From facb7da701e8153c8279a5ffd3b14a75d11b7501 Mon Sep 17 00:00:00 2001
From: "Max Vollmer (Microsoft Havok)"
 <60260460+ms-maxvollmer@users.noreply.github.com>
Date: Wed, 24 Feb 2021 14:19:29 +0000
Subject: [PATCH] Check that normal count and tangent count matches vertex
 count. Ignore data and warn if counts don't match.

---
 code/AssetLib/glTF2/glTF2Importer.cpp | 34 +++++++++++++++++----------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/code/AssetLib/glTF2/glTF2Importer.cpp b/code/AssetLib/glTF2/glTF2Importer.cpp
index 0eba5512b..fb91d8ac3 100644
--- a/code/AssetLib/glTF2/glTF2Importer.cpp
+++ b/code/AssetLib/glTF2/glTF2Importer.cpp
@@ -452,24 +452,32 @@ void glTF2Importer::ImportMeshes(glTF2::Asset &r) {
             }
 
             if (attr.normal.size() > 0 && attr.normal[0]) {
-                attr.normal[0]->ExtractData(aim->mNormals);
+                if (attr.normal[0]->count != aim->mNumVertices) {
+                    DefaultLogger::get()->warn("Normal count in mesh \"" + mesh.name + "\" does not match the vertex count");
+                } else {
+                    attr.normal[0]->ExtractData(aim->mNormals);
 
-                // only extract tangents if normals are present
-                if (attr.tangent.size() > 0 && attr.tangent[0]) {
-                    // generate bitangents from normals and tangents according to spec
-                    Tangent *tangents = nullptr;
+                    // only extract tangents if normals are present
+                    if (attr.tangent.size() > 0 && attr.tangent[0]) {
+                        if (attr.tangent[0]->count != aim->mNumVertices) {
+                            DefaultLogger::get()->warn("Tangent count in mesh \"" + mesh.name + "\" does not match the vertex count");
+                        } else {
+                            // generate bitangents from normals and tangents according to spec
+                            Tangent *tangents = nullptr;
 
-                    attr.tangent[0]->ExtractData(tangents);
+                            attr.tangent[0]->ExtractData(tangents);
 
-                    aim->mTangents = new aiVector3D[aim->mNumVertices];
-                    aim->mBitangents = new aiVector3D[aim->mNumVertices];
+                            aim->mTangents = new aiVector3D[aim->mNumVertices];
+                            aim->mBitangents = new aiVector3D[aim->mNumVertices];
 
-                    for (unsigned int i = 0; i < aim->mNumVertices; ++i) {
-                        aim->mTangents[i] = tangents[i].xyz;
-                        aim->mBitangents[i] = (aim->mNormals[i] ^ tangents[i].xyz) * tangents[i].w;
+                            for (unsigned int i = 0; i < aim->mNumVertices; ++i) {
+                                aim->mTangents[i] = tangents[i].xyz;
+                                aim->mBitangents[i] = (aim->mNormals[i] ^ tangents[i].xyz) * tangents[i].w;
+                            }
+
+                            delete[] tangents;
+                        }
                     }
-
-                    delete[] tangents;
                 }
             }