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<html> | |
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<meta charset='utf-8'> | |
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<title>Hit Test with Anchors</title> | |
</head> | |
<body> | |
<header> | |
<details open> | |
<summary>Hit Test with Anchors</summary> | |
<p> | |
This sample demonstrates using hit testing to find intersections on real-world surfaces and then using Anchors to attach a virtual object to that location. | |
<a class="back" href="./">Back</a> | |
</p> | |
</details> | |
</header> | |
<script type="module"> | |
import {WebXRButton} from './js/util/webxr-button.js'; | |
import {Scene} from './js/render/scenes/scene.js'; | |
import {Renderer, createWebGLContext} from './js/render/core/renderer.js'; | |
import {Node} from './js/render/core/node.js'; | |
import {Gltf2Node} from './js/render/nodes/gltf2.js'; | |
import {DropShadowNode} from './js/render/nodes/drop-shadow.js'; | |
import {vec3} from './js/render/math/gl-matrix.js'; | |
import {Ray} from './js/render/math/ray.js'; | |
// XR globals. | |
let xrButton = null; | |
let xrRefSpace = null; | |
let xrViewerSpace = null; | |
let xrHitTestSource = null; | |
// WebGL scene globals. | |
let gl = null; | |
let renderer = null; | |
let scene = new Scene(); | |
scene.enableStats(false); | |
let arObject = new Node(); | |
arObject.visible = false; | |
scene.addNode(arObject); | |
let flower = new Gltf2Node({url: 'media/gltf/sunflower/sunflower.gltf'}); | |
arObject.addNode(flower); | |
let reticle = new Gltf2Node({url: 'media/gltf/reticle/reticle.gltf'}); | |
reticle.visible = false; | |
scene.addNode(reticle); | |
let reticleHitTestResult = null; | |
// Having a really simple drop shadow underneath an object helps ground | |
// it in the world without adding much complexity. | |
let shadow = new DropShadowNode(); | |
vec3.set(shadow.scale, 0.15, 0.15, 0.15); | |
arObject.addNode(shadow); | |
const MAX_FLOWERS = 30; | |
let flowers = []; | |
// Ensure the background is transparent for AR. | |
scene.clear = false; | |
function initXR() { | |
xrButton = new WebXRButton({ | |
onRequestSession: onRequestSession, | |
onEndSession: onEndSession, | |
textEnterXRTitle: "START AR", | |
textXRNotFoundTitle: "AR NOT FOUND", | |
textExitXRTitle: "EXIT AR", | |
}); | |
document.querySelector('header').appendChild(xrButton.domElement); | |
if (navigator.xr) { | |
navigator.xr.isSessionSupported('immersive-ar') | |
.then((supported) => { | |
xrButton.enabled = supported; | |
}); | |
} | |
} | |
function onRequestSession() { | |
return navigator.xr.requestSession('immersive-ar', {requiredFeatures: ['local', 'hit-test', 'anchors']}) | |
.then((session) => { | |
xrButton.setSession(session); | |
onSessionStarted(session); | |
}); | |
} | |
function onSessionStarted(session) { | |
session.addEventListener('end', onSessionEnded); | |
session.addEventListener('select', onSelect); | |
if (!gl) { | |
gl = createWebGLContext({ | |
xrCompatible: true | |
}); | |
renderer = new Renderer(gl); | |
scene.setRenderer(renderer); | |
} | |
session.updateRenderState({ baseLayer: new XRWebGLLayer(session, gl) }); | |
// In this sample we want to cast a ray straight out from the viewer's | |
// position and render a reticle where it intersects with a real world | |
// surface. To do this we first get the viewer space, then create a | |
// hitTestSource that tracks it. | |
session.requestReferenceSpace('viewer').then((refSpace) => { | |
xrViewerSpace = refSpace; | |
session.requestHitTestSource({ space: xrViewerSpace }).then((hitTestSource) => { | |
xrHitTestSource = hitTestSource; | |
}); | |
}); | |
session.requestReferenceSpace('local').then((refSpace) => { | |
xrRefSpace = refSpace; | |
session.requestAnimationFrame(onXRFrame); | |
}); | |
} | |
function onEndSession(session) { | |
anchoredObjects.clear(); | |
xrHitTestSource.cancel(); | |
xrHitTestSource = null; | |
session.end(); | |
} | |
function onSessionEnded(event) { | |
xrButton.setSession(null); | |
} | |
const MAX_ANCHORED_OBJECTS = 30; | |
let anchoredObjects = []; | |
function addAnchoredObjectsToScene(anchor) { | |
let flower = new Gltf2Node({url: 'media/gltf/sunflower/sunflower.gltf'}); | |
scene.addNode(flower); | |
anchoredObjects.push({ | |
anchoredObject: flower, | |
anchor: anchor | |
}); | |
// For performance reasons if we add too many objects start | |
// removing the oldest ones to keep the scene complexity | |
// from growing too much. | |
if (anchoredObjects.length > MAX_ANCHORED_OBJECTS) { | |
let objectToRemove = anchoredObjects.shift(); | |
scene.removeNode(objectToRemove.anchoredObject); | |
objectToRemove.anchor.delete(); | |
} | |
} | |
let rayOrigin = vec3.create(); | |
let rayDirection = vec3.create(); | |
function onSelect(event) { | |
if (reticle.visible) { | |
// Create an anchor. | |
reticleHitTestResult.createAnchor().then((anchor) => { | |
addAnchoredObjectsToScene(anchor); | |
}, (error) => { | |
console.error("Could not create anchor: " + error); | |
}); | |
} | |
} | |
// Called every time a XRSession requests that a new frame be drawn. | |
function onXRFrame(t, frame) { | |
let session = frame.session; | |
let pose = frame.getViewerPose(xrRefSpace); | |
reticle.visible = false; | |
// If we have a hit test source, get its results for the frame | |
// and use the pose to display a reticle in the scene. | |
if (xrHitTestSource && pose) { | |
let hitTestResults = frame.getHitTestResults(xrHitTestSource); | |
if (hitTestResults.length > 0) { | |
let pose = hitTestResults[0].getPose(xrRefSpace); | |
reticle.visible = true; | |
reticle.matrix = pose.transform.matrix; | |
reticleHitTestResult = hitTestResults[0]; | |
} | |
} | |
for (const {anchoredObject, anchor} of anchoredObjects) { | |
// only update the object's position if it's still in the list | |
// of frame.trackedAnchors | |
if (!frame.trackedAnchors.has(anchor)) { | |
continue; | |
} | |
const anchorPose = frame.getPose(anchor.anchorSpace, xrRefSpace); | |
anchoredObject.matrix = anchorPose.transform.matrix; | |
} | |
scene.startFrame(); | |
session.requestAnimationFrame(onXRFrame); | |
scene.drawXRFrame(frame, pose); | |
scene.endFrame(); | |
} | |
// Start the XR application. | |
initXR(); | |
</script> | |
</body> | |
</html> |