Phase 2 of fix for SL-18458 material overrides not being cached properly

indra/newview/llfetchedgltfmaterial.h

@@ -46,6 +46,8 @@ public:
     //   media_tex - optional media texture that may override the base color texture
     void bind(LLViewerTexture* media_tex = nullptr);
 
+    bool isFetching() const { return mFetching; }
+
     // Textures used for fetching/rendering
     LLPointer<LLViewerFetchedTexture> mBaseColorTexture;
     LLPointer<LLViewerFetchedTexture> mNormalTexture;

indra/newview/llgltfmateriallist.cpp

@@ -157,8 +157,8 @@ public:
         // receive override data from simulator via LargeGenericMessage
         // message should have:
         //  object_id - UUID of LLViewerObject
-        //  side - S32 index of texture entry
-        //  gltf_json - String of GLTF json for override data
+        //  sides - array of S32 indices of texture entries
+        //  gltf_json - array of corresponding Strings of GLTF json for override data
 
 
         LLSD message;
@@ -380,11 +380,22 @@ void LLGLTFMaterialList::applyQueuedOverrides(LLViewerObject* obj)
                 { // object doesn't have its base GLTF material yet, don't apply override (yet)
                     return;
                 }
-                obj->setTEGLTFMaterialOverride(i, overrides[i]);
+
+                S32 status = obj->setTEGLTFMaterialOverride(i, overrides[i]);
+                if (status == TEM_CHANGE_NONE)
+                {
+                    // can't apply this yet, since failure to change the material override
+                    // probably means the base material is still being fetched.  leave in
+                    // the queue for later
+                    return;
+                }
+
                 if (obj->getTE(i)->isSelected())
                 {
                     handle_gltf_override_message.doSelectionCallbacks(id, i);
                 }
+                // success!
+                overrides[i] = nullptr;
             }
         }
 

indra/newview/llviewerobject.cpp

@@ -5375,6 +5375,12 @@ S32 LLViewerObject::setTEGLTFMaterialOverride(U8 te, LLGLTFMaterial* override_ma
         return retval;
     }
 
+    if(src_mat->isFetching())
+    {
+        // if still fetching, we need to wait until it is done and try again
+        return retval;
+    }
+
     tep->setGLTFMaterialOverride(override_mat);
 
     // if override mat exists, we must also have a source mat