Use crossbeam for sending events and audio samples in xsynth-render

render/Cargo.toml

@@ -21,4 +21,5 @@ midi-toolkit-rs = "0.1.0"
 spin_sleep = "1.2.1"
 atomic_float = "1.0.0"
 thiserror = "1.0.63"
-clap = { version = "4.5.16", features = ["cargo"] }
+clap = { version = "4.5.16", features = ["cargo"] }
+crossbeam = "0.8.4"

render/src/main.rs

@@ -74,6 +74,14 @@ fn main() {
         |>unwrap_items()
     );
 
+    let (snd, rcv) = crossbeam_channel::bounded(100);
+
+    thread::spawn(move || {
+        for batch in merged {
+            snd.send(batch).unwrap();
+        }
+    });
+
     let position = Arc::new(AtomicF64::new(0.0));
     let voices = Arc::new(AtomicU64::new(0));
 
@@ -94,14 +102,17 @@ fn main() {
             }
             print!("] {progress:.3}% | ");
             print!("Voice Count: {}", voices.load(Ordering::Relaxed));
+            for _ in 0..10 {
+                print!(" ");
+            }
             if progress >= 100.0 {
                 println!();
                 break;
             }
         });
     }
 
-    for batch in merged {
+    for batch in rcv {
         if batch.delta > 0.0 {
             synth.render_batch(batch.delta);
             position.fetch_add(batch.delta, Ordering::Relaxed);

render/src/rendered.rs

@@ -124,7 +124,6 @@ impl XSynthRender {
             self.audio_writer
                 .write_samples(&mut self.render_elements.output_vec);
         }
-        self.audio_writer.finalize();
     }
 
     /// Returns the active voice count of the MIDI synthesizer.

render/src/writer.rs

@@ -1,11 +1,12 @@
 use crate::config::XSynthRenderConfig;
 
-use std::{fs::File, io::BufWriter, path::PathBuf};
+use std::{path::PathBuf, thread};
 
+use crossbeam_channel::Sender;
 use hound::{WavSpec, WavWriter};
 
 pub struct AudioFileWriter {
-    writer: WavWriter<BufWriter<File>>,
+    sender: Sender<Vec<f32>>,
 }
 
 impl AudioFileWriter {
@@ -16,18 +17,23 @@ impl AudioFileWriter {
             bits_per_sample: 32,
             sample_format: hound::SampleFormat::Float,
         };
-        let writer = WavWriter::create(path, spec).unwrap();
+        let mut writer = WavWriter::create(path, spec).unwrap();
 
-        Self { writer }
-    }
+        let (snd, rcv) = crossbeam_channel::unbounded::<Vec<f32>>();
 
-    pub fn write_samples(&mut self, samples: &mut Vec<f32>) {
-        for s in samples.drain(0..) {
-            self.writer.write_sample(s).unwrap();
-        }
+        thread::spawn(move || {
+            for batch in rcv {
+                for s in batch {
+                    writer.write_sample(s).unwrap();
+                }
+            }
+            writer.finalize().unwrap();
+        });
+
+        Self { sender: snd }
     }
 
-    pub fn finalize(self) {
-        self.writer.finalize().unwrap();
+    pub fn write_samples(&mut self, samples: &mut Vec<f32>) {
+        self.sender.send(std::mem::take(samples)).unwrap();
     }
 }