From b8725ffa221b53afd97381463748d3a7eff9b080 Mon Sep 17 00:00:00 2001
From: Philip Rideout <philiprideout@gmail.com>
Date: Wed, 9 Feb 2022 10:07:14 -0800
Subject: [PATCH] WebGL: remove buffer sharing optimization.

If emscripten grows the heap inside one of our BufferDescriptor binding
functions, then the old heap becomes "detached" and an error can
occur.

This fixes the issue seen with the Parquet demo that Ben caught.
---
 web/filament-js/utilities.js | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/web/filament-js/utilities.js b/web/filament-js/utilities.js
index 5ae313f21d..b3172220f9 100644
--- a/web/filament-js/utilities.js
+++ b/web/filament-js/utilities.js
@@ -30,10 +30,12 @@
 Filament.Buffer = function(typedarray) {
     console.assert(typedarray.buffer instanceof ArrayBuffer);
     console.assert(typedarray.byteLength > 0);
-    if (Filament.HEAPU32.buffer == typedarray.buffer) {
-        typedarray = new Uint8Array(typedarray);
-    }
-    const ta = typedarray;
+
+    // Note that the following line is essentially a memcpy, and in some situations this memcpy
+    // isn't required. However emscripten might "grow" the heap when we instantiate the low-level
+    // BufferDescriptor, so unconditionally making a copy is the safest option.
+    const ta = new Uint8Array(typedarray);
+
     const bd = new Filament.driver$BufferDescriptor(ta.byteLength);
     const uint8array = new Uint8Array(ta.buffer, ta.byteOffset, ta.byteLength);
     bd.getBytes().set(uint8array);
@@ -49,10 +51,7 @@ Filament.Buffer = function(typedarray) {
 Filament.PixelBuffer = function(typedarray, format, datatype) {
     console.assert(typedarray.buffer instanceof ArrayBuffer);
     console.assert(typedarray.byteLength > 0);
-    if (Filament.HEAPU32.buffer == typedarray.buffer) {
-        typedarray = new Uint8Array(typedarray);
-    }
-    const ta = typedarray;
+    const ta = new Uint8Array(typedarray);
     const bd = new Filament.driver$PixelBufferDescriptor(ta.byteLength, format, datatype);
     const uint8array = new Uint8Array(ta.buffer, ta.byteOffset, ta.byteLength);
     bd.getBytes().set(uint8array);
@@ -69,10 +68,7 @@ Filament.CompressedPixelBuffer = function(typedarray, cdatatype, faceSize) {
     console.assert(typedarray.buffer instanceof ArrayBuffer);
     console.assert(typedarray.byteLength > 0);
     faceSize = faceSize || typedarray.byteLength;
-    if (Filament.HEAPU32.buffer == typedarray.buffer) {
-        typedarray = new Uint8Array(typedarray);
-    }
-    const ta = typedarray;
+    const ta = new Uint8Array(typedarray);
     const bd = new Filament.driver$PixelBufferDescriptor(ta.byteLength, cdatatype, faceSize, true);
     const uint8array = new Uint8Array(ta.buffer, ta.byteOffset, ta.byteLength);
     bd.getBytes().set(uint8array);