spherical.txt

/**
* Function: CalculateSphericalTextureCoord
* Description: Calculates the spherical texture coordinate for a coordinate.
* Parameters:
*	coord {Coord} the coordinate
*	normal {Vector} the normal vector for calculation
*	system {CoordSystem} the coordinate system
* Returns:
*	{Coord2D} the result
*/
JSM.CalculateSphericalTextureCoord = function (coord, normal, system)
{
	var result = new JSM.Coord2D (0.0, 0.0);

	var e3Direction = system.e3.Clone ().Normalize ();
	if (e3Direction.IsCollinearWith (normal)) {
		result = JSM.CalculateCubicTextureCoord (coord, normal, system);
		return [result, 0.0];
	}

	var baseLine = new JSM.Line (system.origo, e3Direction);
	var projectedCoord = baseLine.ProjectCoord (coord);
	var radius = system.e1.Length ();

	if (!coord.IsEqual (projectedCoord)) {
		var coordDirection = JSM.CoordSub (coord, projectedCoord);
		var e1Direction = system.e1.Clone ().Normalize ();
		var longitudeAngle = JSM.GetVectorsFullAngle (coordDirection, e1Direction, e3Direction);
		result.x = longitudeAngle * radius;
	} else {
		result.x = null;
	}

	var projectedDistance = JSM.CoordSignedDistance (system.origo, projectedCoord, e3Direction);
	var coordDistance = system.origo.DistanceTo (coord);
	var latitudeAngle = JSM.ArcCos (projectedDistance / coordDistance);
	result.y = -latitudeAngle * radius;
	
	return [result, longitudeAngle];
};