Finally fully fixed #2213.

src/graphics/shaders.cpp

@@ -150,6 +150,7 @@ void Shaders::destroy()
         m_callbacks[i] = NULL;
     }
     m_has_been_initialised = false;
+    SharedGPUObjects::reset();
 }   // destroy
 
 // ----------------------------------------------------------------------------

src/graphics/shared_gpu_objects.cpp

@@ -196,3 +196,10 @@ void SharedGPUObjects::init()
 
     m_has_been_initialised = true;
 }   // SharedGPUObjects
+
+// ----------------------------------------------------------------------------
+
+void SharedGPUObjects::reset()
+{
+    m_has_been_initialised = false;
+}

src/graphics/shared_gpu_objects.hpp

@@ -49,6 +49,7 @@ private:
 
 public:
     static void init();
+    static void reset();
     // ------------------------------------------------------------------------
     static GLuint getBillboardVBO() 
     {