From d233a2539c5d522316e53a957de8b1fdfa5cf44d Mon Sep 17 00:00:00 2001
From: Gwilym Inzani <email@gwilym.dev>
Date: Sun, 23 Jul 2023 22:10:25 +0100
Subject: [PATCH] Improve accuracy of the volume

---
 tracker/agb-tracker-interop/src/lib.rs |  8 ++++----
 tracker/agb-tracker/src/lib.rs         | 20 ++++++++++----------
 tracker/agb-xm-core/src/lib.rs         | 12 ++++++------
 3 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/tracker/agb-tracker-interop/src/lib.rs b/tracker/agb-tracker-interop/src/lib.rs
index 61b4deb9..26026d9a 100644
--- a/tracker/agb-tracker-interop/src/lib.rs
+++ b/tracker/agb-tracker-interop/src/lib.rs
@@ -19,7 +19,7 @@ pub struct Sample<'a> {
     pub data: &'a [u8],
     pub should_loop: bool,
     pub restart_point: u32,
-    pub volume: Num<i16, 4>,
+    pub volume: Num<i16, 8>,
 }
 
 #[derive(Debug)]
@@ -46,9 +46,9 @@ pub enum PatternEffect {
     /// Plays an arpeggiation of three notes in one row, cycling betwen the current note, current note + first speed, current note + second speed
     Arpeggio(Num<u16, 8>, Num<u16, 8>),
     Panning(Num<i16, 4>),
-    Volume(Num<i16, 4>),
-    VolumeSlide(Num<i16, 4>),
-    FineVolumeSlide(Num<i16, 4>),
+    Volume(Num<i16, 8>),
+    VolumeSlide(Num<i16, 8>),
+    FineVolumeSlide(Num<i16, 8>),
     NoteCut(u32),
     Portamento(Num<u16, 8>),
     /// Slide each tick the first amount to at most the second amount
diff --git a/tracker/agb-tracker/src/lib.rs b/tracker/agb-tracker/src/lib.rs
index 22ffb5d0..297b40bc 100644
--- a/tracker/agb-tracker/src/lib.rs
+++ b/tracker/agb-tracker/src/lib.rs
@@ -102,7 +102,7 @@ pub struct Tracker {
 struct TrackerChannel {
     channel_id: Option<ChannelId>,
     base_speed: Num<u32, 8>,
-    volume: Num<i16, 4>,
+    volume: Num<i32, 8>,
 }
 
 impl Tracker {
@@ -143,7 +143,7 @@ impl Tracker {
         let pattern_slots =
             &self.track.pattern_data[pattern_data_pos..pattern_data_pos + self.track.num_channels];
 
-        for (channel, pattern_slot) in self.channels.iter_mut().zip(pattern_slots).skip(3) {
+        for (channel, pattern_slot) in self.channels.iter_mut().zip(pattern_slots) {
             if pattern_slot.sample != 0 && self.tick == 0 {
                 let sample = &self.track.samples[pattern_slot.sample as usize - 1];
                 channel.play_sound(mixer, sample);
@@ -210,7 +210,7 @@ impl TrackerChannel {
 
         let mut new_channel = SoundChannel::new(sample.data);
 
-        new_channel.volume(sample.volume);
+        new_channel.volume(sample.volume.change_base());
 
         if sample.should_loop {
             new_channel
@@ -219,7 +219,7 @@ impl TrackerChannel {
         }
 
         self.channel_id = mixer.play_sound(new_channel);
-        self.volume = sample.volume;
+        self.volume = sample.volume.change_base();
     }
 
     fn set_speed(&mut self, mixer: &mut Mixer<'_>, speed: Num<u32, 8>) {
@@ -259,19 +259,19 @@ impl TrackerChannel {
                     channel.panning(*panning);
                 }
                 PatternEffect::Volume(volume) => {
-                    channel.volume(*volume);
-                    self.volume = *volume;
+                    channel.volume(volume.change_base());
+                    self.volume = volume.change_base();
                 }
                 PatternEffect::VolumeSlide(amount) => {
                     if tick != 0 {
-                        self.volume = (self.volume + *amount).max(0.into());
-                        channel.volume(self.volume);
+                        self.volume = (self.volume + amount.change_base()).max(0.into());
+                        channel.volume(self.volume.try_change_base().unwrap());
                     }
                 }
                 PatternEffect::FineVolumeSlide(amount) => {
                     if tick == 0 {
-                        self.volume = (self.volume + *amount).max(0.into());
-                        channel.volume(self.volume);
+                        self.volume = (self.volume + amount.change_base()).max(0.into());
+                        channel.volume(self.volume.try_change_base().unwrap());
                     }
                 }
                 PatternEffect::NoteCut(wait) => {
diff --git a/tracker/agb-xm-core/src/lib.rs b/tracker/agb-xm-core/src/lib.rs
index 34fd935c..1bf6803a 100644
--- a/tracker/agb-xm-core/src/lib.rs
+++ b/tracker/agb-xm-core/src/lib.rs
@@ -55,7 +55,7 @@ pub fn parse_module(module: &Module) -> TokenStream {
         fine_tune: f64,
         relative_note: i8,
         restart_point: u32,
-        volume: Num<i16, 4>,
+        volume: Num<i16, 8>,
     }
 
     let mut samples = vec![];
@@ -76,7 +76,7 @@ pub fn parse_module(module: &Module) -> TokenStream {
                 usize::MAX
             };
 
-            let volume = Num::from_raw((sample.volume * (1 << 4) as f32) as i16);
+            let volume = Num::from_raw((sample.volume * (1 << 8) as f32) as i16);
 
             let sample = match &sample.data {
                 SampleDataType::Depth8(depth8) => depth8
@@ -163,10 +163,10 @@ pub fn parse_module(module: &Module) -> TokenStream {
                                     .unwrap_or(1.into()),
                         ),
                         0x80..=0x8F => PatternEffect::FineVolumeSlide(
-                            -Num::new((slot.volume - 0x80) as i16) / 16,
+                            -Num::new((slot.volume - 0x80) as i16) / 64,
                         ),
                         0x90..=0x9F => PatternEffect::FineVolumeSlide(
-                            Num::new((slot.volume - 0x90) as i16) / 16,
+                            Num::new((slot.volume - 0x90) as i16) / 64,
                         ),
                         0xC0..=0xCF => PatternEffect::Panning(
                             Num::new(slot.volume as i16 - (0xC0 + (0xCF - 0xC0) / 2)) / 64,
@@ -299,10 +299,10 @@ pub fn parse_module(module: &Module) -> TokenStream {
                     }
                     0xE => match slot.effect_parameter >> 4 {
                         0xA => PatternEffect::FineVolumeSlide(
-                            Num::new((slot.effect_parameter & 0xf) as i16) / 16,
+                            Num::new((slot.effect_parameter & 0xf) as i16) / 64,
                         ),
                         0xB => PatternEffect::FineVolumeSlide(
-                            -Num::new((slot.effect_parameter & 0xf) as i16) / 16,
+                            -Num::new((slot.effect_parameter & 0xf) as i16) / 64,
                         ),
                         0xC => PatternEffect::NoteCut((slot.effect_parameter & 0xf).into()),
                         _ => PatternEffect::None,