perf: Optimize ModuleSystemHeatHarvester (#168)

* perf: Optimize ModuleSystemHeatHarvester

SystemHeat is actually pretty good here, and most of the overhead is in
the stock module. The main thing we can optimize is to entirely disable
the module when it is not active.

Other than that I have gone through and changed stuff to make better use
of the hooks that stock provides:
* systemEfficency is used to replace GetHeatThrottle. This makes it so
  that it actually changes the converter rate like it is supposed to.
  Before the changes written to outputList and inputList were stomped
  over in PrepareRecipe.
* We do UpdateFlux in PostProcess and reuse the TimeFactor.

* Properly handle AlwaysActive

Author: Phantomical

Source/Modules/ModuleSystemHeatHarvester.cs

@@ -4,6 +4,7 @@
 using System.Text;
 using UnityEngine;
 using KSP.Localization;
+using Unity.Profiling;
 
 namespace SystemHeat
 {
@@ -49,128 +50,142 @@ public void ToggleEditorThermalSim()
     [KSPField(isPersistant = false, guiActive = true, guiActiveEditor = true, guiName = "Harvester Efficiency")]
     public string HarvesterEfficiency = "-1%";
 
-    // base paramters
-    private List<ResourceBaseRatio> inputs;
-    private List<ResourceBaseRatio> outputs;
     protected ModuleSystemHeat heatModule;
+
+    private static readonly ProfilerMarker BaseFixedUpdateMarker = new("ModuleResourceHarvester.FixedUpdate");
+
     public override string GetInfo()
     {
       string info = base.GetInfo();
 
       int pos = info.IndexOf("\n\n");
       if (pos < 0)
         return info;
-      else
-        return info.Substring(0, pos) + Localizer.Format("#LOC_SystemHeat_ModuleSystemHeatHarvester_PartInfoAdd",
-          Utils.ToSI(systemPower, "F0"),
-          systemOutletTemperature.ToString("F0"),
-          shutdownTemperature.ToString("F0")
-          ) + info.Substring(pos);
+
+      var extraInfo = Localizer.Format("#LOC_SystemHeat_ModuleSystemHeatHarvester_PartInfoAdd",
+        Utils.ToSI(systemPower, "F0"),
+        systemOutletTemperature.ToString("F0"),
+        shutdownTemperature.ToString("F0")
+      );
+      return info.Substring(0, pos) + extraInfo + info.Substring(pos);
     }
+
     public void Start()
     {
+      heatModule = ModuleUtils.FindHeatModule(part, systemHeatModuleID);
 
-      heatModule = ModuleUtils.FindHeatModule(this.part, systemHeatModuleID);
+      Utils.Log("[ModuleSystemHeatHarvester] Setup completed", LogType.Modules);
+      Events["ToggleEditorThermalSim"].guiName = Localizer.Format("#LOC_SystemHeat_ModuleSystemHeatHarvester_Field_SimulateEditor", ConverterName);
+      Fields["HarvesterEfficiency"].guiName = Localizer.Format("#LOC_SystemHeat_ModuleSystemHeatHarvester_Field_Efficiency", ConverterName);
+    }
 
+    public override void FixedUpdate()
+    {
       if (HighLogic.LoadedSceneIsFlight)
       {
-        SetupResourceRatios();
+        FixedUpdateFlight();
       }
       else
       {
-        SetupResourceRatios();
+        UpdateFlux();
+        Fields["HarvesterEfficiency"].guiActiveEditor = editorThermalSim;
       }
+    }
 
-      Utils.Log("[ModuleSystemHeatHarvester] Setup completed", LogType.Modules);
-      Events["ToggleEditorThermalSim"].guiName = Localizer.Format("#LOC_SystemHeat_ModuleSystemHeatHarvester_Field_SimulateEditor", base.ConverterName);
-      Fields["HarvesterEfficiency"].guiName = Localizer.Format("#LOC_SystemHeat_ModuleSystemHeatHarvester_Field_Efficiency", base.ConverterName);
+    void Update()
+    {
+      if (!part.IsPAWVisible())
+        return;
+
+      HarvesterEfficiency = Localizer.Format(
+        "#LOC_SystemHeat_ModuleSystemHeatHarvester_Field_Efficiency_Value",
+        (GetHeatThrottle() * 100f).ToString("F1")
+      );
     }
-    public override void FixedUpdate()
+
+    void OnDisable()
     {
-      base.FixedUpdate();
-      if (heatModule != null)
-      {
-        if (HighLogic.LoadedSceneIsFlight)
-        {
-          GenerateHeatFlight();
-          UpdateSystemHeatFlight();
-        }
-        else if (HighLogic.LoadedSceneIsEditor)
-        {
-          GenerateHeatEditor();
-
-          Fields["HarvesterEfficiency"].guiActiveEditor = editorThermalSim;
-        }
-      }
+      heatModule?.AddFlux(moduleID, 0f, 0f, false);
+      HarvesterEfficiency = "-";
     }
 
-    void Update()
+    void FixedUpdateFlight()
     {
-      if (heatModule != null && part.IsPAWVisible())
+      if (heatModule == null)
       {
-        HarvesterEfficiency = Localizer.Format("#LOC_SystemHeat_ModuleSystemHeatHarvester_Field_Efficiency_Value", (systemEfficiency.Evaluate(heatModule.currentLoopTemperature) * 100f).ToString("F1"));
+        // This disables this module entirely, so it won't be called every frame.
+        enabled = false;
+        return;
       }
-    }
 
-    protected void GenerateHeatEditor()
-    {
-      if (base.IsActivated)
-        heatModule.AddFlux(moduleID, systemOutletTemperature, systemPower, true);
-      else
-        heatModule.AddFlux(moduleID, 0f, 0f, false);
+      CheckOverheat();
+
+      if (!IsActivated && !AlwaysActive)
+        enabled = false;
+
+      using (BaseFixedUpdateMarker.ConditionalAuto())
+        base.FixedUpdate();
     }
 
-    protected void GenerateHeatFlight()
+    void UpdateFlux() => UpdateFlux(lastTimeFactor);
+    void UpdateFlux(double timeFactor)
     {
-      if (base.ModuleIsActive())
+      if (heatModule == null)
+        return;
+
+      if (ModuleIsActive())
       {
-        float fluxScale = 1f;
-        if (base.lastTimeFactor == 0d)
-        {
-          fluxScale = 0f;
-        }
-        heatModule.AddFlux(moduleID, systemOutletTemperature, systemPower * fluxScale, true);
+        float scale = timeFactor != 0.0 ? 1f : 0f;
+        if (HighLogic.LoadedSceneIsEditor)
+          scale = 1f;
+
+        heatModule.AddFlux(moduleID, systemOutletTemperature, systemPower * scale, true);
       }
       else
       {
         heatModule.AddFlux(moduleID, 0f, 0f, false);
       }
     }
-    protected void UpdateSystemHeatFlight()
+
+    void CheckOverheat()
     {
-      if (base.ModuleIsActive())
-      {
-        if (heatModule.currentLoopTemperature > shutdownTemperature)
-        {
-          ScreenMessages.PostScreenMessage(
-            new ScreenMessage(
-              Localizer.Format("#LOC_SystemHeat_ModuleSystemHeatHarvester_Message_Shutdown",
-                                                             part.partInfo.title),
-                                                             3.0f,
-                                                             ScreenMessageStyle.UPPER_CENTER));
-          ToggleResourceConverterAction(new KSPActionParam(0, KSPActionType.Activate));
-
-          Utils.Log("[ModuleSystemHeatConverter]: Overheated, shutdown fired", LogType.Modules);
-
-        }
-        base.recipe = ModuleUtils.RecalculateRatios(systemEfficiency.Evaluate(heatModule.currentLoopTemperature), inputs, outputs, inputList, outputList, base.recipe);
-      }
+      if (!ModuleIsActive())
+        return;
+      if (heatModule.currentLoopTemperature <= shutdownTemperature)
+        return;
+
+      ScreenMessages.PostScreenMessage(
+        new ScreenMessage(
+          Localizer.Format(
+            "#LOC_SystemHeat_ModuleSystemHeatHarvester_Message_Shutdown",
+            part.partInfo.title),
+          3.0f,
+          ScreenMessageStyle.UPPER_CENTER));
+      StopResourceConverter();
+
+      Utils.Log("[ModuleSystemHeatConverter]: Overheated, shutdown fired", LogType.Modules);
     }
 
-    private void SetupResourceRatios()
+    public override void StartResourceConverter()
     {
+      enabled = true;
+      base.StartResourceConverter();
+    }
 
-      inputs = new List<ResourceBaseRatio>();
-      outputs = new List<ResourceBaseRatio>();
+    // In stock this would use the ModuleCoreHeat on the same part. We don't
+    // want that, and just override it to point to our own efficiency multiplier.
+    public override float GetHeatThrottle()
+    {
+      if (heatModule == null)
+        return 1f;
 
-      for (int i = 0; i < inputList.Count; i++)
-      {
-        inputs.Add(new ResourceBaseRatio(inputList[i].ResourceName, inputList[i].Ratio));
-      }
-      for (int i = 0; i < outputList.Count; i++)
-      {
-        outputs.Add(new ResourceBaseRatio(outputList[i].ResourceName, outputList[i].Ratio));
-      }
+      return systemEfficiency.Evaluate(heatModule.currentLoopTemperature);
+    }
+
+    protected override void PostProcess(ConverterResults result, double deltaTime)
+    {
+      base.PostProcess(result, deltaTime);
+      UpdateFlux(result.TimeFactor);
     }
   }
 }