Proof of concept udp client/server for viz

Author: gridbugs

Cargo.toml

@@ -24,5 +24,7 @@ members = [
     "patches",
     "player",
     "utils",
+    "viz-udp-app",
+    "viz-udp-app-lib",
     "widgets",
 ]

interactive/src/window.rs

@@ -222,7 +222,6 @@ impl WindowRunning {
                 Event::MouseButtonUp { mouse_btn, .. } => {
                     self.window.input.set_mouse_button(mouse_btn, false);
                 }
-
                 _ => (),
             }
         }

viz-udp-app-lib/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "viz_udp_app_lib"
+version = "0.1.0"
+edition = "2024"
+description = "Library for launching and interacting with instances of caw_viz_udp_app"
+authors = ["Stephen Sherratt <[email protected]>"]
+license = "MIT"
+homepage = "https://github.com/gridbugs/caw.git"
+repository = "https://github.com/gridbugs/caw.git"
+documentation = "https://docs.rs/viz_udp_app_lib"
+
+[dependencies]
+anyhow = "1.0"
+
+[[example]]
+name = "viz_udp_app_lib_handshake"

viz-udp-app-lib/examples/viz_udp_app_lib_handshake.rs

@@ -0,0 +1,30 @@
+use std::{
+    net::{Ipv4Addr, UdpSocket},
+    process::Command,
+    time::Duration,
+};
+
+// TODO
+const PROGRAM_NAME: &str = "/home/s/src/caw/target/debug/caw_viz_udp_app";
+
+fn main() -> anyhow::Result<()> {
+    let socket = UdpSocket::bind((Ipv4Addr::UNSPECIFIED, 0))?;
+    println!("Our address: {:?}", socket.local_addr()?);
+    let mut command = Command::new(PROGRAM_NAME);
+    command.args(["--server".to_string(), socket.local_addr()?.to_string()]);
+    let _child = command.spawn()?;
+    let mut buf = [0];
+    let (size, client_addr) = socket.recv_from(&mut buf)?;
+    // TODO: expect a magic number here
+    assert_eq!(size, 1);
+    assert_eq!(buf, [42]);
+    println!("Client address: {:?}", client_addr);
+    socket.connect(client_addr)?;
+    let mut i = 0;
+    loop {
+        // TODO: gracefully shut down if the client dissapears
+        assert_eq!(socket.send(&[i])?, 1);
+        i = i.wrapping_add(1);
+        std::thread::sleep(Duration::from_millis(100));
+    }
+}

viz-udp-app-lib/src/lib.rs

@@ -0,0 +1,14 @@
+pub fn add(left: u64, right: u64) -> u64 {
+    left + right
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn it_works() {
+        let result = add(2, 2);
+        assert_eq!(result, 4);
+    }
+}

viz-udp-app/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "caw_viz_udp_app"
+version = "0.1.0"
+edition = "2024"
+description = "App for visualizing audio data from the caw synthesizer framework"
+authors = ["Stephen Sherratt <[email protected]>"]
+license = "MIT"
+homepage = "https://github.com/gridbugs/caw.git"
+repository = "https://github.com/gridbugs/caw.git"
+documentation = "https://docs.rs/caw_viz_udp_app"
+
+[dependencies]
+anyhow = "1.0"
+sdl2 = { version = "0.37" }
+line_2d = "0.5"
+clap = { version = "4", features = ["derive"] }

viz-udp-app/src/main.rs

@@ -0,0 +1,52 @@
+use std::net::{Ipv4Addr, UdpSocket};
+
+use anyhow::anyhow;
+use clap::Parser;
+use sdl2::{event::Event, pixels::Color};
+
+#[derive(Parser)]
+struct Args {
+    #[arg(long)]
+    server: String,
+    #[arg(long, default_value_t = 640)]
+    width: u32,
+    #[arg(long, default_value_t = 480)]
+    height: u32,
+}
+
+fn main() -> anyhow::Result<()> {
+    let args = Args::parse();
+    let sdl_context = sdl2::init().map_err(|e| anyhow!(e))?;
+    let video_subsystem = sdl_context.video().map_err(|e| anyhow!(e))?;
+    let window = video_subsystem
+        .window("CAW Visualization", args.width, args.height)
+        .build()?;
+    let mut canvas = window
+        .into_canvas()
+        .target_texture()
+        .present_vsync()
+        .build()?;
+    let mut event_pump = sdl_context.event_pump().map_err(|e| anyhow!(e))?;
+    let socket = UdpSocket::bind((Ipv4Addr::UNSPECIFIED, 0))?;
+    socket.connect(args.server)?;
+    // TODO: send a magic number here
+    assert_eq!(socket.send(&[42])?, 1);
+    socket.set_nonblocking(true)?;
+    loop {
+        for event in event_pump.poll_iter() {
+            if let Event::Quit { .. } = event {
+                std::process::exit(0);
+            }
+        }
+        // TODO: larger buffer
+        let mut buf = [0];
+        if let Ok(size) = socket.recv(&mut buf) {
+            // TODO: check for "would block" errors here
+            assert_eq!(size, 1);
+            println!("{}", buf[0]);
+        }
+        canvas.set_draw_color(Color::RGB(0, 0, 0));
+        canvas.clear();
+        canvas.present();
+    }
+}