Fix #251: Fix stock code that fails to limit timewarp when approaching a SOI transition (#259)

- Fix warp rate not being always limited correctly when approaching SOI transitions

Author: JonnyOThan

GameData/KSPCommunityFixes/Settings.cfg

@@ -225,6 +225,11 @@ KSP_COMMUNITY_FIXES
   // Fix loading of drag cubes without a name failing with an IndexOutOfRangeException
   DragCubeLoadException = true
 
+  // Fix the stock code that tries to reduce timewarp when approaching a SOI transition.
+  // Jumping to high warp levels with a SOI change on your trajectory could often warp through
+  // the encounter entirely, and even through bodies.
+  TimeWarpBodyCollision = true
+
   // ##########################
   // Obsolete bugfixes
   // ##########################

KSPCommunityFixes/BugFixes/TimeWarpBodyCollision.cs

@@ -0,0 +1,46 @@
+using HarmonyLib;
+using System;
+using System.Collections.Generic;
+using UnityEngine;
+using static TimeWarp;
+
+namespace KSPCommunityFixes.BugFixes
+{
+    class TimeWarpBodyCollision : BasePatch
+    {
+        protected override Version VersionMin => new Version(1, 12, 0);
+
+        protected override void ApplyPatches(List<PatchInfo> patches)
+        {
+            patches.Add(new PatchInfo(
+                PatchMethodType.Prefix,
+                AccessTools.Method(typeof(TimeWarp), nameof(TimeWarp.ClampRateToOrbitTransitions)),
+                this));
+        }
+
+        static bool TimeWarp_ClampRateToOrbitTransitions_Prefix(TimeWarp __instance, int rate, Orbit obt, int maxAllowedSOITransitionRate, int secondsBeforeSOItransition, out int __result)
+        {
+            __result = rate;
+
+            // the stock version of this method is designed to aid in ramping down timewarp when you approach a SOI change.
+            // it fails to limit the warp rate if you suddenly jump to a very high warp rate while you have an SOI change in your trajectory
+            // - doing this will often warp you all the way through the SOI and sometimes even through the body.
+            // Instead, we treat the SOI transition like a "warp to here" point and use the existing logic for limiting the warp rate to get to that point
+            if (obt.patchEndTransition != Orbit.PatchTransitionType.FINAL && rate > maxAllowedSOITransitionRate)
+            {
+                double warpDeltaTime = obt.EndUT - Planetarium.GetUniversalTime() - secondsBeforeSOItransition;
+                __instance.getMaxWarpRateForTravel(warpDeltaTime, 1, 4, out var rateIdx);
+                if (rate < rateIdx)
+                {
+                    __result = rate;
+                }
+                else
+                {
+                    __result = Math.Max(rateIdx, maxAllowedSOITransitionRate);
+                }
+            }
+
+            return false;
+        }
+    }
+}

KSPCommunityFixes/KSPCommunityFixes.csproj

@@ -139,6 +139,7 @@
     <Compile Include="BugFixes\ReRootPreserveSurfaceAttach.cs" />
     <Compile Include="BugFixes\RespawnDeadKerbals.cs" />
     <Compile Include="BugFixes\ThumbnailSpotlight.cs" />
+    <Compile Include="BugFixes\TimeWarpBodyCollision.cs" />
     <Compile Include="BugFixes\TimeWarpOrbitShift.cs" />
     <Compile Include="BugFixes\UpgradeBugs.cs" />
     <Compile Include="BugFixes\PartTooltipUpgradesApplyToSubstituteParts.cs" />