osg.CameraRenderOrderSortOp

osg.CameraRenderOrderSortOp是一个OpenSceneGraph操作类，它用于按照摄像机渲染顺序对场景图进行排序。该操作可用于实现多摄像机渲染，并确保场景图在每个摄像机的视觉下正确地排序。

构造函数

osg::CameraRenderOrderSortOp::CameraRenderOrderSortOp();

该构造函数创建一个默认的CameraRenderOrderSortOp对象。

成员函数

void osg::CameraRenderOrderSortOp::operator()(osg::RenderInfo& renderInfo, const osg::Drawable* drawable) const;

该成员函数实现了osg::StateSortFunctor虚基类中的虚函数。它负责在渲染场景图之前对场景图进行按照摄像机渲染顺序的排序。该函数具体实现需要在派生类中重新定义。

使用方法

osg::ref_ptr<osg::Camera> camera1 = new osg::Camera;
//设置摄像机参数
...
osg::ref_ptr<osg::Camera> camera2 = new osg::Camera;
//设置摄像机参数
...

osg::ref_ptr<osg::CameraRenderOrderSortOp> sortop = new osg::CameraRenderOrderSortOp;

osg::ref_ptr<osg::StateSet> stateSet = new osg::StateSet;
stateSet->setRenderingHint(osg::StateSet::TRANSPARENT_BIN);
stateSet->setRenderBinDetails(0, "RenderBin");
stateSet->setRenderBinDetails(1, "OpaqueBin", osg::StateSet::OVERRIDE_RENDERBIN_DETAILS | osg::StateSet::PROTECTED_RENDERBIN_DETAILS);
stateSet->setRenderBinDetails(2, "TransparentBin", osg::StateSet::OVERRIDE_RENDERBIN_DETAILS | osg::StateSet::PROTECTED_RENDERBIN_DETAILS);

osg::ref_ptr<osg::Node> rootNode = new osg::Node;
//添加子节点
...

rootNode->setStateSet(stateSet);
rootNode->setNodeMask(nodeMask); // 设置节点遮罩

camera1->setRenderOrder(osg::Camera::PRE_RENDER);
camera1->setRenderTargetImplementation(osg::Camera::FRAME_BUFFER_OBJECT);
camera1->setViewport(0, 0, 800, 600);
camera1->setClearMask(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
camera1->addChild(rootNode);
camera1->setCullMask(cullMask); // 设置裁剪遮罩
camera1->setClearColor(osg::Vec4(0.0f, 0.0f, 0.0f, 1.0f));

camera2->setRenderOrder(osg::Camera::PRE_RENDER);
camera1->setRenderTargetImplementation(osg::Camera::FRAME_BUFFER_OBJECT);
camera2->setViewport(0, 0, 800, 600);
camera2->setClearMask(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
camera2->addChild(rootNode);
camera2->setCullMask(cullMask); // 设置裁剪遮罩
camera2->setClearColor(osg::Vec4(0.0f, 0.0f, 0.0f, 1.0f));

osg::ref_ptr<osg::Group> root = new osg::Group;
root->addChild(sortop.get());
root->addChild(camera1.get());
root->addChild(camera2.get());

以上代码创建了两个摄像机并将它们添加到场景图中。通过osg::CameraRenderOrderSortOp操作对象，我们将场景图按照摄像机渲染顺序排序，确保场景图在每个摄像机的视觉下正确地排序。