comments, whitespace

1 files changed, 11 insertions, 1 deletions

diff --git a/src/render_loop.rs b/src/render_loop.rs
index 5dcf653..8fc0164 100644
--- a/src/render_loop.rs
+++ b/src/render_loop.rs
@@ -4,6 +4,8 @@ use std::rc::Rc;
 use log::error;
 use wasm_bindgen::prelude::*;
 
+/// use `window.requestAnimationFrame()` to schedule calling a
+/// function as long as the function returns true.
 pub struct RenderLoop {
     inner: Rc<RefCell<Closure<dyn FnMut(f64)>>>,
 }
@@ -16,10 +18,16 @@ impl RenderLoop {
         Ok(())
     }
 
+    /// `fun` takes a timestamp in the same space as the document
+    /// timeline and returns a flag specifying whether we should
+    /// schedule another frame..
     pub fn new<T: FnMut(f64) -> bool + 'static>(mut fun: T) -> Self {
+        // use stub closure so we don't need an `Option` to flag
+        // whether the `RefCell` is filled or not, and otherwise we'd
+        // need to use `MaybeUninit` and `unsafe`.
         let inner = Rc::new(RefCell::new(Closure::new(|_| {})));
-        let rloop = inner.clone();
 
+        let rloop = inner.clone();
         *inner.borrow_mut() = Closure::new(move |t| {
             if fun(t) {
                 if let Err(e) = Self::request_animation_frame(&rloop.borrow()) {
@@ -27,9 +35,11 @@ impl RenderLoop {
                 }
             }
         });
+
         Self { inner }
     }
 
+    /// start animating.
     pub fn start(&self) -> Result<(), JsValue> {
         Self::request_animation_frame(&self.inner.borrow())?;
         Ok(())