- Qt 5.15
- Qt 3D
- C++ Classes
- QAspectEngine
- Qt 5.15.11 Reference Documentation

# QAspectEngine Class

class Qt3DCore::QAspectEngine

Responsible for handling all the QAbstractAspect subclasses that have been registered with the scene. More...

Header: | #include <Qt3DCore/QAspectEngine>
qmake: | QT += 3dcore

- List of all members, including inherited members

## Public Functions

| QAspectEngine(QObject *parent = nullptr)
virtual | ~QAspectEngine()
QVector<QAbstractAspect *> | aspects() const
QVariant | executeCommand(const QString &command)
void | processFrame()
void | registerAspect(QAbstractAspect *aspect)
void | registerAspect(const QString &name)
QEntityPtr | rootEntity() const
void | setRootEntity(QEntityPtr root)
void | unregisterAspect(QAbstractAspect *aspect)
void | unregisterAspect(const QString &name)

## Related Non-Members

typedef | QEntityPtr

## Detailed Description

The Qt3D run loop is controlled by the Qt3DRender::QAspectEngine.

Qt3DCore::QAbstractAspect subclasses can be registered by calling Qt3DCore::QAspectEngine::registerAspect() which will take care of registering the aspect and in turn that will call Qt3DCore::QAbstractAspect::onRegistered();

The simulation loop is launched as soon as a root Qt3DCore::QEntity is set on the Qt3DCore::QAspectEngine. This is followed by a call to onEngineStartup() on each aspect so that they can start their simulation work.

The simulation loop is stopped when the root entity is set to Qt3DCore::QEntityPtr(). This calls onEngineShutdown() on each aspect so that they can stop performing their simulation work.

Setting a new valid root entity would restart the simulation loop again.

## Member Function Documentation

### QAspectEngine::QAspectEngine(QObject *parent = nullptr)

Constructs a new QAspectEngine with parent.

### `[virtual]` QAspectEngine::~QAspectEngine()

Destroys the engine.

### QVector<QAbstractAspect *> QAspectEngine::aspects() const

Returns the aspects owned by the aspect engine.

### QVariant QAspectEngine::executeCommand(const QString &command)

Executes the given command on aspect engine. Valid commands are:

- "list aspects"

Returns the reply for the command.

### void QAspectEngine::processFrame()

If using the manual run mode, this function executes the jobs for each aspect. It is blocking and won't return until all jobs have been completed.

If you are using the QRenderAspect,

### void QAspectEngine::registerAspect(QAbstractAspect *aspect)

Registers a new aspect to the AspectManager. The QAspectEngine takes ownership of the aspect and will delete it when the aspect is unregistered.

### void QAspectEngine::registerAspect(const QString &name)

Registers a new aspect to the AspectManager based on its name Uses the currently set aspect factory to create the actual aspect instance.

### QEntityPtr QAspectEngine::rootEntity() const

Returns the root entity of the aspect engine.

See also setRootEntity().

### void QAspectEngine::setRootEntity(QEntityPtr root)

Sets the root entity for the aspect engine.

See also rootEntity().

### void QAspectEngine::unregisterAspect(QAbstractAspect *aspect)

Unregisters and deletes the given aspect.

### void QAspectEngine::unregisterAspect(const QString &name)

Unregisters and deletes the aspect with the given name.

## Related Non-Members

### typedef QEntityPtr

A shared pointer for QEntity.