SDLPP: Save texture before rendering

In some cases texture might be changed after render() has been called
but before renderer presented the render, causing errors.

sdlpp/sdlpp_renderobject.hpp

@@ -78,11 +78,13 @@ public:
     bool isStatic();
     void setStatic( bool stat = true );
     std::shared_ptr< Renderer > getRenderer() const;
+    void saveCurTexture();
 
 protected:
-    virtual void copyTo(std::shared_ptr<RenderObject> other);
+    virtual void copyTo( std::shared_ptr< RenderObject > other );
     std::vector< std::shared_ptr< CollisionPolygon > > collisions;
     std::shared_ptr< Texture > texture;
+    std::shared_ptr< Texture > cur_texture;
     std::shared_ptr< Renderer > renderer;
     std::shared_ptr< CollisionPolygon > polygon;
     double movementSpeed = 0;