UnityPhysXPlugin - macOS (Intel x64)

Experimental Unity package to enable access to NVIDIA PhysX SDK 4 from within Unity.

This fork is specifically set up for building on macOS. All references to CUDA have been commented out.

Tested on Unity 2020.2.0f1, built with Xcode 12.2 on macOS 10.15.

Prerequisites

1. CMake 3.14+ SWIG 4.0+ brew install cmake
2. SWIG 4.0+ brew install swig
3. A Windows machine/VM with Visual Studio 2017, CMake 3.14+ and SWIG 4.0+

Build Instructions

Build PhysX on macOS

1. Get PhysX 4.1 from GitHub (https://github.com/NVIDIAGameWorks/PhysX)
2. In <PhysX Dir>/physx/buildtools/presets/public/mac64.xml make sure PX_GENERATE_STATIC_LIBRARIES is set to True.
3. Use generate_projects.sh to generate your Xcode project. Additional information
   1. You may have to remove -Werror and add -Wanon-enum-enum-conversion -Wno-alloca to the compiler flags in ./physx/source/compiler/cmake/mac/CMakeLists.txt
4. Build the PhysX project, use the ALL_BUILD scheme in Release.

Build Native Libraries on macOS

1. Set the PHYSX_DIR variable in the CMakeLists.txt in ./NVIDIA.PhysX.Native to your PhysX root folder. For example /Users/username/PhysX.
2. Set your working directory to ./NVIDIA.PhysX.Native and run cmake ./ -G Xcode to generate your Xcode project.
3. Open the Xcode project and set the ALL_BUILD scheme to Release
4. Build the project.
5. The built NVIDIA.PhysX.Native.dylib file will be in ./NVIDIA.PhysX.Native/Release

Build C# Bindings on Windows

Note: cmake does not support C# on macOS. However, SWIG does and this step might work on macOS if done manually.

1. Copy your local repository over to your Windows partition/machine.
2. Build PhysX (for Release) for Windows following the instructions for nvidia's plugin repository
3. Using nvidia's fork as a base, replace the Header, Helpers, and Interface folder from this fork in ./NVIDIA.PhysX.Native/.
4. Generate and Build the VS2017 solution and collect the NVIDIA.PhysX.dll C# library.
   1. Alternatively, you can also copy the generated Partial.cs and Wrapper folder to your Unity project.
5. Back to your macOS machine. Put NVIDIA.PhysX.dll in your Unity projects's Wrapper (or Plugins) directory.

IL2CPP Support

You can grab the binaries and example project from the macos-il2cpp branch

I've documented the process of getting IL2CPP to work here. It was a long and arduous process because of some antiquated toolchains that were involved. Again, you will need Windows because cmake does not support c# on macOS.

1. Get this particular fork of SWIG and build it.
   1. For macOS/Unix, follow these instructions: http://www.swig.org/svn.html.
   2. For Windows, use these instructions as a guideline: http://www.swig.org/Doc4.0/Windows.html#Windows_swig_exe. However, instead of using mingw-32, set up MSYS2 and use that for building. First build PCRE according to the instructions and then ./autogen.sh, ./configure and make.
2. Make sure where swig (which swig for Windows) points to your newly built swig. (Set PATH variable)

On Windows

1. Store a copy of the previously generated .cs files in Wrapper somewhere. We will need most of it later.
2. Add the -monoaotcompat flag to your CMAKE_SWIG_FLAGS (set(CMAKE_SWIG_FLAGS ${CMAKE_SWIG_FLAGS} -namespace NVIDIA.PhysX -nodefaultctor -monoaotcompat))
3. Generate and build the VS2017 solution as usual. (It might fail, but the required files should have been generated.) Store the resulting Wrapper folder seperately and copy it over to your macOS partition.

Back to macOS

1. Here, we're only building the NVIDIA.Physx.Native.dylib library, but with the -monoaotcompat flag added to the CMAKE_SWIG_FLAGS.
2. Follow the above instructions to get the native library.
3. In your Unity project (with the previous non-IL2CPP Wrapper), replace these files with the Wrapper .cs files that we just generated.
   • NativePINVOKE.cs
   • All files that end with *Callback.cs (such as PxErrorCallback.cs)
4. In those *Callback.cs files, find in files to replace calls to Dispose() with destroy() to be compatible with the sample code.
5. Done! Whew!

Hints gathered along the way:

• swig/swig#1262
• swig/swig#1832

Run

Start Unity and open .\Unity\PhysX project and try out the sample scenes.