bevy_fmod

This crate aims to provide an idiomatic Bevy plugin for FMOD. This crate wraps libfmod.

cargo add bevy_fmod

FMOD

FMOD is a cross-platform audio engine that is used in many games. It is a commercial product, with a free license available for specific terms.

FMOD attribution

This crate is not affiliated with FMOD in any way. It is not endorsed by or affiliated with Firelight Technologies Pty, Ltd. To use FMOD in your application, you are required to include attribution by Firelight Technologies' terms. Learn more here.

Supported platforms

Currently, this crate is only tested and developed for Windows (non-UWP) and Linux. More platforms are planned eventually.

Web: https://github.com/Salzian/bevy_fmod/issues/51

Pull requests are welcome.

Linking the FMOD library

Due to FMOD's licensing, this crate does not include the required FMOD libraries. You will need to download the appropriate libraries here. This requires a free FMOD account.

Windows

The linking process on Windows is straight forward. Download and install the "FMOD Engine" for Windows. When installing, a folder will be created with FMOD libraries. Copy the following files into root of your project:

• api/core/lib/x64/fmod.dll
• api/studio/lib/x64/fmodstudio.dll

When publishing your game, you will need to include these libraries in the same directory as the executable.

[!CAUTION]

The libfmod crate requires you to suffix the libraries with _vc like this:

• fmod_vc.dll
• fmodstudio_vc.dll

This is only necessary for Windows. I don't know the background of this requirement, but it was too little of a problem to investigate further.

For the nerds that want to dive deeper, this behavior is defined in the crates build.rs file.

The final game will ship with the following structure:

My Game/
├── My Game.exe
├── fmod_vc.dll
└── fmodstudio_vc.dll

MacOS

• Download "FMOD Engine" for MacOS.
• In the dmg file, open the FMOD Programmers API folder.
• You will need these files:
  • api/core/lib/libfmod.dylib
  • api/studio/lib/libfmodstudio.dylib

Linking on MacOS is a bit different to Windows, as the defaults of the OS are not as straight forward as Windows. Also, Windows seems to take parent directories into account. During development, it is sufficient to put the libraries in the root of your project. When building, the built executable is contained in the target/debug directory. Now on Windows, this doesn't seem to be a problem, but on MacOS, the executable is unable to find the libraries.

To fix this, you have to pass some flags to cargo during development. Have a look at this .cargo/config.toml:

[target.aarch64-apple-darwin]
rustflags = [
    "-L", "native=./vendor/fmod",
    "-C", "link-arg=-Wl,-rpath,./vendor/fmod",
]

The first line tells cargo where to look for libraries during development. If you keep the libraries in the root of your project, there is no problem when building the project. However, when running the executable, it will not find the libraries, as the executable is in the target/debug directory.

I recommend putting the libraries in a known folder like vendor/fmod and then pass the path to cargo using the -L flag. There are different ways to do this, but using the .cargo/config.toml is the most convenient to me.

The second line will determine the rpath of the executable. This is the path where the executable will look for the libraries. By default, executables will look in a variety of places, including the directory the executable is in. This is fine when publishing the game, as you can just use the Windows method and put the libraries in the same directory as the executable. However, during development, the executable is in the target/debug directory, which gets generated automatically by cargo and does not contain the libraries. The "-C", "link-arg=-Wl,-rpath,./vendor/macos" flag will tell the executable to look in the vendor/fmod directory of your project for the libraries.

By the end, your project structure should look like this:

my_game/
├── .cargo/
│   └── config.toml
├── src/
│   └── <source files>
├── vendor/
│   ├── fmod/
│   │   ├── libfmod.dylib
│   │   ├── libfmodL.dylib
│   │   ├── libfmodstudio.dylib
│   │   └── libfmodstudioL.dylib
│   └── <other external libraries>
└── Cargo.toml

Linux

[!WARNING] This section might be outdated. The approach described here does work, but does not align with what is described in the Windows and MacOS sections.

Below are the steps for a fairly minimal method to link the libraries. See the comments in build.rs for more information.

• Download the "FMOD Studio" and "FMOD Engine" package for Linux.
• Create a new folder fmod in the root of your project.
• Extract the api folder into it.
• Copy the contents of build.rs into your own build script.

Examples

To test the examples of this library, clone the repository. FMOD Studio comes with an Examples project. Open it and select File > Save as.... Save the project as <bevy_fmod>\assets\audio\demo_project.fspro. Now, build the project ( File > Build). This will create a folder called .\assets\audio\demo_project\Build which is used by our examples.

Run examples with cargo run --example <example_name>. Find the list of examples in the Cargo.toml See the source code of the examples for more details.

Live Update

Live update is a way of connecting FMOD Studio to your game as it runs, allowing you to update and monitor audio content in real time. Read more about it here.

To enable live update, you need to enable the live-update feature. While you can do so in Cargo.toml, we recommend to explicitly enable it with the --features flag. This way, you won't accidentally include it in your release builds.

cargo run --example minimal --features live-update