From 5378626d85b69b53b79d2539dea9c8746af88616 Mon Sep 17 00:00:00 2001
From: brian cully <bjc@spork.org>
Date: Mon, 29 Dec 2025 11:20:12 -0500
Subject: wasm: separate update/render for later benching

---
 src/lib.rs         |  5 +++--
 src/render_loop.rs | 16 +++++++++++-----
 src/state.rs       | 12 ++++++++----
 3 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index a798872..87f31ff 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -52,8 +52,9 @@ pub fn init() -> JSResult<()> {
     s.render_frame(0.0)?;
 
     let render_loop = RenderLoop::new(move |t| {
-        s.render_frame(t).expect("should render frame");
-        !*paused.lock().unwrap()
+        s.render_frame(t)?;
+        s.update()?;
+        Ok(!*paused.lock().unwrap())
     });
 
     let a: HandlerClosure = Closure::new(move |e| {
diff --git a/src/render_loop.rs b/src/render_loop.rs
index 628e687..7056493 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 crate::JSResult;
+
 /// use `window.requestAnimationFrame()` to schedule calling a
 /// function as long as the function returns true.
 pub struct RenderLoop {
@@ -21,7 +23,7 @@ impl RenderLoop {
     /// `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 {
+    pub fn new<T: FnMut(f64) -> JSResult<bool> + 'static>(mut fun: T) -> Self {
         // init with stub closure because rust wants that, then change
         // it later once we have our rc clone.
         let inner = Rc::new(UnsafeCell::new(Closure::new(|_| {})));
@@ -29,11 +31,15 @@ impl RenderLoop {
         let rloop = inner.clone();
         let f = unsafe { &mut *inner.get() };
         *f = Closure::new(move |t| {
-            if fun(t) {
-                let cl = unsafe { &*rloop.get() };
-                if let Err(e) = Self::request_animation_frame(cl) {
-                    error!("couldn't request animation frame: {:?}", e);
+            match fun(t) {
+                Err(e) => error!("render callback error: {:?}", e),
+                Ok(true) => {
+                    let cl = unsafe { &*rloop.get() };
+                    if let Err(e) = Self::request_animation_frame(cl) {
+                        error!("couldn't request animation frame: {:?}", e);
+                    }
                 }
+                Ok(false) => {},
             }
         });
 
diff --git a/src/state.rs b/src/state.rs
index 61e82c9..09120fb 100644
--- a/src/state.rs
+++ b/src/state.rs
@@ -67,10 +67,6 @@ impl State {
             self.canvas.height().into(),
         );
         self.render_points()?;
-        if self.bounce_points() {
-            //debug!("point bounced");
-        }
-        self.move_points();
 
         // poly finding assumes sorted
         self.points.sort_by(|a, b| {
@@ -100,6 +96,14 @@ impl State {
         Ok(())
     }
 
+    pub fn update(&mut self) -> JSResult<()> {
+        if self.bounce_points() {
+            //debug!("point bounced");
+        }
+        self.move_points();
+        Ok(())
+    }
+
     fn render_points(&self) -> JSResult<()> {
         for p in &self.points {
             self.ctx.set_fill_style_str(&p.color);
-- 
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