From f5c4ff8c352004f0982ff54c277f27a5954b84ac Mon Sep 17 00:00:00 2001
From: Michael Sippel <micha@fragmental.art>
Date: Tue, 3 Dec 2024 15:41:08 +0100
Subject: [PATCH] add sine example

---
 01-play-sine/.gitignore  |   2 +
 01-play-sine/Cargo.toml  |   7 +++
 01-play-sine/src/main.rs | 124 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 133 insertions(+)
 create mode 100644 01-play-sine/.gitignore
 create mode 100644 01-play-sine/Cargo.toml
 create mode 100644 01-play-sine/src/main.rs

diff --git a/01-play-sine/.gitignore b/01-play-sine/.gitignore
new file mode 100644
index 0000000..96ef6c0
--- /dev/null
+++ b/01-play-sine/.gitignore
@@ -0,0 +1,2 @@
+/target
+Cargo.lock
diff --git a/01-play-sine/Cargo.toml b/01-play-sine/Cargo.toml
new file mode 100644
index 0000000..23c88f9
--- /dev/null
+++ b/01-play-sine/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "play-sine"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+pipewire = "0.8.0"
diff --git a/01-play-sine/src/main.rs b/01-play-sine/src/main.rs
new file mode 100644
index 0000000..6ede0bf
--- /dev/null
+++ b/01-play-sine/src/main.rs
@@ -0,0 +1,124 @@
+use std::io::Cursor;
+
+use pipewire::{
+    context::Context,
+    main_loop::MainLoop,
+    properties::properties,
+    spa::{
+        param::audio::{AudioFormat, AudioInfoRaw},
+        pod::{serialize::PodSerializer, Object, Pod, Value},
+        sys::{SPA_PARAM_EnumFormat, SPA_TYPE_OBJECT_Format},
+        utils::Direction,
+    },
+    stream::{Stream, StreamFlags},
+};
+
+struct MyData {
+    time: u64,
+}
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let mainloop = MainLoop::new(None)?;
+    let context = Context::new(&mainloop)?;
+    let core = context.connect(None)?;
+    let registry = core.get_registry()?;
+
+    let _global_listener = registry
+        .add_listener_local()
+        .global(|global| println!("New global: {:?}", global))
+        .register();
+
+    let sample_rate = 48000;
+    let channel_count = 2;
+
+    let mut audio_info = AudioInfoRaw::new();
+    audio_info.set_format(AudioFormat::F32LE);
+    audio_info.set_rate(sample_rate);
+    audio_info.set_channels(channel_count);
+
+    let param_bytes = PodSerializer::serialize(
+        Cursor::new(vec![]),
+        &Value::Object(Object {
+            type_: SPA_TYPE_OBJECT_Format,
+            id: SPA_PARAM_EnumFormat,
+            properties: audio_info.into(),
+        }),
+    )
+    .expect("failed to serialize param")
+    .0
+    .into_inner();
+
+    let mut params = vec![Pod::from_bytes(&param_bytes).expect("failed to create pod")];
+
+    let out_stream = Stream::new(
+        &core,
+        "out1",
+        properties! {
+            *pipewire::keys::MEDIA_TYPE => "Audio",
+            *pipewire::keys::MEDIA_CATEGORY => "Playback",
+            *pipewire::keys::MEDIA_ROLE => "Music"
+        },
+    )
+    .expect("failed to create stream");
+
+    out_stream
+        .connect(
+            Direction::Output,
+            None,
+            StreamFlags::AUTOCONNECT | StreamFlags::MAP_BUFFERS | StreamFlags::RT_PROCESS,
+            params.as_mut_slice(),
+        )
+        .expect("failed to connect stream");
+
+    let my_data = MyData { time: 0 };
+
+    let _out_stream_listener = out_stream
+        .add_local_listener_with_user_data(my_data)
+        .process(move |stream, my_data: &mut MyData| {
+            let mut buffer = match stream.dequeue_buffer() {
+                Some(buf) => buf,
+                None => {
+                    eprintln!("stream is out of buffers");
+                    return;
+                }
+            };
+
+            let stride = std::mem::size_of::<f32>() * (channel_count as usize);
+            let datas = buffer.datas_mut();
+
+            let data = &mut datas[0];
+
+            let mut samples_written = 0;
+            if let Some(slice) = data.data() {
+                let slice = unsafe { &mut *(slice as *mut _ as *mut [f32]) };
+
+                for i in 0..(slice.len() / stride) {
+                    let time_samples = {
+                        let t = my_data.time;
+                        my_data.time += 1;
+                        t
+                    };
+                    let time_secs = (time_samples as f32) / 48000.0 as f32;
+                    let sine_freq = 440.0;
+                    let pi2 = 2.0 * 3.141;
+                    let phi = pi2 * time_secs * sine_freq;
+                    let value = 0.5 + 0.5 * f32::sin(phi);
+
+                    slice[2 * i] = value;
+                    slice[2 * i + 1] = value;
+                    samples_written += 2;
+                }
+            }
+
+            let chunk = data.chunk_mut();
+            *chunk.offset_mut() = 0;
+            *chunk.stride_mut() = stride as _;
+            *chunk.size_mut() = (stride * samples_written) as _;
+        })
+        .register()
+        .expect("failed to add listener");
+
+    mainloop.run();
+
+    Ok(())
+}