Made extensible, had to remove manual controls (for now)

Source/CapMod/EndCapper/EndCapper.csproj

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
   <PropertyGroup>
@@ -12,10 +12,11 @@
     <TargetFrameworkVersion>v4.8.1</TargetFrameworkVersion>
     <FileAlignment>512</FileAlignment>
     <Deterministic>true</Deterministic>
+	<LangVersion>11.0</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
     <DebugSymbols>true</DebugSymbols>
-    <DebugType>full</DebugType>
+    <DebugType>portable</DebugType>
     <Optimize>false</Optimize>
     <OutputPath>bin\Debug\</OutputPath>
     <DefineConstants>DEBUG;TRACE</DefineConstants>
@@ -69,7 +70,7 @@
     </Reference>
   </ItemGroup>
   <ItemGroup>
-    <Compile Include="ModuleEndCap.cs" />
+    <Compile Include="ModuleAttachmentVisuals.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />

Source/CapMod/EndCapper/ModuleAttachmentVisuals.cs

@@ -0,0 +1,143 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using UnityEngine;
+
+namespace AttachmentVisuals
+{
+    public class ModuleAttachmentVisuals : PartModule
+    {
+        // todo: dynamically add buttons for manual control of each registered
+        // attachment node (only when advanced tweakables is enabled). Will
+        // need implement IConfigNode on NodeData so state can be saved rather than inferred.
+
+        // todo: serialise per-node state so that they never change during flight.
+
+        public class NodeVisual
+        {
+            public AttachNode attachNode;
+            public List<Transform> showWhenAttached;
+            public List<Transform> showWhenFree;
+
+            public bool Load(Part part, ConfigNode configNode)
+            {
+                string name = "";
+                if (!configNode.TryGetValue("name", ref name))
+                {
+                    Debug.LogError("[ModuleAttachmentVisuals]: NodeVisuals is missing an attachment node name.");
+                    return false;
+                }
+
+                attachNode = part.FindAttachNode(name);
+                if (attachNode == null)
+                {
+                    Debug.LogError($"[ModuleAttachmentVisuals]: Node '{name}' not found on part '{part.name}'");
+                    return false;
+                }
+
+                return TryLoadList(ref showWhenAttached, part, configNode, "showWhenAttached")
+                    | TryLoadList(ref showWhenFree, part, configNode, "showWhenFree");
+            }
+
+            private bool TryLoadList(ref List<Transform> list, Part part, ConfigNode configNode, string listName)
+            {
+                string listString = null;
+                if (!configNode.TryGetValue(listName, ref listString) || string.IsNullOrWhiteSpace(listString))
+                    return false;
+
+                foreach (string transformName in listString.Split(','))
+                {
+                    Transform t = part.FindModelTransform(transformName.Trim());
+
+                    if (t != null)
+                        (list ??= new List<Transform>()).Add(t);
+                    else
+                        Debug.LogError($"[ModuleAttachmentVisuals]: Could not find transform '{transformName}' on {part.name}");
+                }
+
+                return true;
+            }
+
+            public void UpdateVisibility()
+            {
+                if (attachNode != null)
+                    ApplyVisibility(attachNode.attachedPart != null);
+            }
+
+            public void ApplyVisibility(bool attached)
+            {
+                showWhenAttached?.ForEach(t => t?.gameObject.SetActive(attached));
+                showWhenFree?.ForEach(t => t?.gameObject.SetActive(!attached));
+            }
+        }
+
+        [NonSerialized] public List<NodeVisual> nodeVisuals;
+        [SerializeField] private string[] nodeVisualConfigs;
+        private HashSet<Part> directChildren;
+
+        // --- Lifecycle ---
+
+        public override void OnLoad(ConfigNode node)
+        {
+            if (nodeVisualConfigs != null)
+                return;
+
+            ConfigNode[] nodesCfg = node.GetNodes("NODEVISUAL");
+            if (nodesCfg.Length > 0)
+                nodeVisualConfigs = nodesCfg.Select(n => n.ToString()).ToArray();
+        }
+
+        public override void OnStart(StartState state)
+        {
+            if (nodeVisualConfigs == null)
+                return;
+
+            for (int i = 0; i < nodeVisualConfigs.Length; i++)
+            {
+                try
+                {
+                    var newNode = new NodeVisual();
+
+                    if (newNode.Load(part, ConfigNode.Parse(nodeVisualConfigs[i]).GetNode("NODEVISUAL")))
+                        (nodeVisuals ??= new List<NodeVisual>()).Add(newNode);
+                }
+                catch { }
+            }
+
+            // Module doesn't need to do anything from here if no valid node visuals were found.
+            if (nodeVisuals == null)
+                return;
+
+            if (HighLogic.LoadedSceneIsEditor)
+            {
+                GameEvents.onEditorPartEvent.Add(OnEditorEvent);
+                directChildren = part.children.ToHashSet();
+            }
+
+            UpdateVisuals();
+        }
+
+        public void OnDestroy()
+        {
+            if (nodeVisuals != null && HighLogic.LoadedSceneIsEditor)
+                GameEvents.onEditorPartEvent.Remove(OnEditorEvent);
+        }
+
+        // --- Functions ---
+
+        private void UpdateVisuals() => nodeVisuals?.ForEach(n => n.UpdateVisibility());
+
+        private void OnEditorEvent(ConstructionEventType evt, Part p)
+        {
+            if (evt != ConstructionEventType.PartAttached && evt != ConstructionEventType.PartDetached)
+                return;
+
+            if (p == part
+                || (evt == ConstructionEventType.PartAttached && p.parent == part && directChildren.Add(p))
+                || (evt == ConstructionEventType.PartDetached && directChildren.Remove(p)))
+            {
+                UpdateVisuals();
+            }
+        }
+    }
+}