improve frame timings some more in both runtimes

.github/workflows/ci.yml

@@ -27,7 +27,7 @@ jobs:
 
     steps:
     - name: Install dependencies
-      run: sudo apt-get install -y libxkbcommon-dev
+      run: sudo apt-get install -y libxkbcommon-dev libasound2-dev
       if: matrix.os == 'ubuntu-latest'
     - name: Checkout
       uses: actions/checkout@v2

Cargo.toml

@@ -1,19 +1,19 @@
 [package]
 name = "uw8"
-version = "0.1.2"
+version = "0.2.0-rc2"
 edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [features]
 default = ["native", "browser"]
-native = ["wasmtime"]
+native = ["wasmtime", "minifb", "cpal", "rubato"]
 browser = ["warp", "tokio", "tokio-stream", "webbrowser"]
 
 [dependencies]
 wasmtime = { version = "0.35.3", optional = true }
 anyhow = "1"
-minifb = { version = "0.22", default-features = false, features = ["x11"] }
+minifb = { version = "0.22", default-features = false, features = ["x11"], optional = true }
 notify = "4"
 pico-args = "0.4"
 curlywas = { git = "https://github.com/exoticorn/curlywas.git", rev = "aac7bbd" }
@@ -25,4 +25,5 @@ tokio = { version = "1.17.0", features = ["sync", "rt"], optional = true }
 tokio-stream = { version = "0.1.8", features = ["sync"], optional = true }
 webbrowser = { version = "0.6.0", optional = true }
 ansi_term = "0.12.1"
-cpal = "0.13.5"
+cpal = { version = "0.13.5", optional = true }
+rubato = { version = "0.11.0", optional = true }

examples/curlywas/cracklebass.cwa

@@ -0,0 +1,55 @@
+// port of cracklebass by pestis (originally on TIC-80)
+
+include "../include/microw8-api.cwa"
+
+const MUSIC_DATA = 0x20000;
+
+export fn upd() {
+    let inline t = 32!32 * 6 / 100;
+    let inline p = t / 1024;
+
+    let channel:i32;
+
+    loop channels {
+        let inline e = t * channel?MUSIC_DATA / 8;
+        let lazy pattern = (8 * channel + p)?(MUSIC_DATA + 56);
+        let lazy n = !!pattern * (8 * pattern + e / 16 % 8)?MUSIC_DATA;
+        let inline prev_ctrl = (channel * 6)?80;
+        (channel * 6)?80 = if n {
+            let inline base_note = 12 + 12 * channel?(MUSIC_DATA + 4) + n;
+            let inline pitch_drop = e % 16 * channel?(MUSIC_DATA + 94);
+            let inline key_pattern = p?(MUSIC_DATA + 8*4 + 56);
+            let inline key = select(key_pattern, (8 * key_pattern + t / 128 % 8)?MUSIC_DATA, 1);
+            (channel * 6)?83 = base_note - pitch_drop / 4 + key;
+            prev_ctrl & 0xfc | (e / 8 & 2) | 1
+        } else {
+            prev_ctrl & 0xfe
+        };
+
+        branch_if (channel := channel + 1) < 4: channels;
+    }
+}
+
+data 80 {
+    i8(
+        0x44, 0, 0, 0, 0x50, 0x40,
+        0x4, 0x50, 0, 0, 0x80, 0x80,
+        0x40, 0x80, 0, 0, 0x40, 0x40,
+        0, 0, 0, 0, 0x50, 0x50
+    )
+}
+
+data MUSIC_DATA {
+    i8(
+ 16, 2, 8, 8, 1, 2, 2, 3, 1, 0,
+  1,13,16, 0, 1, 8, 1, 0, 1,13,
+ 16, 1, 1, 8, 1, 0, 8,13,13, 0,
+ 16,13, 1, 0, 1, 0, 1, 0, 1, 1,
+  1, 0, 0, 0, 1, 0,13, 1, 1, 1,
+  6, 8, 1, 1, 6, 8, 1, 1, 2, 1,
+  2, 1, 2, 0, 0, 0, 0, 3, 3, 3,
+  5, 0, 0, 2, 1, 2, 1, 2, 1, 2,
+  0, 4, 4, 0, 4, 4, 4, 4, 0, 0,
+  0, 0, 6, 6, 0, 0, 0, 8
+    )
+}

site/content/_index.md

@@ -29,6 +29,33 @@ Examplers for older versions:
 
 ## Versions
 
+### v0.2.0-rc2
+
+* [Web runtime](v0.2.0-rc2)
+* [Linux](https://github.com/exoticorn/microw8/releases/download/v0.2.0-rc2/microw8-0.2.0-rc2-linux.tgz)
+* [MacOS](https://github.com/exoticorn/microw8/releases/download/v0.2.0-rc2/microw8-0.2.0-rc2-macos.tgz)
+* [Windows](https://github.com/exoticorn/microw8/releases/download/v0.2.0-rc2/microw8-0.2.0-rc2-windows.zip)
+
+Changes:
+
+* fix timing issues of sound playback, especially on systems with large sound buffers
+
+### v0.2.0-rc1
+
+* [Web runtime](v0.2.0-rc1)
+* [Linux](https://github.com/exoticorn/microw8/releases/download/v0.2.0-rc1/microw8-0.2.0-rc1-linux.tgz)
+* [MacOS](https://github.com/exoticorn/microw8/releases/download/v0.2.0-rc1/microw8-0.2.0-rc1-macos.tgz)
+* [Windows](https://github.com/exoticorn/microw8/releases/download/v0.2.0-rc1/microw8-0.2.0-rc1-windows.zip)
+
+Changes:
+
+* [add sound support](docs#sound)
+* "integer constant cast to float" literal syntax in CurlyWas (ex. `1_f` is equivalent to `1 as f32`)
+
+Known issues:
+
+* timing accuracy/update frequency of sound support currently depends on sound buffer size
+
 ### v0.1.2
 
 * [Web runtime](v0.1.2)

site/content/docs.md

@@ -286,6 +286,12 @@ As the only means of communication, 32 bytes starting at address 0x00050 are cop
 By default, the `sndGes` function generates sound based on the 32 bytes at 0x00050. This means that in the default configuration those 32 bytes act
 as sound registers. See the `sndGes` function for the meaning of those registers.
 
+### export fn snd(sampleIndex: i32) -> f32
+
+If the module exports a `snd` function, it is called 88200 times per second to provide PCM sample data for playback (44.1kHz stereo).
+The `sampleIndex` will start at 0 and increments by 1 for each call. On even indices the function is expected to return a sample value for
+the left channel, on odd indices for the right channel.
+
 ### fn playNote(channel: i32, note: i32)
 
 Triggers a note (1-127) on the given channel (0-3). Notes are semitones with 69 being A4 (same as MIDI). A note value of 0 stops the

src/main.rs

@@ -16,7 +16,7 @@ fn main() -> Result<()> {
     let mut args = Arguments::from_env();
 
     // try to enable ansi support in win10 cmd shell
-    #[cfg(target_os="windows")]
+    #[cfg(target_os = "windows")]
     let _ = ansi_term::enable_ansi_support();
 
     match args.subcommand()?.as_deref() {
@@ -79,6 +79,8 @@ fn run(mut args: Arguments) -> Result<()> {
     #[cfg(not(feature = "native"))]
     let run_browser = args.contains(["-b", "--browser"]) || true;
 
+    let disable_audio = args.contains(["-m", "--disable-audio"]);
+
     let filename = args.free_from_os_str::<PathBuf, bool>(|s| Ok(s.into()))?;
 
     let mut watcher = uw8::FileWatcher::new()?;
@@ -89,7 +91,13 @@ fn run(mut args: Arguments) -> Result<()> {
         #[cfg(not(feature = "native"))]
         unimplemented!();
         #[cfg(feature = "native")]
-        Box::new(MicroW8::new()?)
+        {
+            let mut microw8 = MicroW8::new()?;
+            if disable_audio {
+                microw8.disable_audio();
+            }
+            Box::new(microw8)
+        }
     } else {
         #[cfg(not(feature = "browser"))]
         unimplemented!();

src/run_native.rs

@@ -5,6 +5,7 @@ use std::{thread, time::Instant};
 use anyhow::{anyhow, Result};
 use cpal::traits::*;
 use minifb::{Key, Window, WindowOptions};
+use rubato::Resampler;
 use wasmtime::{
     Engine, GlobalType, Memory, MemoryType, Module, Mutability, Store, TypedFunc, ValType,
 };
@@ -27,6 +28,7 @@ pub struct MicroW8 {
     window_buffer: Vec<u32>,
     instance: Option<UW8Instance>,
     timeout: u32,
+    disable_audio: bool,
 }
 
 struct UW8Instance {
@@ -35,9 +37,10 @@ struct UW8Instance {
     end_frame: TypedFunc<(), ()>,
     update: Option<TypedFunc<(), ()>>,
     start_time: Instant,
+    next_frame: Instant,
     module: Vec<u8>,
     watchdog: Arc<Mutex<UW8WatchDog>>,
-    sound: Uw8Sound,
+    sound: Option<Uw8Sound>,
 }
 
 impl Drop for UW8Instance {
@@ -67,8 +70,7 @@ impl MicroW8 {
             resize: true,
             ..Default::default()
         };
-        let mut window = Window::new("MicroW8", 320, 240, options)?;
-        window.limit_update_rate(Some(std::time::Duration::from_micros(16666)));
+        let window = Window::new("MicroW8", 320, 240, options)?;
 
         Ok(MicroW8 {
             engine,
@@ -77,6 +79,7 @@ impl MicroW8 {
             window_buffer: vec![0u32; 320 * 240],
             instance: None,
             timeout: 30,
+            disable_audio: false,
         })
     }
 
@@ -86,11 +89,10 @@ impl MicroW8 {
             *v = 0;
         }
     }
-}
 
-struct Uw8Sound {
-    stream: cpal::Stream,
-    tx: mpsc::SyncSender<[u8; 32]>,
+    pub fn disable_audio(&mut self) {
+        self.disable_audio = true;
+    }
 }
 
 impl super::Runtime for MicroW8 {
@@ -126,60 +128,8 @@ impl super::Runtime for MicroW8 {
         let module_length = load_uw8.call(&mut store, module_data.len() as i32)? as u32 as usize;
         let module = wasmtime::Module::new(&self.engine, &memory.data(&store)[..module_length])?;
 
-        fn add_native_functions(
-            linker: &mut wasmtime::Linker<()>,
-            store: &mut wasmtime::Store<()>,
-        ) -> Result<()> {
-            linker.func_wrap("env", "acos", |v: f32| v.acos())?;
-            linker.func_wrap("env", "asin", |v: f32| v.asin())?;
-            linker.func_wrap("env", "atan", |v: f32| v.atan())?;
-            linker.func_wrap("env", "atan2", |x: f32, y: f32| x.atan2(y))?;
-            linker.func_wrap("env", "cos", |v: f32| v.cos())?;
-            linker.func_wrap("env", "exp", |v: f32| v.exp())?;
-            linker.func_wrap("env", "log", |v: f32| v.ln())?;
-            linker.func_wrap("env", "sin", |v: f32| v.sin())?;
-            linker.func_wrap("env", "tan", |v: f32| v.tan())?;
-            linker.func_wrap("env", "pow", |a: f32, b: f32| a.powf(b))?;
-            for i in 10..64 {
-                linker.func_wrap("env", &format!("reserved{}", i), || {})?;
-            }
-            for i in 0..16 {
-                linker.define(
-                    "env",
-                    &format!("g_reserved{}", i),
-                    wasmtime::Global::new(
-                        &mut *store,
-                        GlobalType::new(ValType::I32, Mutability::Const),
-                        0.into(),
-                    )?,
-                )?;
-            }
-
-            Ok(())
-        }
-
         add_native_functions(&mut linker, &mut store)?;
 
-        fn instantiate_platform(
-            linker: &mut wasmtime::Linker<()>,
-            store: &mut wasmtime::Store<()>,
-            platform_module: &wasmtime::Module,
-        ) -> Result<wasmtime::Instance> {
-            let platform_instance = linker.instantiate(&mut *store, &platform_module)?;
-
-            for export in platform_instance.exports(&mut *store) {
-                linker.define(
-                    "env",
-                    export.name(),
-                    export
-                        .into_func()
-                        .expect("platform surely only exports functions"),
-                )?;
-            }
-
-            Ok(platform_instance)
-        }
-
         let platform_instance = instantiate_platform(&mut linker, &mut store, &platform_module)?;
 
         let watchdog = Arc::new(Mutex::new(UW8WatchDog {
@@ -215,91 +165,28 @@ impl super::Runtime for MicroW8 {
         let end_frame = platform_instance.get_typed_func::<(), (), _>(&mut store, "endFrame")?;
         let update = instance.get_typed_func::<(), (), _>(&mut store, "upd").ok();
 
-        let sound = {
-            let mut store = wasmtime::Store::new(&self.engine, ());
-
-            let memory = wasmtime::Memory::new(&mut store, MemoryType::new(4, Some(4)))?;
-
-            let mut linker = wasmtime::Linker::new(&self.engine);
-            linker.define("env", "memory", memory)?;
-            add_native_functions(&mut linker, &mut store)?;
-
-            let platform_instance =
-                instantiate_platform(&mut linker, &mut store, &platform_module)?;
-            let instance = linker.instantiate(&mut store, &module)?;
-
-            let snd = instance
-                .get_typed_func::<(i32,), f32, _>(&mut store, "snd")
-                .or_else(|_| {
-                    platform_instance.get_typed_func::<(i32,), f32, _>(&mut store, "gesSnd")
-                })?;
-
-            let host = cpal::default_host();
-            let device = host
-                .default_output_device()
-                .ok_or_else(|| anyhow!("No audio output device available"))?;
-            let config = device
-                .supported_output_configs()?
-                .find(|config| {
-                    config.min_sample_rate().0 <= 44100
-                        && config.max_sample_rate().0 >= 44100
-                        && config.channels() == 2
-                        && config.sample_format() == cpal::SampleFormat::F32
-                })
-                .ok_or_else(|| anyhow!("Could not find 44.1kHz float config"))?;
-            let config = config.with_sample_rate(cpal::SampleRate(44100));
-            let buffer_size = match *config.buffer_size() {
-                cpal::SupportedBufferSize::Unknown => cpal::BufferSize::Default,
-                cpal::SupportedBufferSize::Range { min, max } => {
-                    cpal::BufferSize::Fixed(256.max(min).min(max))
+        let sound = if self.disable_audio {
+            None
+        } else {
+            match init_sound(&self.engine, &platform_module, &module) {
+                Ok(sound) => {
+                    sound.stream.play()?;
+                    Some(sound)
                 }
-            };
-            let config = cpal::StreamConfig {
-                buffer_size,
-                ..config.config()
-            };
-
-            let (tx, rx) = mpsc::sync_channel::<[u8; 32]>(1);
-
-            let start_time = Instant::now();
-
-            let mut sample_index = 0;
-            let stream = {
-                device.build_output_stream(
-                    &config,
-                    move |buffer: &mut [f32], _| {
-                        if let Ok(regs) = rx.try_recv() {
-                            memory.write(&mut store, 80, &regs).unwrap();
-                        }
-
-                        {
-                            let time = start_time.elapsed().as_millis() as i32;
-                            let mem = memory.data_mut(&mut store);
-                            mem[64..68].copy_from_slice(&time.to_le_bytes());
-                        }
-
-                        for v in buffer {
-                            *v = snd.call(&mut store, (sample_index,)).unwrap_or(0.0);
-                            sample_index = sample_index.wrapping_add(1);
-                        }
-                    },
-                    move |err| {
-                        dbg!(err);
-                    },
-                )?
-            };
-
-            Uw8Sound { stream, tx }
+                Err(err) => {
+                    eprintln!("Failed to init sound: {}", err);
+                    None
+                }
+            }
         };
 
-        sound.stream.play()?;
-
         self.instance = Some(UW8Instance {
             store,
             memory,
             end_frame,
             update,
             start_time: Instant::now(),
+            next_frame: Instant::now(),
             module: module_data.into(),
             watchdog,
             sound,
@@ -312,7 +199,19 @@ impl super::Runtime for MicroW8 {
         let mut result = Ok(());
         if let Some(mut instance) = self.instance.take() {
             {
-                let time = instance.start_time.elapsed().as_millis() as i32;
+                if let Some(sleep) = instance.next_frame.checked_duration_since(Instant::now()) {
+                    std::thread::sleep(sleep);
+                }
+            }
+
+            let now = Instant::now();
+            let time = (now - instance.start_time).as_millis() as i32;
+            {
+                let offset = ((time as u32 as i64 * 6) % 100 - 50) / 6;
+                instance.next_frame = now + Duration::from_millis((16 - offset) as u64);
+            }
+
+            {
                 let mut gamepad: u32 = 0;
                 for key in self.window.get_keys() {
                     if let Some(index) = GAMEPAD_KEYS
@@ -345,7 +244,12 @@ impl super::Runtime for MicroW8 {
 
             let mut sound_regs = [0u8; 32];
             sound_regs.copy_from_slice(&memory[80..112]);
-            instance.sound.tx.send(sound_regs)?;
+            if let Some(ref sound) = instance.sound {
+                sound.tx.send(RegisterUpdate {
+                    time,
+                    data: sound_regs,
+                })?;
+            }
 
             let framebuffer = &memory[120..(120 + 320 * 240)];
             let palette = &memory[0x13000..];
@@ -371,3 +275,244 @@ impl super::Runtime for MicroW8 {
         Ok(())
     }
 }
+
+fn add_native_functions(
+    linker: &mut wasmtime::Linker<()>,
+    store: &mut wasmtime::Store<()>,
+) -> Result<()> {
+    linker.func_wrap("env", "acos", |v: f32| v.acos())?;
+    linker.func_wrap("env", "asin", |v: f32| v.asin())?;
+    linker.func_wrap("env", "atan", |v: f32| v.atan())?;
+    linker.func_wrap("env", "atan2", |x: f32, y: f32| x.atan2(y))?;
+    linker.func_wrap("env", "cos", |v: f32| v.cos())?;
+    linker.func_wrap("env", "exp", |v: f32| v.exp())?;
+    linker.func_wrap("env", "log", |v: f32| v.ln())?;
+    linker.func_wrap("env", "sin", |v: f32| v.sin())?;
+    linker.func_wrap("env", "tan", |v: f32| v.tan())?;
+    linker.func_wrap("env", "pow", |a: f32, b: f32| a.powf(b))?;
+    for i in 10..64 {
+        linker.func_wrap("env", &format!("reserved{}", i), || {})?;
+    }
+    for i in 0..16 {
+        linker.define(
+            "env",
+            &format!("g_reserved{}", i),
+            wasmtime::Global::new(
+                &mut *store,
+                GlobalType::new(ValType::I32, Mutability::Const),
+                0.into(),
+            )?,
+        )?;
+    }
+
+    Ok(())
+}
+
+fn instantiate_platform(
+    linker: &mut wasmtime::Linker<()>,
+    store: &mut wasmtime::Store<()>,
+    platform_module: &wasmtime::Module,
+) -> Result<wasmtime::Instance> {
+    let platform_instance = linker.instantiate(&mut *store, &platform_module)?;
+
+    for export in platform_instance.exports(&mut *store) {
+        linker.define(
+            "env",
+            export.name(),
+            export
+                .into_func()
+                .expect("platform surely only exports functions"),
+        )?;
+    }
+
+    Ok(platform_instance)
+}
+
+struct RegisterUpdate {
+    time: i32,
+    data: [u8; 32],
+}
+
+struct Uw8Sound {
+    stream: cpal::Stream,
+    tx: mpsc::SyncSender<RegisterUpdate>,
+}
+
+fn init_sound(
+    engine: &wasmtime::Engine,
+    platform_module: &wasmtime::Module,
+    module: &wasmtime::Module,
+) -> Result<Uw8Sound> {
+    let mut store = wasmtime::Store::new(engine, ());
+
+    let memory = wasmtime::Memory::new(&mut store, MemoryType::new(4, Some(4)))?;
+
+    let mut linker = wasmtime::Linker::new(engine);
+    linker.define("env", "memory", memory)?;
+    add_native_functions(&mut linker, &mut store)?;
+
+    let platform_instance = instantiate_platform(&mut linker, &mut store, platform_module)?;
+    let instance = linker.instantiate(&mut store, module)?;
+
+    let snd = instance
+        .get_typed_func::<(i32,), f32, _>(&mut store, "snd")
+        .or_else(|_| platform_instance.get_typed_func::<(i32,), f32, _>(&mut store, "gesSnd"))?;
+
+    let host = cpal::default_host();
+    let device = host
+        .default_output_device()
+        .ok_or_else(|| anyhow!("No audio output device available"))?;
+    let mut configs: Vec<_> = device
+        .supported_output_configs()?
+        .filter(|config| {
+            config.channels() == 2 && config.sample_format() == cpal::SampleFormat::F32
+        })
+        .collect();
+    configs.sort_by_key(|config| {
+        let rate = 44100
+            .max(config.min_sample_rate().0)
+            .min(config.max_sample_rate().0);
+        if rate >= 44100 {
+            rate - 44100
+        } else {
+            (44100 - rate) * 1000
+        }
+    });
+    let config = configs
+        .into_iter()
+        .next()
+        .ok_or_else(|| anyhow!("Could not find float output config"))?;
+    let sample_rate = cpal::SampleRate(44100)
+        .max(config.min_sample_rate())
+        .max(config.max_sample_rate());
+    let config = config.with_sample_rate(sample_rate);
+    let buffer_size = match *config.buffer_size() {
+        cpal::SupportedBufferSize::Unknown => cpal::BufferSize::Default,
+        cpal::SupportedBufferSize::Range { min, max } => {
+            cpal::BufferSize::Fixed(65536.max(min).min(max))
+        }
+    };
+    let config = cpal::StreamConfig {
+        buffer_size,
+        ..config.config()
+    };
+
+    let sample_rate = config.sample_rate.0 as usize;
+
+    let (tx, rx) = mpsc::sync_channel::<RegisterUpdate>(30);
+
+    struct Resampler {
+        resampler: rubato::FftFixedIn<f32>,
+        input_buffers: Vec<Vec<f32>>,
+        output_buffers: Vec<Vec<f32>>,
+        output_index: usize,
+    }
+    let mut resampler: Option<Resampler> = if sample_rate == 44100 {
+        None
+    } else {
+        let rs = rubato::FftFixedIn::new(44100, sample_rate, 128, 1, 2)?;
+        let input_buffers = rs.input_buffer_allocate();
+        let output_buffers = rs.output_buffer_allocate();
+        Some(Resampler {
+            resampler: rs,
+            input_buffers,
+            output_buffers,
+            output_index: usize::MAX,
+        })
+    };
+
+    let mut sample_index = 0;
+    let mut pending_updates: Vec<RegisterUpdate> = Vec::with_capacity(30);
+    let mut current_time = 0;
+    let stream = device.build_output_stream(
+        &config,
+        move |mut outer_buffer: &mut [f32], _| {
+            let mut first_update = true;
+            while let Ok(update) = rx.try_recv() {
+                if first_update {
+                    current_time += update.time.wrapping_sub(current_time) / 8;
+                    first_update = false;
+                }
+                pending_updates.push(update);
+            }
+
+            while !outer_buffer.is_empty() {
+                while pending_updates
+                    .first()
+                    .into_iter()
+                    .any(|u| u.time.wrapping_sub(current_time) <= 0)
+                {
+                    let update = pending_updates.remove(0);
+                    memory.write(&mut store, 80, &update.data).unwrap();
+                }
+
+                let duration = if let Some(update) = pending_updates.first() {
+                    ((update.time.wrapping_sub(current_time) as usize) * sample_rate + 999) / 1000
+                } else {
+                    outer_buffer.len()
+                };
+                let step_size = (duration.max(64) * 2).min(outer_buffer.len());
+
+                let mut buffer = &mut outer_buffer[..step_size];
+
+                {
+                    let mem = memory.data_mut(&mut store);
+                    mem[64..68].copy_from_slice(&current_time.to_le_bytes());
+                }
+
+                if let Some(ref mut resampler) = resampler {
+                    while !buffer.is_empty() {
+                        let copy_size = resampler.output_buffers[0]
+                            .len()
+                            .saturating_sub(resampler.output_index)
+                            .min(buffer.len() / 2);
+                        if copy_size == 0 {
+                            resampler.input_buffers[0].clear();
+                            resampler.input_buffers[1].clear();
+                            for _ in 0..resampler.resampler.input_frames_next() {
+                                resampler.input_buffers[0]
+                                    .push(snd.call(&mut store, (sample_index,)).unwrap_or(0.0));
+                                resampler.input_buffers[1]
+                                    .push(snd.call(&mut store, (sample_index + 1,)).unwrap_or(0.0));
+                                sample_index = sample_index.wrapping_add(2);
+                            }
+
+                            resampler
+                                .resampler
+                                .process_into_buffer(
+                                    &resampler.input_buffers,
+                                    &mut resampler.output_buffers,
+                                    None,
+                                )
+                                .unwrap();
+                            resampler.output_index = 0;
+                        } else {
+                            for i in 0..copy_size {
+                                buffer[i * 2] =
+                                    resampler.output_buffers[0][resampler.output_index + i];
+                                buffer[i * 2 + 1] =
+                                    resampler.output_buffers[1][resampler.output_index + i];
+                            }
+                            resampler.output_index += copy_size;
+                            buffer = &mut buffer[copy_size * 2..];
+                        }
+                    }
+                } else {
+                    for v in buffer {
+                        *v = snd.call(&mut store, (sample_index,)).unwrap_or(0.0);
+                        sample_index = sample_index.wrapping_add(1);
+                    }
+                }
+
+                outer_buffer = &mut outer_buffer[step_size..];
+                current_time =
+                    current_time.wrapping_add((step_size * 500 / sample_rate).max(1) as i32);
+            }
+        },
+        move |err| {
+            dbg!(err);
+        },
+    )?;
+
+    Ok(Uw8Sound { stream, tx })
+}

test/frame_time.cwa

@@ -0,0 +1,20 @@
+include "../examples/include/microw8-api.cwa"
+
+global mut pos = 0;
+global mut next = 0;
+
+export fn upd() {
+    let lazy t = 32!32;
+    let lazy tick = t * 6 / 100;
+    let lazy rel = t - tick * 100 / 6;
+
+    setBackgroundColor(select(tick == next, 0, select(tick < next, 0x35, 0x55)));
+    setCursorPosition(pos % 13 * 3, pos / 13 % 30);
+    if rel < 10 {
+        printChar(32);
+    }
+    printInt(rel);
+
+    pos = pos + 1;
+    next = tick + 1;
+}

web/src/audiolet.js

@@ -3,13 +3,17 @@ class APU extends AudioWorkletProcessor {
     constructor() {
         super();
         this.sampleIndex = 0;
+        this.currentTime = 0;
+        this.isFirstMessage = true;
+        this.pendingUpdates = [];
         this.port.onmessage = (ev) => {
             if(this.memory) {
-                if(isNaN(ev.data)) {
-                    U8(this.memory.buffer, 80, 32).set(U8(ev.data));
-                } else {
-                    this.startTime = ev.data;
+                if(this.isFirstMessage)
+                {
+                    this.currentTime += (ev.data.t - this.currentTime) / 8;
+                    this.isFirstMessage = false;
                 }
+                this.pendingUpdates.push(ev.data);
             } else {
                 this.load(ev.data[0], ev.data[1]);
             }
@@ -55,9 +59,13 @@ class APU extends AudioWorkletProcessor {
     }
 
     process(inputs, outputs, parameters) {
-        if(this.snd && this.startTime) {
+        this.isFirstMessage = true;
+        if(this.snd) {
+            while(this.pendingUpdates.length > 0 && this.pendingUpdates[0].t <= this.currentTime) {
+                U8(this.memory.buffer, 80, 32).set(U8(this.pendingUpdates.shift().r));
+            }
             let u32Mem = new Uint32Array(this.memory.buffer);
-            u32Mem[16] = Date.now() - this.startTime;
+            u32Mem[16] = this.currentTime;
             let channels = outputs[0];
             let index = this.sampleIndex;
             let numSamples = channels[0].length;
@@ -66,6 +74,7 @@ class APU extends AudioWorkletProcessor {
                 channels[1][i] = this.snd(index++);
             }
             this.sampleIndex = index & 0xffffffff;
+            this.currentTime += numSamples / 44.1;
         }
 
         return true;

web/src/index.html

@@ -10,7 +10,7 @@
     </head>
     <body>
         <div id="uw8">
-            <a href="https://exoticorn.github.io/microw8">MicroW8</a> 0.1.2
+            <a href="https://exoticorn.github.io/microw8">MicroW8</a> 0.2.0-rc2
         </div>
         <div id="centered">
             <canvas class="screen" id="screen" width="320" height="240">

web/src/microw8.js

@@ -107,7 +107,7 @@ export default function MicroW8(screen, config = {}) {
             audioContext.close();
             keepRunning = false;
             abortController.abort();
-        }
+        };
 
         let cartridgeSize = data.byteLength;
     
@@ -232,7 +232,6 @@ export default function MicroW8(screen, config = {}) {
             let startTime = Date.now();
     
             const timePerFrame = 1000 / 60;
-            let nextFrame = startTime;
 
             audioNode.connect(audioContext.destination);
 
@@ -244,18 +243,16 @@ export default function MicroW8(screen, config = {}) {
                     isPaused = false;
                     audioContext.resume();
                     startTime += now - pauseTime;
-                    audioNode.port.postMessage(startTime);
                 } else {
                     isPaused = true;
                     audioContext.suspend();
                     pauseTime = now;
-                    audioNode.port.postMessage(0);
                 }
             };
             window.addEventListener('focus', () => updateVisibility(true), { signal: abortController.signal });
             window.addEventListener('blur', () => updateVisibility(false), { signal: abortController.signal });
             updateVisibility(document.hasFocus());
-    
+
             function mainloop() {
                 if (!keepRunning) {
                     return;
@@ -263,6 +260,7 @@ export default function MicroW8(screen, config = {}) {
     
                 try {
                     let restart = false;
+                    let thisFrame;
                     if (!isPaused) {
                         let gamepads = navigator.getGamepads();
                         let gamepad = 0;
@@ -291,7 +289,8 @@ export default function MicroW8(screen, config = {}) {
                         }
     
                         let u32Mem = U32(memory.buffer);
-                        u32Mem[16] = Date.now() - startTime;
+                        let time = Date.now() - startTime;
+                        u32Mem[16] = time;
                         u32Mem[17] = pad | gamepad;
                         if(instance.exports.upd) {
                             instance.exports.upd();
@@ -300,21 +299,26 @@ export default function MicroW8(screen, config = {}) {
 
                         let soundRegisters = new ArrayBuffer(32);
                         U8(soundRegisters).set(U8(memory.buffer, 80, 32));
-                        audioNode.port.postMessage(soundRegisters, [soundRegisters]);
+                        audioNode.port.postMessage({t: time, r: soundRegisters}, [soundRegisters]);
     
                         let palette = U32(memory.buffer, 0x13000, 1024);
                         for (let i = 0; i < 320 * 240; ++i) {
                             buffer[i] = palette[memU8[i + 120]] | 0xff000000;
                         }
                         canvasCtx.putImageData(imageData, 0, 0);
+
+                        let timeOffset = ((time * 6) % 100 - 50) / 6;
+                        thisFrame = startTime + time - timeOffset / 8;
+                    } else {
+                        thisFrame = Date.now();
                     }
                     let now = Date.now();
-                    nextFrame = Math.max(nextFrame + timePerFrame, now);
+                    let nextFrame = Math.max(thisFrame + timePerFrame, now);
     
                     if (restart) {
                         runModule(currentData);
                     } else {
-                        window.setTimeout(mainloop, Math.round(nextFrame - now))
+                        window.setTimeout(mainloop, nextFrame - now)
                     }
                 } catch (err) {
                     config.setMessage(cartridgeSize, err.toString());