First opengl/x11/window integration.

src/visual_elements/AbstractVisualNode.h

@@ -14,11 +14,18 @@ public:
 
     }
 
+    virtual ~AbstractVisualNode() = default;
+
     AbstractMesh* getMesh() const
     {
         return mMesh.get();
     }
 
+    virtual void updateMesh()
+    {
+
+    }
+
     Image<unsigned char>* getImage() const
     {
         return mImage.get();
@@ -29,7 +36,7 @@ public:
         return mLocation;
     }
 
-private:
+protected:
     DiscretePoint mLocation;
     std::unique_ptr<AbstractMesh> mMesh;
     std::unique_ptr<Image<unsigned char> > mImage;