qt3d - 除了鼠标单击之外，还可以检测 3D 对象上的触摸

Question

使用方法 Qt3DRender::QObjectPicker与触摸事件？

我正在添加 Qt3DRender::QObjectPicker通过这种方法将组件添加到我的 Qt3D 实体中:

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;
}

我的对象选择器适用于鼠标点击，但不适用于触摸事件。有人知道如何在智能手机上使用带有触摸事件的 Qt3D 对象选择器吗？

Answer 1

@FlorianBlume 帮我解决了这个问题。可以使用 QScreenRayCaster 检测 Qt3D 实体上的触摸.我不得不添加一个 QScreenRayCaster组件到我的根实体:

 /*
  * 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);

我触发 QScreenRayCaster使用 m_screenRayCaster->trigger() 通过这样的触摸事件进行测试方法:

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;
    }

}

处理射线转换结果 MyClass::handleScreenRayCasterHits投币口:

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();
    }
}