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  Hi everybody,I'm tryig to make OpenGl picking to select a point from a curve. I uses hirarchical selection :in the main display function i did somthin like this :    if(mode ==GL_SELECTION)    {   glpushName(curve);    }    drawCurve()    { for (j =0; j< points number; j++) {   if(mode ==GL_SELECTION)   { glpushName(j);   }   draw point(xj, yj, zj);   if(mode ==GL_SELECTION)   { glPopName();   }   }}if(mode ==GL_SELECTION)    {   glPopName();    }------------------------------------------------------------------------------In the main display function there are other drawing ( axis tics, axis titles). The picking is made by clicking with mouse left button down. To implement the reaction of this event in the mouse function, I use exactly the same code in the red book example : glGetIntegerv (GL_VIEWPORT, viewport);    glSelectBuffer (BUFSIZE, selectBuf);    glRenderMode (GL_SELECT);    glInitNames();    glPushName(0);    glMatrixMode (GL_PROJECTION);    glPushMatrix ();    glLoadIdentity ();/* create 5x5 pixel picking region near cursor location */   gluPickMatrix((GLdouble) x,   (GLdouble) (viewport[3] - y), 5.0, 5.0, viewport);   draw(); //call for the main display method  glPopMatrix ();    glFlush ();    hits = glRenderMode (GL_RENDER);    processHits (hits, selectBuf);--------------------------------------------------------------------------The processhits method is the same than in the red book : void processHits (GLint hits, GLuint buffer[]){    unsigned int i, j;    GLuint ii, jj, names, *ptr;    printf ("hits = %d\n", hits);    ptr = (GLuint *) buffer;    for (i = 0; i < hits; i++) {    /* for each hit */   names = *ptr;   printf (" number of names for this hit = %d\n", names);  ptr++;   printf ("  z1 is %u;", *ptr); ptr++;   printf (" z2 is %u\n", *ptr); ptr++;   printf ("   names are ");   for (j = 0; j < names; j++) {   /*  for each name */  printf ("%d ", *ptr);   ptr++;   }    printf ("\n");   }}--------------------------------------------------------------------------------THE RESULT : EVERY WHERE I CLICK (on the curve or outside the curve) there is the same result : hits =2number of names for this hit = 0   z1 is 0.9999999 z2 is 0.9999999   names are 0 0number of names for this hit = 1  z1 is 0.5 z2 is 1.5   names are    Can any one explaine me why that dosent work, why the selection buffer contains the same data whereever i click. When i comment the line glRenderMode (GL_SELECT); the curve is drawn in the rigt place. Where is the problem, how i can debug that. PLEASE HELP PLEASE ! ! !