Start making the frequency field dynamic rather than a feature flag

agb-sound-converter/Cargo.toml

@@ -18,10 +18,6 @@ debug = true
 [lib]
 proc-macro = true
 
-[features]
-freq18157 = []
-freq32768 = []
-
 [dependencies]
 hound = "3.5"
 syn = "1"

agb-sound-converter/src/lib.rs

@@ -6,15 +6,6 @@ use quote::{quote, ToTokens};
 use std::path::Path;
 use syn::parse_macro_input;
 
-#[cfg(all(not(feature = "freq18157"), not(feature = "freq32768")))]
-const FREQUENCY: u32 = 10512;
-#[cfg(feature = "freq18157")]
-const FREQUENCY: u32 = 18157;
-#[cfg(feature = "freq32768")]
-const FREQUENCY: u32 = 32768;
-#[cfg(all(feature = "freq18157", feature = "freq32768"))]
-compile_error!("Must have at most one of freq18157 or freq32768 features enabled");
-
 use quote::TokenStreamExt;
 struct ByteString<'a>(&'a [u8]);
 impl ToTokens for ByteString<'_> {
@@ -37,13 +28,6 @@ pub fn include_wav(input: TokenStream) -> TokenStream {
     let wav_reader = hound::WavReader::open(&path)
         .unwrap_or_else(|_| panic!("Failed to load file {}", include_path));
 
-    assert_eq!(
-        wav_reader.spec().sample_rate,
-        FREQUENCY,
-        "agb currently only supports sample rate of {}Hz",
-        FREQUENCY
-    );
-
     let samples: Vec<u8> = samples_from_reader(wav_reader).collect();
     let samples = ByteString(&samples);
 

agb/Cargo.toml

@@ -17,8 +17,6 @@ debug = true
 
 [features]
 default = ["testing"]
-freq18157 = ["agb_sound_converter/freq18157"]
-freq32768 = ["agb_sound_converter/freq32768"]
 testing = []
 
 [dependencies]
@@ -34,7 +32,3 @@ rustc-hash =  { version = "1", default-features = false }
 [package.metadata.docs.rs]
 default-target = "thumbv6m-none-eabi"
 targets = []
-
-[[example]]
-name = "mixer_32768"
-required-features = ["freq32768"]

agb/examples/mixer_32768.rs

@@ -7,7 +7,7 @@ use agb::{
         Font, Priority,
     },
     include_font, include_wav,
-    sound::mixer::SoundChannel,
+    sound::mixer::{Frequency, SoundChannel},
     Gba,
 };
 
@@ -40,7 +40,7 @@ fn main(mut gba: Gba) -> ! {
     let mut timer = timer_controller.timer2;
     timer.set_enabled(true);
 
-    let mut mixer = gba.mixer.mixer();
+    let mut mixer = gba.mixer.mixer(Frequency::Hz32768);
     mixer.enable();
     let _interrupt = mixer.setup_interrupt_handler();
 

agb/examples/mixer_basic.rs

@@ -3,7 +3,7 @@
 
 use agb::fixnum::Num;
 use agb::input::{Button, ButtonController, Tri};
-use agb::sound::mixer::SoundChannel;
+use agb::sound::mixer::{Frequency, SoundChannel};
 use agb::{fixnum::num, include_wav, Gba};
 
 // Music - "Dead Code" by Josh Woodward, free download at http://joshwoodward.com
@@ -14,7 +14,7 @@ fn main(mut gba: Gba) -> ! {
     let mut input = ButtonController::new();
     let vblank_provider = agb::interrupt::VBlank::get();
 
-    let mut mixer = gba.mixer.mixer();
+    let mut mixer = gba.mixer.mixer(Frequency::Hz10512);
     mixer.enable();
 
     let channel = SoundChannel::new(DEAD_CODE);

agb/examples/stereo_sound.rs

@@ -7,7 +7,7 @@ use agb::{
         Font, Priority,
     },
     include_font, include_wav,
-    sound::mixer::SoundChannel,
+    sound::mixer::{Frequency, SoundChannel},
     Gba,
 };
 
@@ -40,7 +40,7 @@ fn main(mut gba: Gba) -> ! {
     let mut timer = timer_controller.timer2;
     timer.set_enabled(true);
 
-    let mut mixer = gba.mixer.mixer();
+    let mut mixer = gba.mixer.mixer(Frequency::Hz10512);
     mixer.enable();
 
     let mut channel = SoundChannel::new(LET_IT_IN);

agb/src/sound/mixer/mod.rs

@@ -138,8 +138,8 @@ impl MixerController {
     }
 
     /// Get a [`Mixer`] in order to start producing sounds.
-    pub fn mixer(&mut self) -> Mixer {
-        Mixer::new()
+    pub fn mixer(&mut self, frequency: Frequency) -> Mixer {
+        Mixer::new(frequency)
     }
 }
 
@@ -149,6 +149,44 @@ enum SoundPriority {
     Low,
 }
 
+/// The supported frequencies within AGB. These are chosen to work well with
+/// the hardware. Note that the higher the frequency, the better the quality of
+/// the sound but the more CPU time sound mixing will take.
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[non_exhaustive]
+pub enum Frequency {
+    /// 10512Hz
+    Hz10512,
+    /// 18157Hz
+    Hz18157,
+    /// 32768Hz - note that this option requires the timer to do the buffer swapping
+    Hz32768,
+}
+
+// These work perfectly with swapping the buffers every vblank
+// list here: http://deku.gbadev.org/program/sound1.html
+impl Frequency {
+    pub(crate) fn frequency(self) -> i32 {
+        use Frequency::*;
+
+        match self {
+            Hz10512 => 10512,
+            Hz18157 => 18157,
+            Hz32768 => 32768,
+        }
+    }
+
+    pub(crate) fn buffer_size(self) -> usize {
+        use Frequency::*;
+
+        match self {
+            Hz10512 => 176,
+            Hz18157 => 18157,
+            Hz32768 => 32768,
+        }
+    }
+}
+
 /// Describes one sound which should be playing. This could be a sound effect or
 /// the background music. Use the factory methods on this to modify how it is played.
 ///

agb/src/sound/mixer/sw_mixer.rs

@@ -1,12 +1,14 @@
 use core::cell::RefCell;
-use core::intrinsics::transmute;
 
+use alloc::boxed::Box;
+use alloc::vec::Vec;
 use bare_metal::{CriticalSection, Mutex};
 
-use super::hw;
 use super::hw::LeftOrRight;
+use super::{hw, Frequency};
 use super::{SoundChannel, SoundPriority};
 
+use crate::InternalAllocator;
 use crate::{
     fixnum::Num,
     interrupt::free,
@@ -80,6 +82,7 @@ pub struct Mixer {
     buffer: MixerBuffer,
     channels: [Option<SoundChannel>; 8],
     indices: [i32; 8],
+    frequency: Frequency,
 
     timer: Timer,
 }
@@ -108,9 +111,10 @@ pub struct Mixer {
 pub struct ChannelId(usize, i32);
 
 impl Mixer {
-    pub(super) fn new() -> Self {
+    pub(super) fn new(frequency: Frequency) -> Self {
         Self {
-            buffer: MixerBuffer::new(),
+            frequency,
+            buffer: MixerBuffer::new(frequency),
             channels: Default::default(),
             indices: Default::default(),
 
@@ -123,7 +127,7 @@ impl Mixer {
     /// You must call this method in order to start playing sound. You can do as much set up before
     /// this as you like, but you will not get any sound out of the console until this method is called.
     pub fn enable(&mut self) {
-        hw::set_timer_counter_for_frequency_and_enable(&mut self.timer, constants::SOUND_FREQUENCY);
+        hw::set_timer_counter_for_frequency_and_enable(&mut self.timer, self.frequency.frequency());
         hw::set_sound_control_register_for_mixer();
     }
 
@@ -184,7 +188,7 @@ impl Mixer {
             .set_cascade(true)
             .set_divider(Divider::Divider1)
             .set_interrupt(true)
-            .set_overflow_amount(constants::SOUND_BUFFER_SIZE as u16)
+            .set_overflow_amount(self.frequency.buffer_size() as u16)
             .set_enabled(true);
 
         add_interrupt_handler(timer1.interrupt(), move |cs| self.buffer.swap(cs))
@@ -313,47 +317,31 @@ impl Mixer {
     }
 }
 
-// These work perfectly with swapping the buffers every vblank
-// list here: http://deku.gbadev.org/program/sound1.html
-#[cfg(all(not(feature = "freq18157"), not(feature = "freq32768")))]
-mod constants {
-    pub const SOUND_FREQUENCY: i32 = 10512;
-    pub const SOUND_BUFFER_SIZE: usize = 176;
-}
-
-#[cfg(feature = "freq18157")]
-mod constants {
-    pub const SOUND_FREQUENCY: i32 = 18157;
-    pub const SOUND_BUFFER_SIZE: usize = 304;
-}
-
-#[cfg(feature = "freq32768")]
-mod constants {
-    pub const SOUND_FREQUENCY: i32 = 32768;
-    pub const SOUND_BUFFER_SIZE: usize = 560;
-}
-
-fn set_asm_buffer_size() {
+fn set_asm_buffer_size(frequency: Frequency) {
     extern "C" {
         static mut agb_rs__buffer_size: usize;
     }
 
     unsafe {
-        agb_rs__buffer_size = constants::SOUND_BUFFER_SIZE;
+        agb_rs__buffer_size = frequency.buffer_size();
     }
 }
 
-#[repr(C, align(4))]
-struct SoundBuffer([i8; constants::SOUND_BUFFER_SIZE * 2]);
+struct SoundBuffer(Box<[i8], InternalAllocator>);
 
-impl Default for SoundBuffer {
-    fn default() -> Self {
-        Self([0; constants::SOUND_BUFFER_SIZE * 2])
+impl SoundBuffer {
+    fn new(frequency: Frequency) -> Self {
+        let my_size = frequency.buffer_size() * 2;
+        let mut v = Vec::with_capacity_in(my_size, InternalAllocator);
+        v.resize(my_size, 0);
+
+        SoundBuffer(v.into_boxed_slice())
     }
 }
 
 struct MixerBuffer {
     buffers: [SoundBuffer; 3],
+    frequency: Frequency,
 
     state: Mutex<RefCell<MixerBufferState>>,
 }
@@ -391,16 +379,20 @@ impl MixerBufferState {
 }
 
 impl MixerBuffer {
-    fn new() -> Self {
-        set_asm_buffer_size();
-
+    fn new(frequency: Frequency) -> Self {
         MixerBuffer {
-            buffers: Default::default(),
+            buffers: [
+                SoundBuffer::new(frequency),
+                SoundBuffer::new(frequency),
+                SoundBuffer::new(frequency),
+            ],
 
             state: Mutex::new(RefCell::new(MixerBufferState {
                 active_buffer: 0,
                 playing_buffer: 0,
             })),
+
+            frequency,
         }
     }
 
@@ -413,15 +405,17 @@ impl MixerBuffer {
 
         let (left_buffer, right_buffer) = self.buffers[buffer]
             .0
-            .split_at(constants::SOUND_BUFFER_SIZE);
+            .split_at(self.frequency.buffer_size());
 
         hw::enable_dma_for_sound(left_buffer, LeftOrRight::Left);
         hw::enable_dma_for_sound(right_buffer, LeftOrRight::Right);
     }
 
     fn write_channels<'a>(&mut self, channels: impl Iterator<Item = &'a mut SoundChannel>) {
-        let mut buffer: [Num<i16, 4>; constants::SOUND_BUFFER_SIZE * 2] =
-            unsafe { transmute([0i16; constants::SOUND_BUFFER_SIZE * 2]) };
+        set_asm_buffer_size(self.frequency);
+
+        let mut buffer = Vec::with_capacity_in(self.frequency.buffer_size() * 2, InternalAllocator);
+        buffer.resize(self.frequency.buffer_size() * 2, 0.into());
 
         for channel in channels {
             if channel.is_done {
@@ -434,7 +428,7 @@ impl MixerBuffer {
                 channel.playback_speed
             };
 
-            if (channel.pos + playback_speed * constants::SOUND_BUFFER_SIZE).floor()
+            if (channel.pos + playback_speed * self.frequency.buffer_size()).floor()
                 >= channel.data.len()
             {
                 // TODO: This should probably play what's left rather than skip the last bit
@@ -469,7 +463,7 @@ impl MixerBuffer {
                 }
             }
 
-            channel.pos += playback_speed * constants::SOUND_BUFFER_SIZE;
+            channel.pos += playback_speed * self.frequency.buffer_size();
         }
 
         let write_buffer_index = free(|cs| self.state.borrow(cs).borrow_mut().active_advanced());