From 856ee00999fb65ec8defaac9f90dbf5a264cb430 Mon Sep 17 00:00:00 2001
From: Simon Gellis <simongellis@gmail.com>
Date: Sat, 4 Jan 2025 12:17:56 -0500
Subject: [PATCH] Fix bugs around debugging lifecycle

---
 src/emulator.rs | 40 ++++++++++++++++++++++++++--------------
 1 file changed, 26 insertions(+), 14 deletions(-)

diff --git a/src/emulator.rs b/src/emulator.rs
index 43486d2..3de6a38 100644
--- a/src/emulator.rs
+++ b/src/emulator.rs
@@ -177,7 +177,7 @@ impl Emulator {
             messages: HashMap::new(),
             debuggers: HashMap::new(),
             eye_contents: vec![0u8; 384 * 224 * 2],
-            audio_samples: vec![0.0; EXPECTED_FRAME_SIZE],
+            audio_samples: Vec::with_capacity(EXPECTED_FRAME_SIZE),
         })
     }
 
@@ -286,6 +286,7 @@ impl Emulator {
         self.renderers.remove(&SimId::Player2);
         self.sims.truncate(1);
         self.sim_state[SimId::Player2.to_index()].store(SimState::Uninitialized, Ordering::Release);
+        self.stop_debugging(SimId::Player2);
         self.linked.store(false, Ordering::Release);
         Ok(())
     }
@@ -303,7 +304,12 @@ impl Emulator {
     fn stop_debugging(&mut self, sim_id: SimId) {
         self.debuggers.remove(&sim_id);
         if self.debuggers.is_empty() {
-            self.state.store(EmulatorState::Running, Ordering::Release);
+            let _ = self.state.compare_exchange(
+                EmulatorState::Debugging,
+                EmulatorState::Running,
+                Ordering::AcqRel,
+                Ordering::Relaxed,
+            );
         }
     }
 
@@ -364,6 +370,8 @@ impl Emulator {
         let p1_state = self.sim_state[SimId::Player1.to_index()].load(Ordering::Acquire);
         let p2_state = self.sim_state[SimId::Player2.to_index()].load(Ordering::Acquire);
         let state = self.state.load(Ordering::Acquire);
+
+        // Emulation
         // Don't emulate if the state is "paused", or if any sim is paused in the debugger
         let running = match state {
             EmulatorState::Paused => false,
@@ -381,6 +389,7 @@ impl Emulator {
             self.sims[SimId::Player2.to_index()].emulate();
         }
 
+        // Video
         for sim_id in SimId::values() {
             let Some(renderer) = self.renderers.get_mut(&sim_id) else {
                 continue;
@@ -395,24 +404,27 @@ impl Emulator {
                 }
             }
         }
+
+        // Audio
+        // Audio playback speed is how we keep the emulator running in real time.
+        // Even if we're muted, call `read_samples` to know how many frames of silence to play.
         let p1_audio =
             p1_running && self.audio_on[SimId::Player1.to_index()].load(Ordering::Acquire);
         let p2_audio =
             p2_running && self.audio_on[SimId::Player2.to_index()].load(Ordering::Acquire);
-        let weight = if p1_audio && p2_audio { 0.5 } else { 1.0 };
-        if p1_audio {
-            if let Some(sim) = self.sims.get_mut(SimId::Player1.to_index()) {
-                sim.read_samples(&mut self.audio_samples, weight);
-            }
+        let (p1_weight, p2_weight) = match (p1_audio, p2_audio) {
+            (true, true) => (0.5, 0.5),
+            (true, false) => (1.0, 0.0),
+            (false, true) => (0.0, 1.0),
+            (false, false) => (0.0, 0.0),
+        };
+        if let Some(sim) = self.sims.get_mut(SimId::Player1.to_index()) {
+            sim.read_samples(&mut self.audio_samples, p1_weight);
         }
-        if p2_audio {
-            if let Some(sim) = self.sims.get_mut(SimId::Player2.to_index()) {
-                sim.read_samples(&mut self.audio_samples, weight);
-            }
+        if let Some(sim) = self.sims.get_mut(SimId::Player2.to_index()) {
+            sim.read_samples(&mut self.audio_samples, p2_weight);
         }
-        if self.audio_samples.is_empty() {
-            self.audio_samples.resize(EXPECTED_FRAME_SIZE, 0.0);
-        } else {
+        if !self.audio_samples.is_empty() {
             idle = false;
         }
         self.audio.update(&self.audio_samples);