除鼠标单击外，还可检测3D对象上的触摸

Question

如何在触摸事件中使用Qt3DRender :: QObjectPicker ？

我通过这种方法将Qt3DRender::QObjectPicker组件添加到我的Qt3D实体：

Qt3DRender::QObjectPicker *MyClass::createObjectPickerForEntity(Qt3DCore::QEntity *entity)
{
    Qt3DRender::QObjectPicker *picker = new Qt3DRender::QObjectPicker(entity);
    picker->setHoverEnabled(false);
    entity->addComponent(picker);
    connect(picker, &Qt3DRender::QObjectPicker::pressed, this, &MyClass::handlePickerPress);

    return picker;
}

我的对象选择器可以使用鼠标单击，但它不适用于触摸事件。 有谁知道如何在智能手机上使用Qt3D对象选择器和触摸事件？

Answer 1

@FlorianBlume帮我解决了这个问题。 可以使用QScreenRayCaster检测触摸Qt3D实体。 我不得不在我的root实体中添加一个QScreenRayCaster组件：

 /*
  * You have to add the ray caster to the root entity as a component
  * Perform ray casting tests by specifying "touch" coordinates in screen space
  */
    m_screenRayCaster = new Qt3DRender::QScreenRayCaster(m_rootEntity);
    m_screenRayCaster->setRunMode(Qt3DRender::QAbstractRayCaster::SingleShot);
    m_rootEntity->addComponent(m_screenRayCaster);

 /*
  * Handle ray casting results by signal-slot connection
  * "QScreenRayCaster::hitsChanged" signal contains ray casting result for any hit
  * "MyClass::handleScreenRayCasterHits" slot needs to be implemented to handle hit results
  */
    QObject::connect(m_screenRayCaster, &Qt3DRender::QScreenRayCaster::hitsChanged, this, &MyClass::handleScreenRayCasterHits);

我使用m_screenRayCaster->trigger()方法通过这样的触摸事件触发QScreenRayCaster测试：

void MyClass::HandleTouchEvent(QTouchEvent *event)
{
    switch (event->type()) {
    case QEvent::TouchBegin:
        break;
    case QEvent::TouchEnd:
        if (event->touchPoints().count() == 1) {
            QPointF point = event->touchPoints().at(0).pos();
            m_screenRayCaster->trigger(QPoint(static_cast<int>(point.x()), static_cast<int>(point.y())));
        }
        break;
    default:
        break;
    }

}

处理光线投射导致MyClass::handleScreenRayCasterHits插槽：

void MyClass::handleScreenRayCasterHits(const Qt3DRender::QAbstractRayCaster::Hits hits)
{
    for (int i = 0; i < hits.length(); ++i) {
        qDebug() << __func__ << "Hit Type: " << hits.at(i).type();
        qDebug() << __func__ << "Hit entity name: " << hits.at(i).entity()->objectName();
    }
}