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Merge pull request #200 from cabanier/viewportscaling
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Add sample file to demonstrate viewport scaling
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@cabanier
cabanier authored Oct 23, 2024
2 parents 97550eb + fabcd3f commit 76f14bb
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8 changes: 6 additions & 2 deletions index.html
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Expand Up @@ -196,8 +196,12 @@ <h2 class='tagline'>Sample Pages</h2>
description: 'Demonstrates using the Hand Tracking API to track the user\'s hands.'},

{ title: 'Framebuffer Scaling', category: 'Performance',
path: 'framebuffer-scaling.html',
description: 'Demonstrates scaling a layer\'s framebuffer to statically control performance or quality.' },
path: 'framebuffer-scaling.html',
description: 'Demonstrates scaling a layer\'s framebuffer to statically control performance or quality.' },

{ title: 'Viewport Scaling', category: 'Performance',
path: 'viewport-scaling.html',
description: 'Demonstrates dynamcially scaling a layer\'s viewport to control performance at the expense of quality.' },

{ title: '360 Stereo Photos', category: 'Content',
path: '360-photos.html',
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220 changes: 220 additions & 0 deletions viewport-scaling.html
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<!doctype html>
<!--
Copyright 2024 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>Immersive Viewport scaling</title>
</head>
<body>
<header>
<details open>
<summary>Viewport scaling</summary>
<p>
This sample demonstrates how a session can request to render to
a smaller area of its layer. This can be used to dynamically
lower the number of pixels that need to be rendered. This can
help experiences that are fragment bound for a short amount
of time.
<a class="back" href="./">Back</a>
<br/>
Use projection layer: <input id='useLayer' type='checkbox'/>
</p>
</details>
</header>
<main style='text-align: center;'>
<p>Click 'Enter XR' to see content</p>
</main>
<script type="module">
import {WebXRButton} from './js/util/webxr-button.js';
import {Scene, WebXRView} from './js/render/scenes/scene.js';
import {Renderer, createWebGLContext} from './js/render/core/renderer.js';
import {Gltf2Node} from './js/render/nodes/gltf2.js';
import {SkyboxNode} from './js/render/nodes/skybox.js';
import {QueryArgs} from './js/util/query-args.js';

import WebXRPolyfill from './js/third-party/webxr-polyfill/build/webxr-polyfill.module.js';
if (QueryArgs.getBool('usePolyfill', true)) {
let polyfill = new WebXRPolyfill();
}

// XR globals.
let xrButton = null;
let xrRefSpace = null;

// WebGL scene globals.
let gl = null;
let renderer = null;
let scene = new Scene();
let scale = 1;
let scale_down = true;
let useLayerCheckbox = document.getElementById('useLayer');
let useLayer = false;
// layer support
let xrGLFactory = null;
let xrFramebuffer = null;
let proj_layer = null;
let count = true;

scene.addNode(new Gltf2Node({url: 'media/gltf/space/space.gltf'}));
scene.addNode(new SkyboxNode({url: 'media/textures/milky-way-4k.png'}));

function initXR() {
xrButton = new WebXRButton({
onRequestSession: onRequestSession,
onEndSession: onEndSession
});
document.querySelector('header').appendChild(xrButton.domElement);

if (navigator.xr) {
navigator.xr.isSessionSupported('immersive-vr').then((supported) => {
xrButton.enabled = supported;
});
}
}

function onRequestSession() {
useLayer = useLayerCheckbox.checked;
return navigator.xr.requestSession('immersive-vr', {
requiredFeatures: useLayer?['layers']:[],
}).then(onSessionStarted);
}

function onSessionStarted(session) {
xrButton.setSession(session);

session.addEventListener('end', onSessionEnded);

gl = createWebGLContext({
xrCompatible: true, webgl2: true
});

renderer = new Renderer(gl);

scene.setRenderer(renderer);

if (useLayer) {
xrFramebuffer = gl.createFramebuffer();
xrGLFactory = new XRWebGLBinding(session, gl);
} else {
let gllayer = new XRWebGLLayer(session, gl);
gllayer.fixedFoveation = 1.0;
session.updateRenderState({ baseLayer: gllayer });
}

session.requestReferenceSpace('local').then((refSpace) => {
xrRefSpace = refSpace;

if (useLayer) {
proj_layer = xrGLFactory.createProjectionLayer({ stencil: false });
proj_layer.fixedFoveation = 1;
session.updateRenderState({ layers: [proj_layer] });
}
session.requestAnimationFrame(onXRFrame);
});

session.onselectstart = () => {
count = false;
}
session.onselectend = () => {
count = true;
}
}

function onEndSession(session) {
session.end();
}

function onSessionEnded(event) {
xrButton.setSession(null);

renderer = null;
}

function onXRFrame(t, frame) {
let session = frame.session;

scene.startFrame();
scene.updateInputSources(frame, xrRefSpace);

session.requestAnimationFrame(onXRFrame);

let pose = frame.getViewerPose(xrRefSpace);

if (pose) {
if (useLayer) {
let views = [];
for (let view of pose.views) {
view.requestViewportScale(scale);
let subImage = xrGLFactory.getViewSubImage(proj_layer, view);
subImage.framebuffer = xrFramebuffer;
let viewport = subImage.viewport;
gl.bindFramebuffer(gl.FRAMEBUFFER, xrFramebuffer);
gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, subImage.colorTexture, 0);
gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.TEXTURE_2D, subImage.depthStencilTexture, 0);

views.push(new WebXRView(view, subImage, viewport));
}
scene.drawViewArray(views);
} else {
let glLayer = session.renderState.baseLayer;

gl.bindFramebuffer(gl.FRAMEBUFFER, glLayer.framebuffer);

gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

for (let view of pose.views) {
view.requestViewportScale(scale);

let viewport = glLayer.getViewport(view);
gl.viewport(viewport.x, viewport.y,
viewport.width, viewport.height);

scene.draw(view.projectionMatrix, view.transform);
}
}

if (count)
scale += scale_down ? -0.004 : 0.004;

if (scale >= 1) {
scale = 1;
scale_down = true;
} else if (scale <= 0.125) {
scale = 0.125;q
scale_down = false;
}
}

scene.endFrame();
}

initXR();
</script>
</body>
</html>

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