[osg][原创]osg多屏幕显示，会出现透明需要设置的问题

同事由于新加了一个屏幕，本来用

osg::ref_ptr<osgViewer::Viewer> viewer = new osgViewer::Viewer();
viewer->setSceneData(groupRoot.get());
return viewer->run(); 

就直接可以跑全屏的程序了，然是现在会在两块屏出现全屏，他很苦恼。

于是他：

osgViewer::View* createView(int screenNum)
{
unsigned int width = 1920, height = 1080;
osg::GraphicsContext::WindowingSystemInterface* wsi = osg::GraphicsContext::getWindowingSystemInterface();
if (wsi)
{
wsi->getScreenResolution(osg::GraphicsContext::ScreenIdentifier(screenNum),width,height);
}

osg::ref_ptr<osg::GraphicsContext::Traits> traits = new osg::GraphicsContext::Traits;
traits->screenNum = screenNum;
traits->x = 0;
traits->y = 0;
traits->width = width;
traits->height = height;
traits->windowDecoration = false;
traits->doubleBuffer = true;
traits->sharedContext = 0;
osg::ref_ptr<osg::GraphicsContext> gc = osg::GraphicsContext::createGraphicsContext(traits.get());
if (!gc) return NULL;

osg::ref_ptr<osg::Camera> camera = new osg::Camera;
camera->setGraphicsContext(gc.get());
camera->setViewport(new osg::Viewport(0,0,width,height));
camera->setProjectionMatrixAsPerspective(30.0f, static_cast<double>(width) / static_cast<double>(height), 1.0f, 10000.0f);

GLenum buffer = traits->doubleBuffer ? GL_BACK : GL_FRONT;
camera->setDrawBuffer(buffer);
camera->setReadBuffer(buffer);

osg::ref_ptr<osgViewer::View> view = new osgViewer::View;
view->setCamera(camera.get());
view->setCameraManipulator(new osgGA::TrackballManipulator);
return view.release();
}

调用时：

osg::ref_ptr<osgViewer::CompositeViewer> viewer = new osgViewer::CompositeViewer();
    osgViewer::View* view = createView(0);
    if (view)
    {
        view->setSceneData(groupRoot.get());

        viewer->addView(view);
    }
    return viewer->run();

但是遇到问题

他加载了一个使用透明图片的billboard

在之前的代码中显示是透明的，

在用了自己的createView（）函数之后，就不透明的。

百思不得其解啊

我看看了，觉得是透明的问题。

给他的

osg::ref_ptr<osg::StateSet> pStateSet = new osg::StateSet();
// 启用混合
        pStateSet->setMode(GL_BLEND,osg::StateAttribute::ON);


····
//主要是下面这句
pStateSet->setRenderingHint(osg::StateSet::TRANSPARENT_BIN);

pGeometry->setStateSet(pStateSet.get());

设置了TRANSPARENT_BIN就透明了的。

透明的问题解决了。。。

那么新问题来了：

1.为什么用viewer自带的就不需要设置？

2.透明测试和深度测试会有问题（老问题）

那这些以后解决吧

当天又解决了：

// 状态属性对象
        osg::ref_ptr<osg::StateSet> pStateSet = new osg::StateSet();

        // 创建一个2D属性对象
        osg::ref_ptr<osg::Texture2D> pTexture2D = new osg::Texture2D();

        // 关联Image对象
        pTexture2D->setImage(image.get());

        // 关联Texture2D纹理对象
        pStateSet->setTextureAttributeAndModes(0, pTexture2D,osg::StateAttribute::ON);

        // 启用混合
        pStateSet->setMode(GL_BLEND,osg::StateAttribute::ON);

        // 关闭光照
        pStateSet->setMode(GL_LIGHTING,osg::StateAttribute::OFF);

····················

osg::ref_ptr<osgViewer::Viewer> viewer = new osgViewer::Viewer();
    viewer->setSceneData(groupRoot.get());
//其实下面这句话就可以解决我同事多屏幕的问题
    viewer->setUpViewOnSingleScreen();
    return viewer->run();