glutPostOverlayRedisplay(3GLUT) GLUT glutPostOverlayRedisplay(3GLUT)NAME
glutPostOverlayRedisplay, glutPostWindowOverlayRedisplay - marks the
overlay of the current or specified window as needing to be redis‐
played.
SYNTAX
#include <GLUT/glut.h>
void glutPostOverlayRedisplay(void);
void glutPostWindowOverlayRedisplay(int win);
DESCRIPTION
Mark the overlay of current window as needing to be redisplayed. The
next iteration through glutMainLoop, the window's overlay display call‐
back (or simply the display callback if no overlay display callback is
registered) will be called to redisplay the window's overlay plane.
Multiple calls to glutPostOverlayRedisplay before the next display
callback opportunity (or overlay display callback opportunity if one is
registered) generate only a single redisplay. glutPostOverlayRedisplay
may be called within a window's display or overlay display callback to
re-mark that window for redisplay.
Logically, overlay damage notification for a window is treated as a
glutPostOverlayRedisplay on the damaged window. Unlike damage reported
by the window system, glutPostOverlayRedisplay will not set to true the
overlay's damaged status (returned by glutLayerGet(GLUT_OVERLAY_DAM‐
AGED).
If the window you want to post an overlay redisplay on is not already
current (and you do not require it to be immediately made current),
using glutPostWindowOverlayRedisplay is more efficient that calling
glutSetWindow to the desired window and then calling glutPostOverlayRe‐
display.
EXAMPLE
If you are doing an interactive effect like rubberbanding in the over‐
lay, it is a good idea to structure your rendering to minimize flicker
(most overlays are single-buffered). Only clear the overlay if you
know that the window has been damaged. Otherwise, try to simply erase
what you last drew and redraw it in an updated position. Here is an
example overlay display callback used to implement overlay rubberband‐
ing:
void
redrawOverlay(void)
{
static int prevStretchX, prevStretchY;
if (glutLayerGet(GLUT_OVERLAY_DAMAGED)) {
/* Damage means we needwindoay callback 4at theeeeeeeeeeeeeeey displayOverlayRedisplay - marks the
o6s w_COLOR_BUFFER_BITglutCrea} esteck 4at theeeeUnample. Heay(voi-d)
lay - marks thIativi(urrent windglutCreas thBlutns w_LINE_LOOPglutCreas thVesplx2ide chorXow tchorYglutCreas thVesplx2ide chorXowLAY_DAMAGED)glutCreas thVesplx2idrGet(GLUT_OVERLAY_DAMAGED)glutCreas thVesplx2idrGet(GLUT_OVER tchorYglutCreas thEnd(glutCrea}.
}
Iativi( thetInitWindBlutns w_LINE_LOOPglutCreathVesplx2ide chorXow tchorYglutCreathVesplx2ide chorXowsAMAGED)glutCreathVesplx2idsGLUT_OVERsAMAGED)glutCreathVesplx2idsGLUT_OVER tchorYglutCreathEnd(glutCrearGet(GLUT_OV =RsAMAGEDXlutCrearGet(GLUT_OY =RsAMAGEDY;e your program toNostceverla
The overlay display callback can b
menu
stattWina has beallback p is saved fben whe GLUTeeeee;red. has ben b
nred.
ray(voibup misit in an uphutton forawOverlbenerateyou are idia, prevSayRedisplay
AUTH not set thisverlaydow, glutSetColor
GLUT 3.7 glutPostOverlayRedisplay(3GLUT)
