rust-buildgen requestAnimationFrameLoop unable to use struct method inside closure - rust

Question

I am trying to create a requestAnimationFrame loop, which will call game.render() for every frame. I am following this tutorial - https://rustwasm.github.io/wasm-bindgen/examples/request-animation-frame.html
struct Game {
state: GameState,
ctx: web_sys::CanvasRenderingContext2d
}
impl Game {
fn render(self: Game) {
self.ctx.begin_path();
self.ctx.arc(self.state.x, 50.0, 40.0, 0.0, 2.0 * std::f64::consts::PI);
self.ctx.stroke();
}
}
#[wasm_bindgen(start)]
pub fn run() -> Result<(), JsValue> {
let game = init();
let f = Rc::new(RefCell::new(None));
let g = f.clone();
*g.borrow_mut() = Some(Closure::wrap(Box::new(move || {
game.render();
request_animation_frame(f.borrow().as_ref().unwrap());
}) as Box<dyn FnMut()>));
request_animation_frame(g.borrow().as_ref().unwrap());
Ok(())
}
fn init() -> Game {
let doc = document();
let canvas = doc.create_element("canvas").unwrap();
canvas.set_attribute("width", "800px").unwrap();
canvas.set_attribute("height", "800px").unwrap();
canvas.set_id("fp-canvas");
body().append_child(&canvas).expect("Could not attach canvas");
Game {
ctx: context(),
state: GameState {
x: 3.0
}
}
}
But it gives following error -
error[E0277]: expected a `std::ops::FnMut<()>` closure, found `[closure#src/lib.rs:89:51: 92:6 game:Game, f:std::rc::Rc<std::cell::RefCell<std::option::Option<wasm_bindgen::closure::Closure<dyn std::ops::FnMut()>>>>]`
--> src/lib.rs:89:42
|
89 | *g.borrow_mut() = Some(Closure::wrap(Box::new(move || {
| __________________________________________^
90 | | game.render();
91 | | request_animation_frame(f.borrow().as_ref().unwrap());
92 | | }) as Box<dyn FnMut()>));
| |______^ expected an `FnMut<()>` closure, found `[closure#src/lib.rs:89:51: 92:6 game:Game, f:std::rc::Rc<std::cell::RefCell<std::option::Option<wasm_bindgen::closure::Closure<dyn std::ops::FnMut()>>>>]`
|
= help: the trait `std::ops::FnMut<()>` is not implemented for `[closure#src/lib.rs:89:51: 92:6 game:Game, f:std::rc::Rc<std::cell::RefCell<std::option::Option<wasm_bindgen::closure::Closure<dyn std::ops::FnMut()>>>>]`
= note: wrap the `[closure#src/lib.rs:89:51: 92:6 game:Game, f:std::rc::Rc<std::cell::RefCell<std::option::Option<wasm_bindgen::closure::Closure<dyn std::ops::FnMut()>>>>]` in a closure with no arguments: `|| { /* code */ }
= note: required for the cast to the object type `dyn std::ops::FnMut()`
error: aborting due to previous error
For more information about this error, try `rustc --explain E0277`.
error: could not compile `fighting-pixel`.
To learn more, run the command again with --verbose.
If I comment out game.render() it compiles. But I want to keep a state which will be updated to create an animation. What I am doing wrong? Why Closure doesn't allow to call struct methods?
Thanks in advance for your help.

Answer 1

I found the issue. The Game struct would be like -
impl Game {
fn render(self: &Game) {
self.ctx.begin_path();
self.ctx.arc(self.state.x, 50.0, 40.0, 0.0, 2.0 * std::f64::consts::PI);
self.ctx.stroke();
}
}
Forgot to put & symbol for self. Thanks Pauan#6666 from Discord channel #wg-wasm for pointing that out.

Answer 2

Shimul comment worked for me.
I share here my game start_loop blocking function.
where the insteresting line is at the end:
draw_scene(&self.state, &self.gl_context).unwrap();
impl GameGl { pub fn start_loop(mut self) -> Result<(), JsValue> {
// Render loop
// Dont ask me
let f = Rc::new(RefCell::new(None));
let g = f.clone();
const FPS_THROTTLE: f64 = 1000.0 / 60.0; // milliseconds / frames
let mut previous: f64 = js_sys::Date::now();
*g.borrow_mut() = Some(Closure::wrap(Box::new(move || {
request_animation_frame(f.borrow().as_ref().unwrap());
// Get time (miliseconds)
let now = js_sys::Date::now();
// Clause: must work or sleeep ?
// The current rotation angle 1 rad/sec
if now < previous + FPS_THROTTLE {
return ();
}
// Update time
let delta_time = now - previous;
previous = now;
// Update game
self.state.cube_rotation += delta_time as f32 * 0.001;
// Draw
draw_scene(&self.state, &self.gl_context).unwrap();
//&self.gl, &self.program_info, &self.texture, &buffers, &state).unwrap();
}) as Box<dyn FnMut()>));
console::log_1(&"Requesting animation frame".into());
request_animation_frame(g.borrow().as_ref().unwrap());
//let program_info =
Ok(())
}}