show fft in terminal

src/main.rs

@@ -1,4 +1,4 @@
-use std::{thread::sleep, time::Duration};
+use std::{sync::mpsc, thread::sleep, time::Duration};
 
 use color_eyre::eyre::bail;
 use cpal::{
@@ -6,7 +6,11 @@ use cpal::{
     BufferSize, HostId, SupportedBufferSize,
 };
 use log::{debug, error, info, trace};
-use rustfft::{num_complex::Complex, FftPlanner};
+use rustfft::{
+    num_complex::{Complex, ComplexFloat},
+    FftPlanner,
+};
+use textplots::{Chart, Plot, Shape};
 
 fn main() -> color_eyre::Result<()> {
     env_logger::init();
@@ -44,6 +48,7 @@ fn main() -> color_eyre::Result<()> {
     let fft = planner.plan_fft_forward(buffer_size as usize);
     let mut fft_data = vec![Complex::new(0.0, 0.0); buffer_size as usize];
     let mut fft_scratch = vec![Complex::new(0.0, 0.0); buffer_size as usize];
+    let (sender, receiver) = mpsc::channel();
 
     let stream = device.build_input_stream(
         &config,
@@ -51,7 +56,15 @@ fn main() -> color_eyre::Result<()> {
             for i in 0..data.len() {
                 fft_data[i] = Complex::new(data[i], 0.0);
             }
-            fft.process_with_scratch(&mut fft_data[..], &mut fft_scratch[..]);
+            let mut fft_output = vec![Complex::new(0.0, 0.0); data.len()];
+            fft.process_outofplace_with_scratch(
+                &mut fft_data[..],
+                &mut fft_output[..],
+                &mut fft_scratch[..],
+            );
+            if let Err(e) = sender.send(fft_output) {
+                error!("Unable to send fft output: {e}");
+            }
         },
         |err| {
             error!("input stream error: {err}");
@@ -62,6 +75,14 @@ fn main() -> color_eyre::Result<()> {
     stream.play()?;
 
     loop {
-        sleep(Duration::from_secs(1));
+        let data = receiver.recv()?;
+        let plot_data: Vec<_> = data
+            .into_iter()
+            .enumerate()
+            .map(|(i, datum)| ((i as f32).log10(), datum.abs() / 1024.0.sqrt()))
+            .collect();
+        Chart::new_with_y_range(200, 50, 0.0, 1024.0.log10(), 0.0, 2.0)
+            .lineplot(&Shape::Bars(&plot_data[..]))
+            .display();
     }
 }