@pmndrs/xr/dist/plane.js

VR/AR for threejs

import { Box2, BufferGeometry, Shape, ShapeGeometry, Vector2 } from 'three';
export function updateXRPlaneGeometry(plane, geometry) {
    if (geometry != null && geometry.createdAt != null && geometry.createdAt >= plane.lastChangedTime) {
        return geometry;
    }
    return Object.assign(createGeometryFromPolygon(plane.polygon), { createdAt: plane.lastChangedTime });
}
const boxHelper = new Box2();
const sizeHelper = new Vector2();
function createGeometryFromPolygon(polygon) {
    if (polygon.length === 0) {
        return new BufferGeometry();
    }
    const shape = new Shape();
    const points = polygon.map(({ x, z }) => new Vector2(x, z));
    //we measure the size and scale & unscale to have normalized UVs for the geometry
    boxHelper.setFromPoints(points);
    boxHelper.getSize(sizeHelper);
    for (const point of points) {
        point.sub(boxHelper.min);
        point.divide(sizeHelper);
    }
    shape.setFromPoints(points);
    const geometry = new ShapeGeometry(shape);
    geometry.scale(sizeHelper.x, sizeHelper.y, 1);
    geometry.translate(boxHelper.min.x, boxHelper.min.y, 0);
    geometry.rotateX(Math.PI / 2);
    return geometry;
}