Add Portamento

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

@@ -49,6 +49,7 @@ pub enum PatternEffect {
     Volume(Num<i16, 4>),
     VolumeSlide(Num<i16, 4>),
     NoteCut(u32),
+    Portamento(Num<u16, 8>),
 }
 
 #[cfg(feature = "quote")]
@@ -204,6 +205,10 @@ impl quote::ToTokens for PatternEffect {
                 quote! { VolumeSlide(agb_tracker::__private::Num::from_raw(#amount))}
             }
             PatternEffect::NoteCut(wait) => quote! { NoteCut(#wait) },
+            PatternEffect::Portamento(amount) => {
+                let amount = amount.to_raw();
+                quote! { Portamento(agb_tracker::__private::Num::from_raw(#amount))}
+            }
         };
 
         tokens.append_all(quote! {

tracker/agb-tracker/src/lib.rs

@@ -61,7 +61,7 @@ impl Tracker {
             tick: 0,
 
             current_row: 0,
-            current_pattern: 0,
+            current_pattern: 31,
         }
     }
 
@@ -78,7 +78,7 @@ 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) {
+        for (channel, pattern_slot) in self.channels.iter_mut().zip(pattern_slots).skip(3) {
             if pattern_slot.sample != 0 && self.tick == 0 {
                 let sample = &self.track.samples[pattern_slot.sample as usize - 1];
                 channel.play_sound(mixer, sample);
@@ -214,6 +214,12 @@ impl TrackerChannel {
                         self.volume = 0.into();
                     }
                 }
+                PatternEffect::Portamento(amount) => {
+                    if tick != 0 {
+                        self.base_speed *= amount.change_base();
+                        channel.playback(self.base_speed);
+                    }
+                }
             }
         }
     }

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

@@ -197,6 +197,32 @@ pub fn parse_module(module: &Module) -> TokenStream {
                             PatternEffect::None
                         }
                     }
+                    0x1 => {
+                        let c4_speed = note_to_speed(Note::C4, 0.0, 0, module.frequency_type);
+                        let speed = note_to_speed(
+                            Note::C4,
+                            slot.effect_parameter as f64,
+                            0,
+                            module.frequency_type,
+                        );
+
+                        let portamento_amount = speed / c4_speed;
+
+                        PatternEffect::Portamento(portamento_amount.try_change_base().unwrap())
+                    }
+                    0x2 => {
+                        let c4_speed = note_to_speed(Note::C4, 0.0, 0, module.frequency_type);
+                        let speed = note_to_speed(
+                            Note::C4,
+                            -(slot.effect_parameter as f64),
+                            0,
+                            module.frequency_type,
+                        );
+
+                        let portamento_amount = speed / c4_speed;
+
+                        PatternEffect::Portamento(portamento_amount.try_change_base().unwrap())
+                    }
                     0x8 => {
                         PatternEffect::Panning(Num::new(slot.effect_parameter as i16 - 128) / 128)
                     }