JZ_PlanetHelper.cs

using UnityEngine;
using System.Collections;

public class JZ_PlanetHelper : MonoBehaviour 
{
	// return x -180.0 ~ 180.0
	// return y -90.0 ~ 90.0
	public static Vector2 CartesianToPolarDegress(Vector3 point)
	{
		var polar = Vector2.zero;
		
		//calc longitude
		polar.x = Mathf.Atan2(point.x,point.z);
		
		//this is easier to write and read than sqrt(pow(x,2), pow(y,2))!
		var xzLen = new Vector2(point.x,point.z).magnitude; 
		//atan2 does the magic
		polar.y = - Mathf.Atan2(-point.y,xzLen);
		
		//convert to deg
		polar *= Mathf.Rad2Deg;
		
		return polar;
	}

	// return x 0.0 ~ 1.0
	// return y 0.0 ~ 1.0
	public static Vector2 CartesianToPolarUV(Vector3 point)
	{
		var polar = Vector2.zero;
		
		//calc longitude
		polar.x = Mathf.Atan2(point.x,point.z);
		
		//this is easier to write and read than sqrt(pow(x,2), pow(y,2))!
		var xzLen = new Vector2(point.x,point.z).magnitude; 
		//atan2 does the magic
		polar.y = - Mathf.Atan2(-point.y,xzLen);
		
		//convert to deg
		polar *= Mathf.Rad2Deg;

		polar.y = (polar.y + 90.0f)/180.0f;
		polar.x = 1.0f-(polar.x +180.0f)/360.0f;
		
		return polar;
	}

	public static Vector3 PolarUVToCartesian(Vector2 polar)
	{
		//an origin vector, representing lat,lon of 0,0. 
		polar.x = (1.0f - polar.x)*360.0f - 180.0f;
		polar.y = polar.y*180.0f - 90.0f;
		
		var origin= new Vector3(0,0,1);
		//build a quaternion using euler angles for lat,lon
		var rotation = Quaternion.Euler( - polar.y,polar.x,0);
		//transform our reference vector by the rotation. Easy-peasy!
		Vector3 point =rotation*origin;
		
		//Debug.Log("PolarDegreesToCartesian(Vector3 point)" + point.x + " " + point.y + " " + point.z);
		
		return point;
	}

	public static Vector3 PolarDegreesToCartesian(Vector2 polar)
	{
		//an origin vector, representing lat,lon of 0,0. 
		
		var origin= new Vector3(0,0,1);
		//build a quaternion using euler angles for lat,lon
		var rotation = Quaternion.Euler( - polar.y,polar.x,0);
		//transform our reference vector by the rotation. Easy-peasy!
		Vector3 point =rotation*origin;

		//Debug.Log("PolarDegreesToCartesian(Vector3 point)" + point.x + " " + point.y + " " + point.z);

		return point;
	}

}