A GPU Path Tracer written in CUDA C++ with BVH acceleration. (2025 Updated Version)

This 512 x 512 Dragon in a Cornell Box with 1000 samples per pixel took 20.74 seconds to render.

(The Dragon has 871,306 triangles!)

Features:

• Parses a scene in Mitsuba XML file format.
• GPU Path Tracer (with global illumination) using CUDA.
• Implements a BVH acceleration structure.
• Support for spheres and triangle meshes.
• Support for diffuse, mirror, plastic, Phong materials (with Fresnel reflection).
• Anti-aliasing, Russian Roulette termination.
• Exports the scene into a png file.

Running the code

1. To compile, use the command:

make

in the home directory. (If the program cannot find CUDA, adjust the CUDA_PATH in the Makefile)

2. After compiling, use the command:

./torrey scenes/spheres/scene1.xml

'scenes/spheres/scene1.xml' after ./torrey is just an example. Additional scenes can also be rendered. The xml file can be located in various folders within the ‘scenes’ folder like:

./torrey scenes/cbox/cbox.xml

or like:

./torrey scenes/budda/buddha.xml

The resolution and sample size can be adjusted by changing the values of the xml files.

3. The rendered image can be found in the 'output' folder under the name 'img.png'!

Tested on:

• System: Ubuntu 24.04.1 LTS
• CPU: Intel i7-13700k
• GPU: RTX 3080
• Nvidia Driver Version: 560.35.05
• CUDA Version: 12.6

More sample images!

Cornell Box

This 512 x 512 Cornell Box with 500 samples per pixel took 0.88 seconds to render. (A significant change compared to the previous version which took 42 seconds!)

Spheres_Scene1 (Diffuse and Phong spheres)

640 x 480 pixels with 500 samples per pixel. Render time: 0.15 seconds! (Previously took 10 seconds)

Buddha

640 x 480 pixels with 500 samples per pixel. Render time: 16.5 seconds (The Buddha has 1,087,474 triangles, Prev. 44 sec)

Bunny

640 x 480 pixels with 500 samples per pixel. Render time: 5.23 seconds
(The bunny has 144,046 triangles)

Coming Soon..

Image Textures!