vtk.js

CellPicker

Live example

Source

import '@kitware/vtk.js/favicon';

// Load the rendering pieces we want to use (for both WebGL and WebGPU)
import '@kitware/vtk.js/Rendering/Profiles/Geometry';

import vtkActor from '@kitware/vtk.js/Rendering/Core/Actor';
import vtkCellPicker from '@kitware/vtk.js/Rendering/Core/CellPicker';
import vtkConeSource from '@kitware/vtk.js/Filters/Sources/ConeSource';
import vtkFullScreenRenderWindow from '@kitware/vtk.js/Rendering/Misc/FullScreenRenderWindow';
import vtkMapper from '@kitware/vtk.js/Rendering/Core/Mapper';
import vtkSphereSource from '@kitware/vtk.js/Filters/Sources/SphereSource';

// ----------------------------------------------------------------------------
// Standard rendering code setup
// ----------------------------------------------------------------------------

const fullScreenRenderer = vtkFullScreenRenderWindow.newInstance();
const renderer = fullScreenRenderer.getRenderer();
const renderWindow = fullScreenRenderer.getRenderWindow();

// ----------------------------------------------------------------------------
// Add a cone source
// ----------------------------------------------------------------------------
const cone = vtkConeSource.newInstance();
const mapper = vtkMapper.newInstance();
mapper.setInputData(cone.getOutputData());
const actor = vtkActor.newInstance();
actor.setMapper(mapper);
actor.getProperty().setColor(0.0, 0.0, 1.0);

renderer.addActor(actor);
renderer.resetCamera();
renderWindow.render();

// ----------------------------------------------------------------------------
// Setup picking interaction
// ----------------------------------------------------------------------------
// Only try to pick cone
const picker = vtkCellPicker.newInstance();
picker.setPickFromList(1);
picker.setTolerance(0);
picker.initializePickList();
picker.addPickList(actor);

// Pick on mouse right click
renderWindow.getInteractor().onRightButtonPress((callData) => {
  if (renderer !== callData.pokedRenderer) {
    return;
  }

  const pos = callData.position;
  const point = [pos.x, pos.y, 0.0];
  console.log(`Pick at: ${point}`);
  picker.pick(point, renderer);

  if (picker.getActors().length === 0) {
    const pickedPoint = picker.getPickPosition();
    console.log(`No cells picked, default: ${pickedPoint}`);
    const sphere = vtkSphereSource.newInstance();
    sphere.setCenter(pickedPoint);
    sphere.setRadius(0.01);
    const sphereMapper = vtkMapper.newInstance();
    sphereMapper.setInputData(sphere.getOutputData());
    const sphereActor = vtkActor.newInstance();
    sphereActor.setMapper(sphereMapper);
    sphereActor.getProperty().setColor(1.0, 0.0, 0.0);
    renderer.addActor(sphereActor);
  } else {
    const pickedCellId = picker.getCellId();
    console.log('Picked cell: ', pickedCellId);

    const pickedPoints = picker.getPickedPositions();
    for (let i = 0; i < pickedPoints.length; i++) {
      const pickedPoint = pickedPoints[i];
      console.log(`Picked: ${pickedPoint}`);
      const sphere = vtkSphereSource.newInstance();
      sphere.setCenter(pickedPoint);
      sphere.setRadius(0.01);
      const sphereMapper = vtkMapper.newInstance();
      sphereMapper.setInputData(sphere.getOutputData());
      const sphereActor = vtkActor.newInstance();
      sphereActor.setMapper(sphereMapper);
      sphereActor.getProperty().setColor(0.0, 1.0, 0.0);
      renderer.addActor(sphereActor);
    }
  }
  renderWindow.render();
});

// -----------------------------------------------------------
// Make some variables global so that you can inspect and
// modify objects in your browser's developer console:
// -----------------------------------------------------------

global.mapper = mapper;
global.actor = actor;
global.renderer = renderer;
global.renderWindow = renderWindow;
global.picker = renderWindow.getInteractor().getPicker();