Asyncify, timing experiments

Cargo.lock

@@ -17,6 +17,12 @@ version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
+[[package]]
+name = "bumpalo"
+version = "3.16.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "79296716171880943b8470b5f8d03aa55eb2e645a4874bdbb28adb49162e012c"
+
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
@@ -29,6 +35,26 @@ version = "0.2.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9226dbc05df4fb986f48d730b001532580883c4c06c5d1c213f4b34c1c157178"
 
+[[package]]
+name = "getrandom"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94b22e06ecb0110981051723910cbf0b5f5e09a2062dd7663334ee79a9d1286c"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
+[[package]]
+name = "js-sys"
+version = "0.3.69"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "29c15563dc2726973df627357ce0c9ddddbea194836909d655df6a75d2cf296d"
+dependencies = [
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -37,9 +63,9 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.147"
+version = "0.2.153"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b4668fb0ea861c1df094127ac5f1da3409a82116a4ba74fca2e58ef927159bb3"
+checksum = "9c198f91728a82281a64e1f4f9eeb25d82cb32a5de251c6bd1b5154d63a8e7bd"
 
 [[package]]
 name = "log"
@@ -90,11 +116,13 @@ version = "0.1.0"
 dependencies = [
  "colors-transform",
  "lazy_static",
+ "rand",
  "sdl2",
  "spin_sleep",
  "tracing",
  "tracing-error",
  "tracing-subscriber",
+ "web-time",
 ]
 
 [[package]]
@@ -103,6 +131,12 @@ version = "0.2.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8afb450f006bf6385ca15ef45d71d2288452bc3683ce2e2cacc0d18e4be60b58"
 
+[[package]]
+name = "ppv-lite86"
+version = "0.2.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b40af805b3121feab8a3c29f04d8ad262fa8e0561883e7653e024ae4479e6de"
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.66"
@@ -121,6 +155,36 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "rand"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
+dependencies = [
+ "libc",
+ "rand_chacha",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
+dependencies = [
+ "getrandom",
+]
+
 [[package]]
 name = "regex"
 version = "1.9.1"
@@ -324,6 +388,76 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "579a42fc0b8e0c63b76519a339be31bed574929511fa53c1a3acae26eb258f29"
 
+[[package]]
+name = "wasi"
+version = "0.11.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
+
+[[package]]
+name = "wasm-bindgen"
+version = "0.2.92"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4be2531df63900aeb2bca0daaaddec08491ee64ceecbee5076636a3b026795a8"
+dependencies = [
+ "cfg-if",
+ "wasm-bindgen-macro",
+]
+
+[[package]]
+name = "wasm-bindgen-backend"
+version = "0.2.92"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "614d787b966d3989fa7bb98a654e369c762374fd3213d212cfc0251257e747da"
+dependencies = [
+ "bumpalo",
+ "log",
+ "once_cell",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-macro"
+version = "0.2.92"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1f8823de937b71b9460c0c34e25f3da88250760bec0ebac694b49997550d726"
+dependencies = [
+ "quote",
+ "wasm-bindgen-macro-support",
+]
+
+[[package]]
+name = "wasm-bindgen-macro-support"
+version = "0.2.92"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e94f17b526d0a461a191c78ea52bbce64071ed5c04c9ffe424dcb38f74171bb7"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-backend",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.2.92"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "af190c94f2773fdb3729c55b007a722abb5384da03bc0986df4c289bf5567e96"
+
+[[package]]
+name = "web-time"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a6580f308b1fad9207618087a65c04e7a10bc77e02c8e84e9b00dd4b12fa0bb"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "winapi"
 version = "0.3.9"

Cargo.toml

@@ -8,8 +8,10 @@ edition = "2021"
 [dependencies]
 colors-transform = "0.2.11"
 lazy_static = "1.4.0"
+rand = "0.8.5"
 sdl2 = { version = "0.36", features = ["image", "ttf", "mixer"] }
 spin_sleep = "1.1.1"
 tracing = { version = "0.1.37", features = ["max_level_debug", "release_max_level_debug"]}
 tracing-error = "0.2.0"
 tracing-subscriber = {version = "0.3.17", features = ["env-filter"]}
+web-time = "1.1.0"

src/emscripten.rs

@@ -1,44 +1,42 @@
-
+#[allow(dead_code)]
+#[cfg(target_os = "emscripten")]
 pub mod emscripten {
-    use std::cell::RefCell;
+    use std::os::raw::c_uint;
-    use std::os::raw::{c_float, c_int, c_void};
-    use std::ptr::null_mut;
-    
-    #[allow(non_camel_case_types)]
-    type em_callback_func = unsafe extern "C" fn();
 
     extern "C" {
-        pub fn emscripten_set_main_loop(
+        pub fn emscripten_get_now() -> f64;
-            func: em_callback_func,
+        pub fn emscripten_sleep(ms: c_uint);
-            fps: c_int,
+        pub fn emscripten_run_script(script: *const u8);
-            simulate_infinite_loop: c_int,
+        pub fn emscripten_get_element_css_size(
-        );
+            target: *const u8,
-        pub fn emscripten_cancel_main_loop();
+            width: *mut f64,
-        pub fn emscripten_get_now() -> c_float;
+            height: *mut f64,
+        ) -> i32;
     }
 
-    thread_local!(static MAIN_LOOP_CALLBACK: RefCell<*mut c_void> = RefCell::new(null_mut()));
+    // milliseconds since start of program
-
+    pub fn now() -> f64 {
-    pub fn set_main_loop_callback<F>(callback: F)
+        unsafe { emscripten_get_now() }
-    where
+    }
-        F: FnMut(),
-    {
-        MAIN_LOOP_CALLBACK.with(|log| {
-            *log.borrow_mut() = &callback as *const _ as *mut c_void;
-        });
 
+    pub fn sleep(ms: u32) {
         unsafe {
-            emscripten_set_main_loop(wrapper::<F>, 0, 1);
+            emscripten_sleep(ms);
+        }
     }
 
-        unsafe extern "C" fn wrapper<F>()
+    pub fn exec(script: &str) {
-        where
+        unsafe {
-            F: FnMut(),
+            emscripten_run_script(script.as_ptr());
-        {
-            MAIN_LOOP_CALLBACK.with(|z| {
-                let closure = *z.borrow_mut() as *mut F;
-                (*closure)();
-            });
         }
     }
+
+    pub fn get_canvas_size() -> (u32, u32) {
+        let mut width = 0.0;
+        let mut height = 0.0;
+        unsafe {
+            emscripten_get_element_css_size("canvas\0".as_ptr(), &mut width, &mut height);
+        }
+        (width as u32, height as u32)
+    }
 }

src/main.rs

@@ -2,14 +2,42 @@ use std::cell::RefCell;
 use std::process;
 use std::rc::Rc;
 
+use rand::seq::IteratorRandom;
 use sdl2::event::Event;
 use sdl2::image::LoadTexture;
 use sdl2::keyboard::Keycode;
 use sdl2::pixels::Color;
 use sdl2::rect::{Point, Rect};
+use web_time::{Duration, Instant};
 
 static BLACK: Color = Color::RGB(0, 0, 0);
 
+#[cfg(target_os = "emscripten")]
+mod emscripten;
+
+#[cfg(not(target_os = "emscripten"))]
+fn sleep(ms: u32) {
+    std::thread::sleep(Duration::from_millis(ms as u64));
+}
+
+#[cfg(target_os = "emscripten")]
+fn now() -> f64  {
+    emscripten::emscripten::now() / 1000f64
+}
+
+#[cfg(not(target_os = "emscripten"))]
+fn now() -> f64 {
+    std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .unwrap()
+        .as_secs_f64()
+}
+
+#[cfg(target_os = "emscripten")]
+fn sleep(ms: u32) {
+    emscripten::emscripten::sleep(ms);
+}
+
 fn main() {
     let ctx = sdl2::init().unwrap();
     let video_ctx = ctx.video().unwrap();
@@ -24,7 +52,7 @@ fn main() {
         Err(err) => panic!("failed to create window: {}", err),
     };
 
-    let canvas = match window.into_canvas().accelerated().present_vsync().build() {
+    let mut canvas = match window.into_canvas().accelerated().build() {
         Ok(canvas) => canvas,
         Err(err) => panic!("failed to create canvas: {}", err),
     };
@@ -32,19 +60,23 @@ fn main() {
     let texture_creator = canvas.texture_creator();
     let mut point = Point::new(0, 0);
 
-    let ctx = Rc::new(RefCell::new(ctx));
+    // let ctx = Rc::new(RefCell::new(ctx));
-    let canvas = Rc::new(RefCell::new(canvas));
+    // let canvas = Rc::new(RefCell::new(canvas));
-    let texture_creator = Rc::new(texture_creator);
+    // let texture_creator = Rc::new(texture_creator);
 
     let fruit_atlas = texture_creator
         .load_texture("./assets/fruit.png")
         .expect("could not load texture");
 
+    let target_fps = 60;
+    let frame_time = Duration::from_secs_f32(1.0) / target_fps;
+    println!("Frame time: {:?}", frame_time);
     let mut frame = 0;
 
     loop {
+        let start = now();
         let mut moved = false;
-        for event in ctx.borrow_mut().event_pump().unwrap().poll_iter() {
+        for event in ctx.event_pump().unwrap().poll_iter() {
             match event {
                 Event::Quit { .. }
                 | Event::KeyDown {
@@ -61,6 +93,11 @@ fn main() {
                         if frame > 7 {
                             frame = 0;
                         }
+
+                        // random number between 2 and 6
+                        let sleep_time = (15..=500).choose(&mut rand::thread_rng()).unwrap();
+                        println!("Sleeping for {} ms", sleep_time);
+                        sleep(sleep_time);
                     }
                     Keycode::Left => {
                         point.x -= 32;
@@ -86,7 +123,7 @@ fn main() {
 
         // Handle wrapping at the edges
         if moved {
-            let canvas_size = canvas.borrow().window().size();
+            let canvas_size = canvas.window().size();
             if point.x < 0 {
                 point.x = canvas_size.0 as i32 - 32;
             } else if point.x >= 640 {
@@ -99,8 +136,6 @@ fn main() {
             }
         }
 
-        let mut canvas = canvas.borrow_mut();
-
         canvas.set_draw_color(BLACK);
         canvas.clear();
 
@@ -117,21 +152,21 @@ fn main() {
             .expect("could not draw texture");
 
         canvas.present();
+
+        let t2 = now();
+        let elapsed = Duration::from_secs_f64(t2 - start);
+        if elapsed < frame_time {
+            let sleep_time = frame_time - elapsed;
+            sleep(sleep_time.as_millis() as u32);
+            // println!("elapsed: {:?} sleep: {:?}ms ({:?})", elapsed, sleep_time, t2);
+        } else {
+            let excess = elapsed - frame_time;
+            println!("! excess: {:?} ({:?})", excess, t2);
         }
 
-    // #[cfg(target_family = "wasm")]
+        let t3 = now();
-    // {
+        let duration = Duration::from_secs_f64(t3 - start);
-    //     use crate::emscripten::emscripten::set_main_loop_callback;
+        let fps = 1f64 / (duration.as_secs_f64());
-    //     set_main_loop_callback(main_loop);
+        println!("FPS: {}", fps);
-    // }
+    }
-
-    // #[cfg(not(target_family = "wasm"))]
-    // {
-    //     use std::thread::sleep;
-    //     use std::time::Duration;
-    //     loop {
-    //         main_loop();
-    //         sleep(Duration::from_millis(10))
-    //     }
-    // }
 }