C++学习（三三一）有关osgUtil::SceneView

Posted 2021-08-30 hankern

每个渲染器会有两个osgUtil::SceneView，两个是便于在多线程时，一个线程在一个SceneView做裁减，另一个线程在另一个SceneView做绘制，可以并行操作。

osgViewer/Renderer.cpp
Renderer::Renderer(osg::Camera* camera):
    osg::Referenced(true),
    osg::GraphicsOperation("Renderer",true),
    _camera(camera),
    _done(false),
    _graphicsThreadDoesCull(true),
    _compileOnNextDraw(true),
    _serializeDraw(false),
    _initialized(false),
    _startTick(0)
{
    _sceneView[0] = new osgUtil::SceneView;
    _sceneView[1] = new osgUtil::SceneView;
    _availableQueue.add(_sceneView[0].get());
    _availableQueue.add(_sceneView[1].get());
}

void Renderer::cull()
{
    osgUtil::SceneView* sceneView = _availableQueue.takeFront();
    sceneView->cull();
    _drawQueue.add(sceneView);
}

void Renderer::draw()
{
    osgUtil::SceneView* sceneView = _drawQueue.takeFront();
    sceneView->draw();
    _availableQueue.add(sceneView);
}

osgUtil::SceneView负责执行裁减和绘制操作。

osgViewer/Renderer.cpp
void Renderer::cull_draw()
{
    osgUtil::SceneView* sceneView = _sceneView[0].get();
    sceneView->cull();
    sceneView->draw();
}