Pick objects with various methods (GPU picking, raycasting...)

Picking
?

Picking lets you pick Giro3D and native THREE.js objects, and get their coordinates in the CRS of the instance.
Provides various filtering options to enhance precision and performance.

  • pixels
  • Pick latency: 12.1 ms
  • No result to display
100% © IGN

Picking is the action of determining what's underneath the mouse cursor.

index.js
import {
    Vector3,
    Group,
    CanvasTexture,
    Mesh,
    BoxGeometry,
    MeshBasicMaterial,
    SphereGeometry,
    MeshLambertMaterial,
    DirectionalLight,
    AmbientLight,
} from 'three';
import { MapControls } from 'three/examples/jsm/controls/MapControls.js';

import Extent from '@giro3d/giro3d/core/geographic/Extent.js';
import Instance from '@giro3d/giro3d/core/Instance.js';
import Map from '@giro3d/giro3d/entities/Map.js';
import Tiles3D from '@giro3d/giro3d/entities/Tiles3D.js';
import ColorLayer from '@giro3d/giro3d/core/layer/ColorLayer.js';
import ElevationLayer from '@giro3d/giro3d/core/layer/ElevationLayer.js';
import BilFormat from '@giro3d/giro3d/formats/BilFormat.js';
import Tiles3DSource from '@giro3d/giro3d/sources/Tiles3DSource.js';
import Inspector from '@giro3d/giro3d/gui/Inspector.js';

import WmtsSource from '@giro3d/giro3d/sources/WmtsSource.js';
import PointCloudMaterial from '@giro3d/giro3d/renderer/PointCloudMaterial.js';

// Defines projection that we will use (taken from https://epsg.io/2154, Proj4js section)
Instance.registerCRS(
    'EPSG:2154',
    '+proj=lcc +lat_0=46.5 +lon_0=3 +lat_1=49 +lat_2=44 +x_0=700000 +y_0=6600000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs +type=crs',
);
Instance.registerCRS(
    'IGNF:WGS84G',
    'GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]',
);

const extent = new Extent('EPSG:2154', -111629.52, 1275028.84, 5976033.79, 7230161.64);

const viewerDiv = document.getElementById('viewerDiv');

const instance = new Instance(viewerDiv, {
    crs: extent.crs(),
    renderer: {
        clearColor: 0xcccccc,
    },
});

instance.renderingOptions.enableEDL = true;
instance.renderingOptions.enableInpainting = true;
instance.renderingOptions.enablePointCloudOcclusion = true;

// create a map
const map = new Map('map', {
    extent,
    backgroundColor: 'gray',
    supportRaycast: true,
    hillshading: {
        enabled: true,
        elevationLayersOnly: true,
    },
});
instance.add(map);

const noDataValue = -1000;

const capabilitiesUrl =
    'https://data.geopf.fr/wmts?SERVICE=WMTS&VERSION=1.0.0&REQUEST=GetCapabilities';

WmtsSource.fromCapabilities(capabilitiesUrl, {
    layer: 'ELEVATION.ELEVATIONGRIDCOVERAGE.HIGHRES',
    format: new BilFormat(),
    noDataValue,
})
    .then(elevationWmts => {
        map.addLayer(
            new ElevationLayer({
                name: 'wmts_elevation',
                extent: map.extent,
                // We don't need the full resolution of terrain because we are not using any shading
                resolutionFactor: 0.25,
                minmax: { min: 0, max: 5000 },
                noDataOptions: {
                    replaceNoData: false,
                },
                source: elevationWmts,
            }),
        );
    })
    .catch(console.error);

WmtsSource.fromCapabilities(capabilitiesUrl, {
    layer: 'HR.ORTHOIMAGERY.ORTHOPHOTOS',
})
    .then(orthophotoWmts => {
        map.addLayer(
            new ColorLayer({
                name: 'wmts_orthophotos',
                extent: map.extent,
                source: orthophotoWmts,
            }),
        );
    })
    .catch(console.error);

// Create the 3D tiles entity
const pointcloud = new Tiles3D(
    'pointcloud',
    new Tiles3DSource('https://3d.oslandia.com/lidar_hd/tileset.json'),
    {
        material: new PointCloudMaterial(),
    },
);

instance.add(pointcloud);

// also add some lights
const sun = new DirectionalLight('#ffffff', 1.4);
sun.position.set(-1, -2, 1).normalize();
sun.updateMatrixWorld(true);
instance.scene.add(sun);

// We can look below the floor, so let's light also a bit there
const sun2 = new DirectionalLight('#ffffff', 0.5);
sun2.position.set(0, 1, 1);
sun2.updateMatrixWorld();
instance.scene.add(sun2);

// ambient
const ambientLight = new AmbientLight(0xffffff, 0.2);
instance.scene.add(ambientLight);

const cube = new Mesh(new BoxGeometry(300, 300, 300), new MeshLambertMaterial({ color: 'blue' }));
cube.name = 'cube';

cube.position.set(913741, 6459089, 369);
instance.add(cube);
cube.updateMatrixWorld(true);

// place camera above grenoble
instance.camera.camera3D.position.set(913349.2364044407, 6456426.459171033, 1706.0108044011636);

// and look at the Bastille
const lookAt = new Vector3(913896, 6459191, 200);
instance.camera.camera3D.lookAt(lookAt);

// Creates controls
const controls = new MapControls(instance.camera.camera3D, instance.domElement);

// Then looks at extent's center
controls.target.copy(lookAt);
controls.saveState();

controls.enableDamping = true;
controls.dampingFactor = 0.2;

instance.useTHREEControls(controls);

Inspector.attach(document.getElementById('panelDiv'), instance);

const markerMaterial = new MeshLambertMaterial({
    color: 'red',
});

const markerGroup = new Group();
instance.add(markerGroup);

const options = {
    gpuPicking: false,
    showMarkers: true,
    pickPointCloudOnly: false,
    pickMapOnly: false,
    radius: 0,
    limit: 0,
    pickEvent: 'mousemove',
};

function bindCheckBox(name, callback) {
    const elt = document.getElementById(name);
    elt.onchange = () => {
        callback(elt.checked);
    };
}

function bindNumericUpDown(name, callback) {
    const elt = document.getElementById(name);
    elt.onchange = () => {
        const value = parseInt(elt.value, 10);
        callback(value);
    };
}

function bindDropDown(name, callback) {
    const mode = document.getElementById(name);
    mode.onchange = () => {
        callback(mode.value);
    };
}

bindDropDown('pickEvent', v => (options.pickEvent = v));

bindCheckBox('gpuPicking', v => (options.gpuPicking = v));
bindCheckBox('showMarkers', v => {
    options.showMarkers = v;
    if (!v) {
        markerGroup.clear();
        instance.notifyChange();
    }
});
bindCheckBox('pickMap', v => (options.pickMapOnly = v));
bindCheckBox('pickPointCloud', v => (options.pickPointCloudOnly = v));

bindNumericUpDown('radius', v => (options.radius = v));
bindNumericUpDown('limit', v => (options.limit = v));

function updateResultTable(pickResults) {
    const table = document.getElementById('table');
    const resultList = document.getElementById('results');

    resultList.innerHTML = '';

    function column(content) {
        const col = document.createElement('td');
        col.innerHTML = content;
        return col;
    }

    const emptyWarning = document.getElementById('emptyWarning');
    if (pickResults.length > 0) {
        emptyWarning.style.display = 'none';
        table.style.display = 'unset';
    } else {
        emptyWarning.style.display = 'unset';
        table.style.display = 'none';
    }

    for (let index = 0; index < pickResults.length; index++) {
        const pickResult = pickResults[index];
        const tr = document.createElement('tr');

        // result #
        tr.appendChild(column(`${index}`));
        // entity
        const entity = pickResult.entity;
        tr.appendChild(column(entity ? `<code>${pickResult.entity?.id}</code>` : 'none'));
        // picked object
        const type = pickResult.object.type;
        tr.appendChild(column(`<span class="badge rounded-pill text-bg-primary">${type}</span>`));

        /** @type {Vector3} */
        const point = pickResult.point;

        // X, Y, Z coordinates of point
        tr.appendChild(column(point.x.toFixed(0)));
        tr.appendChild(column(point.y.toFixed(0)));
        tr.appendChild(column(point.z.toFixed(0)));

        resultList.appendChild(tr);
    }
}

const sphere = new SphereGeometry(8);

function performPicking(mouseEvent) {
    // Determine which entities to include
    let where = [];
    if (options.pickMapOnly) {
        where.push(map);
    }

    if (options.pickPointCloudOnly) {
        where.push(pointcloud);
    }

    const pickOptions = {
        limit: options.limit === 0 ? undefined : options.limit,
        radius: options.radius,
        gpuPicking: options.gpuPicking,
        where: where.length > 0 ? where : undefined,
        sortByDistance: true,
    };

    const start = performance.now();
    const results = instance.pickObjectsAt(mouseEvent, pickOptions);
    const end = performance.now();

    document.getElementById('latency').innerText = `Latency: ${(end - start).toFixed(1)} ms`;

    const noRaycast = () => {
        /** empty */
    };

    if (options.showMarkers && results.length > 0) {
        const position = results[0].point;
        const marker = new Mesh(sphere, markerMaterial);
        // Disable raycasting on markers to avoid picking them.
        marker.raycast = noRaycast;
        if (markerGroup.children.length > 30) {
            const removed = markerGroup.children.splice(0, markerGroup.children.length - 30);
            removed.forEach(item => item.removeFromParent());
        }

        // - In the case of CPU picking, the Z value is simply the Z-coordinate of
        // the picked point, which itself is affected by the scale of the scene.
        //
        // - In the case of GPU picking, the Z value is sampled from the texture, unaffected
        // by the scale of the scene. That is why we have to apply the scene scale to obtain the
        // correct world space coordinate.
        if (options.gpuPicking) {
            position.multiply(instance.scene.scale);
        }

        marker.position.copy(position);
        // Notice we use attach instead of add so that world position is
        // preserved in case of non-default scale.
        markerGroup.attach(marker);
        marker.updateMatrixWorld(true);
        instance.notifyChange();
    }

    updateResultTable(results);
}

function onMouseMove(mouseEvent) {
    if (options.pickEvent === 'mousemove') {
        performPicking(mouseEvent);
    }
}

function onMouseClick(mouseEvent) {
    if (options.pickEvent === 'click') {
        performPicking(mouseEvent);
    }
}

function bindSlider(name, callback) {
    const slider = document.getElementById(name);
    slider.oninput = function oninput() {
        callback(slider.valueAsNumber);
        instance.notifyChange(map);
    };
}

bindSlider('zScaleSlider', v => {
    instance.scene.scale.setZ(v);
    instance.scene.updateMatrixWorld(true);
    document.getElementById('zScaleLabel').innerText = `Z-scale = ${v.toFixed(1)}`;
});

instance.domElement.addEventListener('mousemove', onMouseMove);
instance.domElement.addEventListener('click', onMouseClick);

instance.scene.updateMatrixWorld(true);

instance.notifyChange();
index.html
<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <title>Giro3D - Picking</title>
  <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.2/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-T3c6CoIi6uLrA9TneNEoa7RxnatzjcDSCmG1MXxSR1GAsXEV/Dwwykc2MPK8M2HN" crossorigin="anonymous">
  <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap-icons@1.11.3/font/bootstrap-icons.min.css">
  <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.2/dist/js/bootstrap.bundle.min.js" integrity="sha384-C6RzsynM9kWDrMNeT87bh95OGNyZPhcTNXj1NW7RuBCsyN/o0jlpcV8Qyq46cDfL" crossorigin="anonymous"></script>
  <style>
    body {
      padding: 0;
      margin: 0;
      width: 100vw;
      height: 100vh;
    }

    #viewerDiv {
      width: 100%;
      height: 100%;
    }

    #panelDiv {
      position: absolute;
      top: 0;
      left: 0;
    }
    
  </style>
</head>

<body>
  <div id="viewerDiv"></div>
  <div id="panelDiv"></div>
  <div class="p-2 h-100 position-absolute top-0 end-0" style="width: 30rem">
    <div class="card" style="height: calc(100% - 1.3rem)">
        <h5 class="card-header">Picking</h5>

        <!-- tooltip -->
        <span
            class="badge bg-secondary position-absolute top-0 end-0 m-2"
            data-bs-toggle="popover"
            data-bs-content="pickingHelper"
            >?</span
        >
        <p class="card-text d-none" id="pickingHelper">
            Picking lets you pick Giro3D and native THREE.js objects, and get their coordinates in
            the CRS of the instance.<br />
            Provides various filtering options to enhance precision and performance.
        </p>

        <ul class="list-group list-group-flush overflow-y-scroll">
            <li class="list-group-item">
                <!-- Parameters -->
                <form>
                    <!-- Z-scale -->
                    <div class="mb-2">
                        <label for="zScaleSlider" class="col-form-label" id="zScaleLabel"
                            >Z-scale = 1</label
                        >
                        <div class="input-group">
                            <input
                                type="range"
                                min="0.1"
                                max="4"
                                step="0.1"
                                value="1"
                                class="form-range"
                                id="zScaleSlider"
                                autocomplete="off"
                            />
                        </div>
                    </div>

                    <!-- Pick events -->
                    <div class="mb-3">
                        <label for="pickEvent" class="form-label">Pick on event</label>
                        <select id="pickEvent" class="form-select">
                            <option value="click">Click</option>
                            <option value="mousemove" selected>Mouse move</option>
                        </select>
                    </div>
                    <!-- Picking radius -->
                    <div class="mb-3">
                        <label for="radius" class="col-form-label">Picking radius</label>
                        <div class="input-group">
                            <input
                                id="radius"
                                type="number"
                                min="0"
                                max="10"
                                value="0"
                                class="form-control"
                            />
                            <span class="input-group-text">pixels</span>
                        </div>
                    </div>
                    <!-- Limit -->
                    <div class="mb-3">
                        <label for="limit" class="col-form-label"
                            >Number of objects (0 for all)</label
                        >
                        <input
                            id="limit"
                            type="number"
                            min="0"
                            max="100"
                            value="0"
                            class="form-control"
                        />
                    </div>

                    <div class="row">
                        <!-- Prefer raycasting -->
                        <div class="col">
                            <div class="form-check">
                                <input class="form-check-input" type="checkbox" id="gpuPicking" />
                                <label class="form-check-label" for="gpuPicking">
                                    GPU picking
                                </label>
                            </div>
                        </div>

                        <!-- Picking markers -->
                        <div class="col">
                            <div class="form-check">
                                <input
                                    class="form-check-input"
                                    type="checkbox"
                                    checked
                                    id="showMarkers"
                                    autocomplete="off"
                                />
                                <label class="form-check-label" for="showMarkers">
                                    Show markers
                                </label>
                            </div>
                        </div>
                    </div>
                    <div class="row">
                        <!-- Pick map -->
                        <div class="col">
                            <div class="form-check">
                                <input
                                    class="form-check-input"
                                    type="checkbox"
                                    id="pickMap"
                                    autocomplete="off"
                                />
                                <label class="form-check-label" for="pickMap">
                                    Pick only map
                                </label>
                            </div>
                        </div>
                        <!-- Pick point cloud -->
                        <div class="col">
                            <div class="form-check">
                                <input
                                    class="form-check-input"
                                    type="checkbox"
                                    id="pickPointCloud"
                                    autocomplete="off"
                                />
                                <label class="form-check-label" for="pickPointCloud">
                                    Pick only point cloud
                                </label>
                            </div>
                        </div>
                    </div>
                </form>
            </li>
            <li class="list-group-item">
                <span id="latency">Pick latency: 12.1 ms</span>
            </li>
            <li class="list-group-item">
                <div id="emptyWarning" class="p-4">
                    <span class="fs-4 text-secondary">No result to display</span>
                </div>
                <!-- Result table -->
                <table id="table" class="table" style="display: none">
                    <thead>
                        <tr>
                            <th scope="col">#</th>
                            <th scope="col">Entity</th>
                            <th scope="col">Object</th>
                            <th scope="col">X</th>
                            <th scope="col">Y</th>
                            <th scope="col">Z</th>
                        </tr>
                    </thead>
                    <tbody id="results">
                        <tr>
                            <td>?</td>
                            <td>?</td>
                            <td>?</td>
                            <td>?</td>
                            <td>?</td>
                            <td>?</td>
                        </tr>
                    </tbody>
                </table>
            </li>
        </ul>
    </div>
</div>

  <script type="module" src="index.js"></script>
  <script>
    /* activate popovers */
    const popoverTriggerList = [].slice.call(document.querySelectorAll('[data-bs-toggle="popover"]'));
    popoverTriggerList.map(
      // bootstrap is used as script in the template, disable warning about undef
      // eslint-disable-next-line no-undef
      popoverTriggerEl => new bootstrap.Popover(popoverTriggerEl, {
        trigger: 'hover',
        placement: 'left',
        content: document.getElementById(popoverTriggerEl.getAttribute('data-bs-content')).innerHTML,
        html: true,
      }),
    );
  </script>
</body>

</html>
package.json
{
  "name": "picking",
  "dependencies": {
    "@giro3d/giro3d": "0.36.0",
    "colormap": "^2.3.2",
    "@turf/turf": "^6.5.0"
  },
  "devDependencies": {
    "vite": "^3.2.3"
  },
  "scripts": {
    "start": "vite",
    "build": "vite build"
  }
}