MT-Tracer

A CPU renderer using Monte-Carlo ray tracing algorithm.

It's a course assignment for Computer Graphics.

Tested under Windows 10, Visual Studio 2015/2017 x64, while it is theoretically cross-platform.

Features

• Ray tracing: Monte-Carlo strategy with stratified sampling and weighted cosine hemisphere sampling
• Lighting: direct and indirect light with reflection and refraction
• Acceleration: KDTree, OpenMP
• Configurable: resolution, ray depth and ray density can be configured as needed

Dependencies

• glm
• tiny obj loader

All the dependencies above are head-only and already included in the repository.

Notice: Due to an unknown bug, other versions of glm may not work with the code. Please use the provided one for now.

File Format

The program can load simple obj models, but your mtl files may need modification to work. The following mtl properties are used:

• Kd - surface color or light color
• Ka - reflection rate (different from the standard)
• Ks - specular intensity
• Ke - emission intensity
• Ns - specular index
• d - dissolve rate, i.e. opacity
• Ni - refraction index

Usage

Build

1. Use CMake (3.9+) to configure the project
2. Compile (use release build, unless there're run time issues)

Run

• Arguments:
  • -s, --scene: scene ID (1-4), default 1
  • -d, --depth: ray depth, default 4
  • -r, --ray: ray sample per pixel, default 4
  • -p, --pixel: image size, default 1024
• If running in Visual Studio, specify command line arguments in Debug Settings
• If running directly from the command line, please make sure the "resources" folder is in the same directory with the executive
• The output image will be at the working directory, i.e. the build directory specified in CMake or the executive directory

If you find the result unsatisfying, just increment the RAYS_PER_PIXEL variable in Main.cpp. You'll wait much longer for a better result.

Demos

The following results are rendered with resolution of 1024 * 1024 and a maximum ray depth of 4.

scene 0: 128 rays / pixel

scene 1: 1024 rays / pixel

scene 2: 256 rays / pixel

scene 3: 256 rays / pixel

scene 4: 256 rays / pixel

To Do

There are several known issues that may be improved in the future.

• BVH.
• Caching.
• PBR.
• Micro facet model.
• Fix the GLM version issue.
  • The latest version of GLM will ruin the whole program. Not sure why