clock+camera: sun and moon always from the SunCalc ephemeris (sine-curve sun and ecliptic-elongation moon removed), virtual clock via startAt/speed, optional camera aim at the moon

background.html

@@ -643,46 +643,38 @@ window.addEventListener('resize', scheduleFitInfoPanel);
             return t * t * (3 - 2 * t);
         }
 
-        // Day simulation: CONFIG.day.simulation runs a full 24h cycle in
+        // ---- Virtual clock (CONFIG.day) ---------------------------------
-        // CONFIG.day.cycleSeconds (sun rises east, culminates south, sets
+        // Sun and moon are ALWAYS the real ones: every position comes from
-        // west). Off = real SunCalc positions.
+        // SunCalc, evaluated at sceneNow(). CONFIG.day only moves that clock.
-        var DAY_SIM = !!(window.CONFIG && window.CONFIG.day && window.CONFIG.day.simulation);
+        //   startAt 'YYYY-MM-DDTHH:MM' - the moment the scene starts at
-        var CYCLE = ((window.CONFIG && window.CONFIG.day && window.CONFIG.day.cycleSeconds) || 20) * 1000;
+        //   speed   virtual seconds per real second (1 = real time,
-        // CONFIG.day.fixedTime freezes the simulated clock at one time of
+        //           1440 = one simulated day per minute)
-        // day: 'HH:MM', 'HH:MM:SS' or a number (0..24). null/unset = the
+        // Clock hands, digital readout, weather, calendar and the whole sky
-        // clock advances as before. Only the TIME OF DAY stops - cloud
+        // all read sceneNow(), so nothing drifts apart. Hash overrides:
-        // drift, car flow and the bobbing camera run on wall time, and
+        // #at=2026-10-27T19:14 and #speed=1.
-        // the weather sim has its own timer, so all of that keeps moving.
+        var SIM_START = (function () {
-        var FIXED_T = (function () {
+            var v = (window.CONFIG && window.CONFIG.day && window.CONFIG.day.startAt)
-            var v = window.CONFIG && window.CONFIG.day && window.CONFIG.day.fixedTime;
+                    || _hashParams.at;
-            if (v == null || v === '') return null;
+            if (!v) return null;
-            var h;
+            var m = String(v).match(/^(\d{4})-(\d{2})-(\d{2})[T ](\d{1,2}):(\d{2})(?::(\d{2}))?/);
-            if (typeof v === 'number') h = v;
+            if (!m) { console.warn('CONFIG.day.startAt not understood: ' + v); return null; }
-            else {
+            return new Date(+m[1], +m[2] - 1, +m[3], +m[4], +m[5], +(m[6] || 0)).getTime();
-                var p = String(v).split(':');
-                h = parseInt(p[0], 10) || 0;
-                if (p.length > 1) h += parseInt(p[1], 10) / 60;
-                if (p.length > 2) h += parseInt(p[2], 10) / 3600;
-            }
-            return (h >= 0 && h < 24) ? h / 24 : null;
         })();
-        // simulated sun altitude (rad): t=0 midnight, 0.25 sunrise, 0.5 noon
+        var SIM_SPEED = (function () {
-        function simSunAlt(t) {
+            var d = (window.CONFIG && window.CONFIG.day) || {};
-            return Math.sin((t - 0.25) * Math.PI * 2) * 1.45;
+            var hs = parseFloat(_hashParams.speed);
+            if (!isNaN(hs) && hs > 0) return hs;
+            if (typeof d.speed === 'number' && d.speed > 0) return d.speed;
+            // legacy: cycleSeconds used to mean "seconds per simulated day"
+            if (typeof d.cycleSeconds === 'number' && d.cycleSeconds > 0) return 86400 / d.cycleSeconds;
+            return 1;
+        })();
+        var SIM_ACTIVE = SIM_START !== null;
+        var SIM_LOAD_MS = Date.now();
+        function sceneNow() {
+            if (SIM_START === null) return new Date();
+            return new Date(SIM_START + (Date.now() - SIM_LOAD_MS) * SIM_SPEED);
         }
-        // Virtual calendar for day-switching features (weather forecast):
-        // same wall clock as reality, but the DATE advances one day per
-        // simulated cycle. The visible clock hands/digital stay real.
-        function simNow() {
-            if (!DAY_SIM) return new Date();
-            if (FIXED_T !== null) {
-                var f = new Date();
-                f.setHours(Math.floor(FIXED_T * 24), Math.round((FIXED_T * 1440) % 60), 0, 0);
-                return f;
-            }
-            return new Date(startTime + (Date.now() - startTime) * (86400000 / CYCLE));
-        }
-        var __simT = 0;
 
         var SITE_LAT = (window.CONFIG && window.CONFIG.location && window.CONFIG.location.lat) || 51.5074;
         var SITE_LON = (window.CONFIG && window.CONFIG.location && window.CONFIG.location.lon) || -0.1278;
@@ -909,12 +901,7 @@ window.sunPalettes = [
         }
 
         function getColor(t) {
-            if (DAY_SIM) {
+            var now = sceneNow();
-                // t: 0 = Mitternacht, 0.25 Sonnenaufgang (Osten),
-                // 0.5 Mittag (Sueden), 0.75 Sonnenuntergang (Westen).
-                return getDayColor(simSunAlt(t));
-            }
-            var now = new Date();
             var sunPos = SunCalc.getPosition(now, SITE_LAT, SITE_LON);
             var moonIllum = SunCalc.getMoonIllumination(now);
 
@@ -1289,20 +1276,10 @@ window.sunPalettes = [
         }
 
         function updateClockAndEvents() {
-            var now = new Date();
+            var now = sceneNow();
-            // Simulated wall clock: with CONFIG.day.simulation the scene runs
-            // a whole day in cycleSeconds, so the clock hands, the digital
-            // readout and every sun/moon table follow the accelerated date
-            // instead of the real one - the scene and the clock stay in step.
-            // simNow() is the same accelerated date the weather/calendar
-            // layer uses, so nothing drifts apart.
-            if (DAY_SIM) now = simNow();
 
             // Calculate real day progress based on sun position
             // 0% = midnight, 50% = noon, 100% = next midnight
-            if (DAY_SIM) {
-                realDayProgress = __simT;
-            } else {
             var sunTimes = SunCalc.getTimes(now, SITE_LAT, SITE_LON);
             var sunrise = sunTimes.sunrise;
             var sunset = sunTimes.sunset;
@@ -1314,8 +1291,7 @@ window.sunPalettes = [
             } else {
                 realDayProgress = 0.5 + (now.getTime() - sunset.getTime()) / (sunrise.getTime() + 24 * 3600 * 1000 - sunset.getTime()) * 0.5;
             }
-                realDayProgress = Math.max(0, Math.min(1, realDayProgress));
+            realDayProgress = Math.max(0, Math.min(1, realDayProgress));
-            }
 
             // Real-time clock hands and digital
             var h = now.getHours();
@@ -1635,8 +1611,9 @@ window.weatherThemes = {
             // At night, weather only tints slightly - we don't want a
             // 'cloudy' sky colour washing over deep night sky and
             // making it look bright.
-            var _sunAlt = DAY_SIM ? (window.__currentSunAlt || 0)
+            var _sunAlt = window.__currentSunAlt !== undefined
-                : SunCalc.getPosition(new Date(), SITE_LAT, SITE_LON).altitude;
+                ? window.__currentSunAlt
+                : SunCalc.getPosition(sceneNow(), SITE_LAT, SITE_LON).altitude;
             var nightFactor = Math.max(0, Math.min(1, -_sunAlt / 0.4));
             // Daytime: 40% weather mix (was 60%) — keeps day/night
             // palette visible underneath, weather only adds tint.
@@ -1701,7 +1678,6 @@ window.weatherThemes = {
             if (typeof fetchWeather === 'function') fetchWeather();
             // Force a debug update so the digital clock shows the new language
             if (typeof updateDebug === 'function') {
-                var now = new Date();
                 updateDebug(0, null,
                     { sky: 0, cloud: 0, light: 0, bg: 0 },
                     currentWeatherThemeName, realDayProgress);
@@ -1778,8 +1754,7 @@ window.weatherThemes = {
         }
 
         function updateDebug(t, palette, sceneColors, themeName, realDayProgress) {
-            var now = new Date();
+            var now = sceneNow();
-            if (DAY_SIM) now = simNow();
             var hh = now.getHours(), mm = now.getMinutes(), ss = now.getSeconds();
             document.getElementById('dbg-time').textContent =
                 (hh < 10 ? '0' : '') + hh + ':' + (mm < 10 ? '0' : '') + mm + ':' + (ss < 10 ? '0' : '') + ss;
@@ -1904,9 +1879,7 @@ window.weatherThemes = {
         var __fpsCount = 0, __fpsT0 = performance.now(), __dbgT0 = 0;
 
         function animate() {
-            var t = (DAY_SIM && FIXED_T !== null)
+            var t = realDayProgress;
-                ? FIXED_T
-                : (Date.now() - startTime) / CYCLE % 1;
             var c = getColor(t);
             c = applyWeatherTheme(c);
             // Expose current palette + weather info for the WebGL scene
@@ -1915,112 +1888,42 @@ window.weatherThemes = {
             window.__currentDayProgress = realDayProgress;
             window.__currentThemeSpeed = currentThemeSpeed;
             // Sun altitude in radians. Negative = below horizon (night).
-            if (DAY_SIM) {
+            var _sunNow = sceneNow();
-                __simT = t;
+            var _sunPos = SunCalc.getPosition(_sunNow, SITE_LAT, SITE_LON);
-                window.__currentDayProgress = t;
+            window.__currentSunAlt = _sunPos.altitude;
-                // virtual weekday: starts at the real one and advances with
+            window.__flightDow = _sunNow.getDay();
-                // every simulated day, so weekends pass by in the 20s cycle
+            // Unit vector towards the sun in world space. SunCalc azimuth
-                if (typeof window.__simDow !== 'number') {
+            // is measured from the south, positive towards the west, so the
-                    window.__simDow = new Date().getDay();
+            // compass bearing (0 = north, clockwise) is azimuth + PI.
-                    window.__simLastT = t;
+            // World frame: +X = west, +Z = north, +Y = up -> east is -X.
-                } else if (t < window.__simLastT) {
+            var _sunBearingR = _sunPos.azimuth + Math.PI;
-                    window.__simDow = (window.__simDow + 1) % 7;
+            window.__currentSunDir = [
-                }
+                -Math.cos(_sunPos.altitude) * Math.sin(_sunBearingR),
-                window.__simLastT = t;
+                Math.sin(_sunPos.altitude),
-                window.__flightDow = window.__simDow;
+                Math.cos(_sunPos.altitude) * Math.cos(_sunBearingR)
-                var _alt = simSunAlt(t);
+            ];
-                window.__currentSunAlt = _alt;
-                // bearing: 6:00 (t=0.25) = east (pi/2), 12:00 = south (pi),
-                // 18:00 = west (3pi/2) -> bearing = 2*PI*t
-                var _sunBearing = t * Math.PI * 2;
-                // World frame (verified from the star frame and the terrain
-                // mesh): +X points WEST, +Y up, +Z north. The star frame maps
-                // RA=0 to +X and rotates it to due west after 6 h of sidereal
-                // time, and the mesh samples the mosaic with u = 0.5 - x/size,
-                // so east is -X. The east component therefore has to land on
-                // -cos(alt)*sin(bearing).
-                window.__currentSunDir = [
-                    -Math.cos(_alt) * Math.sin(_sunBearing),
-                    Math.sin(_alt),
-                    Math.cos(_alt) * Math.cos(_sunBearing)
-                ];
-            } else {
-                var _sunPos = SunCalc.getPosition(new Date(), SITE_LAT, SITE_LON);
-                window.__currentSunAlt = _sunPos.altitude;
-                window.__flightDow = new Date().getDay();
-                // Unit vector towards the sun in world space. SunCalc azimuth
-                // is measured from the south, positive towards the west, so
-                // the compass bearing (0 = north, clockwise) is azimuth + PI.
-                // World frame: +X = west, +Z = north, +Y = up -> east is -X.
-                var _sunBearingR = _sunPos.azimuth + Math.PI;
-                window.__currentSunDir = [
-                    -Math.cos(_sunPos.altitude) * Math.sin(_sunBearingR),
-                    Math.sin(_sunPos.altitude),
-                    Math.cos(_sunPos.altitude) * Math.cos(_sunBearingR)
-                ];
-            }
             // ---- Local sidereal time -------------------------------------
             // Same formula SunCalc uses internally (Meeus): GMST in degrees
             // plus the observer's east longitude. This is what the star
             // frame has to follow - a solar day fraction is 3 min 56 s per
             // day off and has no absolute phase at all.
-            var _sidD = (Date.now() - Date.UTC(2000, 0, 1, 12, 0, 0)) / 86400000;
+            var _sidD = (sceneNow().getTime() - Date.UTC(2000, 0, 1, 12, 0, 0)) / 86400000;
-            var _sidReal = (280.16 + 360.9856235 * _sidD + SITE_LON) * Math.PI / 180;
+            window.__currentSiderealRad = (280.16 + 360.9856235 * _sidD + SITE_LON) * Math.PI / 180;
-            if (DAY_SIM) {
-                if (typeof window.__sidStart !== 'number') {
-                    window.__sidStart = _sidReal;
-                    window.__sidStartMs = Date.now();
-                }
-                // simulated days elapsed * sidereal rate (1.0027379 solar days
-                // per sidereal day)
-                var _sidDays = (Date.now() - window.__sidStartMs) / CYCLE;
-                window.__currentSiderealRad = window.__sidStart + _sidDays * 2 * Math.PI * 1.0027379;
-            } else {
-                window.__currentSiderealRad = _sidReal;
-            }
 
             // ---- Moon direction ------------------------------------------
-            // Start elongation = real lunar phase (SunCalc: 0 new .. 0.5
+            // SunCalc solves the actual lunar ephemeris: the moon's own
-            // full); in day simulation the elongation advances 360/29.53
+            // altitude/azimuth, not a point kept on the sun's declination
-            // deg per simulated day -> correct waxing/waning as cycles pass.
+            // circle (the geometric construction that used to live here put
-            if (typeof window.__moonElong0 !== 'number') {
+            // the moon up to 28.5 deg away from its real sky position).
-                window.__moonElong0 = SunCalc.getMoonIllumination(new Date()).phase * Math.PI * 2;
+            var _moonNow = sceneNow();
-                window.__moonSimStartMs = Date.now();
+            var _moonPos = SunCalc.getMoonPosition(_moonNow, SITE_LAT, SITE_LON);
-            }
+            var _moonBearingR = _moonPos.azimuth + Math.PI;
-            var _simDays = (DAY_SIM && FIXED_T === null) ? (Date.now() - window.__moonSimStartMs) / CYCLE : 0;
+            window.__currentMoonDir = [
-            var _elong = window.__moonElong0 + _simDays * (Math.PI * 2 / 29.53);
+                -Math.cos(_moonPos.altitude) * Math.sin(_moonBearingR),
-            var _sd = window.__currentSunDir;
+                Math.sin(_moonPos.altitude),
-            var _cp = SITE_LAT * Math.PI / 180;
+                Math.cos(_moonPos.altitude) * Math.cos(_moonBearingR)
-            var _kp = [0, Math.sin(_cp), Math.cos(_cp)];   // celestial pole
+            ];
-            var _ecs = Math.cos(_elong), _esn = Math.sin(_elong);
+            window.__currentMoonFrac = SunCalc.getMoonIllumination(_moonNow).fraction;
-            var _kdv = _kp[0]*_sd[0] + _kp[1]*_sd[1] + _kp[2]*_sd[2];
-            var _cx = _kp[1]*_sd[2] - _kp[2]*_sd[1];
-            var _cy = _kp[2]*_sd[0] - _kp[0]*_sd[2];
-            var _cz = _kp[0]*_sd[1] - _kp[1]*_sd[0];
-            if (DAY_SIM) {
-                window.__currentMoonDir = [
-                    _sd[0]*_ecs + _cx*_esn + _kp[0]*_kdv*(1-_ecs),
-                    _sd[1]*_ecs + _cy*_esn + _kp[1]*_kdv*(1-_ecs),
-                    _sd[2]*_ecs + _cz*_esn + _kp[2]*_kdv*(1-_ecs)
-                ];
-                // illuminated fraction straight from the elongation used above
-                // (0 = new, 1 = full) so other layers can light themselves by it
-                window.__currentMoonFrac = (1 - Math.cos(_elong)) * 0.5;
-            } else {
-                // Real mode: the geometric construction above keeps the moon on
-                // the SUN's declination circle. The real moon leaves it by up to
-                // 28.5 deg (obliquity 23.4 + lunar inclination 5.1), which puts
-                // it in the wrong part of the sky. SunCalc solves the actual
-                // lunar ephemeris, so use its altitude/azimuth directly.
-                var _moonPos = SunCalc.getMoonPosition(new Date(), SITE_LAT, SITE_LON);
-                var _moonBearingR = _moonPos.azimuth + Math.PI;
-                window.__currentMoonDir = [
-                    -Math.cos(_moonPos.altitude) * Math.sin(_moonBearingR),
-                    Math.sin(_moonPos.altitude),
-                    Math.cos(_moonPos.altitude) * Math.cos(_moonBearingR)
-                ];
-                window.__currentMoonFrac = SunCalc.getMoonIllumination(new Date()).fraction;
-            }
             var __skyHex = '#' + ('00000' + c.sky.toString(16)).slice(-6);
             if (__skyHex !== window.__lastSkyHex) {
                 window.__lastSkyHex = __skyHex;
@@ -2065,8 +1968,8 @@ window.weatherThemes = {
                 console.error('Tick error:', e);
             }
             // simulated day/hour switch -> refresh the weather block
-            if (DAY_SIM && weatherData) {
+            if (SIM_START !== null && weatherData) {
-                var wh = Math.floor(simNow().getTime() / 3600000);
+                var wh = Math.floor(sceneNow().getTime() / 3600000);
                 if (wh !== __lastWeatherHour) {
                     __lastWeatherHour = wh;
                     try { updateWeatherDisplay(); } catch (e) { console.error(e); }
@@ -2285,8 +2188,8 @@ window.weatherThemes = {
         function updateWeatherDisplay() {
             if (!weatherData) return;
 
-            var now = simNow();   // virtual calendar: real day-of-week start,
+            var now = sceneNow();   // virtual calendar: follows the same
-                                  // one simulated day per CYCLE (clock stays real!)
+                                    // clock the sky and the clock hands use
             var current = weatherData.current;
             var hourly = weatherData.hourly;
             var daily = weatherData.daily;
@@ -2298,11 +2201,11 @@ window.weatherThemes = {
             var spanMs = daily.time.length * 86400000;
             var eff = now;
             var wrapGuard = 0;
-            while (DAY_SIM && eff.getTime() >= firstDay.getTime() + spanMs && wrapGuard++ < 2000) {
+            while (SIM_ACTIVE && eff.getTime() >= firstDay.getTime() + spanMs && wrapGuard++ < 2000) {
                 eff = new Date(eff.getTime() - spanMs);
             }
-            if (DAY_SIM && eff.getTime() < firstDay.getTime()) eff = firstDay;
+            if (SIM_ACTIVE && eff.getTime() < firstDay.getTime()) eff = firstDay;
-            var dayOffset = DAY_SIM
+            var dayOffset = SIM_ACTIVE
                 ? Math.max(0, Math.min(daily.time.length - 4,
                       Math.floor((eff - firstDay) / 86400000)))
                 : 0;
@@ -2312,7 +2215,7 @@ window.weatherThemes = {
             // button has manual control)
             var curTemp = current.temperature_2m;
             var curCode = current.weather_code;
-            if (DAY_SIM) {
+            if (SIM_ACTIVE) {
                 var curIdx = findHourlyIndex(eff, hourly.time);
                 curTemp = hourly.temperature_2m[curIdx];
                 curCode = hourly.weather_code[curIdx];