求助

070001717

为什么我用HUD显示文字，结果是怎样的？
代码：
        // 创建一个投影
        osg::Camera* camera = new osg::Camera;

        // 设置投影矩阵
        camera->setProjectionMatrix(osg::Matrix:rtho2D(0,1920,0,1028));

        // 设置试图矩阵   
        camera->setReferenceFrame(osg::Transform::ABSOLUTE_RF);
        camera->setViewMatrix(osg::Matrix::identity());

        // 清除深度缓存
        camera->setClearMask(GL_DEPTH_BUFFER_BIT);

        // 绘制主投影
        camera->setRenderOrder(osg::Camera:OST_RENDER);

        // 不抢夺主投影的焦点
        camera->setAllowEventFocus(false);

        osg::Geode* geode = new osg::Geode();

        std::string simkai("D:\\OSG\\Data\\fonts\\arial.ttf");

        osg::StateSet* stateset = geode->getOrCreateStateSet();

        stateset->setMode(GL_LIGHTING,osg::StateAttribute::OFF);

        osg::Vec3 position(0,0,0.0f);

        osgText::Text * mMsgText = new osgText::Text;

        geode->addDrawable( mMsgText );
        osg::Vec4 layoutColor(1.0f,0.0f,0.0f,1.0f);
        mMsgText->setFont("D:\OSG\Data\fonts\times.ttf");
        mMsgText->setCharacterSize(100);
        mMsgText->setColor(layoutColor);
        mMsgText->setPosition(position);
        mMsgText->setDrawMode(osgText::Text::TEXT);
        mMsgText->setText(L"123456");
        camera->addChild(geode);