public static float SegmentSphere()

in MREUnityRuntimeLib/ProceduralToolkit/Geometry/Distance3D.cs [203:298]
77 lines of code
21 McCabe index (conditional complexity)

		public static float SegmentSphere(Vector3 segmentA, Vector3 segmentB, Vector3 sphereCenter, float sphereRadius)
		{
			Vector3 segmentAToCenter = sphereCenter - segmentA;
			Vector3 fromAtoB = segmentB - segmentA;
			float segmentLength = fromAtoB.magnitude;
			if (segmentLength < Geometry.Epsilon)
			{
				return segmentAToCenter.magnitude - sphereRadius;
			}

			Vector3 segmentDirection = fromAtoB.normalized;
			float centerProjection = Vector3.Dot(segmentDirection, segmentAToCenter);
			if (centerProjection + sphereRadius < -Geometry.Epsilon ||
				centerProjection - sphereRadius > segmentLength + Geometry.Epsilon)
			{
				// No intersection
				if (centerProjection < 0)
				{
					return segmentAToCenter.magnitude - sphereRadius;
				}
				return (sphereCenter - segmentB).magnitude - sphereRadius;
			}

			float sqrDistanceToA = segmentAToCenter.sqrMagnitude;
			float sqrDistanceToLine = sqrDistanceToA - centerProjection*centerProjection;
			float sqrDistanceToIntersection = sphereRadius*sphereRadius - sqrDistanceToLine;
			if (sqrDistanceToIntersection < -Geometry.Epsilon)
			{
				// No intersection
				if (centerProjection < -Geometry.Epsilon)
				{
					return Mathf.Sqrt(sqrDistanceToA) - sphereRadius;
				}
				if (centerProjection > segmentLength + Geometry.Epsilon)
				{
					return (sphereCenter - segmentB).magnitude - sphereRadius;
				}
				return Mathf.Sqrt(sqrDistanceToLine) - sphereRadius;
			}

			if (sqrDistanceToIntersection < Geometry.Epsilon)
			{
				if (centerProjection < -Geometry.Epsilon)
				{
					// No intersection
					return Mathf.Sqrt(sqrDistanceToA) - sphereRadius;
				}
				if (centerProjection > segmentLength + Geometry.Epsilon)
				{
					// No intersection
					return (sphereCenter - segmentB).magnitude - sphereRadius;
				}
				// Point intersection
				return 0;
			}

			// Line intersection
			float distanceToIntersection = Mathf.Sqrt(sqrDistanceToIntersection);
			float distanceA = centerProjection - distanceToIntersection;
			float distanceB = centerProjection + distanceToIntersection;

			bool pointAIsAfterSegmentA = distanceA > -Geometry.Epsilon;
			bool pointBIsBeforeSegmentB = distanceB < segmentLength + Geometry.Epsilon;

			if (pointAIsAfterSegmentA && pointBIsBeforeSegmentB)
			{
				// Two points intersection
				return 0;
			}
			if (!pointAIsAfterSegmentA && !pointBIsBeforeSegmentB)
			{
				// The segment is inside, but no intersection
				distanceB = -(distanceB - segmentLength);
				return distanceA > distanceB ? distanceA : distanceB;
			}

			bool pointAIsBeforeSegmentB = distanceA < segmentLength + Geometry.Epsilon;
			if (pointAIsAfterSegmentA && pointAIsBeforeSegmentB)
			{
				// Point A intersection
				return 0;
			}
			bool pointBIsAfterSegmentA = distanceB > -Geometry.Epsilon;
			if (pointBIsAfterSegmentA && pointBIsBeforeSegmentB)
			{
				// Point B intersection
				return 0;
			}

			// No intersection
			if (centerProjection < 0)
			{
				return Mathf.Sqrt(sqrDistanceToA) - sphereRadius;
			}
			return (sphereCenter - segmentB).magnitude - sphereRadius;
		}