GPU Path Tracer in C++ and OpenGL

A GPU-accelerated, physically-based path tracer built with C++ and OpenGL — from scratch. This was a project I made over two weeks. I've always thought ray tracers look cool and wanted to try creating one from scratch.

Features

• Physically Based Rendering - Realistic lighting and reflections with energy-conserving materials
• Progressive Rendering - Image quality improves over time with live, frame-by-frame refinement
• Anti-Aliasing - Smooth edges using subpixel jitter and sample accumulation
• HDR Environment Maps - Skybox lighting with exposure (EV) control
• Procedural Sun - Adjustable directional light simulating sunlight
• Scene Management - Load and edit scenes via JSON files
• Interactive UI - Responsive ImGui interface with dockable panels and image export

Technical Features

• GPU Path Tracing - Using OpenGL and GLSL
• Material System - Diffuse, specular (glossy/mirror), emissive, smoothness and procedural checker flag
• Cosine-Weighted Hemisphere Sampling - Physically accurate diffuse light distribution
• Russian Roulette Termination - Unbiased path termination for efficient global illumination
• sRGB Gamma Correction - Converts linear output to perceptual colour space
• Geometry Primitives - Spheres, infinite planes, and quads

Gallery

Installation

Building from Source

To build this project from source, you will need the following prerequisites:

• C++ 17+ Compiler (e.g., GCC, Clang, MSVC)
• CMake 3.16+
• OpenGL 4.4+ drivers and development libraries (usually part of your graphics card driver installation)

Dependencies:

• You do not need to install any dependencies in order to build the project :D
• GLAD and single header files (nlohmann/json, stb) are included in external/ folder
• Other dependencies are managed as git submodules:
  • GLFW
  • GLM
  • ImGui
  • ImGuiFileDialog

Build Process

Tested on Windows 11 with MSVC. Untested, but should also build on Linux with GCC or Clang.

git clone https://github.com/Brooklyn-Dev/ray-tracing.git
cd ray-tracing

# Initialise and update all git submodules recursively
git submodule update --init --recursive

# Create build directory and run CMake
mkdir build && cd build
cmake -DCMAKE_BUILD_TYPE=Release ..

# Build the project
cmake --build . --config Release

# Run the executable
cd bin/Release
ray-tracing.exe

Installing Pre-built Releases

1. Download the latest release from the Releases page
2. Extract the archive to your desired location
3. Run the executable

Usage

• File Menu - Load scenes and export renders
• Camera
  • Movement (relative) - Arrow keys
  • Up/Down - Space / LCtrl
  • Rotate - LMB + Drag
• ImGui Windows
  • Viewport - Displays the render output
  • Settings - Adjust gamma, bounces, samples, skybox, sun, camera, etc.

Potential Future Improvements

• Bounding Volume Hierarchy (BVH)
• Refraction and transmission materials
• Real-time scene editor
• Mesh loading (OBJ, glTF)
• Image-based textures
• Depth of field
• Support for more geometry types (cubes, torus, etc.)
• Basic video render with animated camera path

Credits

• Environment maps by Poly Haven (CC0)
• Inspired by Sebastian Lague's ray tracing devlog
• Inspired by NamePointer's ray tracing devlog
• Ray Tracing in One Weekend
• The Cherno's Ray Tracing series

Like this project?

If you find this project interesting or useful, consider giving it a star ⭐️!

License

This project is licensed under the MIT License. See LICENSE for more information.