SunCalc

SunCalc is a SceneScript library for precise calculations of solar position and related events, such as sunrise, sunset, dusk, and dawn.

Features

• Compute the sun's azimuth and elevation angles for any location and time.
• Calculate solar events: sunrise, sunset, dusk, dawn, and more.
• Adjust for atmospheric refraction and altitude.
• Designed to have a minimal performance impact.

Usage

Example

const sun = new SunCalc(new Vec2(45.5, 10.2)); // Latitude (°), Longitude (°)
const sun = new SunCalc(new Vec3(45.5, 10.2, 100), new Date(), 120); // Latitude (°), Longitude (°), altitude (m), date and time, timezone offset (minutes)

// Set location and time
sun.setLocation(new Vec2(45.5, 10.2)); // Latitude (°), Longitude (°)
sun.setLocation(new Vec3(45.5, 10.2, 100), 120); // Latitude (°), Longitude (°), altitude (m), timezone offset (minutes)
sun.setDateTime(new Date());

// Get sun position
const sunPosition = sun.getSunPosition();
console.log(`Azimuth: ${sunPosition.x}, Elevation: ${sunPosition.y}`);

// Get solar events
const sunrise = sun.getSunrise();
const sunset = sun.getSunset();
console.log(`Sunrise: ${sunrise}, Sunset: ${sunset}`);

Methods

• setLocation(coordinates, timezone) / getLocation() Set/get the latitude, longitude and altitude for calculations.

• setDateTime(date) / getDateTime() Set/get the date and time for calculations.

• getTimezone() Returns the timezone currently used for calculations.

• getSunPosition() Returns a Vec2 object with azimuth (x) and elevation (y) of the sun.

• getSunrise() / getSunset() Returns the Date object for sunrise and sunset.

• getSolarNoon() / getSolarMidnight() Returns the Date object for solar noon and solar midnight.

• get...Dawn() / get...Dusk() Returns the Date object for the three types of dawn and dusk: civil, nautical and astronomical.

Performance

To utilize the performance optimization provided by this it's necessary to create a SunCalc object once as a global variable, then use setDateTime and SetLocation to manipulate it later in the code and in the following frames.

This is because those functions actually run a recalculation only when necessary, if the location and date and time did not change no recalculation will be done, and the get methods will just return the previously stored results.

Limitations

• Accuracy decreases at extreme latitudes.
• Does not account for weather or cloud cover.

License

This project is licensed under the MIT License. See the LICENSE file for details.