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c++qtqt3d

QObjectPicker works strange with QCuboidMesh

I have Qt6.2.4. QObjectPicker picks entity even I click by mouse close to entity.

For test this case you can modify basic shapes example. If I click on red point on image I got "picked" cuboid. Why?

    // Cuboid shape data
    //   ... 
    Qt3DRender::QObjectPicker *cubePicker = new Qt3DRender::QObjectPicker(cuboid);
    connect(cubePicker, &Qt3DRender::QObjectPicker::pressed, this, [] (Qt3DRender::QPickEvent *pick) {
         qDebug() << "pick = " << pick->worldIntersection() << ", " << pick->entity()->objectName();
    });
    
   //Cuboid
   {
        // ...
        m_cuboidEntity->addComponent(cubePicker);
        m_cuboidEntity->setObjectName("Cuboid 1");
   }

Output:

pick =  QVector3D(4.56187, -0.592511, 0.443995) ,  "Cuboid 1"

enter image description here

Solution

  • Qt3DWindow has render settings. It contains QPickingSettings where there is pickMethod(). By default it uses bounding sphere volume picking (PickingSettings.BoundingVolumePicking). You should choose PickingSettings.TrianglePicking. It is the solution.

    Qt3DRender::QPickingSettings *pikingSettings = view->renderSettings()->pickingSettings();
pikingSettings->setPickMethod(Qt3DRender::QPickingSettings::TrianglePicking);