simplify render logic

1 files changed, 26 insertions, 52 deletions

diff --git a/src/lib.rs b/src/lib.rs
index 1c5f028..0c767e7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -12,14 +12,12 @@ mod point;
 mod state;
 
 struct RenderLoop {
-    animation_id: Option<i32>,
-    pub closure: Option<Closure<dyn FnMut(f64)>>,
+    closure: Option<Closure<dyn FnMut(f64)>>,
 }
 
 impl RenderLoop {
     pub fn new() -> Self {
         Self {
-            animation_id: None,
             closure: None,
         }
     }
@@ -54,6 +52,25 @@ fn go() -> Result<web_sys::HtmlElement, JsValue> {
     Ok(x.dyn_into::<web_sys::HtmlElement>()?)
 }
 
+fn request_animation_frame(f: &Closure<dyn FnMut(f64)>) {
+    window()
+        .request_animation_frame(f.as_ref().unchecked_ref())
+        .expect("should register `requestAnimationFrame` OK");
+}
+
+fn rloop2<T: FnMut(f64) -> bool + 'static>(mut fun: T) -> Rc<RefCell<RenderLoop>> {
+    let res = Rc::new(RefCell::new(RenderLoop::new()));
+    let rloop = res.clone();
+
+    (*res).borrow_mut().closure = Some(Closure::new(move |t| {
+        if fun(t) {
+            request_animation_frame(rloop.borrow().closure.as_ref().expect("can borrow rloop"));
+        }
+    }));
+
+    res
+}
+
 #[wasm_bindgen(start)]
 pub fn init() -> Result<(), JsValue> {
     console_log::init_with_level(Level::Debug).expect("couldn't init console log");
@@ -65,44 +82,11 @@ pub fn init() -> Result<(), JsValue> {
     let mut s = State::new(canvas()?, fps()?)?;
     s.render_frame(0.0)?;
 
-    //
-    // from https://users.rust-lang.org/t/wasm-web-sys-how-to-use-window-request-animation-frame-resolved/20882
-    //
-
-    let render_loop: Rc<RefCell<RenderLoop>> = Rc::new(RefCell::new(RenderLoop::new()));
-    {
-        let closure: Closure<dyn FnMut(f64)> = {
-            let render_loop_clone = render_loop.clone();
-            Closure::wrap(Box::new(move |t| {
-                s.render_frame(t).expect("should render frame");
-                let p = paused.lock().unwrap();
-                if !*p {
-                    let mut render_loop_mut = render_loop_clone.borrow_mut();
-                    render_loop_mut.animation_id = if let Some(ref closure) = render_loop_mut.closure {
-                        Some(
-                            window()
-                                .request_animation_frame(closure.as_ref().unchecked_ref())
-                                .expect("req anim frame"),
-                        )
-                    } else {
-                        None
-                    }
-                }
-            }))
-        };
-
-        let mut render_loop_last = render_loop.borrow_mut();
-        render_loop_last.animation_id = Some(
-            window()
-                .request_animation_frame(closure.as_ref().unchecked_ref())
-                .expect("req anim frame"),
-        );
-        render_loop_last.closure = Some(closure);
-    }
-
-    //
-    //
-    //
+    let render_loop = rloop2(move |t| {
+        s.render_frame(t).expect("should render frame");
+        !*paused.lock().unwrap()
+    });
+    request_animation_frame(render_loop.borrow().closure.as_ref().expect("can borrow res"));
 
     let a = Closure::<dyn FnMut()>::new(move || {
         let mut p = p1.lock().unwrap();
@@ -111,17 +95,7 @@ pub fn init() -> Result<(), JsValue> {
         let text = if *p {
             "go"
         } else {
-            let render_loop_clone = render_loop.clone();
-            let mut render_loop_mut = render_loop_clone.borrow_mut();
-            render_loop_mut.animation_id = if let Some(ref closure) = render_loop_mut.closure {
-                Some(
-                    window()
-                        .request_animation_frame(closure.as_ref().unchecked_ref())
-                        .expect("req anim frame"),
-                )
-            } else {
-                None
-            };
+            request_animation_frame(render_loop.borrow().closure.as_ref().expect("render closure exists"));
             "pause"
         };
         go().expect("go button works").set_text_content(Some(text));