gregloryus.github.io/celestial-sim-1.html at master · gregloryus/gregloryus.github.io · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1,maximum-scale=1,user-scalable=no">
<title>Celestial Simulation</title>
<style>
*{margin:0;padding:0;box-sizing:border-box}
html,body{width:100%;height:100%;overflow:hidden;background:#000;touch-action:none}
canvas{display:block}
#loading{position:fixed;top:50%;left:50%;transform:translate(-50%,-50%);color:#889;font:16px monospace;z-index:20;text-align:center}
#ui{position:fixed;bottom:0;left:0;right:0;padding:8px;background:rgba(0,0,10,0.8);
  color:#aab;font:13px monospace;z-index:10;display:flex;flex-wrap:wrap;align-items:center;
  justify-content:center;gap:6px;border-top:1px solid #223}
#ui input,#ui select,#ui button{font:13px monospace;background:#112;color:#aab;
  border:1px solid #334;padding:4px 8px;border-radius:4px;-webkit-appearance:none}
#ui button{cursor:pointer;min-width:36px}
#ui button:active{background:#334}
#datetime-display{width:100%;text-align:center;font-size:11px;opacity:0.6;margin-bottom:2px}
#info{position:fixed;top:8px;left:8px;color:#556;font:11px monospace;z-index:10}
</style>
<script src="https://cdn.jsdelivr.net/npm/astronomy-engine@2.1.19/astronomy.browser.min.js"></script>
<script type="importmap">
{"imports":{"three":"https://cdn.jsdelivr.net/npm/three@0.183.2/build/three.module.js","three/addons/":"https://cdn.jsdelivr.net/npm/three@0.183.2/examples/jsm/"}}
</script>
</head>
<body>
<div id="loading">Loading stars...</div>
<div id="info">Evanston, IL</div>
<div id="ui">
  <span id="datetime-display"></span>
  <input type="date" id="date-input">
  <input type="time" id="time-input" step="60">
  <button id="now-btn">Now</button>
  <button id="play-btn">&#9654;</button>
  <select id="speed-select">
    <option value="1">1m/s</option>
    <option value="10">10m/s</option>
    <option value="60" selected>1h/s</option>
    <option value="1440">1d/s</option>
  </select>
</div>

<script type="module">
import * as THREE from 'three';
import { OrbitControls } from 'three/addons/controls/OrbitControls.js';

// ── Constants ──
const DEG2RAD = Math.PI / 180;
const RAD2DEG = 180 / Math.PI;
const SKY_R = 500;
const OBJ_R = 490;

// ── Observer: Evanston, IL ──
const observer = new Astronomy.Observer(41.88, -87.68, 0);

// ── State ──
let simDate = new Date();
let playing = false;
let speedMinPerSec = 60;
let lastFrameTime = 0;
let starData = null;

// ── Renderer ──
const renderer = new THREE.WebGLRenderer({ antialias: true });
renderer.setSize(window.innerWidth, window.innerHeight);
renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2));
document.body.appendChild(renderer.domElement);

const scene = new THREE.Scene();
scene.background = new THREE.Color(0x000008);

// ── Camera ──
const camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000);
// Start slightly below origin so we look UP at the zenith
camera.position.set(0, -0.001, 0.0001);

// ── Controls ──
const controls = new OrbitControls(camera, renderer.domElement);
controls.target.set(0, 0, 0);
controls.enableZoom = false;
controls.enablePan = false;
controls.enableDamping = true;
controls.dampingFactor = 0.12;
controls.rotateSpeed = 0.5;

// ── Sky Sphere ──
scene.add(new THREE.Mesh(
  new THREE.SphereGeometry(SKY_R, 48, 48),
  new THREE.MeshBasicMaterial({ color: 0x000010, side: THREE.BackSide })
));

// ── Ground Plane (semi-transparent horizon) ──
const ground = new THREE.Mesh(
  new THREE.CircleGeometry(SKY_R * 0.99, 64),
  new THREE.MeshBasicMaterial({ color: 0x1a2a15, side: THREE.DoubleSide, transparent: true, opacity: 0.25 })
);
ground.rotation.x = -Math.PI / 2;
ground.renderOrder = 1;
scene.add(ground);

// ── Coordinate Helpers ──
function azAltToXYZ(azDeg, altDeg, r) {
  const azRad = azDeg * DEG2RAD;
  const phi = (90 - altDeg) * DEG2RAD;
  return new THREE.Vector3(
    r * Math.sin(phi) * Math.sin(azRad),
    r * Math.cos(phi),
    -r * Math.sin(phi) * Math.cos(azRad)
  );
}

function bvToRGB(bv) {
  bv = Math.max(-0.4, Math.min(2.0, bv));
  if (bv < 0) return [0.7 - bv * 0.5, 0.8 - bv * 0.3, 1.0];
  if (bv < 0.4) { const t = bv / 0.4; return [1.0, 1.0 - 0.12 * t, 1.0 - 0.45 * t]; }
  const t = Math.min(1, (bv - 0.4) / 1.2);
  return [1.0, 0.88 - 0.48 * t, 0.55 - 0.4 * t];
}

// ── Stars ──
let starPoints, starPositions, starColors, starSizes;

const starVertShader = `
  attribute float aSize;
  attribute vec3 aColor;
  varying vec3 vColor;
  void main() {
    vColor = aColor;
    gl_PointSize = aSize;
    gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
  }
`;
const starFragShader = `
  varying vec3 vColor;
  void main() {
    float d = length(gl_PointCoord - 0.5);
    if (d > 0.5) discard;
    float a = 1.0 - smoothstep(0.1, 0.5, d);
    gl_FragColor = vec4(vColor, a);
  }
`;

function initStars() {
  const n = starData.length;
  starPositions = new Float32Array(n * 3);
  starColors = new Float32Array(n * 3);
  starSizes = new Float32Array(n);

  const geo = new THREE.BufferGeometry();
  geo.setAttribute('position', new THREE.BufferAttribute(starPositions, 3));
  geo.setAttribute('aColor', new THREE.BufferAttribute(starColors, 3));
  geo.setAttribute('aSize', new THREE.BufferAttribute(starSizes, 1));

  const mat = new THREE.ShaderMaterial({
    vertexShader: starVertShader,
    fragmentShader: starFragShader,
    transparent: true,
    depthTest: false
  });

  starPoints = new THREE.Points(geo, mat);
  starPoints.renderOrder = 0;
  scene.add(starPoints);
}

function updateStars(date) {
  if (!starData) return;
  const gast = Astronomy.SiderealTime(date);
  const lstDeg = gast * 15 + observer.longitude; // local sidereal time in degrees
  const latRad = observer.latitude * DEG2RAD;
  const sinLat = Math.sin(latRad);
  const cosLat = Math.cos(latRad);

  for (let i = 0; i < starData.length; i++) {
    const raDeg = starData[i][2];
    const decDeg = starData[i][3];
    const mag = starData[i][1];
    const bv = starData[i][4];

    const haRad = (lstDeg - raDeg) * DEG2RAD;
    const decRad = decDeg * DEG2RAD;
    const sinDec = Math.sin(decRad);
    const cosDec = Math.cos(decRad);
    const cosHA = Math.cos(haRad);
    const sinHA = Math.sin(haRad);

    // Altitude
    const sinAlt = sinDec * sinLat + cosDec * cosLat * cosHA;
    const altRad = Math.asin(sinAlt);
    const altDeg = altRad * RAD2DEG;

    // Azimuth (from North through East)
    const azRad = Math.atan2(-cosDec * sinHA, sinDec * cosLat - cosDec * sinLat * cosHA);
    const azDeg = azRad * RAD2DEG;

    // 3D position
    const phi = Math.PI / 2 - altRad;
    const sinPhi = Math.sin(phi);
    const azR = azDeg * DEG2RAD;
    const j = i * 3;
    starPositions[j]     = OBJ_R * sinPhi * Math.sin(azR);
    starPositions[j + 1] = OBJ_R * Math.cos(phi);
    starPositions[j + 2] = -OBJ_R * sinPhi * Math.cos(azR);

    // Color + dimming below horizon
    const [cr, cg, cb] = bvToRGB(bv);
    const dim = altDeg < 0 ? 0.12 : 1.0;
    starColors[j]     = cr * dim;
    starColors[j + 1] = cg * dim;
    starColors[j + 2] = cb * dim;

    // Size from magnitude
    starSizes[i] = Math.max(1.5, 7 - mag) * (window.devicePixelRatio || 1);
  }

  starPoints.geometry.attributes.position.needsUpdate = true;
  starPoints.geometry.attributes.aColor.needsUpdate = true;
  starPoints.geometry.attributes.aSize.needsUpdate = true;
}

// ── Celestial Bodies (Sun + Planets) ──
const bodyDefs = [
  { name: 'Sun',     color: 0xffdd33, size: 14, label: '☉' },
  { name: 'Moon',    color: 0xddddcc, size: 11, label: '☽' },
  { name: 'Mercury', color: 0xaaaaaa, size: 5,  label: '☿' },
  { name: 'Venus',   color: 0xffffcc, size: 7,  label: '♀' },
  { name: 'Mars',    color: 0xff5533, size: 6,  label: '♂' },
  { name: 'Jupiter', color: 0xddcc88, size: 7,  label: '♃' },
  { name: 'Saturn',  color: 0xccbb55, size: 6,  label: '♄' },
];

const bodySprites = [];

function makeGlowTexture(hex, label) {
  const c = document.createElement('canvas');
  c.width = 64; c.height = 64;
  const ctx = c.getContext('2d');
  const col = new THREE.Color(hex);
  const r = Math.floor(col.r * 255), g = Math.floor(col.g * 255), b = Math.floor(col.b * 255);

  const grad = ctx.createRadialGradient(32, 32, 0, 32, 32, 28);
  grad.addColorStop(0, `rgba(${r},${g},${b},1)`);
  grad.addColorStop(0.25, `rgba(${r},${g},${b},0.7)`);
  grad.addColorStop(1, `rgba(${r},${g},${b},0)`);
  ctx.fillStyle = grad;
  ctx.fillRect(0, 0, 64, 64);

  // Label
  ctx.fillStyle = '#fff';
  ctx.font = 'bold 20px serif';
  ctx.textAlign = 'center';
  ctx.textBaseline = 'middle';
  ctx.fillText(label, 32, 32);

  return new THREE.CanvasTexture(c);
}

function initBodies() {
  bodyDefs.forEach(b => {
    const tex = makeGlowTexture(b.color, b.label);
    const mat = new THREE.SpriteMaterial({ map: tex, transparent: true, depthTest: false });
    const sprite = new THREE.Sprite(mat);
    sprite.scale.set(b.size, b.size, 1);
    sprite.renderOrder = 2;
    scene.add(sprite);
    bodySprites.push({ def: b, sprite });
  });
}

function updateBodies(date) {
  bodySprites.forEach(({ def, sprite }) => {
    try {
      const equ = Astronomy.Equator(def.name, date, observer, true, true);
      const hor = Astronomy.Horizon(date, observer, equ.ra, equ.dec, 'normal');
      const pos = azAltToXYZ(hor.azimuth, hor.altitude, OBJ_R);
      sprite.position.copy(pos);
      sprite.material.opacity = hor.altitude < 0 ? 0.15 : 1.0;
    } catch (e) {
      sprite.visible = false;
    }
  });
}

// ── Cardinal Direction Labels ──
function initCardinals() {
  ['N','E','S','W'].forEach((txt, i) => {
    const c = document.createElement('canvas');
    c.width = 64; c.height = 64;
    const ctx = c.getContext('2d');
    ctx.fillStyle = '#445566';
    ctx.font = 'bold 44px monospace';
    ctx.textAlign = 'center';
    ctx.textBaseline = 'middle';
    ctx.fillText(txt, 32, 32);

    const tex = new THREE.CanvasTexture(c);
    const mat = new THREE.SpriteMaterial({ map: tex, transparent: true, depthTest: false });
    const sprite = new THREE.Sprite(mat);
    sprite.scale.set(18, 18, 1);
    const pos = azAltToXYZ(i * 90, 3, OBJ_R);
    sprite.position.copy(pos);
    sprite.renderOrder = 3;
    scene.add(sprite);
  });
}

// ── Load Star Data ──
async function loadStars() {
  const loadEl = document.getElementById('loading');
  try {
    const resp = await fetch('https://raw.githubusercontent.com/gmiller123456/hip2000/master/hipparcos_5_concise.js');
    let text = await resp.text();
    text = text.replace('hipparcos_catalog=', '').trim();
    if (text.endsWith(';')) text = text.slice(0, -1);
    // Fix trailing commas (valid JS but invalid JSON)
    text = text.replace(/,\s*]/g, ']').replace(/,\s*}/g, '}');
    starData = JSON.parse(text);
    // Keep stars up to magnitude 5.5
    starData = starData.filter(s => s[1] <= 5.5);
    loadEl.style.display = 'none';
    initStars();
    updateAll();
  } catch (e) {
    loadEl.textContent = 'Error loading stars. Check connection.';
    console.error(e);
    // Still run bodies
    updateBodies(simDate);
  }
}

// ── UI ──
const dateInput = document.getElementById('date-input');
const timeInput = document.getElementById('time-input');
const playBtn = document.getElementById('play-btn');
const speedSelect = document.getElementById('speed-select');
const dtDisplay = document.getElementById('datetime-display');

function pad(n) { return String(n).padStart(2, '0'); }

function syncUI() {
  const d = simDate;
  dateInput.value = `${d.getFullYear()}-${pad(d.getMonth()+1)}-${pad(d.getDate())}`;
  timeInput.value = `${pad(d.getHours())}:${pad(d.getMinutes())}`;
  dtDisplay.textContent = d.toLocaleString();
}

function readUI() {
  if (!dateInput.value || !timeInput.value) return;
  const [y, m, d] = dateInput.value.split('-').map(Number);
  const [hh, mm] = timeInput.value.split(':').map(Number);
  simDate = new Date(y, m - 1, d, hh, mm);
  updateAll();
}

document.getElementById('now-btn').addEventListener('click', () => {
  simDate = new Date(); updateAll();
});
playBtn.addEventListener('click', () => {
  playing = !playing;
  playBtn.innerHTML = playing ? '&#9646;&#9646;' : '&#9654;';
});
speedSelect.addEventListener('change', () => { speedMinPerSec = +speedSelect.value; });
dateInput.addEventListener('change', readUI);
timeInput.addEventListener('change', readUI);

// ── Update All ──
function updateAll() {
  syncUI();
  updateStars(simDate);
  updateBodies(simDate);
}

// ── Resize ──
window.addEventListener('resize', () => {
  camera.aspect = window.innerWidth / window.innerHeight;
  camera.updateProjectionMatrix();
  renderer.setSize(window.innerWidth, window.innerHeight);
});

// ── Animation Loop ──
function animate(t) {
  requestAnimationFrame(animate);

  if (playing && lastFrameTime > 0) {
    const dt = (t - lastFrameTime) / 1000;
    simDate = new Date(simDate.getTime() + dt * speedMinPerSec * 60000);
    updateAll();
  }
  lastFrameTime = t;

  controls.update();
  renderer.render(scene, camera);
}

// ── Init ──
initBodies();
initCardinals();
syncUI();
loadStars();
animate(0);
</script>
</body>
</html>