From 66318c33551c14ea5c76365ddec033c26b8b78ff Mon Sep 17 00:00:00 2001
From: Vladimir Mandic <mandic00@live.com>
Date: Wed, 2 Jun 2021 16:46:07 -0400
Subject: [PATCH] switch worker from module to iife importscripts

---
 demo/index-worker.js |  8 ++++++--
 demo/index.js        |  4 +++-
 src/interpolate.ts   | 10 +++++++++-
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/demo/index-worker.js b/demo/index-worker.js
index 88e17230..231abc85 100644
--- a/demo/index-worker.js
+++ b/demo/index-worker.js
@@ -1,7 +1,11 @@
-import Human from '../dist/human.esm.js';
+// load Human using IIFE script as Chome Mobile does not support Modules as Workers
+// import Human from '../dist/human.esm.js';
+self.importScripts('../dist/human.js');
 
 let busy = false;
-const human = new Human();
+// @ts-ignore // Human is registered as global namespace using IIFE script
+// eslint-disable-next-line no-undef, new-cap
+const human = new Human.default();
 
 function log(...msg) {
   const dt = new Date();
diff --git a/demo/index.js b/demo/index.js
index d9d124e1..bf6767cd 100644
--- a/demo/index.js
+++ b/demo/index.js
@@ -387,7 +387,9 @@ function webWorker(input, image, canvas, timestamp) {
   if (!worker) {
     // create new webworker and add event handler only once
     log('creating worker thread');
-    worker = new Worker(ui.worker, { type: 'module' });
+    // load Human using IIFE script as Chome Mobile does not support Modules as Workers
+    // worker = new Worker(ui.worker, { type: 'module' });
+    worker = new Worker(ui.worker);
     // after receiving message from webworker, parse&draw results and send new frame for processing
     worker.addEventListener('message', (msg) => {
       if (msg.data.result.performance && msg.data.result.performance.total) ui.detectFPS.push(1000 / msg.data.result.performance.total);
diff --git a/src/interpolate.ts b/src/interpolate.ts
index 58386dc4..0009e23a 100644
--- a/src/interpolate.ts
+++ b/src/interpolate.ts
@@ -11,7 +11,15 @@ export function calc(newResult: Result): Result {
   // otherwise bufferedResult is a shallow clone of result plus updated local calculated values
   // thus mixing by-reference and by-value assignments to minimize memory operations
 
-  const bufferedFactor = 1000 / (Date.now() - newResult.timestamp) / 4;
+  const elapsed = Date.now() - newResult.timestamp;
+  // curve fitted: buffer = 8 - ln(delay)
+  // interpolation formula: current = ((buffer - 1) * previous + live) / buffer
+  // - at  50ms delay buffer = ~4.1 => 28% towards live data
+  // - at 250ms delay buffer = ~2.5 => 40% towards live data
+  // - at 500ms delay buffer = ~1.8 => 55% towards live data
+  // - at 750ms delay buffer = ~1.4 => 71% towards live data
+  // - at  1sec delay buffer = 1 which means live data is used
+  const bufferedFactor = elapsed < 1000 ? 8 - Math.log(elapsed) : 1;
 
   // interpolate body results
   if (!bufferedResult.body || (newResult.body.length !== bufferedResult.body.length)) {