Geometry: Highlight clicked parts

A highlighted part is shown with a white halo. This is useful for indicating for instance selection. The highlighting mechanism applies to all types of parts:

• Data parts

• Isosurfaces

• Isovolumes

• Cutting planes

• Geometry parts (using halo effect)

This example shows how highlight parts as a response to a mouse press event.

Pick event

Send a notification when a pick has occurred.

Attach to the mouse pressed event in the viewer. Create a cee::Ray object from the mouse event coordinates and emit a picked signal using this ray.

void TutorialRunnerViewer::mousePressEvent(QMouseEvent* event)
{
    cee::vis::View* theView = view();
    if (!theView) return;

    // Picking!
    cee::Ray ray = theView->camera().rayFromWindowCoordinates(event->pos().x(), height() - event->pos().y());
    m_mainWindow->pick(ray);

    cee::vis::CameraInputHandler* inputHandler = theView->camera().inputHandler();
    if (inputHandler)
    {
        cee::vis::MouseEvent me = cee::qt::UtilsGui::toMouseEvent(*this, *event);
        cee::vis::MouseButton buttonPressed = cee::qt::UtilsGui::toMouseButton(event->button());

        inputHandler->mousePressEvent(buttonPressed, me);
        update();
    }
}

Create the model and connection

Create a geometry model with four boxes.

void TutorialRunnerMainWindow::highlighting()
{
    cee::vis::View* gcView = getTutorialView();

    cee::PtrRef<cee::geo::GeometryModel> geometryModel = new cee::geo::GeometryModel;
    gcView->setModelOpenGLCapabilitiesFromView(geometryModel.get());


    // Add four boxes
    geometryModel->addPart(new cee::geo::Part(cee::geo::DataGenerator::createBox(cee::Vec3d(1.0, 1.0, 1.0), cee::Vec3d(1.0, 1.0, 1.0)).get()));
    geometryModel->addPart(new cee::geo::Part(cee::geo::DataGenerator::createBox(cee::Vec3d(3.0, 1.0, 1.0), cee::Vec3d(1.0, 1.0, 1.0)).get()));
    geometryModel->addPart(new cee::geo::Part(cee::geo::DataGenerator::createBox(cee::Vec3d(1.0, 3.0, 1.0), cee::Vec3d(1.0, 1.0, 1.0)).get()));
    geometryModel->addPart(new cee::geo::Part(cee::geo::DataGenerator::createBox(cee::Vec3d(3.0, 3.0, 1.0), cee::Vec3d(1.0, 1.0, 1.0)).get()));

    // Add model to view. Ensure that old models are removed first
    gcView->removeAllModels();
    gcView->addModel(geometryModel.get());

    cee::BoundingBox bb = gcView->boundingBox();
    gcView->camera().fitView(bb, cee::Vec3d(0, 0, -1), cee::Vec3d(0, 1, 0));
    gcView->camera().inputHandler()->setRotationPoint(bb.center());

    gcView->requestRedraw();
}

Respond to a picking event sent from the viewer

Highlight the last hit box

void TutorialRunnerMainWindow::pick(const cee::Ray& ray)
{
    cee::vis::View* gcView = getTutorialView();

    // Get the current model as a geometry model
    cee::geo::GeometryModel* geometryModel = dynamic_cast<cee::geo::GeometryModel*>(gcView->model(0));
    if (!geometryModel)
    {
        return;
    }

    // Do the picking
    cee::geo::HitItem hitItem;
    if (!geometryModel->rayIntersect(ray, *gcView, &hitItem))
    {
        // No parts were hit, return without doing any changes
        return;
    }

    // Loop all parts. Toggle off highlighting for all parts except the currently hit
    for (size_t i = 0; i < geometryModel->partCount(); i++)
    {
        cee::geo::Part* part = geometryModel->part(i);

        part->settings().removeAllEffectsOfType<cee::geo::EffectHalo>();

        if (part == hitItem.part())
        {
            part->settings().addEffect(new cee::geo::EffectHalo);
        }
    }

    gcView->requestRedraw();
}