This project serve as submission for VRillAR test

Implementation

Plane is created to represent flat ground for shadow
Capsule object with scaleY: 2 is used to represent human (1 unit = 1m)
Directional Light is used to represent sun
Simple input panel UI to allow user to change relevant config (longitude, altiude, month, day, time)
Calculate altitude (rotationX in deg) and azimuth (rotationY in deg) based on relevant equations
Update rotation of sun to reflect user config

Assumption

Use Y axis as reference for azimuth
Use X axis as east/west (with right direction is east)
Use Z axis as north/south (with forward direction is north)

How to run

Method 1

Open project in Unity Editor
Run with play mode
Change values (longitude, altiude, month, day, time) on input panel
Click update to view solar change

Method 2

Open on web browser: https://nguyentong.itch.io/solarcirculation

Reference

https://www.sciencedirect.com/topics/engineering/solar-declination