glutpostoverlayredisplay(3glut) [mojave man page]
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 callback (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_OVER- LAY_DAMAGED). 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 overlay, 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)
Check Out this Related Man Page
glutPostOverlayRedisplay(3GLUT) GLUT glutPostOverlayRedisplay(3GLUT) NAME
glutPostOverlayRedisplay, glutPostWindowOverlayRedisplay - marks the overlay of the current or specified window as needing to be redis- played. SYNTAX
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 callback (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_OVER- LAY_DAMAGED). 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 overlay, 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 need a full clear. */ glClear(GL_COLOR_BUFFER_BIT); } else { /* Undraw last rubber-band. */ glIndexi(transparent); glBegin(GL_LINE_LOOP); glVertex2i(anchorX, anchorY); glVertex2i(anchorX, prevStretchY); glVertex2i(prevStretchX, prevStretchY); glVertex2i(prevStretchX, anchorY); glEnd(); } glIndexi(red); glBegin(GL_LINE_LOOP); glVertex2i(anchorX, anchorY); glVertex2i(anchorX, stretchY); glVertex2i(stretchX, stretchY); glVertex2i(stretchX, anchorY); glEnd(); prevStretchX = stretchX; prevStretchY = stretchY; } Notice how glutLayerGet(GLUT_OVERLAY_DAMAGED) is used to determine if a clear needs to take place because of damage; if a clear is unneces- sary, it is faster to just draw the last rubberband using the transparent pixel. When the application is through with the rubberbanding effect, the best way to get ride of the rubberband is to simply hide the overlay by calling glutHideOverlay. SEE ALSO
glutPostRedisplay, glutEstablishOverlay, glutLayerGet AUTHOR
Mark J. Kilgard (mjk@nvidia.com) GLUT
3.7 glutPostOverlayRedisplay(3GLUT)