The oneAPI Level Zero Ray Tracing Support library is an open source project used by Intel(R) oneAPI Level Zero as the implementation of the RTAS extension ZE_extension_rtas and deprecated experimental RTAS builder extension ZE_experimental_rtas_builder.

The library implements high performance CPU based ray tracing acceleration structure (RTAS) construction algorithms that take input from the above mentioned APIs and produce an RTAS that is compatible with the ray tracing hardware of Intel GPUs.

The oneAPI Level Zero Ray Tracing Support library is distributed under the Apache 2.0 license.

No code changes may be introduced that would regress support for any currently supported hardware. All contributions must ensure continued compatibility and functionality across all supported hardware platforms. Failure to maintain hardware compatibility may result in the rejection or reversion of the contribution. Any deliberate modifications or removal of hardware support will be transparently communicated in the release notes.

Debug parameters, environmental variables, and internal data structures are considered as internal implementation detail and may be changed or removed at any time.

The oneAPI Level Zero Ray Tracing Support library is available for installation on a variety of Linux distributions and can be installed via the distro's package manager.

For example on Ubuntu* 22.04:

apt-get install libze-intel-gpu-raytracing

To compile the library under Linux execute:

cmake -B build -G Ninja -D CMAKE_BUILD_TYPE=Release .
cmake --build build --target package

To compile the library under Windows execute:

cmake -B build -G "Visual Studio 17 2022" -A "x64" -D CMAKE_BUILD_TYPE=Release .
cmake --build build --target package

To compile the library under Linux including SYCL tests:

wget https://github.com/intel/llvm/releases/download/sycl-nightly%2F20230304/dpcpp-compiler.tar.gz
tar xzf dpcpp-compiler
source dpcpp_compiler/startup.sh
cmake -B build -G Ninja -D CMAKE_CXX_COMPILER=clang++ -D CMAKE_C_COMPILER=clang -D CMAKE_BUILD_TYPE=Release -D ZE_RAYTRACING_SYCL_TESTS=INTERNAL_RTAS_BUILDER .
cmake --build build --target package
cd build
ctest

You can configure how TBB is used by setting the ZE_RAYTRACING_TBB cmake variable and ZE_RAYTRACING_TBB_VERSION:

• build_static: build a static library of provided TBB version and link that static library (default)
• inject_headers: link against system provided TBB version, but use headers of specified TBB version
• normal: link against system provided TBB version as normal, using system provided TBB headers

Dynamic linking against new TBB versions may cause the library to use new TBB symbols, making it incompatible with older TBB versions. This has been an issue with applications that ship with an older TBB version. To have the library be compatible with older TBB versions you can use the inject_headers mode to force an older TBB interface version to be used:

cmake -B build -G Ninja -D CMAKE_BUILD_TYPE=Release -D ZE_RAYTRACING_TBB=inject_headers -D ZE_RAYTRACING_TBB_VERSION=v2021.6.0 .
cmake --build build --target package

Some TBB headers are included with the project and do not trigger a download, other TBB headers and sources will get downloaded automatically. You can avoid downloading TBB by putting your own TBB sources (or headers) into a folder called tbb in the main repository folder.

cp -r tbb-src tbb
cmake -B build -G Ninja -D CMAKE_BUILD_TYPE=Release -D ZE_RAYTRACING_TBB=build_static .
cmake --build build --target package

Directly linking to the oneAPI Level Zero Ray Tracing Support library is not supported. Level Zero applications should link with Level Zero Loader and use the ZE_extension_rtas API.

• Intel(R) oneAPI Threading Building Blocks TBB.

Please submit an issue using github.com interface.

Create a pull request on github.com with your patch. A maintainer will contact you if there are questions or concerns.

• oneAPI Level Zero RTAS extension
• oneAPI Level Zero experimental RTAS builder extension
• Intel(R) OneApi Level Zero Specification API C/C++ header files

(*) Other names and brands may be claimed as property of others.