Add audio, fix timing

Cargo.lock

@@ -31,12 +31,43 @@ dependencies = [
  "zerocopy",
 ]
 
+[[package]]
+name = "aho-corasick"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e60d3430d3a69478ad0993f19238d2df97c507009a52b3c10addcd7f6bcb916"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "allocator-api2"
 version = "0.2.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5c6cb57a04249c6480766f7f7cef5467412af1490f8d1e243141daddada3264f"
 
+[[package]]
+name = "alsa"
+version = "0.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ed7572b7ba83a31e20d1b48970ee402d2e3e0537dcfe0a3ff4d6eb7508617d43"
+dependencies = [
+ "alsa-sys",
+ "bitflags 2.6.0",
+ "cfg-if",
+ "libc",
+]
+
+[[package]]
+name = "alsa-sys"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "db8fee663d06c4e303404ef5f40488a53e062f89ba8bfed81f42325aafad1527"
+dependencies = [
+ "libc",
+ "pkg-config",
+]
+
 [[package]]
 name = "android-activity"
 version = "0.6.0"
@@ -51,7 +82,7 @@ dependencies = [
  "jni-sys",
  "libc",
  "log",
- "ndk",
+ "ndk 0.9.0",
  "ndk-context",
  "ndk-sys 0.6.0+11769913",
  "num_enum",
@@ -167,6 +198,24 @@ version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ace50bade8e6234aa140d9a2f552bbee1db4d353f69b8217bc503490fc1a9f26"
 
+[[package]]
+name = "bindgen"
+version = "0.70.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f49d8fed880d473ea71efb9bf597651e77201bdd4893efe54c9e5d65ae04ce6f"
+dependencies = [
+ "bitflags 2.6.0",
+ "cexpr",
+ "clang-sys",
+ "itertools",
+ "proc-macro2",
+ "quote",
+ "regex",
+ "rustc-hash",
+ "shlex",
+ "syn 2.0.87",
+]
+
 [[package]]
 name = "bit-set"
 version = "0.6.0"
@@ -284,6 +333,15 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6d43a04d8753f35258c91f8ec639f792891f748a1edbd759cf1dcea3382ad83c"
 
+[[package]]
+name = "cexpr"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6fac387a98bb7c37292057cffc56d62ecb629900026402633ae9160df93a8766"
+dependencies = [
+ "nom",
+]
+
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
@@ -308,6 +366,17 @@ version = "1.0.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1e10e7569f6ca78ef7664d7d651115172d4875c4410c050306bccde856a99a49"
 
+[[package]]
+name = "clang-sys"
+version = "1.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b023947811758c97c59bf9d1c188fd619ad4718dcaa767947df1cadb14f39f4"
+dependencies = [
+ "glob",
+ "libc",
+ "libloading",
+]
+
 [[package]]
 name = "clap"
 version = "4.5.20"
@@ -454,6 +523,49 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "coreaudio-rs"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "321077172d79c662f64f5071a03120748d5bb652f5231570141be24cfcd2bace"
+dependencies = [
+ "bitflags 1.3.2",
+ "core-foundation-sys",
+ "coreaudio-sys",
+]
+
+[[package]]
+name = "coreaudio-sys"
+version = "0.2.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2ce857aa0b77d77287acc1ac3e37a05a8c95a2af3647d23b15f263bdaeb7562b"
+dependencies = [
+ "bindgen",
+]
+
+[[package]]
+name = "cpal"
+version = "0.15.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "873dab07c8f743075e57f524c583985fbaf745602acbe916a01539364369a779"
+dependencies = [
+ "alsa",
+ "core-foundation-sys",
+ "coreaudio-rs",
+ "dasp_sample",
+ "jni",
+ "js-sys",
+ "libc",
+ "mach2",
+ "ndk 0.8.0",
+ "ndk-context",
+ "oboe",
+ "wasm-bindgen",
+ "wasm-bindgen-futures",
+ "web-sys",
+ "windows 0.54.0",
+]
+
 [[package]]
 name = "crossbeam-utils"
 version = "0.8.20"
@@ -477,6 +589,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "dasp_sample"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0c87e182de0887fd5361989c677c4e8f5000cd9491d6d563161a8f3a5519fc7f"
+
 [[package]]
 name = "dispatch"
 version = "0.2.0"
@@ -513,6 +631,12 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f25c0e292a7ca6d6498557ff1df68f32c99850012b6ea401cf8daf771f22ff53"
 
+[[package]]
+name = "either"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "60b1af1c220855b6ceac025d3f6ecdd2b7c4894bfe9cd9bda4fbb4bc7c0d4cf0"
+
 [[package]]
 name = "equivalent"
 version = "1.0.1"
@@ -588,6 +712,12 @@ dependencies = [
  "xml-rs",
 ]
 
+[[package]]
+name = "glob"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d2fabcfbdc87f4758337ca535fb41a6d701b65693ce38287d856d1674551ec9b"
+
 [[package]]
 name = "glow"
 version = "0.13.1"
@@ -638,7 +768,7 @@ dependencies = [
  "presser",
  "thiserror",
  "winapi",
- "windows",
+ "windows 0.52.0",
 ]
 
 [[package]]
@@ -773,6 +903,15 @@ version = "1.70.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7943c866cc5cd64cbc25b2e01621d07fa8eb2a1a23160ee81ce38704e97b8ecf"
 
+[[package]]
+name = "itertools"
+version = "0.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "413ee7dfc52ee1a4949ceeb7dbc8a33f2d6c088194d9f922fb8318faf1f01186"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "jni"
 version = "0.21.1"
@@ -885,6 +1024,15 @@ version = "0.4.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a7a70ba024b9dc04c27ea2f0c0548feb474ec5c54bba33a7f72f873a39d07b24"
 
+[[package]]
+name = "mach2"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "19b955cdeb2a02b9117f121ce63aa52d08ade45de53e48fe6a38b39c10f6f709"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "malloc_buf"
 version = "0.0.6"
@@ -924,6 +1072,12 @@ dependencies = [
  "paste",
 ]
 
+[[package]]
+name = "minimal-lexical"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"
+
 [[package]]
 name = "mint"
 version = "0.5.9"
@@ -951,6 +1105,20 @@ dependencies = [
  "unicode-xid",
 ]
 
+[[package]]
+name = "ndk"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2076a31b7010b17a38c01907c45b945e8f11495ee4dd588309718901b1f7a5b7"
+dependencies = [
+ "bitflags 2.6.0",
+ "jni-sys",
+ "log",
+ "ndk-sys 0.5.0+25.2.9519653",
+ "num_enum",
+ "thiserror",
+]
+
 [[package]]
 name = "ndk"
 version = "0.9.0"
@@ -990,6 +1158,54 @@ dependencies = [
  "jni-sys",
 ]
 
+[[package]]
+name = "nom"
+version = "7.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d273983c5a657a70a3e8f2a01329822f3b8c8172b73826411a55751e404a0a4a"
+dependencies = [
+ "memchr",
+ "minimal-lexical",
+]
+
+[[package]]
+name = "num-complex"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "73f88a1307638156682bada9d7604135552957b7818057dcef22705b4d509495"
+dependencies = [
+ "num-traits",
+]
+
+[[package]]
+name = "num-derive"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ed3955f1a9c7c0c15e092f9c887db08b1fc683305fdf6eb6684f22555355e202"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.87",
+]
+
+[[package]]
+name = "num-integer"
+version = "0.1.46"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7969661fd2958a5cb096e56c8e1ad0444ac2bbcd0061bd28660485a44879858f"
+dependencies = [
+ "num-traits",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.2.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "num_enum"
 version = "0.7.3"
@@ -1223,6 +1439,29 @@ dependencies = [
  "objc2-foundation",
 ]
 
+[[package]]
+name = "oboe"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e8b61bebd49e5d43f5f8cc7ee2891c16e0f41ec7954d36bcb6c14c5e0de867fb"
+dependencies = [
+ "jni",
+ "ndk 0.8.0",
+ "ndk-context",
+ "num-derive",
+ "num-traits",
+ "oboe-sys",
+]
+
+[[package]]
+name = "oboe-sys"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c8bb09a4a2b1d668170cfe0a7d5bc103f8999fb316c98099b6a9939c9f2e79d"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.20.2"
@@ -1341,6 +1580,15 @@ version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e8cf8e6a8aa66ce33f63993ffc4ea4271eb5b0530a9002db8455ea6050c77bfa"
 
+[[package]]
+name = "primal-check"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc0d895b311e3af9902528fbb8f928688abbd95872819320517cc24ca6b2bd08"
+dependencies = [
+ "num-integer",
+]
+
 [[package]]
 name = "proc-macro-crate"
 version = "3.2.0"
@@ -1395,6 +1643,15 @@ version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "20675572f6f24e9e76ef639bc5552774ed45f1c30e2951e1e99c59888861c539"
 
+[[package]]
+name = "realfft"
+version = "3.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "390252372b7f2aac8360fc5e72eba10136b166d6faeed97e6d0c8324eb99b2b1"
+dependencies = [
+ "rustfft",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.4.1"
@@ -1413,18 +1670,80 @@ dependencies = [
  "bitflags 2.6.0",
 ]
 
+[[package]]
+name = "regex"
+version = "1.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b544ef1b4eac5dc2db33ea63606ae9ffcfac26c1416a2806ae0bf5f56b201191"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "368758f23274712b504848e9d5a6f010445cc8b87a7cdb4d7cbee666c1288da3"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2b15c43186be67a4fd63bee50d0303afffcef381492ebe2c5d87f324e1b8815c"
+
 [[package]]
 name = "renderdoc-sys"
 version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "19b30a45b0cd0bcca8037f3d0dc3421eaf95327a17cad11964fb8179b4fc4832"
 
+[[package]]
+name = "rtrb"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f3f94e84c073f3b85d4012b44722fa8842b9986d741590d4f2636ad0a5b14143"
+
+[[package]]
+name = "rubato"
+version = "0.16.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cdd96992d7e24b3d7f35fdfe02af037a356ac90d41b466945cf3333525a86eea"
+dependencies = [
+ "num-complex",
+ "num-integer",
+ "num-traits",
+ "realfft",
+]
+
 [[package]]
 name = "rustc-hash"
 version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"
 
+[[package]]
+name = "rustfft"
+version = "6.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "43806561bc506d0c5d160643ad742e3161049ac01027b5e6d7524091fd401d86"
+dependencies = [
+ "num-complex",
+ "num-integer",
+ "num-traits",
+ "primal-check",
+ "strength_reduce",
+ "transpose",
+ "version_check",
+]
+
 [[package]]
 name = "rustix"
 version = "0.38.38"
@@ -1506,10 +1825,16 @@ dependencies = [
  "bytemuck",
  "cc",
  "clap",
+ "cpal",
  "imgui",
  "imgui-wgpu",
  "imgui-winit-support",
+ "itertools",
+ "num-derive",
+ "num-traits",
  "pollster",
+ "rtrb",
+ "rubato",
  "wgpu",
  "winit",
 ]
@@ -1587,6 +1912,12 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
 
+[[package]]
+name = "strength_reduce"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fe895eb47f22e2ddd4dabc02bce419d2e643c8e3b585c78158b349195bc24d82"
+
 [[package]]
 name = "strict-num"
 version = "0.1.1"
@@ -1708,6 +2039,16 @@ version = "0.1.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c06d3da6113f116aaee68e4d601191614c9053067f9ab7f6edbcb161237daa54"
 
+[[package]]
+name = "transpose"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ad61aed86bc3faea4300c7aee358b4c6d0c8d6ccc36524c96e4c92ccf26e77e"
+dependencies = [
+ "num-integer",
+ "strength_reduce",
+]
+
 [[package]]
 name = "ttf-parser"
 version = "0.25.0"
@@ -2111,7 +2452,17 @@ version = "0.52.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e48a53791691ab099e5e2ad123536d0fff50652600abaf43bbf952894110d0be"
 dependencies = [
- "windows-core",
+ "windows-core 0.52.0",
+ "windows-targets 0.52.6",
+]
+
+[[package]]
+name = "windows"
+version = "0.54.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9252e5725dbed82865af151df558e754e4a3c2c30818359eb17465f1346a1b49"
+dependencies = [
+ "windows-core 0.54.0",
  "windows-targets 0.52.6",
 ]
 
@@ -2124,6 +2475,25 @@ dependencies = [
  "windows-targets 0.52.6",
 ]
 
+[[package]]
+name = "windows-core"
+version = "0.54.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "12661b9c89351d684a50a8a643ce5f608e20243b9fb84687800163429f161d65"
+dependencies = [
+ "windows-result",
+ "windows-targets 0.52.6",
+]
+
+[[package]]
+name = "windows-result"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e383302e8ec8515204254685643de10811af0ed97ea37210dc26fb0032647f8"
+dependencies = [
+ "windows-targets 0.52.6",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.45.0"
@@ -2351,7 +2721,7 @@ dependencies = [
  "js-sys",
  "libc",
  "memmap2",
- "ndk",
+ "ndk 0.9.0",
  "objc2",
  "objc2-app-kit",
  "objc2-foundation",

Cargo.toml

@@ -7,10 +7,16 @@ edition = "2021"
 anyhow = "1"
 bytemuck = { version = "1", features = ["derive"] }
 clap = { version = "4", features = ["derive"] }
+cpal = "0.15"
 imgui = "0.12"
 imgui-wgpu = { git = "https://github.com/Yatekii/imgui-wgpu-rs", rev = "2edd348" }
 imgui-winit-support = "0.13"
+itertools = "0.13"
+num-derive = "0.4"
+num-traits = "0.2"
 pollster = "0.4"
+rtrb = "0.3"
+rubato = "0.16"
 wgpu = "22.1"
 winit = "0.30"
 

src/audio.rs

@@ -0,0 +1,101 @@
+use anyhow::{bail, Result};
+use cpal::traits::{DeviceTrait, HostTrait, StreamTrait};
+use itertools::Itertools;
+use rubato::{FftFixedInOut, Resampler};
+
+pub struct Audio {
+    #[allow(unused)]
+    stream: cpal::Stream,
+    sampler: FftFixedInOut<f32>,
+    input_buffer: Vec<Vec<f32>>,
+    output_buffer: Vec<Vec<f32>>,
+    sample_sink: rtrb::Producer<f32>,
+}
+
+impl Audio {
+    pub fn init() -> Result<Self> {
+        let host = cpal::default_host();
+        let Some(device) = host.default_output_device() else {
+            bail!("No output device available");
+        };
+        let Some(config) = device
+            .supported_output_configs()?
+            .find(|c| c.channels() == 2 && c.sample_format().is_float())
+        else {
+            bail!("No suitable output config available");
+        };
+        let mut config = config.with_max_sample_rate().config();
+        let sampler = FftFixedInOut::new(41700, config.sample_rate.0 as usize, 834, 2)?;
+        config.buffer_size = cpal::BufferSize::Fixed(sampler.output_frames_max() as u32);
+
+        let input_buffer = sampler.input_buffer_allocate(true);
+        let output_buffer = sampler.output_buffer_allocate(true);
+        let (sample_sink, mut sample_source) =
+            rtrb::RingBuffer::new(sampler.output_frames_max() * 4);
+
+        let stream = device.build_output_stream(
+            &config,
+            move |data: &mut [f32], _| {
+                let requested = data.len();
+                let chunk = match sample_source.read_chunk(data.len()) {
+                    Ok(c) => c,
+                    Err(rtrb::chunks::ChunkError::TooFewSlots(n)) => {
+                        sample_source.read_chunk(n).unwrap()
+                    }
+                };
+                let len = chunk.len();
+                let (first, second) = chunk.as_slices();
+                data[0..first.len()].copy_from_slice(first);
+                data[first.len()..len].copy_from_slice(second);
+                for rest in &mut data[len..requested] {
+                    *rest = 0.0;
+                }
+                chunk.commit_all();
+            },
+            move |err| eprintln!("stream error: {err}"),
+            None,
+        )?;
+        stream.play()?;
+        Ok(Self {
+            stream,
+            sampler,
+            input_buffer,
+            output_buffer,
+            sample_sink,
+        })
+    }
+
+    pub fn update(&mut self, samples: &[f32]) {
+        for sample in samples.chunks_exact(2) {
+            for (channel, value) in self.input_buffer.iter_mut().zip(sample) {
+                channel.push(*value);
+            }
+            if self.input_buffer[0].len() >= self.sampler.input_frames_next() {
+                let (_, output_samples) = self
+                    .sampler
+                    .process_into_buffer(&self.input_buffer, &mut self.output_buffer, None)
+                    .unwrap();
+
+                let chunk = match self.sample_sink.write_chunk_uninit(output_samples * 2) {
+                    Ok(c) => c,
+                    Err(rtrb::chunks::ChunkError::TooFewSlots(n)) => {
+                        self.sample_sink.write_chunk_uninit(n).unwrap()
+                    }
+                };
+                let interleaved = self.output_buffer[0]
+                    .iter()
+                    .interleave(self.output_buffer[1].iter())
+                    .cloned();
+                chunk.fill_from_iter(interleaved);
+
+                for channel in &mut self.input_buffer {
+                    channel.clear();
+                }
+            }
+        }
+
+        while self.sample_sink.slots() < self.sampler.output_frames_max() * 2 {
+            std::hint::spin_loop();
+        }
+    }
+}

src/emulator.rs

@@ -1,29 +1,60 @@
 use std::{
     fs,
-    path::Path,
+    path::{Path, PathBuf},
     sync::mpsc::{self, TryRecvError},
 };
 
 use anyhow::Result;
 
-use crate::{renderer::GameRenderer, shrooms_vb_core::CoreVB};
+use crate::{audio::Audio, renderer::GameRenderer, shrooms_vb_core::CoreVB};
+
+pub struct EmulatorBuilder {
+    rom: Option<PathBuf>,
+    commands: mpsc::Receiver<EmulatorCommand>,
+}
+
+impl EmulatorBuilder {
+    pub fn new() -> (Self, EmulatorClient) {
+        let (queue, commands) = mpsc::channel();
+        let builder = Self {
+            rom: None,
+            commands,
+        };
+        let client = EmulatorClient { queue };
+        (builder, client)
+    }
+
+    pub fn with_rom(self, path: &Path) -> Self {
+        Self {
+            rom: Some(path.into()),
+            ..self
+        }
+    }
+
+    pub fn build(self) -> Result<Emulator> {
+        let mut emulator = Emulator::new(self.commands)?;
+        if let Some(path) = self.rom {
+            emulator.load_rom(&path)?;
+        }
+        Ok(emulator)
+    }
+}
 
 pub struct Emulator {
     sim: CoreVB,
+    audio: Audio,
     commands: mpsc::Receiver<EmulatorCommand>,
     renderer: Option<GameRenderer>,
 }
 
 impl Emulator {
-    pub fn new() -> (Self, EmulatorClient) {
+    fn new(commands: mpsc::Receiver<EmulatorCommand>) -> Result<Self> {
-        let (sink, source) = mpsc::channel();
+        Ok(Self {
-        let emu = Emulator {
             sim: CoreVB::new(),
-            commands: source,
+            audio: Audio::init()?,
+            commands,
             renderer: None,
-        };
+        })
-        let queue = EmulatorClient { queue: sink };
-        (emu, queue)
     }
 
     pub fn load_rom(&mut self, path: &Path) -> Result<()> {
@@ -34,6 +65,7 @@ impl Emulator {
 
     pub fn run(&mut self) {
         let mut eye_contents = vec![0u8; 384 * 224 * 2];
+        let mut audio_samples = vec![];
         loop {
             self.sim.emulate_frame();
             if let Some(renderer) = &mut self.renderer {
@@ -41,6 +73,11 @@ impl Emulator {
                     renderer.render(&eye_contents);
                 }
             }
+            self.sim.read_samples(&mut audio_samples);
+            if !audio_samples.is_empty() {
+                self.audio.update(&audio_samples);
+                audio_samples.clear();
+            }
             loop {
                 match self.commands.try_recv() {
                     Ok(command) => self.handle_command(command),

src/main.rs

@@ -3,10 +3,11 @@ use std::{path::PathBuf, thread};
 use anyhow::Result;
 use app::App;
 use clap::Parser;
-use emulator::Emulator;
+use emulator::EmulatorBuilder;
 use winit::event_loop::{ControlFlow, EventLoop};
 
 mod app;
+mod audio;
 mod emulator;
 mod renderer;
 mod shrooms_vb_core;
@@ -19,9 +20,10 @@ struct Args {
 fn main() -> Result<()> {
     let args = Args::parse();
 
-    let (mut emulator, client) = Emulator::new();
+    let (builder, client) = EmulatorBuilder::new();
-    emulator.load_rom(&args.rom)?;
+    let builder = builder.with_rom(&args.rom);
     thread::spawn(move || {
+        let mut emulator = builder.build().unwrap();
         emulator.run();
     });
 

src/shrooms_vb_core.rs

@@ -1,6 +1,7 @@
-use std::{ffi::c_void, ptr};
+use std::{ffi::c_void, ptr, slice};
 
 use anyhow::{anyhow, Result};
+use num_derive::{FromPrimitive, ToPrimitive};
 
 #[repr(C)]
 struct VB {
@@ -9,6 +10,20 @@ struct VB {
 
 #[allow(non_camel_case_types)]
 type c_int = i32;
+#[allow(non_camel_case_types)]
+type c_uint = u32;
+
+#[repr(u32)]
+#[derive(FromPrimitive, ToPrimitive)]
+enum VBDataType {
+    S8 = 0,
+    U8 = 1,
+    S16 = 2,
+    U16 = 3,
+    S32 = 4,
+    F32 = 5,
+}
+
 type OnFrame = extern "C" fn(sim: *mut VB) -> c_int;
 
 #[link(name = "vb")]
@@ -27,6 +42,13 @@ extern "C" {
         right_stride_x: c_int,
         right_stride_y: c_int,
     );
+    #[link_name = "vbGetSamples"]
+    fn vb_get_samples(
+        sim: *mut VB,
+        typ_: *mut VBDataType,
+        capacity: *mut c_uint,
+        position: *mut c_uint,
+    ) -> *mut c_void;
     #[link_name = "vbGetUserData"]
     fn vb_get_user_data(sim: *mut VB) -> *mut c_void;
     #[link_name = "vbInit"]
@@ -39,6 +61,13 @@ extern "C" {
     fn vb_set_keys(sim: *mut VB, keys: u16) -> u16;
     #[link_name = "vbSetFrameCallback"]
     fn vb_set_frame_callback(sim: *mut VB, on_frame: OnFrame);
+    #[link_name = "vbSetSamples"]
+    fn vb_set_samples(
+        sim: *mut VB,
+        samples: *mut c_void,
+        typ_: VBDataType,
+        capacity: c_uint,
+    ) -> c_int;
     #[link_name = "vbSetUserData"]
     fn vb_set_user_data(sim: *mut VB, tag: *mut c_void);
     #[link_name = "vbSizeOf"]
@@ -53,6 +82,9 @@ extern "C" fn on_frame(sim: *mut VB) -> i32 {
     1
 }
 
+const AUDIO_CAPACITY_SAMPLES: usize = 834 * 4;
+const AUDIO_CAPACITY_FLOATS: usize = AUDIO_CAPACITY_SAMPLES * 2;
+
 struct VBState {
     frame_seen: bool,
 }
@@ -79,6 +111,11 @@ impl CoreVB {
         unsafe { vb_set_user_data(sim, Box::into_raw(Box::new(state)).cast()) };
         unsafe { vb_set_frame_callback(sim, on_frame) };
 
+        // set up audio buffer
+        let audio_buffer = vec![0.0f32; AUDIO_CAPACITY_FLOATS];
+        let samples: *mut c_void = Box::into_raw(audio_buffer.into_boxed_slice()).cast();
+        unsafe { vb_set_samples(sim, samples, VBDataType::F32, AUDIO_CAPACITY_SAMPLES as u32) };
+
         CoreVB { sim }
     }
 
@@ -138,6 +175,25 @@ impl CoreVB {
         true
     }
 
+    pub fn read_samples(&mut self, samples: &mut Vec<f32>) {
+        let mut position = 0;
+        let ptr =
+            unsafe { vb_get_samples(self.sim, ptr::null_mut(), ptr::null_mut(), &mut position) };
+        // SAFETY: position is an offset in a buffer of (f32, f32). so, position * 2 is an offset in a buffer of f32.
+        let read_samples: &mut [f32] =
+            unsafe { slice::from_raw_parts_mut(ptr.cast(), position as usize * 2) };
+        samples.extend_from_slice(read_samples);
+
+        unsafe {
+            vb_set_samples(
+                self.sim,
+                ptr,
+                VBDataType::F32,
+                AUDIO_CAPACITY_SAMPLES as u32,
+            )
+        };
+    }
+
     pub fn set_keys(&mut self, keys: u16) {
         unsafe { vb_set_keys(self.sim, keys) };
     }
@@ -145,6 +201,14 @@ impl CoreVB {
 
 impl Drop for CoreVB {
     fn drop(&mut self) {
+        let ptr =
+            unsafe { vb_get_samples(self.sim, ptr::null_mut(), ptr::null_mut(), ptr::null_mut()) };
+        // SAFETY: the audio buffer originally came from a Vec<u32>
+        let floats: Vec<f32> = unsafe {
+            Vec::from_raw_parts(ptr.cast(), AUDIO_CAPACITY_FLOATS, AUDIO_CAPACITY_FLOATS)
+        };
+        drop(floats);
+
         // SAFETY: the *mut VB owns its userdata.
         // There is no way for the userdata to be null or otherwise invalid.
         let ptr: *mut VBState = unsafe { vb_get_user_data(self.sim).cast() };