From b7cb925178d54cabe2ebb9eaee71ad3ca401ce2a Mon Sep 17 00:00:00 2001
From: David Altenburg <david@gensym.org>
Date: Tue, 24 Jun 2025 13:43:05 -0700
Subject: [PATCH] Fix WebAssembly module initialization in worker.js

- Update worker.js to properly initialize the modularized WebAssembly module
- Use createSimplifyModule() instead of expecting a global Module object
- Make prepare_and_simplify and simplify functions async to handle initialization
- Add EXPORTED_RUNTIME_METHODS to Makefile to export HEAPU8 and HEAPU32

This fixes the "Module._malloc is not a function" error that occurred because
the WebAssembly module is built with MODULARIZE=1 flag.
---
 Makefile  |  1 +
 worker.js | 18 +++++++++++++-----
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index f3b6921..c3906b1 100644
--- a/Makefile
+++ b/Makefile
@@ -2,6 +2,7 @@ CXX := Main.cpp
 O3 := -O3
 WASM := -s NO_FILESYSTEM=1 -s ALLOW_MEMORY_GROWTH=1 -s WASM=1 \
         -s EXPORTED_FUNCTIONS='["_simplify", "_malloc", "_free"]' \
+        -s EXPORTED_RUNTIME_METHODS='["HEAPU8", "HEAPU32"]' \
         -s ENVIRONMENT='web,worker' \
         -s MODULARIZE=1 \
         -s EXPORT_ES6=0 \
diff --git a/worker.js b/worker.js
index a098903..bfa8f20 100644
--- a/worker.js
+++ b/worker.js
@@ -2,20 +2,28 @@ self.addEventListener('message', function(e) {
   prepare_and_simplify(e.data.blob, e.data.percentage);
 }, false);
 
-var Module = {} // imported script installs functions on `Module`
+var Module = null;
 self.importScripts("Fast-Quadric-Mesh-Simplification.js");
 
-function prepare_and_simplify(file, percentage) {
+async function initializeModule() {
+  if (!Module) {
+    Module = await createSimplifyModule();
+  }
+  return Module;
+}
+
+async function prepare_and_simplify(file, percentage) {
+  await initializeModule();
   var fr = new FileReader();
   fr.readAsArrayBuffer(file);
-  fr.onloadend = function () {
-    const outputData = simplify(new Uint8Array(fr.result), percentage);
+  fr.onloadend = async function () {
+    const outputData = await simplify(new Uint8Array(fr.result), percentage);
     let file = new Blob([outputData], {type: 'application/sla'});
     self.postMessage({"blob":file});
   }
 }
 
-function simplify(inputArray, percentage) {
+async function simplify(inputArray, percentage) {
   // Allocate memory for the input buffer and copy the data
   const inputPtr = Module._malloc(inputArray.byteLength);
   Module.HEAPU8.set(inputArray, inputPtr);