First pass ModuleCenterFollowTransform

- Added ModuleCenterFollowTransform to replace ModuleCoPFollowTransform.
- Deprecated ModuleCoPFollowTransform.

Author: SofieBrink

Source/KSPCommunityPartModules.csproj

@@ -36,6 +36,7 @@
   <ItemGroup>
     <Compile Include="HarmonyPatches\ModuleParachutePatch.cs" />
     <Compile Include="Modules\ModuleAutoCutDrogue.cs" />
+    <Compile Include="Modules\ModuleCenterFollowTransform.cs" />
     <Compile Include="Modules\ModuleCoPFollowTransform.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>

Source/Modules/ModuleCenterFollowTransform.cs

@@ -0,0 +1,78 @@
+/*
+    Usecase:        Making the Center of Pressure, Mass or Lift follow a transform on the same part.
+    Example:        BoringCrewServices Starliner main parachutes,
+                    StarshipExpansionProject Starship Flaps
+    Originally By:  Sofie Brink & JonnyOThan
+    Originally For: KSPCommunityPartModules
+*/
+using UnityEngine;
+
+namespace KSPCommunityPartModules.Modules
+{
+    public class ModuleCenterFollowTransform : PartModule
+    {
+        public const string MODULENAME = nameof(ModuleCenterFollowTransform);
+
+        [KSPField]
+        public bool enableCoP = false;
+
+        [KSPField]
+        public bool enableCoM = false;
+
+        [KSPField]
+        public bool enableCoL = false;
+
+        [KSPField]
+        public string transformName;
+
+        [SerializeField]
+        private Transform followTransform;
+
+        // TODO: Reset offset to prefab value if B9PS disables one of the fields.
+        public override void OnLoad(ConfigNode node)
+        {
+            bool anyModeActive = enableCoP || enableCoM || enableCoL;
+
+            if (followTransform == null || followTransform.name != transformName)
+            {
+                if (transformName != null) followTransform = part.FindModelTransform(transformName);
+                if (followTransform == null) Debug.LogError($"[{MODULENAME}] transformName '{transformName}' was empty or does not exist on part '{part.partInfo?.name}'");
+            }
+            if (!anyModeActive)
+            {
+                Debug.LogWarning($"[{MODULENAME}] no center is following transformName '{transformName}' on part '{part.partInfo?.name}'");
+            }
+
+            if (followTransform == null && part.partInfo != null)
+            {
+                // this may be important if someone is swapping out versions of this module with B9PS
+                // Note this probably isn't correct for parts that also have modules that mess with this field (e.g. ModuleProceduralFairing)
+                if (enableCoP) part.CoPOffset = part.partInfo.partPrefab.CoPOffset;
+                if (enableCoM) part.CoMOffset = part.partInfo.partPrefab.CoMOffset;
+                if (enableCoL) part.CoLOffset = part.partInfo.partPrefab.CoLOffset;
+            }
+            
+            // NOTE: isEnabled will be persisted to the save file, but we want to treat it purely as runtime state
+            isEnabled = followTransform != null && anyModeActive;
+            enabled = followTransform != null && anyModeActive && HighLogic.LoadedSceneIsFlight;
+        }
+
+        public void FixedUpdate()
+        {
+            // Note that we shouldn't ever get here if the transform just didn't exist
+            // But it's certainly possible for *something* to delete it later
+            if (followTransform == null)
+            {
+                isEnabled = false;
+                enabled = false;
+            }
+            else
+            {
+                Vector3 offset = part.transform.InverseTransformPoint(followTransform.position);
+                if (enableCoP) part.CoPOffset = offset;
+                if (enableCoM) part.CoMOffset = offset;
+                if (enableCoL) part.CoLOffset = offset;
+            }
+        }
+    }
+}

Source/Modules/ModuleCoPFollowTransform.cs

@@ -20,6 +20,7 @@ public class ModuleCoPFollowTransform : PartModule
 
         public override void OnLoad(ConfigNode node)
         {
+            Debug.LogWarning($"[{MODULENAME}] This module is deprecated! please use ModuleCenterFollowTransform instead!");
             if (followTransform == null || followTransform.name != transformName)
             {
                 if (transformName != null) followTransform = part.FindModelTransform(transformName);