93 lines
2.4 KiB
JavaScript
93 lines
2.4 KiB
JavaScript
// utils.js - Utility functions for coordinate conversion
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import * as THREE from "three";
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import { CONFIG } from "./constants.js";
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// Convert latitude/longitude to 3D vector
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export function latLonToVector3(lat, lon, radius = CONFIG.earthRadius) {
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const phi = (90 - lat) * (Math.PI / 180);
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const theta = (lon + 180) * (Math.PI / 180);
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const x = -(radius * Math.sin(phi) * Math.cos(theta));
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const z = radius * Math.sin(phi) * Math.sin(theta);
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const y = radius * Math.cos(phi);
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return new THREE.Vector3(x, y, z);
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}
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// Convert 3D vector to latitude/longitude
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export function vector3ToLatLon(vector) {
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const radius = Math.sqrt(
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vector.x * vector.x + vector.y * vector.y + vector.z * vector.z,
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);
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const lat = 90 - (Math.acos(vector.y / radius) * 180) / Math.PI;
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let lon = (Math.atan2(vector.z, -vector.x) * 180) / Math.PI - 180;
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while (lon <= -180) lon += 360;
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while (lon > 180) lon -= 360;
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return {
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lat: parseFloat(lat.toFixed(4)),
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lon: parseFloat(lon.toFixed(4)),
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alt: radius - CONFIG.earthRadius,
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};
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}
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// Convert screen coordinates to Earth surface 3D coordinates
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export function screenToEarthCoords(
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clientX,
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clientY,
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camera,
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earth,
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domElement = document.body,
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raycaster = new THREE.Raycaster(),
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mouse = new THREE.Vector2(),
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) {
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if (domElement === document.body) {
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mouse.x = (clientX / window.innerWidth) * 2 - 1;
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mouse.y = -(clientY / window.innerHeight) * 2 + 1;
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} else {
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const rect = domElement.getBoundingClientRect();
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mouse.x = ((clientX - rect.left) / rect.width) * 2 - 1;
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mouse.y = -((clientY - rect.top) / rect.height) * 2 + 1;
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}
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raycaster.setFromCamera(mouse, camera);
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const intersects = raycaster.intersectObject(earth);
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if (intersects.length > 0) {
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const localPoint = intersects[0].point.clone();
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earth.worldToLocal(localPoint);
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return localPoint;
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}
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return null;
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}
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// Calculate accurate spherical distance between two points (Haversine formula)
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export function calculateDistance(
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lat1,
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lon1,
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lat2,
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lon2,
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radius = CONFIG.earthRadius,
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) {
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const toRad = (angle) => (angle * Math.PI) / 180;
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const dLat = toRad(lat2 - lat1);
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const dLon = toRad(lon2 - lon1);
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const a =
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Math.sin(dLat / 2) * Math.sin(dLat / 2) +
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Math.cos(toRad(lat1)) *
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Math.cos(toRad(lat2)) *
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Math.sin(dLon / 2) *
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Math.sin(dLon / 2);
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const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
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return radius * c;
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}
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