Update example to allow you to change where the sound is coming from

agb/examples/mixer_basic.rs

@@ -5,6 +5,8 @@ extern crate agb;
 
 use agb::sound::mixer::SoundChannel;
 use agb::Gba;
+use agb::input::{ButtonController, Tri};
+use agb::number::Num;
 
 // Music - "I will not let you let me down" by Josh Woodward, free download at http://joshwoodward.com
 const I_WILL_NOT_LET_YOU_LET_ME_DOWN: &[u8] = include_bytes!("i-will-not-let-you-let-me-down.raw");
@@ -12,15 +14,36 @@ const I_WILL_NOT_LET_YOU_LET_ME_DOWN: &[u8] = include_bytes!("i-will-not-let-you
 #[no_mangle]
 pub fn main() -> ! {
     let mut gba = Gba::new();
+    let mut input = ButtonController::new();
     let vblank_provider = gba.display.vblank.get();
 
     let mut mixer = gba.mixer.mixer();
     mixer.enable();
 
     let channel = SoundChannel::new(I_WILL_NOT_LET_YOU_LET_ME_DOWN);
-    mixer.play_sound(channel);
+    let channel_id = mixer.play_sound(channel).unwrap();
 
     loop {
+        input.update();
+
+        {
+            let channel = mixer.get_channel(&channel_id).unwrap();
+
+            let half: Num<i16, 4> = Num::new(1) / 2;
+            let half_usize: Num<usize, 8> = Num::new(1) / 2;
+            match input.x_tri() {
+                Tri::Negative => channel.panning(-half),
+                Tri::Zero => channel.panning(0.into()),
+                Tri::Positive => channel.panning(half),
+            };
+
+            match input.y_tri() {
+                Tri::Negative => channel.playback(half_usize.change_base() + 1),
+                Tri::Zero => channel.playback(1.into()),
+                Tri::Positive => channel.playback(half_usize),
+            };
+        }
+
         vblank_provider.wait_for_VBlank();
         mixer.vblank();
     }

agb/src/sound/mixer/sw_mixer.rs

@@ -63,7 +63,7 @@ impl Mixer {
         panic!("Cannot play more than 16 sounds at once");
     }
 
-    pub fn get_channel(&mut self, id: ChannelId) -> Option<&'_ mut SoundChannel> {
+    pub fn get_channel(&mut self, id: &ChannelId) -> Option<&'_ mut SoundChannel> {
         if let Some(channel) = &mut self.channels[id.0] {
             if self.indices[id.0] == id.1 {
                 return Some(channel);