Handle Alt Tab in fullscreen OpenGL application properly

When trying to implement a simple OpenGL application, I was surprised that while it is easy to find plenty of examples and documentation on advanced rendering stuff, the Win32 framework is poorly documented and even most samples and tutorials do not implement this properly even for basic cases, not mentioning advanced stuff like multiple monitors. Despite of several hours of searching I was unable to find a way which would handle Alt-Tab reliably.

How should OpenGL fullscreen application respond to Alt-Tab? Which messages should the app react to (WM_ACTIVATE, WM_ACTIVATEAPP)? What should the reaction be? (Change the display resolution, destroy / create the rend开发者_运维百科ering context, or destroy / create some OpenGL resources?)

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If the application uses some animation loop, suspend the loop, then just minimize the window. If it changed display resolution and gamma revert to the settings before changing them.

There's no need to destroy OpenGL context or resources; OpenGL uses an abstract resource model: If another program requires RAM of the GPU or other resources, your programs resources will be swapped out transparently.

EDIT:

Changing the window visibility status may require to reset the OpenGL viewport, so it's a good idea to either call glViewport apropriately in the display/rendering function, or at least set it in the resize handler, followed by a complete redraw.