cosmo-pd

A monorepo for Casio CZ-101 phase distortion synthesis — including a preset manager web/desktop app, an in-browser phase distortion synthesizer, and a VST3/CLAP/AUv2 plugin.

Pre-built binaries can be obtained from the Purr Audio store. Live Web version of the synth can be found here: Cosmo PD-101.

Overview

This is a Bun monorepo containing:

Package	Description
packages/cosmo-synth-engine	Rust WebAssembly phase distortion synth engine
packages/cosmo-pd101	Reusable library: synth-specific React components, hooks, preset utilities, and SysEx utilities consumed by the plugin webview
packages/cosmo-pd101-plugin	VST3/CLAP/AUv2 plugins with a thin React/Vite WebView shell
packages/cosmo-pd101-plugin-auv3	AUv3 plugin, deprecated (will be replaced with truce AUv3 plugin)
packages/cosmo-pd101-docs	Manual for Cosmo PD-101

Setup

Prerequisites

• Bun
• Rust
• wasm-pack (auto-installed via postinstall)

Installation

bun install

Commands

Development

# Use bun run dev for relevant packages

Build

bun run build            # Full build: plugin + desktop
bun run build:plugin     # Build VST3/CLAP/AUv2 plugin (macOS, current arch)

Install

bun run plugin:install

Testing

bun run test             # All tests across all packages (JS + Rust) — root-level

Lint & Format

bun run lint             # Biome + cargo fmt/clippy check
bun run lint:fix         # Biome auto-fix + cargo fmt

Architecture

Synth Engine (packages/cosmo-synth-engine)

• Rust compiled to WebAssembly via wasm-pack.
• Phase distortion oscillators, CZ envelopes, polyphonic voice management.
• Bindings exported to TypeScript via Specta.

Synth Library (packages/cosmo-pd101)

• Reusable React/TypeScript synth UI and domain library.
• packages/cosmo-pd101/src/index.ts exports synth-specific React components (SynthRenderer), hooks (useAudioEngine, useSynthState, etc.), SysEx decoder utilities, preset storage/conversion utilities, and shared types consumed by the plugin webview.

Plugin (packages/cosmo-pd101-plugin)

• Built using truce framework: VST3 + CLAP + AUv2 from a single Rust codebase.
• Embeds the cosmo-synth-engine and a thin React/Vite WebView app via WebView IPC.
• The plugin webview/ stays as a direct child of the Rust crate for plugin webview integration and imports reusable UI from @cosmo/cosmo-pd101.

Development Tools

• Bun: Package manager and script runner.
• Biome: Linter and formatter (tabs, double quotes).
• Vitest: Unit and browser tests.
• Playwright: Browser test runner.

Testing

Two Vitest projects: unit (Happy DOM) and browser (Playwright/Chromium).

• Unit test files: *.{test,spec}.{ts,tsx} (excluding .browser.test.)
• Browser test files: *.browser.test.{ts,tsx}

For detailed testing patterns, see docs/component-testing.md.

Licensing

Cosmo PD-101 is dual-licensed:

Channel	License	Applies To
GitHub (source)	GPL-3.0-only — see LICENSE	Source code, forks, and self-compiled builds
Gumroad (binaries)	Commercial EULA — see LICENSE-COMMERCIAL	Pre-compiled signed installers

Source code on GitHub is free to view, fork, and compile via cargo build. Pre-compiled binaries sold on Gumroad are distributed under a standard commercial end-user license agreement that prohibits re-distribution of the installer files.

Third-party dependency licenses are documented in THIRD_PARTY_LICENSES.

SysEx Reference

CZ-101 patch format documentation: docs/CZ101_SYSEX_FORMAT.md.