fixes for unstable ignition and burn time calculation

MechJeb2/MechJebModuleNodeExecutor.cs

@@ -36,6 +36,10 @@ public string NextNodeCountdown()
             double dV = node.GetBurnVector(orbit).magnitude;
             double halfBurnTIme;
             double burnTIme = BurnTime(dV, out halfBurnTIme);
+            if (double.IsInfinity(halfBurnTIme))
+            {
+                halfBurnTIme = 0.0;
+            }
             return GuiUtils.TimeToDHMS(node.UT - halfBurnTIme - vesselState.time);
         }
 
@@ -124,8 +128,8 @@ public override void OnFixedUpdate()
             double burnTime = BurnTime(dVLeft, out halfBurnTime);
 
             double timeToNode = node.UT - vesselState.time;
-
-            if (halfBurnTime > 0 && timeToNode < halfBurnTime)
+            //(!double.IsInfinity(num) && num > 0.0 && num2 < num) || num2 <= 0.0
+            if ((!double.IsInfinity(halfBurnTime) && halfBurnTime > 0 && timeToNode < halfBurnTime) || timeToNode < 0)
             {
                 burnTriggered = true;
                 if (!MuUtils.PhysicsRunning()) core.warp.MinimumWarp();
@@ -223,7 +227,27 @@ private double BurnTime(double dv, out double halfBurnTime)
                 // TODO: Be smarter about throttle limits on future stages.
                 if (i == stats.vacStats.Length - 1)
                 {
-                    stageAvgAccel *= vesselState.throttleLimit;
+                    if (this.core.thrust.limiter != MechJebModuleThrustController.LimitMode.UnstableIgnition)
+                    {
+                        stageAvgAccel *= (double)this.vesselState.throttleLimit;
+                    }
+                    else
+                    {
+                        double fLimitTemp = 1.0;
+                        if (this.core.thrust.limitThrottle)
+                        {
+                            fLimitTemp = this.core.thrust.maxThrottle;
+                        }
+                        if (this.core.thrust.limitAcceleration)
+                        {
+                            fLimitTemp = Math.Min(fLimitTemp, this.core.thrust.maxAccelerationLimit);
+                        }
+                        if (this.core.thrust.limiterMinThrottle)
+                        {
+                            fLimitTemp = Math.Max(this.core.thrust.minThrottle, fLimitTemp);
+                        }
+                        stageAvgAccel *= fLimitTemp;
+                    }
                 }
 
                 halfBurnTime += Math.Min(halfDvLeft, stageBurnDv) / stageAvgAccel;

MechJeb2/MechJebModuleThrustController.cs

@@ -113,6 +113,8 @@ public void LimitToPreventUnstableIgnitionInfoItem()
         [Persistent(pass = (int)Pass.Global)]
         public EditableDouble maxAcceleration = 40;
 
+		public double maxAccelerationLimit = 1;
+
         [GeneralInfoItem("Limit acceleration", InfoItem.Category.Thrust)]
         public void LimitAccelerationInfoItem()
         {
@@ -136,7 +138,7 @@ public void LimitThrottleInfoItem()
         {
             GUILayout.BeginHorizontal();
             GUIStyle s = new GUIStyle(GUI.skin.toggle);
-            if (limiter == LimitMode.Throttle) s.onHover.textColor = s.onNormal.textColor = Color.green;
+			if (limiter == LimitMode.Throttle) s.onHover.textColor = s.onNormal.textColor = maxThrottle > 0d ? Color.green : Color.red;
             limitThrottle = GUILayout.Toggle(limitThrottle, "Limit throttle to", s, GUILayout.Width(110));
             maxThrottle.text = GUILayout.TextField(maxThrottle.text, GUILayout.Width(30));
             GUILayout.Label("%", GUILayout.ExpandWidth(false));
@@ -431,6 +433,8 @@ public override void Drive(FlightCtrlState s)
                 float limit = AccelerationLimitedThrottle();
                 if(limit < throttleLimit) limiter = LimitMode.Acceleration;
                 throttleLimit = Mathf.Min(throttleLimit, limit);
+				// to provide an externally facing value. (used when ignition is unstable so we can approximate throttle limit when ignition stablizes)
+				maxAccelerationLimit = throttleLimit;
             }
 
             if (electricThrottle && ElectricEngineRunning())
@@ -458,15 +462,16 @@ public override void Drive(FlightCtrlState s)
             // RealFuels ullage integration.  Stock always has stableUllage.
             if (limitToPreventUnstableIgnition && !vesselState.stableUllage)
             {
-                if (( targetThrottle > 0.0F || s.mainThrottle > 0.0F ) && throttleLimit > 0.0F ) {
+                if (( targetThrottle > 0.0F || s.mainThrottle > 0.0F ) && throttleLimit > 0.0F )
+				{
                     // We want to fire the throttle, and nothing else is limiting us, but we have unstable ullage
-                    limiter = LimitMode.UnstableIgnition;
                     if (vessel.ActionGroups[KSPActionGroup.RCS] && s.Z == 0) {
                         // RCS is on, so use it to ullage
                         s.Z = -1.0F;
                     }
                 }
-                throttleLimit = 0.0F;
+				limiter = LimitMode.UnstableIgnition;
+				throttleLimit = 0.0F;
             }
 
             if (double.IsNaN(throttleLimit)) throttleLimit = 0;