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use num::traits::Float;
use oxcable::types::{SAMPLE_RATE, AudioDevice, MessageReceiver, Sample, Time};
use oxcable::utils::ringbuffer::RingBuffer;
use oxcable::utils::helpers::decibel_to_ratio;
use super::rooms::Room;
#[derive(Clone, Copy, Debug)]
pub enum Message {
SetReverbTime(f32),
SetGain(f32),
SetWetness(f32),
}
pub use self::Message::*;
pub struct MoorerReverb {
num_channels: usize,
gain: f32,
wetness: f32,
tapped_delay_lines: Vec<RingBuffer<Sample>>,
tapped_delays: Vec<Time>,
tapped_gains: Vec<f32>,
comb_delay_lines: Vec<Vec<RingBuffer<Sample>>>,
comb_delays: Vec<Time>,
comb_gains: Vec<f32>,
comb_out_buffer: Vec<RingBuffer<Sample>>,
comb_out_gain: f32,
}
impl MoorerReverb {
pub fn new(room: Room, rev_time: f32, gain: f32, wetness:f32,
num_channels: usize) -> Self {
assert!(room.tapped_delays.len() == room.tapped_gains.len());
let max_tapped_delay = room.tapped_delays[room.tapped_delays.len()-1];
let comb_out_delay = max_tapped_delay;
let (comb_gains, comb_out_gain) =
compute_comb_gains(&room.comb_delays, rev_time);
let init = vec![0.0; max_tapped_delay as usize + 1];
let tapped_delay_lines = vec![RingBuffer::from(&init[..]); num_channels];
let mut comb_delay_lines = Vec::with_capacity(num_channels);
for _ in 0..num_channels {
let mut channel_lines = Vec::with_capacity(room.comb_delays.len());
for j in 0..room.comb_delays.len() {
let delay = room.comb_delays[j];
let init = vec![0.0; delay as usize + 1];
channel_lines.push(RingBuffer::from(&init[..]));
}
comb_delay_lines.push(channel_lines);
}
let init = vec![0.0; comb_out_delay as usize + 1];
let comb_out_buffer = vec![RingBuffer::from(&init[..]); num_channels];
MoorerReverb {
num_channels: num_channels,
gain: decibel_to_ratio(gain),
wetness: wetness,
tapped_delay_lines: tapped_delay_lines,
tapped_delays: Vec::from(room.tapped_delays),
tapped_gains: Vec::from(room.tapped_gains),
comb_delay_lines: comb_delay_lines,
comb_delays: Vec::from(room.comb_delays),
comb_gains: comb_gains,
comb_out_buffer: comb_out_buffer,
comb_out_gain: comb_out_gain,
}
}
}
impl MessageReceiver for MoorerReverb {
type Msg = Message;
fn handle_message(&mut self, msg: Message) {
match msg {
SetReverbTime(rev_time) => {
let (comb_gains, comb_out_gain) =
compute_comb_gains(&self.comb_delays, rev_time);
self.comb_gains = comb_gains;
self.comb_out_gain = comb_out_gain;
},
SetGain(gain) => {
self.gain = decibel_to_ratio(gain);
},
SetWetness(wetness) => {
self.wetness = wetness;
}
}
}
}
impl AudioDevice for MoorerReverb {
fn num_inputs(&self) -> usize {
self.num_channels
}
fn num_outputs(&self) -> usize {
self.num_channels
}
fn tick(&mut self, t: Time, inputs: &[Sample], outputs: &mut[Sample]) {
for (i,x) in inputs.iter().enumerate() {
for (delay, gain) in self.tapped_delays.iter()
.zip(self.tapped_gains.iter()) {
self.tapped_delay_lines[i][t + *delay] += *gain * x;
}
let tapped_out = (x + self.tapped_delay_lines[i][t]) /
(self.tapped_delays.len() as f32);
self.tapped_delay_lines[i].push(0.0);
let comb_out = self.comb_out_buffer[i][t];
let mut next_comb_out = 0.0;
for j in 0..self.comb_delays.len() {
let gain = self.comb_gains[j];
let feedback = self.comb_delay_lines[i][j][t];
self.comb_delay_lines[i][j].push(tapped_out + gain * feedback);
next_comb_out += feedback;
}
next_comb_out *= self.comb_out_gain/(self.comb_delays.len() as f32);
self.comb_out_buffer[i].push(next_comb_out);
let wet_out = tapped_out + comb_out;
let y = self.gain * (self.wetness*wet_out + (1.0-self.wetness)*x);
outputs[i] = y;
}
}
}
fn compute_comb_gains(comb_delays: &[Time], rev_time: f32)
-> (Vec<f32>, f32) {
let mut comb_gains = Vec::with_capacity(comb_delays.len());
for &delay in comb_delays.iter() {
let gain = 10.0.powf(-3.0*(delay as f32)*rev_time / (SAMPLE_RATE as f32));
comb_gains.push(gain);
}
let comb_out_gain = 1.0 - 0.366/rev_time;
(comb_gains, comb_out_gain)
}