Hello,
OpenGL is a graphics library without GUI support. OpenGL do not have any functions to show a button,list box, edit box etc.
You can draw whatever you want, to the OpenGL rendering window. Therefore you have to write code to display the button.
There are many gui frameworks developed in OpenGL, like GLUI.
http://glui.sourceforge.net/
GLUI is a GLUT based user interface library.
Another suggestion is to use windows controls. Create a dialog based application with a static window for rendering your model to screen, and additional controls to handle zoom, close etc. Then create opengl rendering context with the device context of static window. Then you can handle windows GUI for GUI interaction and opengl for graphics output.
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