Volume slides - ish

tracker/agb-tracker-interop/src/lib.rs

@@ -46,6 +46,7 @@ pub enum PatternEffect {
     Arpeggio(Num<u16, 8>, Num<u16, 8>),
     Panning(Num<i16, 4>),
     Volume(Num<i16, 4>),
+    VolumeSlide(Num<i16, 4>),
 }
 
 #[cfg(feature = "quote")]
@@ -185,6 +186,10 @@ impl quote::ToTokens for PatternEffect {
                 let volume = volume.to_raw();
                 quote! { Volume(agb_tracker::__private::Num::from_raw(#volume))}
             }
+            PatternEffect::VolumeSlide(amount) => {
+                let amount = amount.to_raw();
+                quote! { VolumeSlide(agb_tracker::__private::Num::from_raw(#amount))}
+            }
         };
 
         tokens.append_all(quote! {

tracker/agb-tracker/src/lib.rs

@@ -40,6 +40,7 @@ pub struct Tracker {
 struct TrackerChannel {
     channel_id: Option<ChannelId>,
     base_speed: Num<u32, 8>,
+    volume: Num<i16, 4>,
 }
 
 impl Tracker {
@@ -48,6 +49,7 @@ impl Tracker {
         channels.resize_with(track.num_channels, || TrackerChannel {
             channel_id: None,
             base_speed: 0.into(),
+            volume: 0.into(),
         });
 
         Self {
@@ -183,6 +185,14 @@ impl TrackerChannel {
                 }
                 PatternEffect::Volume(volume) => {
                     channel.volume(*volume);
+                    self.volume = *volume;
+                }
+                PatternEffect::VolumeSlide(amount) => {
+                    self.volume += *amount;
+                    if self.volume < 0.into() {
+                        self.volume = 0.into();
+                    }
+                    channel.volume(self.volume);
                 }
             }
         }

tracker/agb-xm-core/src/lib.rs

@@ -188,6 +188,16 @@ pub fn parse_module(module: &Module) -> TokenStream {
                     0x8 => {
                         PatternEffect::Panning(Num::new(slot.effect_parameter as i16 - 128) / 128)
                     }
+                    0xA => {
+                        let first = slot.effect_parameter >> 4;
+                        let second = slot.effect_parameter & 0xF;
+
+                        if first == 0 {
+                            PatternEffect::VolumeSlide(-Num::new(second as i16) / 16)
+                        } else {
+                            PatternEffect::VolumeSlide(Num::new(first as i16) / 16)
+                        }
+                    }
                     0xC => PatternEffect::Volume(Num::new(slot.effect_parameter as i16) / 255),
                     _ => PatternEffect::None,
                 };