A canvas with a transparent background.

100% © U.S. Geological Survey

You can render Giro3D's scene on a transparent background, using the appropriate options in the Instance constructor.

index.js
import colormap from 'colormap';
import { Color } from 'three';
import { MapControls } from 'three/examples/jsm/controls/MapControls.js';
import XYZ from 'ol/source/XYZ.js';

import Extent from '@giro3d/giro3d/core/geographic/Extent.js';
import Instance from '@giro3d/giro3d/core/Instance.js';
import ElevationLayer from '@giro3d/giro3d/core/layer/ElevationLayer.js';
import Map from '@giro3d/giro3d/entities/Map.js';
import GeoTIFFFormat from '@giro3d/giro3d/formats/GeoTIFFFormat.js';
import ColorMap, { ColorMapMode } from '@giro3d/giro3d/core/layer/ColorMap.js';
import TiledImageSource from '@giro3d/giro3d/sources/TiledImageSource.js';
import Inspector from '@giro3d/giro3d/gui/Inspector.js';



const x = -13602000;
const y = 5812000;
const halfWidth = 2500;

// Defines geographic extent: CRS, min/max X, min/max Y
const extent = new Extent('EPSG:3857', x - halfWidth, x + halfWidth, y - halfWidth, y + halfWidth);

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

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

const map = new Map('planar', {
    extent,
    hillshading: true,
    doubleSided: true,
    backgroundColor: 'white',
});

instance.add(map);

const source = new TiledImageSource({
    source: new XYZ({
        minZoom: 10,
        maxZoom: 16,
        url: 'https://3d.oslandia.com/dem/MtStHelens-tiles/{z}/{x}/{y}.tif',
    }),
    format: new GeoTIFFFormat(),
});

const floor = 1100;
const ceiling = 2500;

const values = colormap({ colormap: 'viridis', nshades: 256 });
const colors = values.map(v => new Color(v));

const dem = new ElevationLayer({
    name: 'dem',
    source,
    extent,
    colorMap: new ColorMap(colors, floor, ceiling, ColorMapMode.Elevation),
});

map.addLayer(dem);

instance.camera.camera3D.position.set(-13594700, 5819700, 7300);

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

controls.target.set(-13603000, 5811000, 0);

instance.useTHREEControls(controls);

instance.notifyChange();

Inspector.attach(document.getElementById('panelDiv'), instance);
index.html
<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <title>Giro3D - Transparent canvas background</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;
    }
    #viewerDiv canvas {
  background-image: linear-gradient(45deg, #aaaaaa 25%, transparent 25%),
    linear-gradient(-45deg, #aaaaaa 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #aaaaaa 75%),
    linear-gradient(-45deg, transparent 75%, #aaaaaa 75%);
  background-size: 20px 20px;
  background-position:
    0 0,
    0 10px,
    10px -10px,
    -10px 0px;
}

  </style>
</head>

<body>
  <div id="viewerDiv"></div>
  <div id="panelDiv"></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": "transparent_background",
  "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"
  }
}