Refactor gamepad code to be sync

red/src/gamepad.rs

@@ -4,11 +4,11 @@ use gilrs::Button::LeftTrigger2;
 use gilrs::Button::RightTrigger2;
 use gilrs::EventType::*;
 use gilrs::Gilrs;
+use std::sync::mpsc;
 use std::sync::Arc;
 use std::sync::Mutex;
 use std::thread::sleep;
 use std::time::Duration;
-use tokio::sync::mpsc;
 
 #[derive(Debug)]
 pub enum Axis {
@@ -41,73 +41,70 @@ pub enum GamepadEvent {
 /// }
 /// ```
 pub struct Gamepad {
-    speed_setpoint: Mutex<(f32, f32, f32)>,
+    gilrs: Gilrs,
+    // Cached speed setpoint for (X, Y, Positive-Z, Negative-Z)
+    speed_setpoint: (f32, f32, f32, f32),
 }
 
 impl Gamepad {
     /// Create a new `Gamepad` and spawn the underlying tasks for updating internal setpoints
     ///
     /// The tasks are terminated on drop.
-    pub async fn new() -> Result<Arc<Self>, gilrs::Error> {
-        let (gamepad_tx, gamepad_rx) = mpsc::channel(8);
-        let res = Arc::new(Gamepad {
-            speed_setpoint: Mutex::new((0.0, 0.0, 0.0)),
-        });
-        tokio::task::spawn_blocking(move || {
-            let mut gilrs = Gilrs::new().unwrap();
-            for (_id, gamepad) in gilrs.gamepads() {
-                println!("{} is {:?}", gamepad.name(), gamepad.power_info());
-            }
-            loop {
-                sleep(Duration::from_millis(1));
-                if let Some(event) = gilrs.next_event() {
-                    if let Some(internal_event) = Self::map_event(event) {
-                        if gamepad_tx.blocking_send(internal_event).is_err() {
-                            // receiver dropped
-                            break;
-                        }
-                    }
-                }
-            }
-        });
+    pub fn new() -> Result<Self, gilrs::Error> {
+        let gilrs = Gilrs::new().unwrap();
+        for (_id, gamepad) in gilrs.gamepads() {
+            println!(
+                "Found gamepad {}: {:?}",
+                gamepad.name(),
+                gamepad.power_info()
+            );
+        }
 
-        tokio::spawn(Self::handle_events(res.clone(), gamepad_rx));
-
-        Ok(res)
+        Ok(Self {
+            gilrs,
+            speed_setpoint: (0.0, 0.0, 0.0, 0.0),
+        })
     }
 
-    /// Get the current speed that the user is dialing in on the gamepad
-    pub fn speed_setpoint(&self) -> (f32, f32, f32) {
-        *self.speed_setpoint.lock().unwrap()
+    fn get_next(&mut self) -> Option<GamepadEvent> {
+        self.gilrs
+            .next_event()
+            .and_then(|event| Self::map_event(event))
     }
 
-    /// Update the setpoints in accordance to incoming `GamepadEvent`s
-    async fn handle_events(self_arc: Arc<Self>, mut events_rx: mpsc::Receiver<GamepadEvent>) {
-        // There is two z-axes that counter each other.
-        let mut z_positive = 0.0;
-        let mut z_negative = 0.0;
-        while let Some(event) = events_rx.recv().await {
+    // Get all `GamepadEvent`s since the last call
+    pub fn get_pending(&mut self) -> Vec<GamepadEvent> {
+        (0..).map_while(|_| self.get_next()).collect()
+    }
+
+    /// Update the current speed via the movements on the controller and return the current setpoint
+    ///
+    /// If you don't want to update, just supply an empty `updates` slice
+    pub fn speed_setpoint(&mut self, updates: &[GamepadEvent]) -> (f32, f32, f32) {
+        for event in updates {
             match event {
                 GamepadEvent::TerminatePressed => break,
                 GamepadEvent::AxisPosition(axis, value) => {
                     // I won't panic if you don't panic!
-                    let mut speed_setpoint = self_arc.speed_setpoint.lock().unwrap();
+                    let mut speed_setpoint = self.speed_setpoint;
                     match axis {
-                        Axis::X => speed_setpoint.0 = value,
-                        Axis::Y => speed_setpoint.1 = value,
+                        Axis::X => speed_setpoint.0 = *value,
+                        Axis::Y => speed_setpoint.1 = *value,
                         Axis::ZPositive => {
-                            z_positive = value;
-                            speed_setpoint.2 = z_positive - z_negative;
+                            speed_setpoint.2 = *value;
                         }
                         Axis::ZNegative => {
-                            z_negative = value;
-                            speed_setpoint.2 = z_positive - z_negative;
+                            speed_setpoint.3 = *value;
                         }
                     }
                 }
             }
         }
-        println!("Game pad quit!")
+        (
+            self.speed_setpoint.0,
+            self.speed_setpoint.1,
+            self.speed_setpoint.2 - self.speed_setpoint.3,
+        )
     }
 
     fn map_event(event: gilrs::Event) -> Option<GamepadEvent> {