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glutdisplayfunc(3glut) [osx man page]

glutDisplayFunc(3GLUT)						       GLUT						    glutDisplayFunc(3GLUT)

NAME
glutDisplayFunc - sets the display callback for the current window. SYNTAX
#include <GLUT/glut.h> void glutDisplayFunc(void (*func)(void)); ARGUMENTS
func The new display callback function. DESCRIPTION
glutDisplayFunc sets the display callback for the current window. When GLUT determines that the normal plane for the window needs to be redisplayed, the display callback for the window is called. Before the callback, the current window is set to the window needing to be redisplayed and (if no overlay display callback is registered) the layer in use is set to the normal plane. The display callback is called with no parameters. The entire normal plane region should be redisplayed in response to the callback (this includes ancillary buffers if your program depends on their state). GLUT determines when the display callback should be triggered based on the window's redisplay state. The redisplay state for a window can be either set explicitly by calling glutPostRedisplay or implicitly as the result of window damage reported by the window system. Multiple posted redisplays for a window are coalesced by GLUT to minimize the number of display callbacks called. When an overlay is established for a window, but there is no overlay display callback registered, the display callback is used for redis- playing both the overlay and normal plane (that is, it will be called if either the redisplay state or overlay redisplay state is set). In this case, the layer in use is not implicitly changed on entry to the display callback. See glutOverlayDisplayFunc to understand how distinct callbacks for the overlay and normal plane of a window may be established. When a window is created, no display callback exists for the window. It is the responsibility of the programmer to install a display call- back for the window before the window is shown. A display callback must be registered for any window that is shown. If a window becomes displayed without a display callback being registered, a fatal error occurs. Passing NULL to glutDisplayFunc is illegal as of GLUT 3.0; there is no way to ``deregister'' a display callback (though another callback routine can always be registered). Upon return from the display callback, the normal damaged state of the window (returned by calling glutLayerGet(GLUT_NORMAL_DAMAGED) is cleared. If there is no overlay display callback registered the overlay damaged state of the window (returned by calling glutLayer- Get(GLUT_OVERLAY_DAMAGED) is also cleared. SEE ALSO
glutCreateMenu, glutPostRedisplay, glutOverlayDisplayFunc AUTHOR
Mark J. Kilgard (mjk@nvidia.com) GLUT
3.7 glutDisplayFunc(3GLUT)

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glutOverlayDisplayFunc(3GLUT)					       GLUT					     glutOverlayDisplayFunc(3GLUT)

NAME
glutOverlayDisplayFunc - sets the overlay display callback for the current window. SYNTAX
void glutOverlayDisplayFunc(void (*func)(void)); ARGUMENTS
func The new overlay display callback function. DESCRIPTION
glutDisplayFunc sets the overlay display callback for the current window. The overlay display callback is functionally the same as the win- dow's display callback except that the overlay display callback is used to redisplay the window's overlay. When GLUT determines that the overlay plane for the window needs to be redisplayed, the overlay display callback for the window is called. Before the callback, the current window is set to the window needing to be redisplayed and the layer in use is set to the overlay. The overlay display callback is called with no parameters. The entire overlay region should be redisplayed in response to the callback (this includes ancillary buffers if your program depends on their state). GLUT determines when the overlay display callback should be triggered based on the window's overlay redisplay state. The overlay redisplay state for a window can be either set explicitly by calling glutPostOverlayRedisplay or implicitly as the result of window damage reported by the window system. Multiple posted overlay redisplays for a window are coalesced by GLUT to minimize the number of overlay display call- backs called. Upon return from the overlay display callback, the overlay damaged state of the window (returned by calling glutLayerGet(GLUT_OVERLAY_DAM- AGED) is cleared. The overlay display callback can be deregistered by passing NULL to glutOverlayDisplayFunc. The overlay display callback is initially NULL when an overlay is established. See glutDisplayFunc to understand how the display callback alone is used if an overlay display callback is not registered. SEE ALSO
glutDisplayFunc, glutPostOverlayRedisplay AUTHOR
Mark J. Kilgard (mjk@nvidia.com) GLUT
3.7 glutOverlayDisplayFunc(3GLUT)
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