ether-dream

A pure-rust implementation of the Ether Dream Laser DAC protocol.

Features

This implementation provides:

• A full implementation of the Ether Dream DAC protocol.

  Find all types described within the Ether Dream protocol in the protocol module. This module also provides traits to simplify the process of writing and reading protocol types to and from little-endian bytes respectively. This is particularly useful for working with TcpStreams - the primary method of communication between a DAC and the user.

• An iterator yielding all DAC broadcasts appearing on the network.

  See the recv_dac_broadcasts.rs example for a simple overview. This is the first step in locating DACs on the network before attempting to establish connections to them.

  for dac_broadcast in ether_dream::recv_dac_broadcasts().unwrap() {
      println!("{:#?}", dac_broadcast);
  }

• A simple, low-level and thorough Stream API.

  This is a thin layer around the TCP stream communication channel described within the Ether Dream protocol. It simplifies the process of queueing and sending Commands to the DAC and receiving Responses.

  Here's how one might connect to the first DAC they find:

  let (dac_broadcast, source_addr) = ether_dream::recv_dac_broadcasts()
      .unwrap()
      .filter_map(Result::ok)
      .next()
      .unwrap();
  println!("Discovered DAC \"{}\" at \"{}\"! Connecting...", mac_address, source_addr);
  let stream = dac::stream::connect(&dac_broadcast, source_addr.ip().clone()).unwrap();

  Here's an example of queueing multiple commands for the DAC at once. The following code sends the "prepare stream" command, submits some initial point data to the DAC and then tells the DAC to begin processing point data at the given rate.

  stream
      .queue_commands()
      .prepare_stream()
      .data(generate_points())
      .begin(0, point_hz)
      .submit()
      .unwrap();

  The submit method sends all queued commands over the TCP stream and then waits to validate the response for each one. A result is returned along with any errors (including NAKs and io::Errors) that might have occurred.

  See the dac_stream.rs example for a more thorough demonstration of the stream API.

  Note that this API provides no high-level wrapper around the concept of "frame"s of "point"s. This is considered a higher-level implementation detail and is expected to be implemented by downstream crates. E.g. the nannou creative coding framework provides (or will provide) a higher-level laser API which uses this crate as one of multiple possible laser protocol targets.

• A rust-esque representation of the DAC protocol types. The dac module contains several types that mirror the DAC protocol types but with a rust-friendly API.

  E.g. Many of the bit-field sets that describe sets of DAC properties have bitflags! struct representations in this module. Similarly, some state machines described by integers in the protocol have rust enum representations in this module.

  Methods are provided for converting the protocol representation to this rust-esque representation (from_protocol) and vice-versa (to_protocol).

• Conventional, clear error handling for all areas of the API.

DAC Emulator

This repository also contains an ether-dream-dac-emulator crate. This crate may be used to build and run custom, virtual Ether Dream DACs which may be useful for testing and visualisation.

Emulation includes all networking (UDP broadcasting, TCP listening, TCP streaming) and the full set of state machines within the DAC (light engine, playback and source).

Seeing as the virtual DAC does not have a means of emitting physical light, it instead yields "frame"s of points via an Output queue. The rate at which frames are pushed to this queue may be controlled by specifying the frame_rate field within the DAC Description.

The ./dac-emulator/examples demonstrate how the crate may be used for both simple command-line testing and for full visualisation of the DAC emulator output.

extern crate ether_dream_dac_emulator;

fn main() {
    let dac_description = Default::default();
    println!("Creating an emulator for the following Ether Dream DAC:\n{:#?}", dac_description);
    let (broadcaster, mut listener) = ether_dream_dac_emulator::new(dac_description).unwrap();
    println!("Broadcasting DAC once per second...");
    let broadcaster_handle = broadcaster.spawn().unwrap();
    broadcaster_handle.spawn_once_per_second_timer().unwrap();
    println!("Listening for stream connection requests...");
    while let Ok((stream, addr)) = listener.accept() {
        println!("Connected to {}!", addr);
        let output = stream.output();
        loop {
            match output.next_frame() {
                Ok(frame) => println!("\tReceived frame with {} points", frame.len()),
                Err(_) => break,
            }
        }
        println!("Stream connection shutdown. Awaiting new requests...");
    }
}

Acknowledgements

This crate is based upon the work of Jacob Potter, the creator of the Ether Dream DAC. Many of the documentation comments are transcribed directly from their writings in the protocol, while many others are adaptations based on my understanding of the original writings and the source code itself.

• ether-dream.com - The Ether Dream site.
• ether-dream.com/protocol - The protocol reference.
• github.com/j4cbo/j4cDAC - The original C implementnation.

License

Licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contributions

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.