cuPathTracer

A Monte Carlo Path Tracer implemented in CUDA.

Features

Current

• Anti-aliasing
• Depth of Field
• Diffusion & Specular Reflection
• Fresnel Equation for Transmission
• Support obj & mtl Format
• Store Result in ppm Format

TODO

• Bidirection Tracing
• Accelerating Intersection using BVH
• Use float4 instead of float3
• Memory Access Accelerating via CUDA Constant & Texture Memory

System Environment

• Debian 8 (Jessie) 64bits, other systems are not tested
• GCC 4.9, GCC 6 is not allowed!!!
• CUDA 8.0, lower versions are not tested
• CMake >= 2.8
• NVIDIA GeForce Titan Black (CUDA capability: 3.5) lower CUDA capabilities are not tested

Project Structure

Folders

• include/ - 3rd-party headers, including tinyobjloader & some helper functions from NVIDIA's offical CUDA examples (with filename starts with "helper_")
• src/ - Source code
• scenes/ - 2 demo scenes - scene-1/ for Cornell Box & scene-2/ for Glossy Plane
• results/ - Some demo results

Source Files

In src/ directory:

• types.hpp & types.cpp implement some essential data structures such as Ray, Triangle, Material, Camera, Scene, etc.
• constants.hpp defines some useful constant values.
• utils.hpp implements some helper functions.
• path_tracer.hpp & path_tracer.cu implement the Monte Carlo Path Tracing algorithm.

The code style of the source code files above follows Google C++ Code Style

Usage Guide

Step 1. Create Working Directory

$ cd /PATH/TO/PROJECT
$ mkdir build
$ cd build

Step 2. Compile

$ cmake ..
$ make -j8

Step 3. Execute

The demo program needs 5 command-line parameters - scene id, output filename samples per pixel, maximum tracing bounces and gpu id respectively.

Currently only 3 scenes are supported:

• 1 for scene 1 (Cornell Box)
• 2 for scene 2 (Glossy Planes)
• 3 for my own scene (modified Cornell Box)

Here is an example:

$ ./PathTracerDemo 1 scene-1.ppm 2000 10    # Create scene 1 on default gpu (gpu 0)
$ ./PathTracerDemo 2 scene-2.ppm 1000 10 1  # Create Scene 2 on gpu 1
$ ./PathTracerDemo 3 scene-3.ppm 10000 20 2 # Create Scene 3 on gpu 2

Results

Note: Execution time information are measured by time command, e,g.:

$ time ./PathTracerDemo 1 scene01-10000-ppm 10000 10 0

Scene 1 (Cornell Box)

• Samples per pixel (spp): 100, 1000, 10000
• Maximum tracing bounces: 10

100 spp, 15 sec

1000 spp, 140 sec

10000 spp, 23 min

Scene 2 (Glossy Planes)

• Samples per pixel (spp): 100, 1000, 10000
• Maximum tracing bounces: 10

100 spp, 12 sec

1000 spp, 125 sec

10000 spp, 21 min

My Own Scene (modified Cornell Box)

• Samples per pixel (spp): 10000
• Maximum tracing bounces: 20

Note: This scene has Depth of Field effect.

10000 spp, 45 min

License

See LICENSE