The Hello GL2 example demonstrates the basic use of the OpenGL-related classes provided with Qt.
Qt 提供 QOpenGLWidget class to enable OpenGL graphics to be rendered within a standard application user interface. By subclassing this class, and providing reimplementations of event handler functions, 3D scenes can be displayed on widgets that can be placed in layouts, connected to other objects using signals and slots, and manipulated like any other widget.
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