   calling a subwindow from main window
  hi   I have a main window and a sub window. in response to a mouse event in the main window I want to call glutpostredisplay for the sub window?is it doable and how?best wishes   
  I think you are looking for glutSetWindow().Call it before glutPostRedisplay() for each window (main or sub).For example,// update both main and sub windowglutSetWindow(mainWin);glutPostRedisplay();glutSetWindow(subWin);glutPostRedisplay();