WebGL Overlay (native API)

AI-generated Key Takeaways

• This example showcases the use of WebGLOverlayView to render a 3D model with animation on a Google Map.

• It uses the Three.js library for 3D rendering and a GLTF model of a pin as the displayed object.

• The WebGLOverlayView handles the integration between the 3D scene and the map, ensuring proper georeferencing and rendering.

• The code includes a simple animation loop that rotates the map and the 3D model, providing a dynamic visual experience.

• Users can interact with the provided code snippets in Typescript, JavaScript, CSS, and HTML, and there's an option to try a live sample or clone the repository for local execution.

This example demonstrates using the WebGLOverlayView to display a 3D image with animation on a vector map.

Read the documentation.

TypeScript

import {
  AmbientLight,
  DirectionalLight,
  Matrix4,
  PerspectiveCamera,
  Scene,
  WebGLRenderer,
} from "three";

import { GLTFLoader } from "three/examples/jsm/loaders/GLTFLoader";

let map: google.maps.Map;

const mapOptions = {
  tilt: 0,
  heading: 0,
  zoom: 18,
  center: { lat: 35.6594945, lng: 139.6999859 },
  mapId: "15431d2b469f209e",
  // disable interactions due to animation loop and moveCamera
  disableDefaultUI: true,
  gestureHandling: "none",
  keyboardShortcuts: false,
};

function initMap(): void {
  const mapDiv = document.getElementById("map") as HTMLElement;
  map = new google.maps.Map(mapDiv, mapOptions);
  initWebglOverlayView(map);
}

function initWebglOverlayView(map: google.maps.Map): void {
  let scene, renderer, camera, loader;
  const webglOverlayView = new google.maps.WebGLOverlayView();

  webglOverlayView.onAdd = () => {
    // Set up the scene.

    scene = new Scene();

    camera = new PerspectiveCamera();

    const ambientLight = new AmbientLight(0xffffff, 0.75); // Soft white light.
    scene.add(ambientLight);

    const directionalLight = new DirectionalLight(0xffffff, 0.25);
    directionalLight.position.set(0.5, -1, 0.5);
    scene.add(directionalLight);

    // Load the model.
    loader = new GLTFLoader();
    const source =
      "https://raw.githubusercontent.com/googlemaps/js-samples/main/assets/pin.gltf";
    loader.load(source, (gltf) => {
      gltf.scene.scale.set(10, 10, 10);
      gltf.scene.rotation.x = Math.PI; // Rotations are in radians.
      scene.add(gltf.scene);
    });
  };

  webglOverlayView.onContextRestored = ({ gl }) => {
    // Create the js renderer, using the
    // maps's WebGL rendering context.
    renderer = new WebGLRenderer({
      canvas: gl.canvas,
      context: gl,
      ...gl.getContextAttributes(),
    });
    renderer.autoClear = false;

    // Wait to move the camera until the 3D model loads.
    loader.manager.onLoad = () => {
      renderer.setAnimationLoop(() => {
        webglOverlayView.requestRedraw();
        const { tilt, heading, zoom } = mapOptions;
        map.moveCamera({ tilt, heading, zoom });

        // Rotate the map 360 degrees.
        if (mapOptions.tilt < 67.5) {
          mapOptions.tilt += 0.5;
        } else if (mapOptions.heading <= 360) {
          mapOptions.heading += 0.2;
          mapOptions.zoom -= 0.0005;
        } else {
          renderer.setAnimationLoop(null);
        }
      });
    };
  };

  webglOverlayView.onDraw = ({ gl, transformer }): void => {
    const latLngAltitudeLiteral: google.maps.LatLngAltitudeLiteral = {
      lat: mapOptions.center.lat,
      lng: mapOptions.center.lng,
      altitude: 100,
    };

    // Update camera matrix to ensure the model is georeferenced correctly on the map.
    const matrix = transformer.fromLatLngAltitude(latLngAltitudeLiteral);
    camera.projectionMatrix = new Matrix4().fromArray(matrix);

    webglOverlayView.requestRedraw();
    renderer.render(scene, camera);

    // Sometimes it is necessary to reset the GL state.
    renderer.resetState();
  };
  webglOverlayView.setMap(map);
}

declare global {
  interface Window {
    initMap: () => void;
  }
}
window.initMap = initMap;
index.ts

Note: Read the guide on using TypeScript and Google Maps.

JavaScript

import {
  AmbientLight,
  DirectionalLight,
  Matrix4,
  PerspectiveCamera,
  Scene,
  WebGLRenderer,
} from "three";
import { GLTFLoader } from "three/examples/jsm/loaders/GLTFLoader";
let map;
const mapOptions = {
  tilt: 0,
  heading: 0,
  zoom: 18,
  center: { lat: 35.6594945, lng: 139.6999859 },
  mapId: "15431d2b469f209e",
  // disable interactions due to animation loop and moveCamera
  disableDefaultUI: true,
  gestureHandling: "none",
  keyboardShortcuts: false,
};

function initMap() {
  const mapDiv = document.getElementById("map");

  map = new google.maps.Map(mapDiv, mapOptions);
  initWebglOverlayView(map);
}

function initWebglOverlayView(map) {
  let scene, renderer, camera, loader;
  const webglOverlayView = new google.maps.WebGLOverlayView();

  webglOverlayView.onAdd = () => {
    // Set up the scene.
    scene = new Scene();
    camera = new PerspectiveCamera();

    const ambientLight = new AmbientLight(0xffffff, 0.75); // Soft white light.

    scene.add(ambientLight);

    const directionalLight = new DirectionalLight(0xffffff, 0.25);

    directionalLight.position.set(0.5, -1, 0.5);
    scene.add(directionalLight);
    // Load the model.
    loader = new GLTFLoader();

    const source =
      "https://raw.githubusercontent.com/googlemaps/js-samples/main/assets/pin.gltf";

    loader.load(source, (gltf) => {
      gltf.scene.scale.set(10, 10, 10);
      gltf.scene.rotation.x = Math.PI; // Rotations are in radians.
      scene.add(gltf.scene);
    });
  };

  webglOverlayView.onContextRestored = ({ gl }) => {
    // Create the js renderer, using the
    // maps's WebGL rendering context.
    renderer = new WebGLRenderer({
      canvas: gl.canvas,
      context: gl,
      ...gl.getContextAttributes(),
    });
    renderer.autoClear = false;
    // Wait to move the camera until the 3D model loads.
    loader.manager.onLoad = () => {
      renderer.setAnimationLoop(() => {
        webglOverlayView.requestRedraw();

        const { tilt, heading, zoom } = mapOptions;

        map.moveCamera({ tilt, heading, zoom });
        // Rotate the map 360 degrees.
        if (mapOptions.tilt < 67.5) {
          mapOptions.tilt += 0.5;
        } else if (mapOptions.heading <= 360) {
          mapOptions.heading += 0.2;
          mapOptions.zoom -= 0.0005;
        } else {
          renderer.setAnimationLoop(null);
        }
      });
    };
  };

  webglOverlayView.onDraw = ({ gl, transformer }) => {
    const latLngAltitudeLiteral = {
      lat: mapOptions.center.lat,
      lng: mapOptions.center.lng,
      altitude: 100,
    };
    // Update camera matrix to ensure the model is georeferenced correctly on the map.
    const matrix = transformer.fromLatLngAltitude(latLngAltitudeLiteral);

    camera.projectionMatrix = new Matrix4().fromArray(matrix);
    webglOverlayView.requestRedraw();
    renderer.render(scene, camera);
    // Sometimes it is necessary to reset the GL state.
    renderer.resetState();
  };

  webglOverlayView.setMap(map);
}

window.initMap = initMap;
index.js

Note: The JavaScript is compiled from the TypeScript snippet.

CSS

/* 
 * Always set the map height explicitly to define the size of the div element
 * that contains the map. 
 */
#map {
  height: 100%;
}

/* 
 * Optional: Makes the sample page fill the window. 
 */
html,
body {
  height: 100%;
  margin: 0;
  padding: 0;
}

#map {
  pointer-events: none;
}
style.css

HTML

<html>
  <head>
    <title>Simple WebGL Overlay</title>

    <script src="https://unpkg.com/three@0.129.0/build/three.min.js"></script>

    <link rel="stylesheet" type="text/css" href="./style.css" />
    <script type="module" src="./index.js"></script>
  </head>
  <body>
    <div id="map" class="map"></div>

    <!-- 
      The `defer` attribute causes the script to execute after the full HTML
      document has been parsed. For non-blocking uses, avoiding race conditions,
      and consistent behavior across browsers, consider loading using Promises. See
      https://developers.google.com/maps/documentation/javascript/load-maps-js-api
      for more information.
      -->
    <script
      src="https://maps.googleapis.com/maps/api/js?key=AIzaSyB41DRUbKWJHPxaFjMAwdrzWzbVKartNGg&callback=initMap&v=weekly"
      defer
    ></script>
  </body>
</html>
index.html

Try Sample

Google Cloud Shell

Clone Sample

Git and Node.js are required to run this sample locally. Follow these instructions to install Node.js and NPM. The following commands clone, install dependencies and start the sample application.

  git clone -b sample-webgl-overlay-simple https://github.com/googlemaps/js-samples.git
  cd js-samples
  npm i
  npm start

Other samples can be tried by switching to any branch beginning with sample-SAMPLE_NAME.

  git checkout sample-SAMPLE_NAME
  npm i
  npm start