Make PSG Atlas-friendly

MechJeb2/MechJebModuleStageStats.cs

@@ -1,4 +1,4 @@
-extern alias JetBrainsAnnotations;
+extern alias JetBrainsAnnotations;
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
@@ -21,6 +21,10 @@ public class MechJebModuleStageStats : ComputerModule
         public double        AltSLT  = 0;
         public double        Mach    = 0;
 
+        public int HalfStageIndex => _vesselManagerVac.HalfStageIndex;
+        [Persistent(pass = (int)(Pass.TYPE | Pass.GLOBAL))]
+        public readonly EditableDoubleMult HalfStageEndMass = new EditableDoubleMult(0, 0.001);
+
         private int _vabRebuildTimer = 1;
 
         public readonly List<FuelStats> AtmoStats = new List<FuelStats>();
@@ -144,6 +148,7 @@ private void RunSimulation()
                 _vesselManagerVac.SetConditions(0, 0, 0);
                 _vesselManagerVac.SetInitial(VesselState.time, VesselState.orbitalPosition.WorldToV3Rotated(),
                     VesselState.orbitalVelocity.WorldToV3Rotated(), VesselState.forward.WorldToV3Rotated());
+                _vesselManagerVac.SetupStageAndAHalf(HalfStageEndMass);
                 if (!_vesselManagerVac.TryStartFuelFlowSimulationJob())
                     throw new Exception("[MechJebModuleStageStats] could not start vac stats job");
             }
@@ -154,6 +159,7 @@ private void RunSimulation()
                 _vesselManagerAtmo.SetConditions(atmDensity, staticPressureKpa * PhysicsGlobals.KpaToAtmospheres, mach);
                 _vesselManagerAtmo.SetInitial(VesselState.time, VesselState.orbitalPosition.WorldToV3Rotated(),
                     VesselState.orbitalVelocity.WorldToV3Rotated(), VesselState.forward.WorldToV3Rotated());
+                _vesselManagerAtmo.SetupStageAndAHalf(HalfStageEndMass);
                 if (!_vesselManagerAtmo.TryStartFuelFlowSimulationJob())
                     throw new Exception("[MechJebModuleStageStats] could not start atmo stats job");
             }

MechJeb2/MechJebModuleStagingController.cs

@@ -290,6 +290,12 @@ public override void OnUpdate()
             UpdateActiveModuleEngines(_allModuleEngines);
             UpdateBurnedResources();
 
+            if (Vessel.currentStage == _stats.HalfStageIndex && Vessel.totalMass <= _stats.HalfStageEndMass)
+            {
+                Stage();
+                return;
+            }
+
             // don't decouple active or idle engines or tanks
             if (InverseStageDecouplesActiveOrIdleEngineOrTank(Vessel.currentStage - 1, _burnedResources, _activeModuleEngines) &&
                 !InverseStageReleasesClamps(Vessel.currentStage - 1))
@@ -308,6 +314,7 @@ public override void OnUpdate()
             if (!InverseStageHasActiveEngines(Vessel.currentStage))
             {
                 Stage();
+                return;
             }
 
             // prevent staging when the current stage has active engines and the next stage has any engines (but not decouplers or clamps)
@@ -324,6 +331,7 @@ public override void OnUpdate()
             if (InverseStageDecouplesDeactivatedEngineOrTank(Vessel.currentStage - 1))
             {
                 Stage();
+                return;
             }
 
             // only decouple fairings if the dynamic pressure, altitude, and aerothermal flux conditions are respected
@@ -453,7 +461,7 @@ private double LastNonZeroDVStageBurnTime()
         private bool InverseStageHasActiveEngines(int inverseStage)
         {
             foreach (ModuleEngines engine in _allModuleEngines)
-                if (engine.part.inverseStage == inverseStage && engine.EngineHasFuel())
+                if (engine.part.inverseStage >= inverseStage && engine.EngineHasFuel())
                     return true;
             return false;
         }

MechJeb2/MechJebStageStatsHelper.cs

@@ -294,6 +294,15 @@ public void AllStageStats()
 
             Profiler.EndSample();
 
+            if (stats.HalfStageIndex != -1)
+            {
+                GUILayout.BeginHorizontal();
+                GUILayout.Label($"Half-stage index: {stats.HalfStageIndex}", GUILayout.Width(130));
+                GUILayout.Space(30);
+                GuiUtils.SimpleTextBox("End mass: ", stats.HalfStageEndMass, "kg");
+                GUILayout.EndHorizontal();
+            }
+
             Profiler.BeginSample("AllStageStats.DrawColumns");
 
             GUILayout.BeginHorizontal();

MechJebLib/FuelFlowSimulation/FuelFlowSimulation.cs

@@ -1,10 +1,11 @@
-/*
+/*
  * Copyright Lamont Granquist, Sebastien Gaggini and the MechJeb contributors
  * SPDX-License-Identifier: LicenseRef-PD-hp OR Unlicense OR CC0-1.0 OR 0BSD OR MIT-0 OR MIT OR LGPL-2.1+
  */
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Runtime.CompilerServices;
 using MechJebLib.FuelFlowSimulation.PartModules;
 using MechJebLib.Utils;
@@ -25,6 +26,7 @@ public class FuelFlowSimulation : AsyncJob
         private readonly HashSet<SimPart> _partsWithRCSDrains      = new HashSet<SimPart>();
         private readonly HashSet<SimPart> _partsWithRCSDrains2     = new HashSet<SimPart>();
         private          bool             _allocatedFirstSegment;
+        private          bool             _halfStageIsDetected;
 
         public override void Run(object? o = null)
         {
@@ -34,6 +36,7 @@ public override void Run(object? o = null)
             if (!(o is SimVessel vessel))
                 throw new ArgumentException("o is not a SimVessel", nameof(o));
 
+            _halfStageIsDetected   = false;
             _allocatedFirstSegment = false;
             _time                  = 0;
             Segments.Clear();
@@ -53,6 +56,9 @@ public override void Run(object? o = null)
             Segments.Reverse();
 
             _partsWithResourceDrains.Clear();
+
+            if (!_halfStageIsDetected)
+                vessel.HalfStageIndex = -1;
         }
 
         private void SimulateRCS(SimVessel vessel, bool max)
@@ -110,12 +116,30 @@ private void SimulateStage(SimVessel vessel)
             UpdateResourceDrainsAndResiduals(vessel);
             double currentThrust = vessel.ThrustMagnitude;
 
+            if (!_halfStageIsDetected //is anyone insane enough to build a rocket with multiple half-stages? You never know
+                && vessel.ActiveEngines.Count > 0
+                && _sources.Count > 0)
+            {
+                int earliestDroppedEgineInStage = vessel.ActiveEngines.Max(x => x.Part.DecoupledInStage);
+                int earliestDroppedTankInStage = _sources.Max(x => x.DecoupledInStage);
+                if (earliestDroppedEgineInStage > earliestDroppedTankInStage)
+                {
+                    _halfStageIsDetected = true;
+                    vessel.HalfStageIndex = earliestDroppedEgineInStage + 1;
+                }
+            }
+
             for (int steps = MAXSTEPS; steps > 0; steps--)
             {
                 if (AllowedToStage(vessel))
                     return;
 
                 double dt = MinimumTimeStep();
+                if (_currentSegment.KSPStage == vessel.HalfStageIndex)
+                {   
+                    double massFlow = ResourceMaxMassFlow(vessel);
+                    dt = Min(dt, (vessel.Mass - vessel.HalfStageEndMass) / massFlow);
+                }
 
                 // FIXME: if we have constructed a segment which is > 0 dV, but less than 0.02s, and there's a
                 // prior > 0dV segment in the same kspStage we should add those together to reduce clutter.
@@ -381,6 +405,17 @@ private double ResourceMaxTime()
             return maxTime;
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private double ResourceMaxMassFlow(SimVessel vessel)
+        {
+            double massFlow = 0;
+
+            foreach (SimModuleEngines engine in vessel.ActiveEngines)
+                massFlow += engine.MassFlowRate;
+
+            return massFlow;
+        }
+
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private void FinishRcsSegment(bool max, double deltaTime, double startMass, double endMass, double rcsThrust)
         {
@@ -457,6 +492,9 @@ private static bool AllowedToStage(SimVessel vessel)
             if (vessel.ActiveEngines.Count == 0)
                 return true;
 
+            if (vessel.CurrentStage == vessel.HalfStageIndex && vessel.Mass - vessel.HalfStageEndMass < 1e-6)
+                return true;
+
             for (int i = 0; i < vessel.ActiveEngines.Count; i++)
             {
                 SimModuleEngines e = vessel.ActiveEngines[i];

MechJebLib/FuelFlowSimulation/SimVessel.cs

@@ -1,4 +1,4 @@
-/*
+/*
  * Copyright Lamont Granquist, Sebastien Gaggini and the MechJeb contributors
  * SPDX-License-Identifier: LicenseRef-PD-hp OR Unlicense OR CC0-1.0 OR 0BSD OR MIT-0 OR MIT OR LGPL-2.1+
  */
@@ -46,6 +46,9 @@ public class SimVessel : IDisposable
         public  double T;
         public  V3     R, V, U;
 
+        public int HalfStageIndex = -1;
+        public double HalfStageEndMass = 0;
+
         // CurrentStage gets scribbled over by the FuelFlowSimulation, SetCurrentStage() is intended to be used in
         // the VesselBuilder and DecouplingAnalyzer to figure out the right value, ResetCurrentStage() is called by
         // the VesselUpdater to reset it back.
@@ -80,6 +83,15 @@ public void SetInitial(double t, V3 r, V3 v, V3 u)
             U = u;
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void SetupStageAndAHalf(double endMass)
+        {
+            if (HalfStageIndex != -1)
+            {
+                HalfStageEndMass = endMass;
+            }
+        }
+
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void UpdateMass()
         {

MechJebLibBindings/FuelFlowSimulation/SimVesselBuilder.cs

@@ -1,4 +1,4 @@
-/*
+/*
  * Copyright Lamont Granquist, Sebastien Gaggini and the MechJeb contributors
  * SPDX-License-Identifier: LicenseRef-PD-hp OR Unlicense OR CC0-1.0 OR 0BSD OR MIT-0 OR MIT OR LGPL-2.1+
  */
@@ -29,17 +29,9 @@ public class SimVesselBuilder
 
             private static readonly CrewMass _crewMassDelegate;
 
-            private SimVessel _vessel
-            {
-                get => _manager._vessel;
-                set => _manager._vessel = value;
-            }
+            private SimVessel _vessel => _manager._vessel;
 
-            private IShipconstruct _kspVessel
-            {
-                get => _manager._kspVessel;
-                set => _manager._kspVessel = value;
-            }
+            private IShipconstruct _kspVessel => _manager._kspVessel;
 
             private readonly        SimVesselManager _manager;
             private static readonly Type?            _rfType;
@@ -68,7 +60,7 @@ static SimVesselBuilder()
 
             private static double CrewMassNew(ProtoCrewMember crew) => PhysicsGlobals.KerbalCrewMass + crew.ResourceMass() + crew.InventoryMass();
 
-            public SimVesselBuilder(SimVesselManager manager)
+            internal SimVesselBuilder(SimVesselManager manager)
             {
                 _manager = manager;
             }
@@ -126,14 +118,12 @@ internal void UpdateSymmetryParts()
                 }
             }
 
-            internal void BuildVessel(IShipconstruct kspVessel)
+            internal void BuildVessel()
             {
-                _vessel.Dispose();
-                _vessel    = SimVessel.Borrow();
-                _kspVessel = kspVessel;
+                BuildParts();
             }
 
-            internal void BuildParts()
+            private void BuildParts()
             {
                 _vessel.SetCurrentStage(StageManager.CurrentStage);
 

MechJebLibBindings/FuelFlowSimulation/SimVesselManager.cs

@@ -1,4 +1,4 @@
-/*
+/*
  * Copyright Lamont Granquist, Sebastien Gaggini and the MechJeb contributors
  * SPDX-License-Identifier: LicenseRef-PD-hp OR Unlicense OR CC0-1.0 OR 0BSD OR MIT-0 OR MIT OR LGPL-2.1+
  */
@@ -14,8 +14,6 @@ namespace MechJebLibBindings.FuelFlowSimulation
     // need to link against KSP GameObjects (MechJebLibBindings.dll or something like that)
     public partial class SimVesselManager
     {
-        public List<FuelStats> Segments => FuelFlowSimulation.Segments;
-
         private readonly SimVesselBuilder                                 _builder;
         private readonly SimVesselUpdater                                 _updater;
         private          SimVessel                                        _vessel;
@@ -32,6 +30,8 @@ public partial class SimVesselManager
         public V3     V => _vessel.V;
         public V3     U => _vessel.U;
 
+        public int HalfStageIndex => _vessel.HalfStageIndex;
+
         public SimVesselManager()
         {
             _builder   = new SimVesselBuilder(this);
@@ -42,9 +42,12 @@ public SimVesselManager()
 
         public void Build(IShipconstruct vessel)
         {
+            _vessel.Dispose();
+            _vessel = SimVessel.Borrow();
+            _kspVessel = vessel;
+
             Clear();
-            _builder.BuildVessel(vessel);
-            _builder.BuildParts();
+            _builder.BuildVessel();
             Update();
             _builder.UpdateLinks();
             _builder.UpdateCrossFeedSet();
@@ -60,6 +63,8 @@ public void SetConditions(double atmDensity, double atmPressure, double machNumb
 
         public void SetInitial(double t, V3 r, V3 v, V3 u) => _vessel.SetInitial(t, r, v, u);
 
+        public void SetupStageAndAHalf(double endMass) => _vessel.SetupStageAndAHalf(endMass);
+
         public bool TryStartFuelFlowSimulationJob()
         {
             FuelFlowSimulation.DVLinearThrust = DVLinearThrust;

MechJebLibBindings/FuelFlowSimulation/SimVesselUpdater.cs

@@ -1,4 +1,4 @@
-/*
+/*
  * Copyright Lamont Granquist, Sebastien Gaggini and the MechJeb contributors
  * SPDX-License-Identifier: LicenseRef-PD-hp OR Unlicense OR CC0-1.0 OR 0BSD OR MIT-0 OR MIT OR LGPL-2.1+
  */
@@ -49,7 +49,7 @@ static SimVesselUpdater()
                 }
             }
 
-            public SimVesselUpdater(SimVesselManager manager)
+            internal SimVesselUpdater(SimVesselManager manager)
             {
                 _manager = manager;
             }