From ca153e70ab16c3bb29bcfbc124085725954a98aa Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Fri, 7 Mar 2025 21:23:54 +0100
Subject: [PATCH] Fix crash when loading cloth that has different paint data
 size than mesh

#3264
---
 Source/Engine/Physics/Actors/Cloth.cpp | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/Source/Engine/Physics/Actors/Cloth.cpp b/Source/Engine/Physics/Actors/Cloth.cpp
index 2781cb161..3b7bf6718 100644
--- a/Source/Engine/Physics/Actors/Cloth.cpp
+++ b/Source/Engine/Physics/Actors/Cloth.cpp
@@ -641,6 +641,14 @@ void Cloth::CalculateInvMasses(Array<float>& invMasses)
     int32 indicesCount;
     if (mesh.Actor->GetMeshData(mesh, MeshBufferType::Index, indicesData, indicesCount))
         return;
+    if (_paint.Count() != verticesCount)
+    {
+        // Fix incorrect paint data
+        int32 countBefore = _paint.Count();
+        _paint.Resize(verticesCount);
+        for (int32 i = countBefore; i < verticesCount; i++)
+            _paint.Get()[i] = 0.0f;
+    }
     const int32 verticesStride = verticesData.Length() / verticesCount;
     const bool indices16bit = indicesData.Length() / indicesCount == sizeof(uint16);
     const int32 trianglesCount = indicesCount / 3;
@@ -692,12 +700,12 @@ void Cloth::CalculateInvMasses(Array<float>& invMasses)
     float massSum = 0;
     for (int32 i = 0; i < verticesCount; i++)
     {
-        float& mass = invMasses[i];
+        float& mass = invMasses.Get()[i];
 #if USE_CLOTH_SANITY_CHECKS
         // Sanity check
         ASSERT(!isnan(mass) && !isinf(mass) && mass >= 0.0f);
 #endif
-        const float maxDistance = _paint[i];
+        const float maxDistance = _paint.Get()[i];
         if (maxDistance < 0.01f)
         {
             // Fixed
@@ -717,7 +725,7 @@ void Cloth::CalculateInvMasses(Array<float>& invMasses)
         const float massScale = (float)(verticesCount - fixedCount) / massSum;
         for (int32 i = 0; i < verticesCount; i++)
         {
-            float& mass = invMasses[i];
+            float& mass = invMasses.Get()[i];
             if (mass > 0.0f)
             {
                 mass *= massScale;
@@ -772,6 +780,8 @@ bool Cloth::OnPreUpdate()
         int32 verticesCount;
         if (mesh.Actor->GetMeshData(mesh, MeshBufferType::Vertex0, verticesData, verticesCount))
             return false;
+        if (verticesCount != _paint.Count())
+            return false;
         PROFILE_CPU_NAMED("Skinned Pose");
         auto vbStride = (uint32)verticesData.Length() / verticesCount;
         ASSERT(vbStride == sizeof(VB0SkinnedElementType));