From 0f919c612ce8c990e14ffa4577c736c131ba8f4b Mon Sep 17 00:00:00 2001
From: Alex Janka <alex@alexjanka.com>
Date: Wed, 8 Mar 2023 15:41:17 +1100
Subject: [PATCH] dont fully reinitialise if u dont need to

---
 gb-vst/src/lib.rs                    | 34 +++++++++++++++++-----------
 lib/src/lib.rs                       |  4 ++++
 lib/src/processor/memory.rs          |  4 ++++
 lib/src/processor/memory/mmio/apu.rs |  5 ++++
 4 files changed, 34 insertions(+), 13 deletions(-)

diff --git a/gb-vst/src/lib.rs b/gb-vst/src/lib.rs
index 5008c03..143c7e1 100644
--- a/gb-vst/src/lib.rs
+++ b/gb-vst/src/lib.rs
@@ -112,24 +112,32 @@ impl Plugin for GameboyEmu {
             verbose: false,
             cycle_count: false,
         };
-        let (sender, receiver) = channel::<EmulatorMessage>();
 
-        let (output, rx) = AudioOutput::new_unfilled(buffer_config.sample_rate, false);
+        if let Some(ref mut vars) = self.vars {
+            let (output, rx) = AudioOutput::new_unfilled(buffer_config.sample_rate, false);
 
-        let (renderer, frame_receiver, key_handler) = EmulatorRenderer::new();
+            vars.emulator_core.replace_output(output);
+            vars.rx = rx;
+        } else {
+            let (sender, receiver) = channel::<EmulatorMessage>();
 
-        *self.frame_receiver.lock().unwrap() = Some(frame_receiver);
-        *self.key_handler.lock().unwrap() = Some(key_handler);
+            let (output, rx) = AudioOutput::new_unfilled(buffer_config.sample_rate, false);
 
-        let mut emulator_core =
-            EmulatorCore::init(receiver, options, Box::new(renderer), output, None);
-        emulator_core.run_until_buffer_full();
+            let (renderer, frame_receiver, key_handler) = EmulatorRenderer::new();
 
-        self.vars = Some(EmuVars {
-            rx,
-            sender,
-            emulator_core,
-        });
+            *self.frame_receiver.lock().unwrap() = Some(frame_receiver);
+            *self.key_handler.lock().unwrap() = Some(key_handler);
+
+            let mut emulator_core =
+                EmulatorCore::init(receiver, options, Box::new(renderer), output, None);
+            emulator_core.run_until_buffer_full();
+
+            self.vars = Some(EmuVars {
+                rx,
+                sender,
+                emulator_core,
+            });
+        }
 
         true
     }
diff --git a/lib/src/lib.rs b/lib/src/lib.rs
index 56012c4..ce21e06 100644
--- a/lib/src/lib.rs
+++ b/lib/src/lib.rs
@@ -124,6 +124,10 @@ impl<ColourFormat: From<Colour> + Clone> EmulatorCore<ColourFormat> {
         }
     }
 
+    pub fn replace_output(&mut self, new: AudioOutput) {
+        self.cpu.memory.replace_output(new);
+    }
+
     pub fn run(&mut self) {
         self.process_messages();
         self.cycle_num += 1;
diff --git a/lib/src/processor/memory.rs b/lib/src/processor/memory.rs
index 2e8ff56..f8e6331 100644
--- a/lib/src/processor/memory.rs
+++ b/lib/src/processor/memory.rs
@@ -226,6 +226,10 @@ impl<ColourFormat: From<Colour> + Clone> Memory<ColourFormat> {
     pub fn is_audio_buffer_full(&self) -> bool {
         self.apu.is_buffer_full()
     }
+
+    pub fn replace_output(&mut self, new: AudioOutput) {
+        self.apu.replace_output(new);
+    }
 }
 
 impl<ColourFormat: From<Colour> + Clone> Cpu<ColourFormat> {
diff --git a/lib/src/processor/memory/mmio/apu.rs b/lib/src/processor/memory/mmio/apu.rs
index 12a4608..7749ebf 100644
--- a/lib/src/processor/memory/mmio/apu.rs
+++ b/lib/src/processor/memory/mmio/apu.rs
@@ -64,6 +64,11 @@ impl Apu {
         }
     }
 
+    pub fn replace_output(&mut self, new: AudioOutput) {
+        self.converter = Downsampler::new(new.sample_rate);
+        self.output = new;
+    }
+
     pub fn div_apu_tick(&mut self) {
         self.div_apu = self.div_apu.wrapping_add(1);
         if self.div_apu % 8 == 0 {