viewer: use internal texture to allow viewer to control texture as part of its

context

More intuitive code flow and allows the user to undock the viewer (which
forcibly destroys and recreates the context) and the viewer will handle
creation of the new texture in said new context.

app/widget/viewer/viewerglwidget.h

@@ -74,6 +74,11 @@ public:
    */
   void SetMatrix(const QMatrix4x4& mat);
 
+  /**
+   * @brief Set an image to load and display on screen
+   */
+  void SetImage(const QString& fn);
+
 public slots:
   /**
    * @brief Set the texture to draw and draw it
@@ -82,7 +87,7 @@ public slots:
    *
    * @param tex
    */
-  void SetTexture(OpenGLTexturePtr tex);
+  //void SetTexture(OpenGLTexturePtr tex);
 
   void SetOCIOParameters(const QString& display, const QString& view, const QString& look);
 
@@ -157,7 +162,7 @@ private:
   /**
    * @brief Internal reference to the OpenGL texture to draw. Set in SetTexture() and used in paintGL().
    */
-  OpenGLTexturePtr texture_;
+  OpenGLTexture texture_;
 
   /**
    * @brief Internal shader object to use as the pipeline shader