Fix: use global realDayProgress in animate and tick

index.html

@@ -420,6 +420,8 @@ var effect = (VANTA.CLOUDS2 || VANTA.CLOUDS)({
         var PASSAU_LAT = 48.5667;
         var PASSAU_LON = 13.4319;
 
+        var realDayProgress = 0;
+
 // Read color palette from CSS variables
         function getColors() {
             var root = getComputedStyle(document.documentElement);
@@ -847,7 +849,6 @@ var effect = (VANTA.CLOUDS2 || VANTA.CLOUDS)({
             var sunTimes = SunCalc.getTimes(now, PASSAU_LAT, PASSAU_LON);
             var sunrise = sunTimes.sunrise;
             var sunset = sunTimes.sunset;
-            var realDayProgress;
             if (now < sunrise) {
                 var prevSunset = new Date(sunset.getTime() - 24 * 3600 * 1000);
                 realDayProgress = (now.getTime() - prevSunset.getTime()) / (sunrise.getTime() - prevSunset.getTime());