From a364b5ee1d4c009b2e571fde66272ae06e434c21 Mon Sep 17 00:00:00 2001
From: Andrey Lihatskiy <alihatskiy@productengine.com>
Date: Mon, 26 May 2025 17:43:56 +0300
Subject: #4109 Add validation for non-triangulated geometry in GLTF loader

---
 indra/newview/gltf/llgltfloader.cpp                          | 10 ++++++++++
 indra/newview/skins/default/xui/en/floater_model_preview.xml |  1 +
 2 files changed, 11 insertions(+)

diff --git a/indra/newview/gltf/llgltfloader.cpp b/indra/newview/gltf/llgltfloader.cpp
index de7c341cdf..93ed904f2e 100644
--- a/indra/newview/gltf/llgltfloader.cpp
+++ b/indra/newview/gltf/llgltfloader.cpp
@@ -461,6 +461,16 @@ bool LLGLTFLoader::populateModelFromMesh(LLModel* pModel, const LL::GLTF::Mesh&
                 vertices.push_back(vert);
             }
 
+            if (prim.getIndexCount() % 3 != 0)
+            {
+                LL_WARNS("GLTF_IMPORT") << "Invalid primitive: index count " << prim.getIndexCount()
+                                       << " is not divisible by 3. GLTF files must contain triangulated geometry." << LL_ENDL;
+                LLSD args;
+                args["Message"] = "InvalidGeometryNonTriangulated";
+                mWarningsArray.append(args);
+                continue; // Skip this primitive
+            }
+
             // When processing indices, flip winding order if needed
             for (U32 i = 0; i < prim.getIndexCount(); i += 3)
             {
diff --git a/indra/newview/skins/default/xui/en/floater_model_preview.xml b/indra/newview/skins/default/xui/en/floater_model_preview.xml
index 99c348c236..067a1e0c8b 100644
--- a/indra/newview/skins/default/xui/en/floater_model_preview.xml
+++ b/indra/newview/skins/default/xui/en/floater_model_preview.xml
@@ -61,6 +61,7 @@
   <string name="ParsingErrorNoRoot">Document has no root</string>
   <string name="ParsingErrorNoScene">Document has no visual_scene</string>
   <string name="ParsingErrorPositionInvalidModel">Unable to process mesh without position data. Invalid model.</string>
+  <string name="InvalidGeometryNonTriangulated">Invalid geometry: GLTF files must contain triangulated meshes only.</string>
 
   <panel
     follows="top|left"
-- 
cgit v1.2.3