From a4df095031884b6bd3f3cbf1e484c5c8ad6873df Mon Sep 17 00:00:00 2001
From: Gwilym Inzani <email@gwilym.dev>
Date: Sun, 23 Jul 2023 22:15:30 +0100
Subject: [PATCH] Improve accuracy of the panning and volume until the last
 second

---
 agb/src/sound/mixer/mod.rs      | 8 ++++----
 agb/src/sound/mixer/sw_mixer.rs | 7 +++++--
 tracker/agb-tracker/src/lib.rs  | 2 +-
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/agb/src/sound/mixer/mod.rs b/agb/src/sound/mixer/mod.rs
index 7cb4c055..f3dc224c 100644
--- a/agb/src/sound/mixer/mod.rs
+++ b/agb/src/sound/mixer/mod.rs
@@ -229,9 +229,9 @@ pub struct SoundChannel {
     restart_point: Num<u32, 8>,
 
     playback_speed: Num<u32, 8>,
-    volume: Num<i16, 4>, // between 0 and 1
+    volume: Num<i16, 8>, // between 0 and 1
 
-    panning: Num<i16, 4>, // between -1 and 1
+    panning: Num<i16, 8>, // between -1 and 1
     is_done: bool,
 
     is_stereo: bool,
@@ -366,7 +366,7 @@ impl SoundChannel {
     /// Defaults to 0 (meaning equal on left and right) and doesn't affect stereo
     /// sounds.
     #[inline(always)]
-    pub fn panning(&mut self, panning: impl Into<Num<i16, 4>>) -> &mut Self {
+    pub fn panning(&mut self, panning: impl Into<Num<i16, 8>>) -> &mut Self {
         let panning = panning.into();
 
         debug_assert!(panning >= Num::new(-1), "panning value must be >= -1");
@@ -381,7 +381,7 @@ impl SoundChannel {
     ///
     /// Must be a value >= 0 and defaults to 1.
     #[inline(always)]
-    pub fn volume(&mut self, volume: impl Into<Num<i16, 4>>) -> &mut Self {
+    pub fn volume(&mut self, volume: impl Into<Num<i16, 8>>) -> &mut Self {
         let volume = volume.into();
 
         assert!(volume >= Num::new(0), "volume must be >= 0");
diff --git a/agb/src/sound/mixer/sw_mixer.rs b/agb/src/sound/mixer/sw_mixer.rs
index 26556f97..2fa951a1 100644
--- a/agb/src/sound/mixer/sw_mixer.rs
+++ b/agb/src/sound/mixer/sw_mixer.rs
@@ -449,14 +449,14 @@ impl MixerBuffer {
                 agb_rs__mixer_add_stereo_first(
                     channel.data.as_ptr().add(channel.pos.floor() as usize),
                     working_buffer.as_mut_ptr(),
-                    channel.volume,
+                    channel.volume.change_base(),
                     self.frequency.buffer_size(),
                 );
             } else {
                 agb_rs__mixer_add_stereo(
                     channel.data.as_ptr().add(channel.pos.floor() as usize),
                     working_buffer.as_mut_ptr(),
-                    channel.volume,
+                    channel.volume.change_base(),
                     self.frequency.buffer_size(),
                 );
             }
@@ -475,6 +475,9 @@ impl MixerBuffer {
         let right_amount = ((channel.panning + 1) / 2) * channel.volume;
         let left_amount = ((-channel.panning + 1) / 2) * channel.volume;
 
+        let right_amount: Num<i16, 4> = right_amount.change_base();
+        let left_amount: Num<i16, 4> = left_amount.change_base();
+
         let channel_len = Num::<u32, 8>::new(channel.data.len() as u32);
         let mut playback_speed = channel.playback_speed;
 
diff --git a/tracker/agb-tracker/src/lib.rs b/tracker/agb-tracker/src/lib.rs
index 297b40bc..6c100e6a 100644
--- a/tracker/agb-tracker/src/lib.rs
+++ b/tracker/agb-tracker/src/lib.rs
@@ -256,7 +256,7 @@ impl TrackerChannel {
                     };
                 }
                 PatternEffect::Panning(panning) => {
-                    channel.panning(*panning);
+                    channel.panning(panning.change_base());
                 }
                 PatternEffect::Volume(volume) => {
                     channel.volume(volume.change_base());