+ glVertex3i( lineLength, 0.0, 0.0 );
+ glVertex3i( lineLength - arrowLength, 0.0, -1.0 );
+
+ glVertex3i( -lineLength, 0.0, 0.0 );
+ glVertex3i( -lineLength - arrowLength, 0.0, 1.0 );
+
+ glVertex3i( -lineLength, 0.0, 0.0 );
+ glVertex3i( -lineLength - arrowLength, 0.0, -1.0 );
+
+ // z arrow