First pass at implementing envelope playing

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

@@ -126,7 +126,7 @@ impl quote::ToTokens for Envelope<'_> {
 
         let amount = amount.iter().map(|value| {
             let value = value.to_raw();
-            quote! { agb_tracker::__private::agb_tracker_interop::Num::from_raw(#value) }
+            quote! { agb_tracker::__private::Num::from_raw(#value) }
         });
 
         let sustain = match sustain {
@@ -143,7 +143,8 @@ impl quote::ToTokens for Envelope<'_> {
         };
 
         tokens.append_all(quote! {
-            const AMOUNTS: &[agb_tracker::__private::agb_tracker_interop::Num<i16, 8>] = &[#(#amount),*];
+            {
+                const AMOUNTS: &[agb_tracker::__private::Num<i16, 8>] = &[#(#amount),*];
 
                 agb_tracker::__private::agb_tracker_interop::Envelope {
                     amount: AMOUNTS,
@@ -151,6 +152,7 @@ impl quote::ToTokens for Envelope<'_> {
                     loop_start: #loop_start,
                     loop_end: #loop_end,
                 }
+            }
         });
     }
 }

tracker/agb-tracker/src/lib.rs

@@ -90,6 +90,7 @@ pub use agb_tracker_interop::Track;
 pub struct Tracker {
     track: &'static Track<'static>,
     channels: Vec<TrackerChannel>,
+    envelopes: Vec<Option<EnvelopeState>>,
 
     frame: Num<u32, 8>,
     tick: u32,
@@ -101,12 +102,18 @@ pub struct Tracker {
     current_pattern: usize,
 }
 
+#[derive(Default)]
 struct TrackerChannel {
     channel_id: Option<ChannelId>,
     base_speed: Num<u32, 16>,
     volume: Num<i32, 8>,
 }
 
+struct EnvelopeState {
+    frame: usize,
+    envelope_id: usize,
+}
+
 #[derive(Clone)]
 struct GlobalSettings {
     ticks_per_step: u32,
@@ -118,11 +125,10 @@ impl Tracker {
     /// Create a new tracker playing a specified track. See the [example](crate#example) for how to use the tracker.
     pub fn new(track: &'static Track<'static>) -> Self {
         let mut channels = Vec::new();
-        channels.resize_with(track.num_channels, || TrackerChannel {
-            channel_id: None,
-            base_speed: 0.into(),
-            volume: 0.into(),
-        });
+        channels.resize_with(track.num_channels, Default::default);
+
+        let mut envelopes = Vec::new();
+        envelopes.resize_with(track.num_channels, || None);
 
         let global_settings = GlobalSettings {
             ticks_per_step: track.ticks_per_step,
@@ -132,6 +138,7 @@ impl Tracker {
         Self {
             track,
             channels,
+            envelopes,
 
             frame: 0.into(),
             first: true,
@@ -148,6 +155,7 @@ impl Tracker {
     /// See the [example](crate#example) for how to use the tracker.
     pub fn step(&mut self, mixer: &mut Mixer) {
         if !self.increment_frame() {
+            self.update_envelopes(mixer);
             return;
         }
 
@@ -183,7 +191,37 @@ impl Tracker {
             );
         }
 
-        self.increment_step();
+        self.update_envelopes(mixer);
+    }
+
+    fn update_envelopes(&mut self, mixer: &mut Mixer) {
+        for (channel, envelope_state_option) in self.channels.iter_mut().zip(&mut self.envelopes) {
+            if let Some(envelope_state) = envelope_state_option {
+                let envelope = &self.track.envelopes[envelope_state.envelope_id];
+
+                if !channel.update_volume_envelope(mixer, envelope_state.frame, envelope) {
+                    envelope_state_option.take();
+                } else {
+                    envelope_state.frame += 1;
+
+                    if let Some(sustain) = envelope.sustain {
+                        if envelope_state.frame >= sustain {
+                            envelope_state.frame = sustain;
+                        }
+                    }
+
+                    if let Some(loop_end) = envelope.loop_end {
+                        if envelope_state.frame >= loop_end {
+                            envelope_state.frame = envelope.loop_start.unwrap_or(0);
+                        }
+                    }
+
+                    if envelope_state.frame >= envelope.amount.len() {
+                        envelope_state_option.take();
+                    }
+                }
+            }
+        }
     }
 
     fn increment_frame(&mut self) -> bool {
@@ -220,8 +258,6 @@ impl Tracker {
             false
         }
     }
-
-    fn increment_step(&mut self) {}
 }
 
 impl TrackerChannel {
@@ -350,6 +386,31 @@ impl TrackerChannel {
             _ => {}
         }
     }
+
+    #[must_use]
+    fn update_volume_envelope(
+        &self,
+        mixer: &mut Mixer<'_>,
+        frame: usize,
+        envelope: &agb_tracker_interop::Envelope<'_>,
+    ) -> bool {
+        if let Some(channel) = self
+            .channel_id
+            .as_ref()
+            .and_then(|channel_id| mixer.channel(channel_id))
+        {
+            let amount = envelope.amount[frame];
+
+            channel.volume(
+                (self.volume * amount.change_base())
+                    .try_change_base()
+                    .unwrap(),
+            );
+            true
+        } else {
+            false
+        }
+    }
 }
 
 #[cfg(test)]

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

@@ -1,4 +1,4 @@
-use std::{collections::HashMap, env, error::Error, fs, path::Path};
+use std::{collections::HashMap, error::Error, fs, path::Path};
 
 use agb_tracker_interop::PatternEffect;
 use proc_macro2::TokenStream;
@@ -9,7 +9,7 @@ use syn::LitStr;
 
 use agb_fixnum::Num;
 
-use xmrs::{envelope, prelude::*, xm::xmmodule::XmModule};
+use xmrs::{prelude::*, xm::xmmodule::XmModule};
 
 pub fn agb_xm_core(args: TokenStream) -> TokenStream {
     let input = match syn::parse::<LitStr>(args.into()) {
@@ -489,7 +489,46 @@ struct EnvelopeData {
 }
 
 impl From<&xmrs::envelope::Envelope> for EnvelopeData {
-    fn from(value: &xmrs::envelope::Envelope) -> Self {
-        todo!()
+    fn from(e: &xmrs::envelope::Envelope) -> Self {
+        let mut amounts = vec![Num::new(e.point[0].value as i16) / 0xff];
+
+        // it should be sampled at 50fps, but we're sampling at 60fps, so need to do a bit of cheating here.
+        for frame in 1..(e.point.last().unwrap().frame * 60 / 50) {
+            let xm_frame = (frame * 50 / 60).max(1);
+            let index = e
+                .point
+                .iter()
+                .rposition(|point| point.frame < xm_frame)
+                .unwrap();
+
+            let first_point = &e.point[index];
+            let second_point = &e.point[index + 1];
+
+            let amount = EnvelopePoint::lerp(first_point, second_point, xm_frame) / 255.0;
+            let amount = Num::from_raw((amount * (1 << 8) as f32) as i16);
+
+            amounts.push(amount);
+        }
+
+        let sustain = if e.sustain_enabled {
+            Some(e.point[e.sustain_point as usize].frame as usize * 60 / 50)
+        } else {
+            None
+        };
+        let (loop_start, loop_end) = if e.loop_enabled {
+            (
+                Some(e.point[e.loop_start_point as usize].frame as usize * 60 / 50),
+                Some(e.point[e.loop_end_point as usize].frame as usize * 60 / 50),
+            )
+        } else {
+            (None, None)
+        };
+
+        EnvelopeData {
+            amounts,
+            sustain,
+            loop_start,
+            loop_end,
+        }
     }
 }