rayme (early alpha)

A path tracing renderer for static glTF 2.0 scenes.

Examples

Some scenes produced using rayme (all images produced with 1024 samples per pixel, denoising, and no auto-exposure):

A scene with different materials (scene designed by Ariel Monti)

A more complex scene, with many light sources (scene designed by Ariel Monti)

A typical test scene, showcasing the behavior of different roughnesses in the presence of lights of different sizes:

A Cornell box (adapted from J.D.B. Walter's model):

The Conference Room scene (created by Anat Grynberg and Greg Ward):

Dependencies

The program requires the Boost library to build. Note for Windows users: rayme depends on Boost.ProgramOptions, which is one of the few Boost libraries needing separate compilation. See the Boost documentation for further details.

Optional dependencies

In order to have the deniosing option available (recommended), the library Intel(R) Open Image Denoise is required (see also the project's GitHub page); precompiled binary packages can be downloaded here. On Arch Linux, it can be installed from the repositories, by running pacman -S openimagedenoise.

Build

On Linux

Clone the repository using git's --recurse-submodules option, then, in the project folder, run

cmake -S . -B build/ && cd build/
make

the executable rayme will be availale in the build folder. If building fails, try running

cmake -DNO_AVX512=ON -S . -B build/ && cd build/
make

instead (the program by default uses the AVX512 set of instructions, which might be incompatible with some older CPUs).

On Windows

Make sure to be able to run cmake.exe through the PowerShell (e.g. by installing the CMake tools module) in Visual Studio. Clone the repository, either through Visual Studio or via command line using git's --recurse-submodules option. Then, in the project folder, run (using the PowerShell)

> cmake -DBOOST_ROOT="[boost directory (typically, C:/Program Files/Boost/boost_1_XX_0)]" -DBOOST_LIBRARYDIR="[boost directory]" -A x64 -DCMAKE_BUILD_TYPE=Release -S . -B build/

> cd .\build\

> cmake --build . --target ALL_BUILD --config Release -- /maxcpucount

the executable rayme.exe will be availale in the build\Release folder. If building fails, try running

> cmake -DBOOST_ROOT="C:/Program Files/Boost/boost_1_78_0" -DBOOST_LIBRARYDIR="C:/Program Files/Boost/boost_1_78_0" -A x64 -DCMAKE_BUILD_TYPE=Release -DNO_AVX512=ON -S . -B build/

> cd .\build\

> cmake --build . --target ALL_BUILD --config Release -- /maxcpucount

instead (the program by default uses the AVX512 set of instructions, which might be incompatible with some older CPUs).

Usage

rayme [-i] gltf-file [options]

For example:

rayme scene.gltf -H 1080 -s 512 -o rendered-scene

Available options

• -h, --help, outputs a help message,

• -i, ``input-filename, specify name of the input glTF 2.0 file (including extension),

• -H, --height, specify height (in pixels) of the output image (default: 400),

• -s, --spp, specify the number of samples per pixel (default: 128),

• -d, --min-depth, specify the minimum number of ray bounces (default: 5),

• -e, --auto-exposure, apply automatic exposure (experimental, disabled by default),

• -N, --no-denoise, disable image denoising (available only if Intel(R)'s Open Image Denoise library is installed before building the project),

• -o, --output-filename, specify name of the output PNG file (without extension)".

Currently, fine-grained exposure control is not supported. If a render results too dark or too bright, try enabling the auto-exposure feature (still experimental).

glTF 2.0 compliance

The program expects valid glTF 2.0 files as input and does not guarantee any validation, hence providing invalid inputs will result in undefined behavior (most likely a crash). Currently, only a subset of glTF 2.0's core specification is supported, and none of its extensions.

The support is in undergoing expansion; the biggest current restrictions are:

• Only text-encoded glTF files are supported (both with external binary data and with embedded Base64-encoded binary data); glb files are currently not supported;

• The only primitives supported are triangle meshes; in particular, emissive meshes are the only kind of lights currently supported;

• Alpha channels (and related transparency information) are currently ignored;

• Image textures are currently not supported.