From 8c1713aff5eedd229aaf1319adb5d96801ae27c2 Mon Sep 17 00:00:00 2001
From: Evan Martin <evan.martin@gmail.com>
Date: Sat, 5 Oct 2024 10:41:50 -0700
Subject: [PATCH] audio: pocoman opening works

---
 cli/src/host.rs                |  2 +-
 cli/src/sdl.rs                 | 78 +++++++++++++++++++++++++++++++++-
 web/glue/src/host.rs           |  2 +-
 win32/src/host.rs              |  2 +-
 win32/src/winapi/winmm/wave.rs | 11 ++++-
 5 files changed, 88 insertions(+), 7 deletions(-)

diff --git a/cli/src/host.rs b/cli/src/host.rs
index 568683db..296106fa 100644
--- a/cli/src/host.rs
+++ b/cli/src/host.rs
@@ -220,7 +220,7 @@ impl win32::Host for EnvRef {
         gui.create_surface(opts)
     }
 
-    fn write_audio(&mut self, buf: &[i16]) {
+    fn write_audio(&mut self, buf: &[u8]) {
         let mut env = self.0.borrow_mut();
         let gui = env.ensure_gui().unwrap();
         gui.write_audio(buf);
diff --git a/cli/src/sdl.rs b/cli/src/sdl.rs
index f198dee7..dcbeeba4 100644
--- a/cli/src/sdl.rs
+++ b/cli/src/sdl.rs
@@ -78,11 +78,13 @@ fn message_from_events(
 }
 
 pub struct GUI {
+    sdl: sdl2::Sdl,
     video: sdl2::VideoSubsystem,
     pump: sdl2::EventPump,
     timer: sdl2::TimerSubsystem,
     win: Option<WindowRef>,
     msg_queue: Option<win32::Message>,
+    audio: Option<Audio>,
 }
 
 impl GUI {
@@ -94,11 +96,13 @@ impl GUI {
         let timer = sdl.timer().map_err(|err| anyhow::anyhow!(err))?;
 
         Ok(GUI {
+            sdl,
             video,
             pump,
             timer,
             win: None,
             msg_queue: None,
+            audio: None,
         })
     }
 
@@ -158,8 +162,11 @@ impl GUI {
         Box::new(Texture::new(self.win.as_ref().unwrap(), opts))
     }
 
-    pub fn write_audio(&mut self, _buf: &[i16]) {
-        log::warn!("TODO: write_audio");
+    pub fn write_audio(&mut self, buf: &[u8]) {
+        if self.audio.is_none() {
+            self.audio = Some(Audio::init(&self.sdl));
+        }
+        self.audio.as_mut().unwrap().write_audio(buf);
     }
 }
 
@@ -278,3 +285,70 @@ impl win32::Surface for Texture {
             .unwrap();
     }
 }
+
+#[derive(Default)]
+struct AudioBuffer {
+    buf: Vec<i16>,
+    ofs: usize,
+}
+impl AudioBuffer {
+    fn write(&mut self, buf: &[u8]) {
+        if self.ofs > 0 {
+            todo!();
+        }
+
+        if self.buf.len() < 44100 {
+            self.buf.resize(44100, 0);
+        }
+
+        assert!(buf.len() % 2 == 0);
+        let write_buf = unsafe {
+            let data = self.buf.as_mut_ptr().add(self.ofs) as *mut u8;
+            let len = (buf.len() - self.ofs) * 2;
+            std::slice::from_raw_parts_mut(data, len)
+        };
+        if write_buf.len() < buf.len() {
+            panic!("audio buffer overflow");
+        }
+        write_buf[..buf.len()].copy_from_slice(buf);
+    }
+}
+
+impl sdl2::audio::AudioCallback for AudioBuffer {
+    type Channel = i16;
+    fn callback(&mut self, buf: &mut [i16]) {
+        let available = &self.buf[self.ofs..];
+        if available.len() > buf.len() {
+            buf.copy_from_slice(&available[..buf.len()]);
+        } else {
+            log::warn!("audiobuf underflow");
+            buf[..available.len()].copy_from_slice(available);
+            buf[available.len()..].fill(0);
+        }
+        self.ofs += buf.len();
+    }
+}
+
+struct Audio {
+    dev: sdl2::audio::AudioDevice<AudioBuffer>,
+}
+
+impl Audio {
+    fn init(sdl: &sdl2::Sdl) -> Self {
+        let audio = sdl.audio().unwrap();
+        let spec = sdl2::audio::AudioSpecDesired {
+            freq: Some(11025), // TODO: accept from caller I guess?
+            channels: Some(1),
+            samples: None,
+        };
+        let dev = audio
+            .open_playback(None, &spec, |_spec| AudioBuffer::default())
+            .unwrap();
+        dev.resume();
+        Audio { dev }
+    }
+
+    fn write_audio(&mut self, buf: &[u8]) {
+        self.dev.lock().write(buf);
+    }
+}
diff --git a/web/glue/src/host.rs b/web/glue/src/host.rs
index bfae27fa..6cf93d3c 100644
--- a/web/glue/src/host.rs
+++ b/web/glue/src/host.rs
@@ -359,7 +359,7 @@ impl win32::Host for JsHost {
         todo!("remove_dir {path}")
     }
 
-    fn write_audio(&mut self, _buf: &[i16]) {
+    fn write_audio(&mut self, _buf: &[u8]) {
         log::warn!("TODO: write_audio");
     }
 }
diff --git a/win32/src/host.rs b/win32/src/host.rs
index b8b0d746..b7f5cab1 100644
--- a/win32/src/host.rs
+++ b/win32/src/host.rs
@@ -159,5 +159,5 @@ pub trait Host {
     fn create_window(&mut self, hwnd: u32) -> Box<dyn Window>;
     fn create_surface(&mut self, hwnd: u32, opts: &SurfaceOptions) -> Box<dyn Surface>;
 
-    fn write_audio(&mut self, buf: &[i16]);
+    fn write_audio(&mut self, buf: &[u8]);
 }
diff --git a/win32/src/winapi/winmm/wave.rs b/win32/src/winapi/winmm/wave.rs
index b235469c..9ca16e95 100644
--- a/win32/src/winapi/winmm/wave.rs
+++ b/win32/src/winapi/winmm/wave.rs
@@ -1,6 +1,7 @@
 use super::MMRESULT;
 use crate::machine::Machine;
 use bitflags::bitflags;
+use memory::Extensions;
 
 #[win32_derive::dllexport]
 pub fn waveOutGetNumDevs(_machine: &mut Machine) -> u32 {
@@ -237,12 +238,18 @@ pub fn waveOutUnprepareHeader(
 
 #[win32_derive::dllexport]
 pub fn waveOutWrite(
-    _machine: &mut Machine,
+    machine: &mut Machine,
     hwo: HWAVEOUT,
     pwh: Option<&WAVEHDR>,
     cbwh: u32,
 ) -> MMRESULT {
-    log::info!("TODO: write audio");
     assert_eq!(cbwh, std::mem::size_of::<WAVEHDR>() as u32);
+    let hdr = pwh.unwrap();
+    let buf = machine
+        .emu
+        .memory
+        .mem()
+        .sub32(hdr.lpData, hdr.dwBufferLength);
+    machine.host.write_audio(buf);
     MMRESULT::MMSYSERR_NOERROR
 }