From 5d64e644585798e90362ab0dad0969e25aca5010 Mon Sep 17 00:00:00 2001
From: Andrey Kleshchev <andreykproductengine@lindenlab.com>
Date: Fri, 13 Dec 2024 19:15:53 +0200
Subject: #3285 Crash at remapIndexBuffer

---
 indra/llmath/llvolume.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

(limited to 'indra/llmath')

diff --git a/indra/llmath/llvolume.cpp b/indra/llmath/llvolume.cpp
index 700e61467b..44b6e7923b 100644
--- a/indra/llmath/llvolume.cpp
+++ b/indra/llmath/llvolume.cpp
@@ -5159,7 +5159,10 @@ bool LLVolumeFace::VertexMapData::ComparePosition::operator()(const LLVector3& a
 void LLVolumeFace::remap()
 {
     // Generate a remap buffer
-    std::vector<unsigned int> remap(mNumVertices);
+    // Documentation for meshopt_generateVertexRemapMulti claims that remap should use vertice count
+    // but all examples use indice count. There are out of bounds crashes when using vertice count.
+    // To be on the safe side use bigger of the two.
+    std::vector<unsigned int> remap(llmax(mNumIndices, mNumVertices));
     S32 remap_vertices_count = static_cast<S32>(LLMeshOptimizer::generateRemapMultiU16(&remap[0],
         mIndices,
         mNumIndices,
-- 
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