Crate rytm_rs

Source
Expand description

§rytm-rs

More than safe rust abstractions over rytm-sys, an unofficial SDK for writing software for Analog Rytm running on firmware 1.70.

On top of CC and NRPN messages, Rytm also accepts sysex messages which are undocumented and not officially supported by Elektron.

The effort of reverse engineering the sysex format started with libanalogrytm which is a C library powers parts of rytm-rs through rytm-sys bindings.

libanalogrytm though a great foundation, is not accessible to many developers due to its low level nature and also lacks high level abstractions for common tasks. The scope of the libanalogrytm is to provide the necessary types for the encoded and decoded sysex messages and focus on the low level details of the sysex protocol.

rytm-rs builds on top of libanalogrytm and provides high level abstractions for common tasks and designed to provide an SDK like experience for developers with ease of use in mind abstracting the low level details completely.

§Features

  • All structures in a Rytm project is completely represented with RytmProject including all the necessary fields and methods to receive manipulate and send the project to the device.
  • All getter and setter methods have range and validity checks including comments about the range and validity of the values.
  • The Rytm device project defaults are represented in all the struct Default implementations.
  • Sysex encoding and decoding is completely abstracted away. Update the project with a single method call.
  • Convert parts of the project to sysex with one method call and send it to the device with your choice of transport.
  • Separate query types provided for Pattern, Kit, Sound, Settings and Global types which covers the entire Rytm project parameters except songs.
  • Different methods provided for setting, getting, clearing parameter locks exhaustively and available in Trig struct.
  • All 34 machine types are represented including parameter lock setters getters and clearers.
  • All getters and setters use the actual range of values on the device not the internal ranges which are used in the sysex protocol.

§Purpose

The purpose of this crate is to provide a safe and easy to use SDK like experience for developers who would like to write software for Analog Rytm.

The first priority for this crate is to provide an easy to use api for developers who would like to

  • Develop a software products for Analog Rytm
  • Develop custom creative software for artistic purposes
  • Discover and experiment with generative and algorithmic music but don’t want to deal with the low level details of the sysex protocol communicating with the device.

The crate is not optimized for the best performance or memory. On the other hand the memory footprint is not that big and the performance is good enough since the performance bottleneck is the device itself when it comes to sysex communication.

I believe that Rytm uses a low priority thread for sysex communication in their internal RTOS. If you flood Rytm with sysex messages it will queue the responses and get back to you when it can. This is not an issue for most use cases but it is a nice to know.

§Layers

rytm-rs is composed of 3 main layers.

§rytm-sys

  • Encoding/decoding sysex messages
  • Providing #[repr(C,packed)] structs to identically represent the sysex messages in memory keeping the original memory layout of the messages.
  • Exposing types from libanalogrytm through rytm-sys bindings. Which is the main hub for reverse engineering.

§rytm-rs

Internal layer which deals with communicating with rytm-sys and deals with conversion from/to raw types (#[repr(C,packed)] structs).

User facing layer which provides high level abstractions for common tasks. Getters, setters etc.

§Usage

Starting with importing the prelude is a good idea since it brings the necessary traits and types into scope.

Also the midir library will be used for midi communication with the device in these examples but you can use any midi library you want.

use std::sync::Arc; use parking_lot::Mutex;
use midir::{Ignore, MidiInputConnection, MidiOutputConnection};
use rytm_rs::prelude::*;

// We'll be using this connection for sending sysex messages to the device.
//
// Using an Arc<Mutex<MidiOutputConnection>> is a good idea since you can share the connection between threads.
// Which will be common in this context.
fn get_connection_to_rytm() -> Arc<Mutex<MidiOutputConnection>> {
    let output = port::MidiOut::new("rytm_test_out").unwrap();
    let rytm_out_identifier = "Elektron Analog Rytm MKII";
    let rytm_output_port = output.find_output_port(rytm_out_identifier).unwrap();

    Arc::new(Mutex::new(
        output.make_output_connection(&rytm_output_port, 0).unwrap(),
    ))
}

// We'll be using this connection for receiving sysex messages from the device and forwarding them to our main thread.
pub fn make_input_message_forwarder() -> (
    MidiInputConnection<()>,
    std::sync::mpsc::Receiver<(Vec<u8>, u64)>,
) {
    let mut input = crate::port::MidiIn::new("rytm_test_in").unwrap();
    input.ignore(Ignore::None);
    let rytm_in_identifier = "Elektron Analog Rytm MKII";
    let rytm_input_port = input.find_input_port(rytm_in_identifier).unwrap();

    let (tx, rx) = std::sync::mpsc::channel::<(Vec<u8>, u64)>();

    let conn_in: midir::MidiInputConnection<()> = input
        .into_inner()
        .connect(
            &rytm_input_port,
            "rytm_test_in",
            move |stamp, message, _| {
                // Do some filtering here if you like.
                tx.send((message.to_vec(), stamp)).unwrap();
            },
            (),
        )
        .unwrap();

    (conn_in, rx)
}

fn main() {
    // Make a default rytm project
    let mut rytm = RytmProject::default();

    // Get a connection to the device
    let conn_out = get_connection_to_rytm();

    // Listen for incoming messages from the device
    let (_conn_in, rx) = make_input_message_forwarder();

    // Make a query for the pattern in the work buffer
    let query = PatternQuery::new_targeting_work_buffer();

    // Send the query to the device
    conn_out
        .lock()
        .unwrap()
        .send(&query.as_sysex().unwrap())
        .unwrap();

    // Wait for the response
    match rx.recv() {
        Ok((message, _stamp)) => {
            match rytm.update_from_sysex_response(&message) {
                Ok(_) => {
                    for track in rytm.work_buffer_mut().pattern_mut().tracks_mut() {
                        // Set the number of steps to 64
                        track.set_number_of_steps(64).unwrap();
                        for (i, trig) in track.trigs_mut().iter_mut().enumerate() {
                            // Enable every 4th trig.
                            // Set retrig on.
                            if i % 4 == 0 {
                                trig.set_trig_enable(true);
                                trig.set_retrig(true);
                            }
                        }
                    }

                    // Send the updated pattern to the device if you like
                    conn_out
                        .lock()
                        .unwrap()
                        .send(&rytm.work_buffer().pattern().as_sysex().unwrap())
                        .unwrap();
                }
                Err(err) => {
                    println!("Error: {:?}", err);
                }
            }
        }
        Err(err) => {
            println!("Error: {:?}", err);
        }
    }
}

§Remarks

The people mentioned here are major contributors to the reverse engineering effort and I would like to thank them for their work. This crate would not be possible in this form and time frame without their work.

§bsp2

The maintainer of libanalogrytm and the original author of the reverse engineering effort. He is the one who started the reverse engineering effort and provided the initial C library which is the foundation of rytm-rs.

§mekohler

Author of the Collider app which is available for iPad in the app store. Another contributor to the reverse engineering effort.

§void

Author of the STROM app which is available for iPad in the app store. Another contributor to the reverse engineering effort.

Many thanks to Başak Ünal for the logo.

Modules§

  • error
    Error types for the rytm crate.
  • object
    Re-exports all object types. Kits, patterns, sounds, globals and settings are called objects.
  • prelude
    Re-exports the necessary traits, the RytmProject struct, all query types and necessary public sysex types.
  • query
    Query structures for the rytm.

Macros§

Structs§

Enums§

Traits§

  • SysexCompatible
    A trait which is implemented by all objects which can be converted to sysex messages including queries and rytm project structures.