在QML Scene3D中使用Qt3D QEntity

Question

我想在QML Scene3D中添加一个C++ QEntity,如下所示:

//C++
class MapEntity : public Qt3DCore::QEntity {
    public:
    MapEntity( Qt3DCore::QEntity* parent ) : Qt3DCore::QEntity(parent) {
        ...
    }
}

// QML
Scene3D {
    MapEntity {
        id: map
        ...
    }
}

可能吗？如果是的话,该怎么做？

或者也许可以创建C++场景(例如Qt3DExtras :: Qt3DWindow)并在QML中使用？

Answer 1

是的，可以在C ++代码中定义QEntity然后再使用它。该方法描述如下：

http://doc.qt.io/qt-5/qtqml-cppintegration-definetypes.html

首先，您要创建QEntity。球形例如：

class MyEntity : public Qt3DCore::QEntity {
    public:
        MyEntity( Qt3DCore::QEntity* parent=0 ) : Qt3DCore::QEntity(parent) {
                Qt3DRender::QMaterial *material = new Qt3DExtras::QPhongMaterial;

                Qt3DExtras::QSphereMesh *sphereMesh = new Qt3DExtras::QSphereMesh;
                sphereMesh->setRadius(8);

                addComponent(sphereMesh);
                addComponent(material);
        }
        virtual         ~MyEntity() {}
};

然后将其注册为qml组件：

qmlRegisterType<MyEntity>("com.company.my", 1, 0, "MyEntity");

并在QML中使用它：

Scene3D {
    id: myScene
    anchors.fill: parent
    cameraAspectRatioMode: Scene3D.AutomaticAspectRatio
    focus: true
    enabled: true



    Entity {
        id: sceneRoot

        Quick.Camera {
            id: camera
            projectionType: Quick.CameraLens.PerspectiveProjection
            fieldOfView: 45
            nearPlane : 0.1
            farPlane : 1000.0
            position: Qt.vector3d( 0.0, 0.0, 40.0 )
            upVector: Qt.vector3d( 0.0, 1.0, 0.0 )
            viewCenter: Qt.vector3d( 0.0, 0.0, 0.0 )
        }

        components: [
            Quick.RenderSettings {
                activeFrameGraph: ForwardRenderer {
                    clearColor: Qt.rgba(0, 0.5, 1, 0)
                    camera: camera
                }
            }
        ]

        MyEntity {
            id: myEnt
        }
    }
}