt to target your GPU. Or simple comment out all lines referencing ARCH_CODE and let nvcc auto detect your GPU.

Features and TODOs

⚠️ The project is still in development ⚠️

• Parallel Ray Tracing
• Real-Time Ray Tracing (for simple and lower resolution scene)
• CPU Recursive BVH Construction
• Parallel BVH Construction - Linear BVH Original Author's Blog
• Parallel Iterative BVH Traversal- Same Author's Blog
• Flexible Scene Configuration with JSON and .stl (see data folder)

Notes:

• CPU BVH construction and Blinn-Phong Shading are Naively implemented. Major improvement is possible from current results.
• For faster development cycles as API are still changing, implementation are done mostly in .cuh header files.

Down the line

Will probably not get to all of them, but hopefully most 😎👌

• Refraction
• Soft Shadows
• Global Illumination
• Anti-Aliasing
• Transparency and Opacity
• Depth of Field
• Caustics
• Volume Scattering
• Interactive Real-Time Ray Tracing
• Fast Parallel BVH reconstruction

Quick Start

❗ Since BVH Traversal is not completly implemented. Planes are not rendered. use -n or --no-bvh to turn off BVH for plane rendering.

VSCode

• Open command palette (Ctrl+Shift+P) then select Tasks: Run Test
• After build it will run the binary automatically.
• You can see raytracing and rgb.png in build-release folder for the binary.

Manual

# cd to project root
mkdir build -p 
cd build
cmake -DCMAKE_BUILD_TYPE=Release .. # or just cmake .. for debug build
make

./raytracing

Help

$ ./raytracing --help

Usage: raytracing [OPTION...]
            [-f FILE='../data/bunny.json'] [-b SIZE=16] [-r RESOLUTION=720]
            [--no-bvh] [--landscape] [-o FILE='rgb.png']
Real-Time Ray Tracing with CUDA.

Involve parallel Ray Tracing and parallel BVH construction. (WIP)
Intend to provide interactive component for ray tracing.

  -b, --blocksize=SIZE       Block size for CUDA processing. Mutually Exclusive
                             with Block size (format: [x] or [y,x]. Single
                             value expands to [x,x]). Default: 16
  -f, --filename=FILE        Path to the Scene JSON config file. Default:
                             ../data/bunny.json
  -g, --gridsize=SIZE        Grid size for CUDA processing. Mutually Exclusive
                             with Grid size (format: same as blocksize).
                             Default: 16
  -l, --landscape            Render in landscape mode. Default: portrait mode
  -n, --no-bvh               Turn off Ray Tracing with BVH. Default: BVH is ON
  -o, --output=FILE          Output file name. We only support .png and .ppm
                             format. Default: rgb.png
  -r, --resolution=RESOLUTION   Resolution of the output image (e.g. 360, 720,
                             1080). Default: 720
  -?, --help                 Give this help list
      --usage                Give a short usage message
  -V, --version              Print program version

Mandatory or optional arguments to long options are also mandatory or optional
for any corresponding short options.

Report bugs to hxr.richard@gmail.com.

Scene Configuration and Current Results

$ ./raytracing -r 360 

Resolution:    640 x 360
Block size:    10 x 6 
Grid size:     64 x 64
Time:          34.9327 ms
Throughput:    6.5955 M rays/s
FPS:           28.6264 fps     <------------ ~30 fps :)
Scene size:    68484 bytes
# of objects:  1000
# of lights:   4
BVH enabled:   True

Writing image to rgb.png