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vr-barebones.html
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vr-barebones.html
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<!doctype html>
<!--
Copyright 2018 The Immersive Web Community Group
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-->
<html>
<head>
<meta charset='utf-8'>
<meta name='viewport' content='width=device-width, initial-scale=1, user-scalable=no'>
<meta name='mobile-web-app-capable' content='yes'>
<meta name='apple-mobile-web-app-capable' content='yes'>
<link rel='icon' type='image/png' sizes='32x32' href='favicon-32x32.png'>
<link rel='icon' type='image/png' sizes='96x96' href='favicon-96x96.png'>
<link rel='stylesheet' href='css/common.css'>
<title>Barebones VR</title>
</head>
<body>
<header>
<details open>
<summary>Barebones VR</summary>
<p>
This sample demonstrates extremely simple use of an "immersive-vr"
session with no library dependencies. It doesn't render anything
exciting, just clears your headset's display to a slowly changing
color to prove it's working.
<a class="back" href="./">Back</a>
</p>
<button id="xr-button" class="barebones-button" disabled>XR not found</button>
</details>
</header>
<main style='text-align: center;'>
<p>Click 'Enter VR' to see content</p>
</main>
<script>
(function () {
'use strict';
// XR globals.
let xrButton = document.getElementById('xr-button');
let xrSession = null;
let xrRefSpace = null;
// WebGL scene globals.
let gl = null;
// Checks to see if WebXR is available and, if so, requests an XRDevice
// that is connected to the system and tests it to ensure it supports the
// desired session options.
function initXR() {
// Is WebXR available on this UA?
if (navigator.xr) {
// If the device allows creation of exclusive sessions set it as the
// target of the 'Enter XR' button.
navigator.xr.isSessionSupported('immersive-vr').then((supported) => {
if (supported) {
// Updates the button to start an XR session when clicked.
xrButton.addEventListener('click', onButtonClicked);
xrButton.textContent = 'Enter VR';
xrButton.disabled = false;
}
});
}
}
// Called when the user clicks the button to enter XR. If we don't have a
// session we'll request one, and if we do have a session we'll end it.
function onButtonClicked() {
if (!xrSession) {
navigator.xr.requestSession('immersive-vr').then(onSessionStarted);
} else {
xrSession.end();
}
}
// Called when we've successfully acquired a XRSession. In response we
// will set up the necessary session state and kick off the frame loop.
function onSessionStarted(session) {
xrSession = session;
xrButton.textContent = 'Exit VR';
// Listen for the sessions 'end' event so we can respond if the user
// or UA ends the session for any reason.
session.addEventListener('end', onSessionEnded);
// Create a WebGL context to render with, initialized to be compatible
// with the XRDisplay we're presenting to.
let canvas = document.createElement('canvas');
gl = canvas.getContext('webgl', { xrCompatible: true });
// Use the new WebGL context to create a XRWebGLLayer and set it as the
// sessions baseLayer. This allows any content rendered to the layer to
// be displayed on the XRDevice.
session.updateRenderState({ baseLayer: new XRWebGLLayer(session, gl) });
// Get a reference space, which is required for querying poses. In this
// case an 'local' reference space means that all poses will be relative
// to the location where the XRDevice was first detected.
session.requestReferenceSpace('local').then((refSpace) => {
xrRefSpace = refSpace;
// Inform the session that we're ready to begin drawing.
session.requestAnimationFrame(onXRFrame);
});
}
// Called either when the user has explicitly ended the session by calling
// session.end() or when the UA has ended the session for any reason.
// At this point the session object is no longer usable and should be
// discarded.
function onSessionEnded(event) {
xrSession = null;
xrButton.textContent = 'Enter VR';
// In this simple case discard the WebGL context too, since we're not
// rendering anything else to the screen with it.
gl = null;
}
// Called every time the XRSession requests that a new frame be drawn.
function onXRFrame(time, frame) {
let session = frame.session;
// Inform the session that we're ready for the next frame.
session.requestAnimationFrame(onXRFrame);
// Get the XRDevice pose relative to the reference space we created
// earlier.
let pose = frame.getViewerPose(xrRefSpace);
// Getting the pose may fail if, for example, tracking is lost. So we
// have to check to make sure that we got a valid pose before attempting
// to render with it. If not in this case we'll just leave the
// framebuffer cleared, so tracking loss means the scene will simply
// disappear.
if (pose) {
let glLayer = session.renderState.baseLayer;
// If we do have a valid pose, bind the WebGL layer's framebuffer,
// which is where any content to be displayed on the XRDevice must be
// rendered.
gl.bindFramebuffer(gl.FRAMEBUFFER, glLayer.framebuffer);
// Update the clear color so that we can observe the color in the
// headset changing over time.
gl.clearColor(Math.cos(time / 2000),
Math.cos(time / 4000),
Math.cos(time / 6000), 1.0);
// Clear the framebuffer
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
// Normally you'd loop through each of the views reported by the frame
// and draw them into the corresponding viewport here, but we're
// keeping this sample slim so we're not bothering to draw any
// geometry.
/*for (let view of pose.views) {
let viewport = glLayer.getViewport(view);
gl.viewport(viewport.x, viewport.y,
viewport.width, viewport.height);
// Draw a scene using view.projectionMatrix as the projection matrix
// and view.transform to position the virtual camera. If you need a
// view matrix, use view.transform.inverse.matrix.
}*/
}
}
// Start the XR application.
initXR();
})();
</script>
</body>
</html>