Merge pull request #451 from sswelm/patch-1

Calculate shield rating with correct exponential function

CHANGELOG.md

@@ -13,6 +13,7 @@
 * Added mod support for CME prediction accuracy that influences the probability that you get an advanced warning, and its accuracy (Sir Mortimer)
 * Configs for SoundingRockets (Arthur, Breach Candy)
 * Fixed DMOS experiment restriction to plantary space. This breaks some DMOS contracts that require experiments in solar orbit (Sir Mortimer)
+* Improved shielding efficiency calculation (Free Thinker)
 
 ## v3.0.2 for all versions of KSP from 1.4.0 to 1.7.x
 

src/Kerbalism/Modules/Habitat.cs

@@ -463,11 +463,12 @@ public static double Humidity(Vessel v)
 			return ResourceCache.Info(v, "MoistAtmosphere").level + 0.6;
 		}
 
-		// return shielding factor in a vessel
+		/// <summary>
+		/// Return vessel shielding factor.
+		/// </summary>
 		public static double Shielding(Vessel v)
 		{
-			// the shielding factor is simply the level of shielding, scaled by the 'shielding efficiency' setting
-			return ResourceCache.Info(v, "Shielding").level * PreferencesStorm.Instance.shieldingEfficiency;
+			return Radiation.ShieldingEfficiency(ResourceCache.Info(v, "Shielding").level);
 		}
 
 		// return living space factor in a vessel

src/Kerbalism/Radiation.cs

@@ -763,6 +763,21 @@ static CelestialBody Interesting_body()
 			  : null;
 		}
 
+		/// <summary>
+		/// Calculate radiation shielding efficiency. Parameter shielding should be in range [0..1]
+		/// <para>
+		/// If you have a thickness which stops a known amount of radiation of a known and constant
+		/// type, then if you have a new thickness, you can calculate how much it stops by:
+		/// </para>
+		/// Stoppage = 1 - ((1 - AmountStoppedByKnownThickness)^(NewThickness / KnownThickness))
+		/// <para>
+		/// source : http://www.projectrho.com/public_html/rocket/radiation.php#id--Radiation_Shielding--Shielding--Shield_Rating
+		/// </para>
+		/// </summary>
+		public static double ShieldingEfficiency(double shielding)
+		{
+			return 1 - Math.Pow(1 - PreferencesStorm.Instance.shieldingEfficiency, Lib.Clamp(shielding, 0.0, 1.0));
+		}
 
 		static Dictionary<string, RadiationModel> models = new Dictionary<string, RadiationModel>(16);
 		static Dictionary<string, RadiationBody> bodies = new Dictionary<string, RadiationBody>(32);

src/Kerbalism/UI/Planner/VesselAnalyzer.cs

@@ -167,7 +167,10 @@ void Analyze_radiation(List<Part> parts, ResourceSimulator sim)
 			// calculate shielding factor
 			double amount = sim.Resource("Shielding").amount;
 			double capacity = sim.Resource("Shielding").capacity;
-			shielding = (capacity > double.Epsilon ? amount / capacity : 1.0) * PreferencesStorm.Instance.shieldingEfficiency;
+
+			shielding = capacity > double.Epsilon
+				? Radiation.ShieldingEfficiency(amount / capacity)
+				: PreferencesStorm.Instance.shieldingEfficiency;
 		}
 
 		void Analyze_reliability(List<Part> parts)