Try to avoid updating skidmark each frames.

src/graphics/skid_marks.cpp

@@ -135,6 +135,8 @@ void SkidMarks::update(float dt, bool force_skid_marks,
             // (till these skid mark quads are deleted)
             m_left[m_current]->setHardwareMappingHint(scene::EHM_STATIC);
             m_right[m_current]->setHardwareMappingHint(scene::EHM_STATIC);
+            if (STKMeshSceneNode* stkm = dynamic_cast<STKMeshSceneNode*>(m_nodes[m_current]))
+                stkm->setReloadEachFrame(false);
             return;
         }
 
@@ -190,7 +192,7 @@ void SkidMarks::update(float dt, bool force_skid_marks,
     new_mesh->addMeshBuffer(smq_right);
     scene::IMeshSceneNode *new_node = irr_driver->addMesh(new_mesh);
     if (STKMeshSceneNode* stkm = dynamic_cast<STKMeshSceneNode*>(new_node))
-        stkm->setReloadEachFrame();
+        stkm->setReloadEachFrame(true);
 #ifdef DEBUG
     std::string debug_name = m_kart.getIdent()+" (skid-mark)";
     new_node->setName(debug_name.c_str());

src/graphics/stkmeshscenenode.cpp

@@ -36,9 +36,9 @@ STKMeshSceneNode::STKMeshSceneNode(irr::scene::IMesh* mesh, ISceneNode* parent,
     createGLMeshes();
 }
 
-void STKMeshSceneNode::setReloadEachFrame()
+void STKMeshSceneNode::setReloadEachFrame(bool val)
 {
-    reload_each_frame = true;
+    reload_each_frame = val;
 }
 
 void STKMeshSceneNode::createGLMeshes()

src/graphics/stkmeshscenenode.hpp

@@ -26,7 +26,7 @@ protected:
     bool isMaterialInitialized;
     bool reload_each_frame;
 public:
-    void setReloadEachFrame();
+    void setReloadEachFrame(bool);
     STKMeshSceneNode(irr::scene::IMesh* mesh, ISceneNode* parent, irr::scene::ISceneManager* mgr, irr::s32 id,
         const irr::core::vector3df& position = irr::core::vector3df(0, 0, 0),
         const irr::core::vector3df& rotation = irr::core::vector3df(0, 0, 0),