VOID_Data: Working on multi-stage burn time estimation.
[VOID.git] / VOID_Data.cs
blob:a/VOID_Data.cs -> blob:b/VOID_Data.cs
--- a/VOID_Data.cs
+++ b/VOID_Data.cs
@@ -269,22 +269,22 @@
 						return double.NaN;
 					}
 
+					return Core.LastStage.totalResourceMass;
+				},
+				"tons"
+			);
+
+		public static readonly VOID_DoubleValue stageResourceMass =
+			new VOID_DoubleValue(
+				"Resource Mass (Stage)",
+				delegate()
+				{
+					if (Core.LastStage == null)
+					{
+						return double.NaN;
+					}
+
 					return Core.LastStage.resourceMass;
-				},
-				"tons"
-			);
-
-		public static readonly VOID_DoubleValue stageResourceMass =
-			new VOID_DoubleValue(
-				"Resource Mass (Stage)",
-				delegate()
-				{
-					if (Core.LastStage == null)
-					{
-						return double.NaN;
-					}
-
-					return Core.LastStage.totalResourceMass;
 				},
 				"tons"
 			);
@@ -692,22 +692,25 @@
 					double vesselLongitude = Core.Vessel.longitude * Math.PI / 180d;
 					double vesselLatitude = Core.Vessel.latitude * Math.PI / 180d;
 
-					double diffLon = vesselLongitude - kscLongitude;
-					double diffLat = vesselLatitude - kscLatitude;
-
-					double sinHalfDiffLat = Math.Sin(diffLat / 2d);
-					double sinHalfDiffLon = Math.Sin(diffLon / 2d);
-
-					double cosVesselLon = Math.Cos(vesselLongitude);
-					double cosKSCLon = Math.Cos(kscLongitude);
-
-					double haversine =
-						sinHalfDiffLat * sinHalfDiffLat +
-						cosVesselLon * cosKSCLon * sinHalfDiffLon * sinHalfDiffLon;
-
-					double arc = 2d * Math.Atan2(Math.Sqrt(haversine), Math.Sqrt(1d - haversine));
-
-					return Core.Vessel.mainBody.Radius * arc;
+					double diffLon = Math.Abs(vesselLongitude - kscLongitude);
+
+					double cosVesselLatitude = Math.Cos(vesselLatitude);
+					double sinDiffLon = Math.Sin(diffLon);
+
+					double term1 = cosVesselLatitude * sinDiffLon;
+
+					double cosKSCLatitude = Math.Cos(kscLatitude);
+					double sinVesselLatitude = Math.Sin(vesselLatitude);
+					double sinKSCLatitude = Math.Sin(kscLatitude);
+					double cosDiffLon = Math.Cos(diffLon);
+
+					double term2 = cosKSCLatitude * sinVesselLatitude - sinKSCLatitude * cosVesselLatitude * cosDiffLon;
+
+					double term3 = sinKSCLatitude * sinVesselLatitude + cosKSCLatitude * cosVesselLatitude * cosDiffLon;
+
+					double arc = Math.Atan2(Math.Sqrt(term1 * term1 + term2 * term2), term3);
+
+					return arc * Core.Vessel.mainBody.Radius;
 				},
 				"m"
 			);
@@ -1251,17 +1254,20 @@
 
 			while (dVRemaining > double.Epsilon)
 			{
-				if (stageIdx < 1)
+				if (stageIdx < 0)
 				{
 					return double.PositiveInfinity;
 				}
 
 				Stage stage = Core.Stages[stageIdx];
 
-				double stageDVUsed = Math.Min(stage.deltaV, dVRemaining);
-
-				burntime += burnTime(stageDVUsed, stage.totalMass, stage.MassFlow(), stage.NominalThrust());
-				dVRemaining -= stageDVUsed;
+				if (stage.deltaV > 0)
+				{
+					double stageDVUsed = Math.Min(stage.deltaV, dVRemaining);
+
+					burntime += burnTime(stageDVUsed, stage.totalMass, stage.MassFlow(), stage.NominalThrust());
+					dVRemaining -= stageDVUsed;
+				}
 
 				stageIdx--;
 			}