Rust CLAP-First Plugin Example

Write a CLAP plugin in Rust, get self-contained AU and VST3 plugins for free! Supports Windows, Linux, and macOS (universal binary x86_64 + arm64)

This repository demonstrates a Rust-based approach to audio plugin development that starts with the CLAP plugin format and extends to VST3 and AU formats using the clap-wrapper project. The resulting plugins are self-contained thanks to a static linking approach.

The clack crate is used to provide safe Rust wrappers for the CLAP API without adding an opinionated plugin framework.

Uniquely, this example demonstrates exporting multiple plug-ins from a single binary! To support AU, clap-wrapper's AUv2 plugin factory extension is used.

Bindings for the clap-wrapper extensions are provided in clap-wrapper-extensions. I hope for them to be included in clack directly to reduce the required boilerplate for plugins.

Example Gain Plugins

This example exposes two variations of a simple gain plugin:

• Gain Halver: Multiplies signal with 0.5
• Gain Doubler: Multiplies signal with 2.0

Requirements

• Rust toolchain (2021 edition or later)
• CMake (3.15 or later)
• C++ compiler with C++17 support

Building the Plugins

The project uses the xtask pattern to simplify building:

# Build debug version
cargo xtask build gain-example

# Build release version
cargo xtask build gain-example --release

# Build and install release version to user's plugin directories (macOS/Linux only)
cargo xtask build gain-example --release --install

See the xtask README for more detailed commands and options.

How It Works

1. The Rust code is compiled into a static library that exports a non-standard rust_clap_entry symbol
2. A small C++ shim re-exports this symbol as the standard CLAP entry point
3. clap-wrapper builds self-contained plugins for CLAP, VST3, and AU formats

Customizing

To adapt this example for your own plugin:

1. Rename/duplicate the gain-example plugin directory
2. Modify the implementations in audio_thread.rs and main_thread.rs
3. Update the plugin descriptors in lib.rs
4. Update bundle IDs and other metadata in build commands

Acknowledgements

• @Prokopyl for providing Rust bindings for the clap-wrapper's extensions
• SG60/rust-clap-wrapper-thick for their pioneering work

License

MIT OR Apache-2.0