WebXRHeadFullVolumeCVR

Live example

WebXR Example with Realistic Rendering - Volumetric Shading

This is an XR example with volumetric shading effect. It calculates full global shadow. This example is computationally demanding - recommand driving VR headset with external GPU.

See Also

Gradient Shading Example
Hybrid Shading Example

Source

import { mat4 } from 'gl-matrix';
import '@kitware/vtk.js/favicon';

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

// Force DataAccessHelper to have access to various data source
import '@kitware/vtk.js/IO/Core/DataAccessHelper/HtmlDataAccessHelper';
import '@kitware/vtk.js/IO/Core/DataAccessHelper/JSZipDataAccessHelper';

import vtkColorTransferFunction from '@kitware/vtk.js/Rendering/Core/ColorTransferFunction';
import vtkFullScreenRenderWindow from '@kitware/vtk.js/Rendering/Misc/FullScreenRenderWindow';
import vtkWebXRRenderWindowHelper from '@kitware/vtk.js/Rendering/WebXR/RenderWindowHelper';
import HttpDataAccessHelper from '@kitware/vtk.js/IO/Core/DataAccessHelper/HttpDataAccessHelper';
import vtkPiecewiseFunction from '@kitware/vtk.js/Common/DataModel/PiecewiseFunction';
import vtkURLExtract from '@kitware/vtk.js/Common/Core/URLExtract';
import vtkVolume from '@kitware/vtk.js/Rendering/Core/Volume';
import vtkVolumeMapper from '@kitware/vtk.js/Rendering/Core/VolumeMapper';
import vtkXMLImageDataReader from '@kitware/vtk.js/IO/XML/XMLImageDataReader';
import vtkImageReslice from '@kitware/vtk.js/Imaging/Core/ImageReslice';
import vtkMath from '@kitware/vtk.js/Common/Core/Math';
import { XrSessionTypes } from '@kitware/vtk.js/Rendering/WebXR/RenderWindowHelper/Constants';

import './WebXRVolume.module.css';

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

const background = [0, 0, 0];
const fullScreenRenderer = vtkFullScreenRenderWindow.newInstance({
  background,
});
const renderer = fullScreenRenderer.getRenderer();
const renderWindow = fullScreenRenderer.getRenderWindow();
const xrRenderWindowHelper = vtkWebXRRenderWindowHelper.newInstance({
  renderWindow: fullScreenRenderer.getApiSpecificRenderWindow(),
});

// ----------------------------------------------------------------------------
// Set up pipeline objects
// ----------------------------------------------------------------------------

const vtiReader = vtkXMLImageDataReader.newInstance();
const reslicer = vtkImageReslice.newInstance();
const actor = vtkVolume.newInstance();
const mapper = vtkVolumeMapper.newInstance();
reslicer.setInputConnection(vtiReader.getOutputPort());
mapper.setInputConnection(reslicer.getOutputPort());
actor.setMapper(mapper);
renderer.addVolume(actor);

// create color and opacity transfer functions
const ctfun = vtkColorTransferFunction.newInstance();
const ofun = vtkPiecewiseFunction.newInstance();

// ----------------------------------------------------------------------------
// Example code
// ----------------------------------------------------------------------------

const {
  fileURL = 'https://data.kitware.com/api/v1/file/59de9dca8d777f31ac641dc2/download',
  xrSessionType = null,
} = vtkURLExtract.extractURLParameters();

// Validate input parameters
let requestedXrSessionType = xrSessionType;
if (!Object.values(XrSessionTypes).includes(requestedXrSessionType)) {
  console.warn(
    'Could not parse requested XR session type: ',
    requestedXrSessionType
  );
  requestedXrSessionType = null;
}

if (requestedXrSessionType === XrSessionTypes.LookingGlassVR) {
  // Import the Looking Glass WebXR Polyfill override
  // Assumes that the Looking Glass Bridge native application is already running.
  // See https://docs.lookingglassfactory.com/developer-tools/webxr
  import(
    // eslint-disable-next-line import/no-unresolved, import/extensions
    /* webpackIgnore: true */ 'https://unpkg.com/@lookingglass/webxr@0.3.0/dist/@lookingglass/bundle/webxr.js'
  ).then((obj) => {
    // eslint-disable-next-line no-new
    new obj.LookingGlassWebXRPolyfill({ numViews: 12 });
  });
} else if (requestedXrSessionType === null) {
  // Determine supported session type
  navigator.xr.isSessionSupported('immersive-ar').then((arSupported) => {
    if (arSupported) {
      requestedXrSessionType = XrSessionTypes.MobileAR;
    } else {
      navigator.xr.isSessionSupported('immersive-vr').then((vrSupported) => {
        requestedXrSessionType = vrSupported ? XrSessionTypes.HmdVR : null;
      });
    }
  });
}

HttpDataAccessHelper.fetchBinary(fileURL).then((fileContents) => {
  // Read data
  vtiReader.parseAsArrayBuffer(fileContents);

  // Rotate 90 degrees forward so that default head volume faces camera
  const rotateX = mat4.create();
  mat4.fromRotation(rotateX, vtkMath.radiansFromDegrees(90), [-1, 0, 0]);
  reslicer.setResliceAxes(rotateX);

  const data = reslicer.getOutputData(0);

  // Restyle visual appearance
  const sampleDistance =
    0.7 *
    Math.sqrt(
      data
        .getSpacing()
        .map((v) => v * v)
        .reduce((a, b) => a + b, 0)
    );
  mapper.setSampleDistance(sampleDistance);

  ofun.addPoint(0.0, 0.0);
  ofun.addPoint(1100.58, 0.0117188);
  ofun.addPoint(2334.07, 0.808594);
  ofun.addPoint(3305.9, 0.0);
  ofun.addPoint(4095, 0.0);
  ctfun.addRGBPoint(0.0, 0.0, 0.0, 0.0);
  ctfun.addRGBPoint(490.071, 0.901961, 0.0, 0.0);
  ctfun.addRGBPoint(1449.45, 0.866667, 0.0745098, 0.0196078);
  ctfun.addRGBPoint(1511.74, 0.631373, 0.552941, 0.152941);
  ctfun.addRGBPoint(2321.61, 0.992157, 0.992157, 0.984314);
  ctfun.addRGBPoint(4095, 1.0, 1.0, 1.0);
  actor.getProperty().setRGBTransferFunction(0, ctfun);
  actor.getProperty().setScalarOpacity(0, ofun);
  actor.getProperty().setInterpolationTypeToLinear();

  // CVR
  actor.getProperty().setShade(true);
  actor.getProperty().setAmbient(0.0);
  actor.getProperty().setDiffuse(2.0);
  actor.getProperty().setSpecular(0.0);
  mapper.setGlobalIlluminationReach(1.0);
  mapper.setVolumetricScatteringBlending(1.0);
  mapper.setVolumeShadowSamplingDistFactor(1.0);
  mapper.setAutoAdjustSampleDistances(false);

  // Set up rendering
  renderer.resetCamera();
  renderWindow.render();

  // Add button to launch AR (default) or VR scene
  const xrButton = document.createElement('button');
  let enterText = 'XR not available!';
  const exitText = 'Exit XR';
  xrButton.textContent = enterText;
  if (navigator.xr !== undefined && xrRenderWindowHelper.getXrSupported()) {
    enterText =
      requestedXrSessionType === XrSessionTypes.MobileAR
        ? 'Start AR'
        : 'Start VR';
    xrButton.textContent = enterText;
  }
  xrButton.addEventListener('click', () => {
    if (xrButton.textContent === enterText) {
      xrRenderWindowHelper.startXR(requestedXrSessionType);
      xrButton.textContent = exitText;
    } else {
      xrRenderWindowHelper.stopXR();
      xrButton.textContent = enterText;
    }
  });
  document.querySelector('.content').appendChild(xrButton);
});

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

global.source = vtiReader;
global.mapper = mapper;
global.actor = actor;
global.ctfun = ctfun;
global.ofun = ofun;
global.renderer = renderer;
global.renderWindow = renderWindow;