   FLipping using glPixelZoom
  Hello,I am trying to flip my output...glDrawPixels(c1.getWidth(),c1.getHeight(),GL_BGRA,GL_UNSIGNED_BYTE,c1.getBuffer());updateGL();the above code displays my video frames but is inverted. If i add glPixelZoom(1.0f, -1.0f); before glDrawPixles the display is blank...  please help...regardsVasanth   