Hydrogent

Hydrogent is an implementation of the Hydra rendering API in Diligent Engine.

Build Instructions

1. Download and build OpenUSD
   • Make sure all required dependencies are installed, in particular, the following python packages:
     • PySide6
     • PyOpenGL
   • Clone the repository bash git clone https://github.com/PixarAnimationStudios/OpenUSD.git cd OpenUSD
   • On Windows, use the Visual Studio generator and build each configuration in a respective folder. Start a developer command prompt for Visual Studio and run the following commands: bash python .\build_scripts\build_usd.py --build-variant debug .\build\Debug python .\build_scripts\build_usd.py --build-variant release .\build\Release python .\build_scripts\build_usd.py --build-variant relwithdebuginfo .\build\RelWithDebInfo
     • :warning: Use new shell for each configuration to avoid issues with environment variables.
   • On MacOS, use the Xcode generator and build each configuration in a respective folder, for example: bash python3 ./build_scripts/build_usd.py --build-variant debug --generator Xcode ./build/Debug python3 ./build_scripts/build_usd.py --build-variant release --generator Xcode ./build/Release python3 ./build_scripts/build_usd.py --build-variant relwithdebuginfo --generator Xcode ./build/RelWithDebInfo
2. Optionally, download and build USD File Format Plugins to support additional file formats (fbx, gltf, obj, etc.):
   • Use the following options --draco --openimageio to build OpenUSD with Draco and OpenImageIO support in step 1.
     • :warning: if you already built OpenUSD, you will need to delete the build folder and start over as OpenUSD does not handle changing build options well.
   • On Windows and MacOS, follow the build instructions, but build each configuration in a respective folder. For example, on Windows: bash cmake -S . -B build/Debug -DCMAKE_INSTALL_PREFIX=bin/Debug -Dpxr_ROOT=<OPEN_USD_ROOT>/build/Debug -DUSD_FILEFORMATS_BUILD_TESTS=OFF <OPTIONS> cmake --build build/Debug --config debug cmake --install build/Debug --config debug
3. Provide the path to the USD build folder with DILIGENT_USD_PATH CMake variable, for example: -DDILIGENT_USD_PATH=<OPEN_USD_ROOT>\build
4. Build the engine by following standard instructions

Run Instructions

To run an application that uses Hydrogent on Windows, the following paths must be added to the PATH environment variable for the application to find required USD DLLs. For example, for Debug configuration:

<OPEN_USD_ROOT>\build\Debug\lib
<OPEN_USD_ROOT>\build\Debug\bin

If you are using USD File Format Plugins, the following paths must be also added to the PATH environment variable:

<USD_FILEFORMAT_PLUGINS_ROOT>\bin\Debug\lib
<USD_FILEFORMAT_PLUGINS_ROOT>\bin\Debug\plugin\usd

Additionally, the following path must be added to the PXR_PLUGINPATH_NAME environment variable:

<USD_FILEFORMAT_PLUGINS_ROOT>\bin\Debug\plugin\usd