A serializable Texture2D wrapper to fix icon loading

Fixes #18

Texture2D objects get thrown away by Unity even though they're serialized, because Unity wants to be very conservative about the things it keeps in memory, and games can load large amounts of textures during play mode which Unity clears up. This means that it also throws away all the textures we load, so we lose all the icons.

This adds a class that decomposes Texture2D into separate fields that Unity won't throw away, so we can recreate textures on demand whenever we detect that it has thrown the texture away.

Author: shana

src/UnityExtension/Assets/Editor/GitHub.Unity/Misc/Utility.cs

@@ -7,6 +7,40 @@
 
 namespace GitHub.Unity
 {
+    [Serializable]
+    public class SerializableTexture2D
+    {
+        [SerializeField] private byte[] bytes;
+        [SerializeField] private int height;
+        [SerializeField] private int width;
+        [SerializeField] private TextureFormat format;
+        [SerializeField] private bool mipmap;
+        [SerializeField] private Texture2D texture;
+
+        public Texture2D Texture
+        {
+            get
+            {
+                if (texture == null)
+                {
+                    texture = new Texture2D(width, height, format, mipmap);
+                    texture.LoadRawTextureData(bytes);
+                    texture.Apply();
+                }
+                return texture;
+            }
+            set
+            {
+                texture = value;
+                bytes = value.GetRawTextureData();
+                height = value.height;
+                width = value.width;
+                format = value.format;
+                mipmap = value.mipmapCount > 1;
+            }
+        }
+    }
+
     class Utility : ScriptableObject
     {
         public static Texture2D GetIcon(string filename, string filename2x = "")

src/UnityExtension/Assets/Editor/GitHub.Unity/UI/TreeControl.cs

@@ -11,23 +11,33 @@ namespace GitHub.Unity
     [Serializable]
     public class Tree
     {
-        [SerializeField] private List<TreeNode> nodes = new List<TreeNode>();
-        [SerializeField] private TreeNode selectedNode = null;
-        [SerializeField] private TreeNode activeNode = null;
         [SerializeField] public float ItemHeight = EditorGUIUtility.singleLineHeight;
         [SerializeField] public float ItemSpacing = EditorGUIUtility.standardVerticalSpacing;
         [SerializeField] public float Indentation = 12f;
         [SerializeField] public Rect Margin = new Rect();
         [SerializeField] public Rect Padding = new Rect();
-        [SerializeField] private List<string> foldersKeys = new List<string>();
-        [SerializeField] public Texture2D ActiveNodeIcon;
-        [SerializeField] public Texture2D NodeIcon;
-        [SerializeField] public Texture2D FolderIcon;
-        [SerializeField] public Texture2D RootFolderIcon;
+
+        [SerializeField] private SerializableTexture2D activeNodeIcon = new SerializableTexture2D();
+        public Texture2D ActiveNodeIcon {  get { return activeNodeIcon.Texture; } set { activeNodeIcon.Texture = value; } }
+
+        [SerializeField] private SerializableTexture2D nodeIcon = new SerializableTexture2D();
+        public Texture2D NodeIcon {  get { return nodeIcon.Texture; } set { nodeIcon.Texture = value; } }
+
+        [SerializeField] private SerializableTexture2D folderIcon = new SerializableTexture2D();
+        public Texture2D FolderIcon {  get { return folderIcon.Texture; } set { folderIcon.Texture = value; } }
+
+        [SerializeField] private SerializableTexture2D rootFolderIcon = new SerializableTexture2D();
+        public Texture2D RootFolderIcon {  get { return rootFolderIcon.Texture; } set { rootFolderIcon.Texture = value; } }
+
         [SerializeField] public GUIStyle FolderStyle;
         [SerializeField] public GUIStyle TreeNodeStyle;
         [SerializeField] public GUIStyle ActiveTreeNodeStyle;
 
+        [SerializeField] private List<TreeNode> nodes = new List<TreeNode>();
+        [SerializeField] private TreeNode selectedNode = null;
+        [SerializeField] private TreeNode activeNode = null;
+        [SerializeField] private List<string> foldersKeys = new List<string>();
+
         [NonSerialized] private Stack<bool> indents = new Stack<bool>();
         [NonSerialized] private Hashtable folders;
 
@@ -105,20 +115,10 @@ public void Load(IEnumerable<ITreeData> data, string title)
                         if (node.IsActive)
                         {
                             activeNode = node;
-                            node.Icon = ActiveNodeIcon;
-                        }
-                        else if (node.IsFolder)
-                        {
-                            if (node.Level == 1)
-                                node.Icon = RootFolderIcon;
-                            else
-                                node.Icon = FolderIcon;
-                        }
-                        else
-                        {
-                            node.Icon = NodeIcon;
                         }
 
+                        ResetNodeIcons(node);
+
                         node.Load();
 
                         nodes.Add(node);
@@ -142,6 +142,7 @@ public Rect Render(Rect rect, Vector2 scroll, Action<TreeNode> singleClick = nul
             rect = new Rect(0f, rect.y, rect.width, ItemHeight);
 
             var titleNode = nodes[0];
+            ResetNodeIcons(titleNode);
             bool selectionChanged = titleNode.Render(rect, 0f, selectedNode == titleNode, FolderStyle, TreeNodeStyle, ActiveTreeNodeStyle);
 
             if (selectionChanged)
@@ -159,6 +160,7 @@ public Rect Render(Rect rect, Vector2 scroll, Action<TreeNode> singleClick = nul
             for (; i < nodes.Count; i++)
             {
                 var node = nodes[i];
+                ResetNodeIcons(node);
 
                 if (node.Level > level && !node.IsHidden)
                 {
@@ -374,6 +376,26 @@ private void Unindent()
         {
             indents.Pop();
         }
+
+        private void ResetNodeIcons(TreeNode node)
+        {
+            if (node.IsActive)
+            {
+                node.Icon = ActiveNodeIcon;
+            }
+            else if (node.IsFolder)
+            {
+                if (node.Level == 1)
+                    node.Icon = RootFolderIcon;
+                else
+                    node.Icon = FolderIcon;
+            }
+            else
+            {
+                node.Icon = NodeIcon;
+            }
+            node.Load();
+        }
     }
 
     [Serializable]