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<!-- Licensed under a BSD license. See license.html for license -->
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
<title>Three.js - OffscreenCanvas Picking</title>
<style>
html, body {
height: 100%;
margin: 0;
}
#c {
width: 100%;
height: 100%;
display: block;
}
</style>
</head>
<body>
<canvas id="c"></canvas>
</body>
<script type="module">
import {state, init, pickPosition} from './shared-picking.js';
let sendMouse;
function startWorker(canvas) {
const offscreen = canvas.transferControlToOffscreen();
const worker = new Worker('offscreencanvas-worker-picking.js', {type: 'module'});
worker.postMessage({type: 'init', canvas: offscreen}, [offscreen]);
sendMouse = (x, y) => {
worker.postMessage({
type: 'mouse',
x,
y,
});
};
function sendSize() {
worker.postMessage({
type: 'size',
width: canvas.clientWidth,
height: canvas.clientHeight,
});
}
window.addEventListener('resize', sendSize);
sendSize();
console.log('using OffscreenCanvas'); /* eslint-disable-line no-console */
}
function startMainPage(canvas) {
init({canvas});
sendMouse = (x, y) => {
pickPosition.x = x;
pickPosition.y = y;
};
function sendSize() {
state.width = canvas.clientWidth;
state.height = canvas.clientHeight;
}
window.addEventListener('resize', sendSize);
sendSize();
console.log('using regular canvas'); /* eslint-disable-line no-console */
}
function main() { /* eslint consistent-return: 0 */
const canvas = document.querySelector('#c');
if (canvas.transferControlToOffscreen) {
startWorker(canvas);
} else {
startMainPage(canvas);
}
function getCanvasRelativePosition(event) {
const rect = canvas.getBoundingClientRect();
return {
x: (event.clientX - rect.left) * canvas.width / rect.width,
y: (event.clientY - rect.top ) * canvas.height / rect.height,
};
}
function setPickPosition(event) {
const pos = getCanvasRelativePosition(event);
sendMouse(
(pos.x / canvas.width ) * 2 - 1,
(pos.y / canvas.height) * -2 + 1); // note we flip Y
}
function clearPickPosition() {
// unlike the mouse which always has a position
// if the user stops touching the screen we want
// to stop picking. For now we just pick a value
// unlikely to pick something
sendMouse(-100000, -100000);
}
window.addEventListener('mousemove', setPickPosition);
window.addEventListener('mouseout', clearPickPosition);
window.addEventListener('mouseleave', clearPickPosition);
window.addEventListener('touchstart', (event) => {
// prevent the window from scrolling
event.preventDefault();
setPickPosition(event.touches[0]);
}, {passive: false});
window.addEventListener('touchmove', (event) => {
setPickPosition(event.touches[0]);
});
window.addEventListener('touchend', clearPickPosition);
}
main();
</script>
</html>