From 93d0fe570029bf02c341470226e57cb1fc3eae91 Mon Sep 17 00:00:00 2001
From: Gwilym Kuiper <email@gwilym.dev>
Date: Sat, 10 Dec 2022 00:19:05 +0000
Subject: [PATCH] Start refactoring towards needing &self in write_channels

---
 agb/src/sound/mixer/sw_mixer.rs | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/agb/src/sound/mixer/sw_mixer.rs b/agb/src/sound/mixer/sw_mixer.rs
index af2d68ef..285e086b 100644
--- a/agb/src/sound/mixer/sw_mixer.rs
+++ b/agb/src/sound/mixer/sw_mixer.rs
@@ -89,6 +89,8 @@ pub struct Mixer {
     indices: [i32; 8],
     frequency: Frequency,
 
+    working_buffer: Box<[Num<i16, 4>], InternalAllocator>,
+
     fifo_timer: Timer,
 }
 
@@ -142,6 +144,10 @@ impl Mixer {
 
         set_asm_buffer_size(frequency);
 
+        let mut working_buffer =
+            Vec::with_capacity_in(frequency.buffer_size() * 2, InternalAllocator);
+        working_buffer.resize(frequency.buffer_size() * 2, 0.into());
+
         Self {
             frequency,
             buffer,
@@ -151,6 +157,7 @@ impl Mixer {
             interrupt_timer,
             _interrupt_handler: interrupt_handler,
 
+            working_buffer: working_buffer.into_boxed_slice(),
             fifo_timer,
         }
     }
@@ -198,7 +205,7 @@ impl Mixer {
         }
 
         self.buffer
-            .write_channels(self.channels.iter_mut().flatten());
+            .write_channels(&mut self.working_buffer, self.channels.iter_mut().flatten());
     }
 
     /// Start playing a given [`SoundChannel`].
@@ -315,7 +322,6 @@ impl SoundBuffer {
 
 struct MixerBuffer {
     buffers: [SoundBuffer; 3],
-    working_buffer: Box<[Num<i16, 4>], InternalAllocator>,
     frequency: Frequency,
 
     state: Mutex<RefCell<MixerBufferState>>,
@@ -355,10 +361,6 @@ impl MixerBufferState {
 
 impl MixerBuffer {
     fn new(frequency: Frequency) -> Self {
-        let mut working_buffer =
-            Vec::with_capacity_in(frequency.buffer_size() * 2, InternalAllocator);
-        working_buffer.resize(frequency.buffer_size() * 2, 0.into());
-
         MixerBuffer {
             buffers: [
                 SoundBuffer::new(frequency),
@@ -366,8 +368,6 @@ impl MixerBuffer {
                 SoundBuffer::new(frequency),
             ],
 
-            working_buffer: working_buffer.into_boxed_slice(),
-
             state: Mutex::new(RefCell::new(MixerBufferState {
                 active_buffer: 0,
                 playing_buffer: 0,
@@ -392,8 +392,12 @@ impl MixerBuffer {
         hw::enable_dma_for_sound(right_buffer, LeftOrRight::Right);
     }
 
-    fn write_channels<'a>(&mut self, channels: impl Iterator<Item = &'a mut SoundChannel>) {
-        self.working_buffer.fill(0.into());
+    fn write_channels<'a>(
+        &mut self,
+        working_buffer: &mut [Num<i16, 4>],
+        channels: impl Iterator<Item = &'a mut SoundChannel>,
+    ) {
+        working_buffer.fill(0.into());
 
         for channel in channels {
             if channel.is_done {
@@ -422,7 +426,7 @@ impl MixerBuffer {
                 unsafe {
                     agb_rs__mixer_add_stereo(
                         channel.data.as_ptr().add(channel.pos.floor()),
-                        self.working_buffer.as_mut_ptr(),
+                        working_buffer.as_mut_ptr(),
                         channel.volume,
                     );
                 }
@@ -433,7 +437,7 @@ impl MixerBuffer {
                 unsafe {
                     agb_rs__mixer_add(
                         channel.data.as_ptr().add(channel.pos.floor()),
-                        self.working_buffer.as_mut_ptr(),
+                        working_buffer.as_mut_ptr(),
                         playback_speed,
                         left_amount,
                         right_amount,
@@ -449,7 +453,7 @@ impl MixerBuffer {
         let write_buffer = &mut self.buffers[write_buffer_index].0;
 
         unsafe {
-            agb_rs__mixer_collapse(write_buffer.as_mut_ptr(), self.working_buffer.as_ptr());
+            agb_rs__mixer_collapse(write_buffer.as_mut_ptr(), working_buffer.as_ptr());
         }
     }
 }