void dawn(int dawn){ //second try from Stuart
  if(dawn) { //in drawcons before Frustum 
    static float Cbottom[] = { 0.1, 0.1, 0.15 };        /* deep blue @ bottom */
    static float Ctop[]    = { 0.3, 0.3, 0.45 };        /* paler blue @ top */
   //  glDrawBuffer(GL_BACK);    slevy 8pm 3jun07
    glDepthMask(GL_FALSE);
    glMatrixMode(GL_PROJECTION);
    glPushMatrix();
    glLoadIdentity();

    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();
    glLoadIdentity();

    glShadeModel( GL_SMOOTH );
    /* draw a colored quad spanning the whole [[-1..1, -1..1] viewport,
     * just shy of Z=+1 which is the far clip plane
     * when the projection matrix = identity
     */
    glBegin( GL_QUADS );
    glColor3fv( Cbottom );      /* deep blue at bottom */
    glVertex3f( -1,-1, 0.9999 );
    glVertex3f( 1,-1, 0.9999 );
    glColor3fv( Ctop );         /* pale blue at top */
    glVertex3f( 1,1, 0.9999 );
    glVertex3f( -1,1, 0.9999 );
    glEnd();

    glMatrixMode(GL_PROJECTION);
    glPopMatrix();

    glMatrixMode(GL_MODELVIEW);
    glPopMatrix();
    glDepthMask(GL_TRUE); //slevy 8pm 3jun07
  }
} // end dawn()