cherry pick secondlife/viewer#912 BugSplat Crash 1412267: nvoglv64+0xadcd00 (#2785)

* secondlife/viewer#912 BugSplat Crash 1412267: nvoglv64+0xadcd00
* fix cherry-pick merge breakage.
* Fix signed/unsigned error

---------

Co-authored-by: Alexander Gavriliuk <alexandrgproductengine@lindenlab.com>

6 files changed, 140 insertions, 148 deletions

diff --git a/indra/llprimitive/lldaeloader.cpp b/indra/llprimitive/lldaeloader.cpp
index f286bff353..7fa4230237 100644
--- a/indra/llprimitive/lldaeloader.cpp
+++ b/indra/llprimitive/lldaeloader.cpp
@@ -1115,19 +1115,17 @@ bool LLDAELoader::OpenFile(const std::string& filename)
 
         if (skin)
         {
-            domGeometry* geom = daeSafeCast<domGeometry>(skin->getSource().getElement());
-
-            if (geom)
+            if (domGeometry* geom = daeSafeCast<domGeometry>(skin->getSource().getElement()))
             {
-                domMesh* mesh = geom->getMesh();
-                if (mesh)
+                if (domMesh* mesh = geom->getMesh())
                 {
-                    std::vector< LLPointer< LLModel > >::iterator i = mModelsMap[mesh].begin();
-                    while (i != mModelsMap[mesh].end())
+                    dae_model_map::const_iterator it = mModelsMap.find(mesh);
+                    if (it != mModelsMap.end())
                     {
-                        LLPointer<LLModel> mdl = *i;
-                        LLDAELoader::processDomModel(mdl, &dae, root, mesh, skin);
-                        i++;
+                        for (const LLPointer<LLModel>& model : it->second)
+                        {
+                            LLDAELoader::processDomModel(model, &dae, root, mesh, skin);
+                        }
                     }
                 }
             }
@@ -1297,6 +1295,7 @@ void LLDAELoader::processDomModel(LLModel* model, DAE* dae, daeElement* root, do
             }
         }
         else
+        {
             //Has one or more skeletons
             for (std::vector<domInstance_controller::domSkeleton*>::iterator skel_it = skeletons.begin();
                  skel_it != skeletons.end(); ++skel_it)
@@ -1381,6 +1380,7 @@ void LLDAELoader::processDomModel(LLModel* model, DAE* dae, daeElement* root, do
                     }
                 }//got skeleton?
             }
+        }
 
 
         domSkin::domJoints* joints = skin->getJoints();
@@ -1681,7 +1681,7 @@ void LLDAELoader::processDomModel(LLModel* model, DAE* dae, daeElement* root, do
             materials[model->mMaterialList[i]] = LLImportMaterial();
         }
         mScene[transformation].push_back(LLModelInstance(model, model->mLabel, transformation, materials));
-        stretch_extents(model, transformation, mExtents[0], mExtents[1], mFirstTransform);
+        stretch_extents(model, transformation);
     }
 }
 
@@ -2074,21 +2074,14 @@ void LLDAELoader::processElement( daeElement* element, bool& badElement, DAE* da
         mTransform.condition();
     }
 
-    domInstance_geometry* instance_geo = daeSafeCast<domInstance_geometry>(element);
-    if (instance_geo)
+    if (domInstance_geometry* instance_geo = daeSafeCast<domInstance_geometry>(element))
     {
-        domGeometry* geo = daeSafeCast<domGeometry>(instance_geo->getUrl().getElement());
-        if (geo)
+        if (domGeometry* geo = daeSafeCast<domGeometry>(instance_geo->getUrl().getElement()))
         {
-            domMesh* mesh = daeSafeCast<domMesh>(geo->getDescendant(daeElement::matchType(domMesh::ID())));
-            if (mesh)
+            if (domMesh* mesh = daeSafeCast<domMesh>(geo->getDescendant(daeElement::matchType(domMesh::ID()))))
             {
-
-                std::vector< LLPointer< LLModel > >::iterator i = mModelsMap[mesh].begin();
-                while (i != mModelsMap[mesh].end())
+                for (LLModel* model : mModelsMap.find(mesh)->second)
                 {
-                    LLModel* model = *i;
-
                     LLMatrix4 transformation = mTransform;
 
                     if (mTransform.determinant() < 0)
@@ -2159,8 +2152,7 @@ void LLDAELoader::processElement( daeElement* element, bool& badElement, DAE* da
                     }
 
                     mScene[transformation].push_back(LLModelInstance(model, label, transformation, materials));
-                    stretch_extents(model, transformation, mExtents[0], mExtents[1], mFirstTransform);
-                    i++;
+                    stretch_extents(model, transformation);
                 }
             }
         }
diff --git a/indra/llprimitive/llmodel.cpp b/indra/llprimitive/llmodel.cpp
index 9908a155f2..4e3e49ec9f 100644
--- a/indra/llprimitive/llmodel.cpp
+++ b/indra/llprimitive/llmodel.cpp
@@ -91,19 +91,15 @@ std::string LLModel::getStatusString(U32 status)
 }
 
 
-void LLModel::offsetMesh( const LLVector3& pivotPoint )
+void LLModel::offsetMesh(const LLVector3& pivotPoint)
 {
-    LLVector4a pivot( pivotPoint[VX], pivotPoint[VY], pivotPoint[VZ] );
+    LLVector4a pivot(pivotPoint[VX], pivotPoint[VY], pivotPoint[VZ]);
 
-    for (std::vector<LLVolumeFace>::iterator faceIt = mVolumeFaces.begin(); faceIt != mVolumeFaces.end(); )
+    for (LLVolumeFace& face : mVolumeFaces)
     {
-        std::vector<LLVolumeFace>:: iterator currentFaceIt = faceIt++;
-        LLVolumeFace& face = *currentFaceIt;
-        LLVector4a *pos = (LLVector4a*) face.mPositions;
-
-        for (S32 i=0; i<face.mNumVertices; ++i )
+        for (S32 i = 0; i < face.mNumVertices; ++i)
         {
-            pos[i].add( pivot );
+            face.mPositions[i].add(pivot);
         }
     }
 }
@@ -338,7 +334,7 @@ void LLModel::normalizeVolumeFaces()
     }
 }
 
-void LLModel::getNormalizedScaleTranslation(LLVector3& scale_out, LLVector3& translation_out)
+void LLModel::getNormalizedScaleTranslation(LLVector3& scale_out, LLVector3& translation_out) const
 {
     scale_out = mNormalizedScale;
     translation_out = mNormalizedTranslation;
diff --git a/indra/llprimitive/llmodel.h b/indra/llprimitive/llmodel.h
index 96cfb7151e..fe28926720 100644
--- a/indra/llprimitive/llmodel.h
+++ b/indra/llprimitive/llmodel.h
@@ -206,7 +206,7 @@ public:
     void remapVolumeFaces();
     void optimizeVolumeFaces();
     void offsetMesh( const LLVector3& pivotPoint );
-    void getNormalizedScaleTranslation(LLVector3& scale_out, LLVector3& translation_out);
+    void getNormalizedScaleTranslation(LLVector3& scale_out, LLVector3& translation_out) const;
     LLVector3 getTransformedCenter(const LLMatrix4& mat);
 
     //reorder face list based on mMaterialList in this and reference so
diff --git a/indra/llprimitive/llmodelloader.cpp b/indra/llprimitive/llmodelloader.cpp
index ae69c4f8ab..7facd53a72 100644
--- a/indra/llprimitive/llmodelloader.cpp
+++ b/indra/llprimitive/llmodelloader.cpp
@@ -36,7 +36,7 @@
 
 std::list<LLModelLoader*> LLModelLoader::sActiveLoaderList;
 
-void stretch_extents(LLModel* model, LLMatrix4a& mat, LLVector4a& min, LLVector4a& max, bool& first_transform)
+static void stretch_extents(const LLModel* model, const LLMatrix4a& mat, LLVector4a& min, LLVector4a& max, bool& first_transform)
 {
     LLVector4a box[] =
     {
@@ -84,19 +84,19 @@ void stretch_extents(LLModel* model, LLMatrix4a& mat, LLVector4a& min, LLVector4
     }
 }
 
-void stretch_extents(LLModel* model, LLMatrix4& mat, LLVector3& min, LLVector3& max, bool& first_transform)
+void LLModelLoader::stretch_extents(const LLModel* model, const LLMatrix4& mat)
 {
     LLVector4a mina, maxa;
     LLMatrix4a mata;
 
     mata.loadu(mat);
-    mina.load3(min.mV);
-    maxa.load3(max.mV);
+    mina.load3(mExtents[0].mV);
+    maxa.load3(mExtents[1].mV);
 
-    stretch_extents(model, mata, mina, maxa, first_transform);
+    ::stretch_extents(model, mata, mina, maxa, mFirstTransform);
 
-    min.set(mina.getF32ptr());
-    max.set(maxa.getF32ptr());
+    mExtents[0].set(mina.getF32ptr());
+    mExtents[1].set(maxa.getF32ptr());
 }
 
 //-----------------------------------------------------------------------------
@@ -291,14 +291,7 @@ bool LLModelLoader::loadFromSLM(const std::string& filename)
             {
                 if (idx >= model[lod].size())
                 {
-                    if (model[lod].size())
-                    {
-                        instance_list[i].mLOD[lod] = model[lod][0];
-                    }
-                    else
-                    {
-                        instance_list[i].mLOD[lod] = NULL;
-                    }
+                    instance_list[i].mLOD[lod] = model[lod].front();
                     continue;
                 }
 
@@ -341,7 +334,7 @@ bool LLModelLoader::loadFromSLM(const std::string& filename)
     {
         LLModelInstance& cur_instance = instance_list[i];
         mScene[cur_instance.mTransform].push_back(cur_instance);
-        stretch_extents(cur_instance.mModel, cur_instance.mTransform, mExtents[0], mExtents[1], mFirstTransform);
+        stretch_extents(cur_instance.mModel, cur_instance.mTransform);
     }
 
     setLoadState( DONE );
diff --git a/indra/llprimitive/llmodelloader.h b/indra/llprimitive/llmodelloader.h
index 83bd2f5bbd..530e61e2b8 100644
--- a/indra/llprimitive/llmodelloader.h
+++ b/indra/llprimitive/llmodelloader.h
@@ -34,13 +34,13 @@
 
 class LLJoint;
 
-typedef std::map<std::string, LLMatrix4>            JointTransformMap;
-typedef std::map<std::string, LLMatrix4>::iterator  JointTransformMapIt;
-typedef std::map<std::string, std::string>          JointMap;
-typedef std::deque<std::string>                     JointNameSet;
+typedef std::map<std::string, LLMatrix4> JointTransformMap;
+typedef std::map<std::string, LLMatrix4>::iterator JointTransformMapIt;
+typedef std::map<std::string, std::string> JointMap;
+typedef std::deque<std::string> JointNameSet;
 
 const S32 SLM_SUPPORTED_VERSION = 3;
-const S32 NUM_LOD                       = 4;
+const S32 NUM_LOD = 4;
 
 const U32 LEGACY_RIG_OK = 0;
 const U32 LEGACY_RIG_FLAG_TOO_MANY_JOINTS = 1;
@@ -50,32 +50,32 @@ class LLModelLoader : public LLThread
 {
 public:
 
-    typedef std::map<std::string, LLImportMaterial>         material_map;
-    typedef std::vector<LLPointer<LLModel > >                   model_list;
-    typedef std::vector<LLModelInstance>                        model_instance_list;
-    typedef std::map<LLMatrix4, model_instance_list >       scene;
+    typedef std::map<std::string, LLImportMaterial> material_map;
+    typedef std::vector<LLPointer<LLModel>> model_list;
+    typedef std::vector<LLModelInstance> model_instance_list;
+    typedef std::map<LLMatrix4, model_instance_list> scene;
 
     // Callback with loaded model data and loaded LoD
     //
-    typedef boost::function<void (scene&,model_list&,S32,void*) >       load_callback_t;
+    typedef boost::function<void (scene&, model_list&, S32, void*)> load_callback_t;
 
     // Function to provide joint lookup by name
     // (within preview avi skeleton, for example)
     //
-    typedef boost::function<LLJoint* (const std::string&,void*) >       joint_lookup_func_t;
+    typedef boost::function<LLJoint* (const std::string&, void*)> joint_lookup_func_t;
 
     // Func to load and associate material with all it's textures,
     // returned value is the number of textures loaded
     // intentionally non-const so func can modify material to
     // store platform-specific data
     //
-    typedef boost::function<U32 (LLImportMaterial&,void*) >             texture_load_func_t;
+    typedef boost::function<U32 (LLImportMaterial&, void*)> texture_load_func_t;
 
     // Callback to inform client of state changes
     // during loading process (errors will be reported
     // as state changes here as well)
     //
-    typedef boost::function<void (U32,void*) >                              state_callback_t;
+    typedef boost::function<void (U32, void*)> state_callback_t;
 
     typedef enum
     {
@@ -136,7 +136,7 @@ public:
         JointNameSet&                       jointsFromNodes,
         JointMap&                           legalJointNamesMap,
         U32                                 maxJointsPerMesh);
-    virtual ~LLModelLoader() ;
+    virtual ~LLModelLoader();
 
     virtual void setNoNormalize() { mNoNormalize = true; }
     virtual void setNoOptimize() { mNoOptimize = true; }
@@ -156,13 +156,13 @@ public:
     bool loadFromSLM(const std::string& filename);
 
     void loadModelCallback();
-    void loadTextures() ; //called in the main thread.
+    void loadTextures() ; // called in the main thread.
     void setLoadState(U32 state);
 
+    void stretch_extents(const LLModel* model, const LLMatrix4& mat);
 
-
-    S32 mNumOfFetchingTextures ; //updated in the main thread
-    bool areTexturesReady() { return !mNumOfFetchingTextures; } //called in the main thread.
+    S32 mNumOfFetchingTextures ; // updated in the main thread
+    bool areTexturesReady() { return !mNumOfFetchingTextures; } // called in the main thread.
 
     bool verifyCount( int expected, int result );
 
@@ -212,10 +212,7 @@ protected:
     LLSD mWarningsArray; // preview floater will pull logs from here
 
     static std::list<LLModelLoader*> sActiveLoaderList;
-    static bool isAlive(LLModelLoader* loader) ;
+    static bool isAlive(LLModelLoader* loader);
 };
-class LLMatrix4a;
-void stretch_extents(LLModel* model, LLMatrix4a& mat, LLVector4a& min, LLVector4a& max, bool& first_transform);
-void stretch_extents(LLModel* model, LLMatrix4& mat, LLVector3& min, LLVector3& max, bool& first_transform);
 
 #endif  // LL_LLMODELLOADER_H
diff --git a/indra/newview/llmodelpreview.cpp b/indra/newview/llmodelpreview.cpp
index ef09cfa55b..1e7da126b0 100644
--- a/indra/newview/llmodelpreview.cpp
+++ b/indra/newview/llmodelpreview.cpp
@@ -134,25 +134,17 @@ std::string getLodSuffix(S32 lod)
 
 void FindModel(LLModelLoader::scene& scene, const std::string& name_to_match, LLModel*& baseModelOut, LLMatrix4& matOut)
 {
-    LLModelLoader::scene::iterator base_iter = scene.begin();
-    bool found = false;
-    while (!found && (base_iter != scene.end()))
+    for (auto scene_iter = scene.begin(); scene_iter != scene.end(); scene_iter++)
     {
-        matOut = base_iter->first;
-
-        LLModelLoader::model_instance_list::iterator base_instance_iter = base_iter->second.begin();
-        while (!found && (base_instance_iter != base_iter->second.end()))
+        for (auto model_iter = scene_iter->second.begin(); model_iter != scene_iter->second.end(); model_iter++)
         {
-            LLModelInstance& base_instance = *base_instance_iter++;
-            LLModel* base_model = base_instance.mModel;
-
-            if (base_model && (base_model->mLabel == name_to_match))
+            if (model_iter->mModel && (model_iter->mModel->mLabel == name_to_match))
             {
-                baseModelOut = base_model;
+                baseModelOut = model_iter->mModel;
+                matOut = scene_iter->first;
                 return;
             }
         }
-        base_iter++;
     }
 }
 
@@ -212,9 +204,12 @@ LLModelPreview::LLModelPreview(S32 width, S32 height, LLFloater* fmp)
 
 LLModelPreview::~LLModelPreview()
 {
+    LLMutexLock lock(this);
+
     if (mModelLoader)
     {
         mModelLoader->shutdown();
+        mModelLoader = NULL;
     }
 
     if (mPreviewAvatar)
@@ -262,7 +257,7 @@ void LLModelPreview::updateDimentionsAndOffsets()
             accounted.insert(instance.mModel);
 
             // update instance skin info for each lods pelvisZoffset
-            for (int j = 0; j<LLModel::NUM_LODS; ++j)
+            for (int j = 0; j < LLModel::NUM_LODS; ++j)
             {
                 if (instance.mLOD[j])
                 {
@@ -303,7 +298,7 @@ void LLModelPreview::rebuildUploadData()
     bool legacyMatching = gSavedSettings.getBOOL("ImporterLegacyMatching");
     U32 load_state = 0;
 
-    for (LLModelLoader::scene::iterator iter = mBaseScene.begin(); iter != mBaseScene.end(); ++iter)
+    for (auto iter = mBaseScene.begin(); iter != mBaseScene.end(); ++iter)
     { //for each transform in scene
         LLMatrix4 mat = iter->first;
 
@@ -322,9 +317,9 @@ void LLModelPreview::rebuildUploadData()
 
         mat *= scale_mat;
 
-        for (LLModelLoader::model_instance_list::iterator model_iter = iter->second.begin(); model_iter != iter->second.end();)
+        for (auto model_iter = iter->second.begin(); model_iter != iter->second.end(); ++model_iter)
         { // for each instance with said transform applied
-            LLModelInstance instance = *model_iter++;
+            LLModelInstance instance = *model_iter;
 
             LLModel* base_model = instance.mModel;
 
@@ -910,7 +905,7 @@ void LLModelPreview::clearIncompatible(S32 lod)
                 {
                     mBaseModel = mModel[lod];
                     mBaseScene = mScene[lod];
-                    mVertexBuffer[5].clear();
+                    mVertexBuffer[LLModel::NUM_LODS].clear();
                     replaced_base_model = true;
                 }
             }
@@ -1132,7 +1127,7 @@ void LLModelPreview::loadModelCallback(S32 loaded_lod)
             mBaseModel = mModel[loaded_lod];
 
             mBaseScene = mScene[loaded_lod];
-            mVertexBuffer[5].clear();
+            mVertexBuffer[LLModel::NUM_LODS].clear();
         }
         else
         {
@@ -1248,7 +1243,7 @@ void LLModelPreview::loadModelCallback(S32 loaded_lod)
     {
         if (!mBaseModel.empty())
         {
-            const std::string& model_name = mBaseModel[0]->getName();
+            std::string model_name = mBaseModel.front()->getName();
             LLLineEditor* description_form = mFMP->getChild<LLLineEditor>("description_form");
             if (description_form->getText().empty())
             {
@@ -1269,6 +1264,8 @@ void LLModelPreview::loadModelCallback(S32 loaded_lod)
 
 void LLModelPreview::resetPreviewTarget()
 {
+    LLMutexLock lock(this);
+
     if (mModelLoader)
     {
         mPreviewTarget = (mModelLoader->mExtents[0] + mModelLoader->mExtents[1]) * 0.5f;
@@ -1314,7 +1311,7 @@ void LLModelPreview::generateNormals()
             (*it)->generateNormals(angle_cutoff);
         }
 
-        mVertexBuffer[5].clear();
+        mVertexBuffer[LLModel::NUM_LODS].clear();
     }
 
     bool perform_copy = mModelFacesCopy[which_lod].empty();
@@ -2156,7 +2153,7 @@ void LLModelPreview::updateStatusMessages()
     S32 total_verts[LLModel::NUM_LODS];
     S32 total_submeshes[LLModel::NUM_LODS];
 
-    for (U32 i = 0; i < LLModel::NUM_LODS - 1; i++)
+    for (U32 i = 0; i < LLModel::NUM_LODS; i++)
     {
         total_tris[i] = 0;
         total_verts[i] = 0;
@@ -2460,12 +2457,16 @@ void LLModelPreview::updateStatusMessages()
         }
     }
 
-    if (mModelNoErrors && mModelLoader)
+    if (mModelNoErrors)
     {
-        if (!mModelLoader->areTexturesReady() && mFMP->childGetValue("upload_textures").asBoolean())
+        LLMutexLock lock(this);
+        if (mModelLoader)
         {
-            // Some textures are still loading, prevent upload until they are done
-            mModelNoErrors = false;
+            if (!mModelLoader->areTexturesReady() && mFMP->childGetValue("upload_textures").asBoolean())
+            {
+                // Some textures are still loading, prevent upload until they are done
+                mModelNoErrors = false;
+            }
         }
     }
 
@@ -2794,10 +2795,10 @@ void LLModelPreview::genBuffers(S32 lod, bool include_skin_weights)
 {
     LLModelLoader::model_list* model = NULL;
 
-    if (lod < 0 || lod > 4)
+    if (lod < 0 || lod >= LLModel::NUM_LODS)
     {
         model = &mBaseModel;
-        lod = 5;
+        lod = LLModel::NUM_LODS;
     }
     else
     {
@@ -3034,8 +3035,9 @@ void LLModelPreview::loadedCallback(
     S32 lod,
     void* opaque)
 {
-    LLModelPreview* pPreview = static_cast< LLModelPreview* >(opaque);
-    if (pPreview && !LLModelPreview::sIgnoreLoadedCallback)
+    LLModelPreview* pPreview = static_cast<LLModelPreview*>(opaque);
+    LLMutexLock lock(pPreview);
+    if (pPreview && pPreview->mModelLoader && !LLModelPreview::sIgnoreLoadedCallback)
     {
         // Load loader's warnings into floater's log tab
         const LLSD out = pPreview->mModelLoader->logOut();
@@ -3056,7 +3058,9 @@ void LLModelPreview::loadedCallback(
         }
 
         const LLVOAvatar* avatarp = pPreview->getPreviewAvatar();
-        if (avatarp) { // set up ground plane for possible rendering
+        if (avatarp && avatarp->mRoot && avatarp->mDrawable)
+        {
+            // set up ground plane for possible rendering
             const LLVector3 root_pos = avatarp->mRoot->getPosition();
             const LLVector4a* ext = avatarp->mDrawable->getSpatialExtents();
             const LLVector4a min = ext[0], max = ext[1];
@@ -3200,12 +3204,12 @@ bool LLModelPreview::render()
     LLMutexLock lock(this);
     mNeedsUpdate = false;
 
-    bool edges = mViewOption["show_edges"];
-    bool joint_overrides = mViewOption["show_joint_overrides"];
-    bool joint_positions = mViewOption["show_joint_positions"];
-    bool skin_weight = mViewOption["show_skin_weight"];
-    bool textures = mViewOption["show_textures"];
-    bool physics = mViewOption["show_physics"];
+    bool show_edges = mViewOption["show_edges"];
+    bool show_joint_overrides = mViewOption["show_joint_overrides"];
+    bool show_joint_positions = mViewOption["show_joint_positions"];
+    bool show_skin_weight = mViewOption["show_skin_weight"];
+    bool show_textures = mViewOption["show_textures"];
+    bool show_physics = mViewOption["show_physics"];
 
     S32 width = getWidth();
     S32 height = getHeight();
@@ -3282,15 +3286,15 @@ bool LLModelPreview::render()
                     fmp->childSetValue("upload_skin", true);
                     mFirstSkinUpdate = false;
                     upload_skin = true;
-                    skin_weight = true;
+                    show_skin_weight = true;
                     mViewOption["show_skin_weight"] = true;
                 }
 
                 fmp->enableViewOption("show_skin_weight");
-                fmp->setViewOptionEnabled("show_joint_overrides", skin_weight);
-                fmp->setViewOptionEnabled("show_joint_positions", skin_weight);
+                fmp->setViewOptionEnabled("show_joint_overrides", show_skin_weight);
+                fmp->setViewOptionEnabled("show_joint_positions", show_skin_weight);
                 mFMP->childEnable("upload_skin");
-                mFMP->childSetValue("show_skin_weight", skin_weight);
+                mFMP->childSetValue("show_skin_weight", show_skin_weight);
 
             }
             else if ((flags & LEGACY_RIG_FLAG_TOO_MANY_JOINTS) > 0)
@@ -3313,11 +3317,12 @@ bool LLModelPreview::render()
             fmp->disableViewOption("show_joint_overrides");
             fmp->disableViewOption("show_joint_positions");
 
-            skin_weight = false;
+            show_skin_weight = false;
             mFMP->childSetValue("show_skin_weight", false);
-            fmp->setViewOptionEnabled("show_skin_weight", skin_weight);
+            fmp->setViewOptionEnabled("show_skin_weight", show_skin_weight);
         }
     }
+    //if (this) return TRUE;
 
     if (upload_skin && !has_skin_weights)
     { //can't upload skin weights if model has no skin weights
@@ -3360,7 +3365,7 @@ bool LLModelPreview::render()
         mFMP->childSetEnabled("upload_joints", upload_skin);
     }
 
-    F32 explode = (F32)mFMP->childGetValue("physics_explode").asReal();
+    F32 physics_explode = (F32)mFMP->childGetValue("physics_explode").asReal();
 
     LLGLDepthTest gls_depth(GL_TRUE); // SL-12781 re-enable z-buffer for 3D model preview
 
@@ -3380,7 +3385,7 @@ bool LLModelPreview::render()
     F32 z_near = 0.001f;
     F32 z_far = mCameraDistance*10.0f + mPreviewScale.magVec() + mCameraOffset.magVec();
 
-    if (skin_weight)
+    if (show_skin_weight)
     {
         target_pos = getPreviewAvatar()->getPositionAgent() + offset;
         z_near = 0.01f;
@@ -3390,7 +3395,7 @@ bool LLModelPreview::render()
         refresh();
     }
 
-    gObjectPreviewProgram.bind(skin_weight);
+    gObjectPreviewProgram.bind(show_skin_weight);
 
     gGL.loadIdentity();
     gPipeline.enableLightsPreview();
@@ -3399,7 +3404,7 @@ bool LLModelPreview::render()
         LLQuaternion(mCameraYaw, LLVector3::z_axis);
 
     LLQuaternion av_rot = camera_rot;
-    F32 camera_distance = skin_weight ? SKIN_WEIGHT_CAMERA_DISTANCE : mCameraDistance;
+    F32 camera_distance = show_skin_weight ? SKIN_WEIGHT_CAMERA_DISTANCE : mCameraDistance;
     LLViewerCamera::getInstance()->setOriginAndLookAt(
         target_pos + ((LLVector3(camera_distance, 0.f, 0.f) + offset) * av_rot),        // camera
         LLVector3::z_axis,                                                                  // up
@@ -3415,9 +3420,9 @@ bool LLModelPreview::render()
     gGL.pushMatrix();
     gGL.color4fv(PREVIEW_EDGE_COL.mV);
 
-    if (!mBaseModel.empty() && mVertexBuffer[5].empty())
+    if (!mBaseModel.empty() && mVertexBuffer[LLModel::NUM_LODS].empty())
     {
-        genBuffers(-1, skin_weight);
+        genBuffers(-1, show_skin_weight);
         //genBuffers(3);
     }
 
@@ -3432,7 +3437,7 @@ bool LLModelPreview::render()
             if (!vb_vec.empty())
             {
                 const LLVertexBuffer* buff = vb_vec[0];
-                regen = buff->hasDataType(LLVertexBuffer::TYPE_WEIGHT4) != skin_weight;
+                regen = buff->hasDataType(LLVertexBuffer::TYPE_WEIGHT4) != show_skin_weight;
             }
             else
             {
@@ -3443,15 +3448,15 @@ bool LLModelPreview::render()
 
         if (regen)
         {
-            genBuffers(mPreviewLOD, skin_weight);
+            genBuffers(mPreviewLOD, show_skin_weight);
         }
 
-        if (physics && mVertexBuffer[LLModel::LOD_PHYSICS].empty())
+        if (show_physics && mVertexBuffer[LLModel::LOD_PHYSICS].empty())
         {
             genBuffers(LLModel::LOD_PHYSICS, false);
         }
 
-        if (!skin_weight)
+        if (!show_skin_weight)
         {
             for (LLMeshUploadThread::instance_list::iterator iter = mUploadData.begin(); iter != mUploadData.end(); ++iter)
             {
@@ -3473,11 +3478,7 @@ bool LLModelPreview::render()
                 auto num_models = mVertexBuffer[mPreviewLOD][model].size();
                 for (size_t i = 0; i < num_models; ++i)
                 {
-                    LLVertexBuffer* buffer = mVertexBuffer[mPreviewLOD][model][i];
-
-                    buffer->setBuffer();
-
-                    if (textures)
+                    if (show_textures)
                     {
                         auto materialCnt = instance.mModel->mMaterialList.size();
                         if (i < materialCnt)
@@ -3501,10 +3502,16 @@ bool LLModelPreview::render()
                         gGL.diffuseColor4fv(PREVIEW_BASE_COL.mV);
                     }
 
+                    // Zero this variable for an obligatory buffer initialization
+                    // See https://github.com/secondlife/viewer/issues/912
+                    LLVertexBuffer::sGLRenderBuffer = 0;
+                    LLVertexBuffer* buffer = mVertexBuffer[mPreviewLOD][model][i];
+                    buffer->setBuffer();
                     buffer->drawRange(LLRender::TRIANGLES, 0, buffer->getNumVerts() - 1, buffer->getNumIndices(), 0);
+
                     gGL.getTexUnit(0)->unbind(LLTexUnit::TT_TEXTURE);
                     gGL.diffuseColor4fv(PREVIEW_EDGE_COL.mV);
-                    if (edges)
+                    if (show_edges)
                     {
                         glLineWidth(PREVIEW_EDGE_WIDTH);
                         glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
@@ -3517,7 +3524,7 @@ bool LLModelPreview::render()
                 gGL.popMatrix();
             }
 
-            if (physics)
+            if (show_physics)
             {
                 glClear(GL_DEPTH_BUFFER_BIT);
 
@@ -3583,12 +3590,12 @@ bool LLModelPreview::render()
 
                                     for (U32 i = 0; i < physics.mMesh.size(); ++i)
                                     {
-                                        if (explode > 0.f)
+                                        if (physics_explode > 0.f)
                                         {
                                             gGL.pushMatrix();
 
                                             LLVector3 offset = model->mHullCenter[i] - model->mCenterOfHullCenters;
-                                            offset *= explode;
+                                            offset *= physics_explode;
 
                                             gGL.translatef(offset.mV[0], offset.mV[1], offset.mV[2]);
                                         }
@@ -3603,7 +3610,7 @@ bool LLModelPreview::render()
                                         gGL.diffuseColor4ubv(hull_colors[i].mV);
                                         LLVertexBuffer::drawArrays(LLRender::TRIANGLES, physics.mMesh[i].mPositions);
 
-                                        if (explode > 0.f)
+                                        if (physics_explode > 0.f)
                                         {
                                             gGL.popMatrix();
                                         }
@@ -3618,14 +3625,17 @@ bool LLModelPreview::render()
                         if (render_mesh)
                         {
                             auto num_models = mVertexBuffer[LLModel::LOD_PHYSICS][model].size();
-                            if (pass > 0){
+                            if (pass > 0)
+                            {
                                 for (size_t i = 0; i < num_models; ++i)
                                 {
-                                    LLVertexBuffer* buffer = mVertexBuffer[LLModel::LOD_PHYSICS][model][i];
-
                                     gGL.getTexUnit(0)->unbind(LLTexUnit::TT_TEXTURE);
                                     gGL.diffuseColor4fv(PREVIEW_PSYH_FILL_COL.mV);
 
+                                    // Zero this variable for an obligatory buffer initialization
+                                    // See https://github.com/secondlife/viewer/issues/912
+                                    LLVertexBuffer::sGLRenderBuffer = 0;
+                                    LLVertexBuffer* buffer = mVertexBuffer[LLModel::LOD_PHYSICS][model][i];
                                     buffer->setBuffer();
                                     buffer->drawRange(LLRender::TRIANGLES, 0, buffer->getNumVerts() - 1, buffer->getNumIndices(), 0);
 
@@ -3685,10 +3695,11 @@ bool LLModelPreview::render()
                                     auto num_models = mVertexBuffer[LLModel::LOD_PHYSICS][model].size();
                                     for (size_t v = 0; v < num_models; ++v)
                                     {
+                                        // Zero this variable for an obligatory buffer initialization
+                                        // See https://github.com/secondlife/viewer/issues/912
+                                        LLVertexBuffer::sGLRenderBuffer = 0;
                                         LLVertexBuffer* buffer = mVertexBuffer[LLModel::LOD_PHYSICS][model][v];
-
                                         buffer->setBuffer();
-
                                         LLStrider<LLVector3> pos_strider;
                                         buffer->getVertexStrider(pos_strider, 0);
                                         LLVector4a* pos = (LLVector4a*)pos_strider.get();
@@ -3752,7 +3763,7 @@ bool LLModelPreview::render()
                         U32 joint_count = LLSkinningUtil::getMeshJointCount(skin);
                         auto bind_count = skin->mAlternateBindMatrix.size();
 
-                        if (joint_overrides
+                        if (show_joint_overrides
                             && bind_count > 0
                             && joint_count == bind_count)
                         {
@@ -3795,16 +3806,15 @@ bool LLModelPreview::render()
                             }
                         }
 
-                        for (U32 i = 0, e = static_cast<U32>(mVertexBuffer[mPreviewLOD][model].size()); i < e; ++i)
+                        std::size_t size = mVertexBuffer[mPreviewLOD][model].size();
+                        for (U32 i = 0; i < size; ++i)
                         {
-                            LLVertexBuffer* buffer = mVertexBuffer[mPreviewLOD][model][i];
-
                             model->mSkinInfo.updateHash();
                             LLRenderPass::uploadMatrixPalette(mPreviewAvatar, &model->mSkinInfo);
 
                             gGL.getTexUnit(0)->unbind(LLTexUnit::TT_TEXTURE);
 
-                            if (textures)
+                            if (show_textures)
                             {
                                 auto materialCnt = instance.mModel->mMaterialList.size();
                                 if (i < materialCnt)
@@ -3828,10 +3838,14 @@ bool LLModelPreview::render()
                                 gGL.diffuseColor4fv(PREVIEW_BASE_COL.mV);
                             }
 
+                            // Zero this variable for an obligatory buffer initialization
+                            // See https://github.com/secondlife/viewer/issues/912
+                            LLVertexBuffer::sGLRenderBuffer = 0;
+                            LLVertexBuffer* buffer = mVertexBuffer[mPreviewLOD][model][i];
                             buffer->setBuffer();
                             buffer->draw(LLRender::TRIANGLES, buffer->getNumIndices(), 0);
 
-                            if (edges)
+                            if (show_edges)
                             {
                                 gGL.getTexUnit(0)->unbind(LLTexUnit::TT_TEXTURE);
                                 gGL.diffuseColor4fv(PREVIEW_EDGE_COL.mV);
@@ -3846,7 +3860,7 @@ bool LLModelPreview::render()
                 }
             }
 
-            if (joint_positions)
+            if (show_joint_positions)
             {
                 LLGLSLShader* shader = LLGLSLShader::sCurBoundShaderPtr;
                 if (shader)