truce-driver

Headless driver for truce plugins.

Overview

Instantiate a plugin, feed it scripted audio + events for a fixed duration, capture the output - no DAW, no format wrapper, no GUI. Three consumers in-tree:

• truce-test - assertion helpers (assert_state_round_trip, assert_nonzero, the driver! macro) layered on top of the captured DriverResult.
• truce-standalone's offline-render path - cargo truce run --no-playback parses CLI flags into an InputSource::Buffer + Script, runs PluginDriver, writes the captured audio out as WAV.
• Plugin authors writing custom main.rs binaries - batch CI renders, demo audio generation, preset-rendering pipelines.

Key types

• PluginDriver<P> - the builder. Carries sample rate, block size, channel count, the input source, the script, the transport state, and the capture spec.
• InputSource - Silence / Constant / Buffer(Vec<Vec<f32>>) / Generator(Box<dyn FnMut(usize, f64) -> f32>).
• Script - sample-accurate sequence of EventBodys with a cursor (note_on, note_off, set_param, wait_ms, …).
• CaptureSpec - what to capture per block (audio, output events, meters, param snapshots).
• DriverResult - the post-run capture, indexable by channel.

Precision

PluginDriver routes through RawBufferScratch<P::Sample> - the same widening/narrowing path the format wrappers use - so prelude64 plugins can be driven in headless tests with the wrapper-boundary conversion done internally. The driver's public input / output buffers are always f32 (host-wire); the plugin's process() sees AudioBuffer<P::Sample>.

Example

use std::time::Duration;
use truce_driver::{InputSource, PluginDriver};

let result = PluginDriver::<MyPlugin>::new()
    .sample_rate(48_000.0)
    .duration(Duration::from_secs(2))
    .input(InputSource::Constant(0.5))
    .set_param(MyParamId::Gain, 0.7)
    .script(|s| {
        s.note_on(60, 0.8);
        s.wait_ms(500);
        s.note_off(60);
    })
    .run();

Part of truce.