OptiX Toolkit

A set of utilities commonly used in applications utilizing the OptiX ray tracing API.

Current Utilities

• PyOptiX - Complete Python bindings for the OptiX host API.
• CuOmmBaking - a C++/CUDA library for baking Opacity Micromap Arrays for textured geometry.
• DemandLoading - a C++/CUDA library for loading CUDA sparse textures on demand in OptiX renderers.
• ImageSource - wrapper for OpenEXR image library (adaptable to other image formats).
• Gui - convenience code for incorporating OpenGL into OptiX applications.
• ShaderOps - vector math and other CUDA helper functions for OptiX kernels.
• Util - file handling and other utility functions.

Requirements

• OptiX 7.4 or later.
• CUDA 11.1 or later.
• C++ compiler (e.g. gcc under Linux, Visual Studio under Windows)
• CMake 3.23 or later. Using the latest CMake is highly recommended, to ensure up-to-date CUDA language support.
• git (any modern version).

Building OTK

• In the directory containing the OTK source code, create a subdirectory called build and cd to that directory.

mkdir build
cd build

• Configure CMake, specifying the location of the OptiX SDK. This can be accomplished using cmake-gui or by entering the following command in a terminal window. (Note that .. specifies the path to the source code in the parent directory.)

cmake -DOptiX_INSTALL_DIR=/path/to/optix ..

Under Windows, it might be necessary to specify a generator and a toolset.

cmake -G "Visual Studio 15 2017 Win64" -T host=x64 -DOptiX_INSTALL_DIR=/path/to/optix ..

• If the configuration is successful, build the OTK libraries. Under Windows, simply load the Visual Studio solution file from the build directory. Under Linux:

cd ..
make -j

If you encounter problems or if you have any questions, we encourage you to post on the OptiX developer forum.

Building statically linked libraries

OptiX Toolkit components are compiled into dynamic libraries (DSOs/DLLs) to simplify linking client applications. This eliminates the need for client applications to link with third-party libraries like OpenEXR and GLFW.

Some clients of the OptiX Toolkit might prefer to use statically linked libraries. This can be accomplished by setting the CMake configuration variable BUILD_SHARED_LIBS=OFF.

Important: when building statically linked libraries, the CMake configuration variable OTK_FETCH_CONTENT should be set to OFF, and various third party libraries must be installed as described below.

Installing third-party libraries.

Normally the OptiX Toolkit CMake files use FetchContent to download and build various third-party libraries:

• Imath 3.1.5 or later
• OpenEXR 3.1.5 or later
• GLFW 3.3 or later
• glad (any recent version)

This behavior can be disabled by setting OTK_FETCH_CONTENT=OFF during CMake configuration, which is necessary when building statically linked libraries, as described above.

When FetchContent is disabled, the following CMake configuration variables should be used to specify the locations of the third-party libraries: Imath_DIR, OpenEXR_DIR, glfw3_DIR, and glad_DIR. The directory specified for each of these variables should be the location of the project's CMake configuration file. For example:

cd build
cmake \
-DBUILD_SHARED_LIBS=OFF \
-DOTK_FETCH_CONTENT=OFF \
-DImath_DIR=/usr/local/Imath/lib/cmake/Imath \
-DOpenEXR_DIR=/usr/local/OpenEXR/lib/cmake/OpenEXR \
-Dglfw3_DIR=/usr/local/glfw3/lib/cmake/glfw3 \
-Dglad_DIR=/usr/local/glad/lib/cmake/glad \
-DOptiX_ROOT_DIR=/usr/local/OptiX-SDK-7.5 \
..

As of this writing, OpenEXR 3.1 binaries are not yet available via most package managers, so we recommend building these third party libraries from source code downloaded from the following locations:

• Imath 3.1.5: https://github.com/AcademySoftwareFoundation/Imath.git
• OpenEXR 3.1.5: https://github.com/AcademySoftwareFoundation/openexr.git
• GLFW 3.3: https://github.com/glfw/glfw.git
• glad: https://github.com/Dav1dde/glad

Troubleshooting

Problem: CMake configuration error: "could not find git for clone of glad-populate"
Solution: git is required in order to download third party libraries (e.g. glad)

Problem: Runtime error: OPTIX_ERROR_UNSUPPORTED_ABI_VERSION: Optix call 'optixInit()' failed
Solution: Download newer driver

Problem: Windows Debug link error: cannot open file '..\zlib-install\lib\zlibstatic.lib'
Solution: Build Release configuration first, then build Debug configuration.

Problem: CMake configuration error: "Failed to detect a default cuda architecture"
Solution: Set configuration variable CMAKE_CUDA_COMPILER to the full path of the NVCC compiler.

Attributions

This project contains build logic from the OptiX Wrapper Library (OWL), which is redistributed under the terms of the Apache License Version 2.0.