lj_rust/examples/etherdream.rs

extern crate ether_dream;

use ether_dream::dac;

fn main() {
	println!("Listening for an Ether Dream DAC...");

	let (dac_broadcast, source_addr) = ether_dream::recv_dac_broadcasts()
		.expect("failed to bind to UDP socket")
		.filter_map(Result::ok)
		.next()
		.unwrap();
	let mac_address = dac::MacAddress(dac_broadcast.mac_address);

	println!(
		"Discovered DAC \"{}\" at \"{}\"! Connecting...",
		mac_address, source_addr
	);

	// Establish the TCP connection.
	let mut stream = dac::stream::connect(&dac_broadcast, source_addr.ip().clone()).unwrap();

	// If we want to create an animation (in our case a moving sine wave) we need a frame rate.
	let frames_per_second = 60.0;
	// Lets use the DAC at an eighth the maximum scan rate.
	let points_per_second = stream.dac().max_point_rate / 32;
	// Determine the number of points per frame given our target frame and point rates.
	let points_per_frame = (points_per_second as f32 / frames_per_second) as u16;

	println!(
		"Preparing for playback:\n\tframe_hz: {}\n\tpoint_hz: {}\n\tpoints_per_frame: {}\n",
		frames_per_second, points_per_second, points_per_frame
	);

	// Prepare the DAC's playback engine and await the repsonse.
	stream
		.queue_commands()
		.prepare_stream()
		.submit()
		.err()
		.map(|err| {
			eprintln!(
				"err occurred when submitting PREPARE_STREAM \
                      command and listening for response: {}",
				err
			);
		});

	println!("Beginning playback!");

	// The sine wave used to generate points.
	let mut sine_wave = SineWave {
		point: 0,
		points_per_frame,
		frames_per_second,
	};

	// Queue the initial frame and tell the DAC to begin producing output.
	let n_points = points_to_generate(stream.dac());
	stream
		.queue_commands()
		.data(sine_wave.by_ref().take(n_points))
		.begin(0, points_per_second)
		.submit()
		.err()
		.map(|err| {
			eprintln!(
				"err occurred when submitting initial DATA and BEGIN \
                      commands and listening for response: {}",
				err
			);
		});
	eprintln!("Stream dac{:?}", stream.dac());

	// Loop and continue to send points forever.
	loop {
		// Determine how many points the DAC can currently receive.
		let n_points = points_to_generate(stream.dac());
		if let Err(err) = stream
			.queue_commands()
			.data(sine_wave.by_ref().take(n_points))
			.submit()
		{
			eprintln!(
				"err occurred when submitting DATA command and listening \
                      for response: {}",
				err
			);
			break;
		}
	}

	// Tell the DAC to stop producing output and return to idle. Wait for the response.
	//
	// Note that the DAC is commanded to stop on `Drop` if this is not called and any errors
	// produced are ignored.
	stream
		.queue_commands()
		.stop()
		.submit()
		.expect("err occurred when submitting STOP command and listening for response");
}

// Determine the number of points needed to fill the DAC.
fn points_to_generate(dac: &ether_dream::dac::Dac) -> usize {
	dac.buffer_capacity as usize - 1 - dac.status.buffer_fullness as usize
}

// An iterator that endlessly generates a sine wave of DAC points.
//
// The sine wave oscillates at a rate of once per second.
struct SineWave {
	point: u32,
	points_per_frame: u16,
	frames_per_second: f32,
}

impl Iterator for SineWave {
	type Item = ether_dream::protocol::DacPoint;
	fn next(&mut self) -> Option<Self::Item> {
		let coloured_points_per_frame = self.points_per_frame - 1;
		let i = (self.point % self.points_per_frame as u32) as u16;
		let hz = 1.0;
		let fract = i as f32 / coloured_points_per_frame as f32;
		let phase = (self.point as f32 / coloured_points_per_frame as f32) / self.frames_per_second;
		let amp = (hz * (fract + phase) * 2.0 * std::f32::consts::PI).sin();
		let (r, g, b) = match i {
			i if i == coloured_points_per_frame || i < 13 => (0, 0, 0),
			_ => (std::u16::MAX, std::u16::MAX, std::u16::MAX),
		};
		let x_min = std::i16::MIN;
		let x_max = std::i8::MAX as i16;
		let x = (x_min as f32 + fract * (x_max as f32 - x_min as f32)) as i16;
		let y = (amp * x_max as f32) as i16;
		let control = 0;
		let (u1, u2) = (0, 0);
		let p = ether_dream::protocol::DacPoint {
			control,
			x,
			y,
			i,
			r,
			g,
			b,
			u1,
			u2,
		};
		self.point += 1;
		Some(p)
	}
}