On the osg interface, when displaying text information, osgText :: Text will be used, and the following properties must be set, otherwise there will be problems with different fonts and brightness and uniform brightness
text->setAxisAlignment(osgText::TextBase::SCREEN);
The reason for this problem may be that the content of the window is seen from the camera of the main scene. Due to the observation angle, the font will be different in brightness and darkness. After the setting is right on the screen, this problem will not appear.