glutWindowStatusFunc

glutWindowStatusFunc sets the window status callback for the current window. The window status callback for a window is called when the window status (visibility) of a window changes. The state callback parameter is one of GLUT_HIDDEN , GLUT_FULLY_RETAINED , GLUT_PARTIALLY_RETAINED , or GLUT_FULLY_COVERED depending on the current window status of the window. GLUT_HIDDEN means that the window is either not shown (often meaning that the window is iconified). GLUT_FULLY_RETAINED means that the window is fully retained (no pixels belonging to the window are covered by other windows). GLUT_PARTIALLY_RETAINED means that the window is partially retained (some but not all pixels belonging to the window are covered by other windows). GLUT_FULLY_COVERED means the window is shown but no part of the window is visible, i.e., until the window's status changes, all further rendering to the window is discarded.

GLUT considers a window visible if any pixel of the window is visible or any pixel of any descendant window is visible on the screen.

GLUT applications are encouraged to disable rendering and/or animation when windows have a status of either GLUT_HIDDEN or GLUT_FULLY_COVERED .

Passing NULL to glutWindowStatusFunc disables the generation of the window status callback.

If the window status callback for a window is disabled and later re-enabled, the window status of the window is undefined; any change in window window status will be reported, that is if you disable a window status callback and re-enable the callback, you are guaranteed the next window status change will be reported.

Setting the window status callback for a window disables the visibility callback set for the window (and vice versa). The visibility callback is set with glutVisibilityFunc . glutVisibilityFunc is deprecated in favor of the more informative glutWindowStatusFunc .