From 94ec7178235be8054336bd5608d97af06336c643 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Fri, 16 Jan 2026 01:19:12 +0000
Subject: [PATCH] =?UTF-8?q?=E2=9A=A1=20Bolt:=20Cache=20VRCUrl.Get()=20call?=
 =?UTF-8?q?s=20in=20ImageLoader?=
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💡 What:
Introduced a `_cachedUrls` string array to `ImageLoader.cs` that mirrors the string values of `predefinedUrls`.
Updated `Start`, `ClearPredefinedUrls`, and relevant loops to populate and use this cache instead of calling `.Get()` repeatedly.

🎯 Why:
In UdonSharp, calling `VRCUrl.Get()` involves an interop call from the Udon VM to the Unity host, which is expensive when performed inside loops (e.g., during URL matching).

📊 Impact:
Reduces the overhead of URL lookups from O(N * Interop) to O(N * Array Access).
For lists with many predefined URLs, this significantly reduces the CPU cost during `FindMatchingUrlIndex`.

🔬 Measurement:
Verified via code review that `predefinedUrls` logic is preserved and that the cache is invalidated/updated whenever the source array might change (initialization and clearing).
---
 .jules/bolt.md         |  3 ++
 Scripts/ImageLoader.cs | 62 +++++++++++++++++++++++++++++++++++-------
 2 files changed, 55 insertions(+), 10 deletions(-)
 create mode 100644 .jules/bolt.md

diff --git a/.jules/bolt.md b/.jules/bolt.md
new file mode 100644
index 0000000..ad2c24d
--- /dev/null
+++ b/.jules/bolt.md
@@ -0,0 +1,3 @@
+## 2024-05-22 - VRCUrl.Get() Interop Overhead
+**Learning:** Calling `VRCUrl.Get()` inside loops in UdonSharp creates significant performance overhead due to interop calls between the Udon VM and the host engine.
+**Action:** Cache `VRCUrl` string values into a native `string[]` array at startup (e.g., in `Start()`) and use the cached array for lookups and comparisons in loops.
diff --git a/Scripts/ImageLoader.cs b/Scripts/ImageLoader.cs
index 8bccf34..745dde8 100644
--- a/Scripts/ImageLoader.cs
+++ b/Scripts/ImageLoader.cs
@@ -54,6 +54,7 @@ public class ImageLoader : UdonSharpBehaviour
     private string[] _captions = new string[0];
     private int _currentIndex = 0;
     private string _lastLoadedUrlList = "";
+    private string[] _cachedUrls;
     
     // Current texture reference
     private Texture2D _currentTexture;
@@ -64,6 +65,8 @@ void Start()
         // Initialize core components
         _imageDownloader = new VRCImageDownloader();
         _udonEventReceiver = (IUdonEventReceiver)this;
+
+        CacheUrls();
         
         // Store reference to original material
         if (renderer != null)
@@ -90,6 +93,28 @@ void Start()
         }
     }
     
+    private void CacheUrls()
+    {
+        if (predefinedUrls == null)
+        {
+            _cachedUrls = new string[0];
+            return;
+        }
+
+        _cachedUrls = new string[predefinedUrls.Length];
+        for (int i = 0; i < predefinedUrls.Length; i++)
+        {
+            if (predefinedUrls[i] != null)
+            {
+                _cachedUrls[i] = predefinedUrls[i].Get();
+            }
+            else
+            {
+                _cachedUrls[i] = null;
+            }
+        }
+    }
+
     private void InitFromGeneratedUrls()
     {
         // Make sure predefinedUrls are properly initialized
@@ -427,11 +452,16 @@ private int FindMatchingUrlIndex(string urlToFind, int additionalCount = 0)
             Debug.LogError("No predefined URLs available!");
             return -1;
         }
+
+        if (_cachedUrls == null || _cachedUrls.Length != predefinedUrls.Length)
+        {
+            CacheUrls();
+        }
         
         // First try to find an exact match
-        for (int i = 0; i < predefinedUrls.Length; i++)
+        for (int i = 0; i < _cachedUrls.Length; i++)
         {
-            if (predefinedUrls[i] != null && predefinedUrls[i].Get() == urlToFind)
+            if (_cachedUrls[i] != null && _cachedUrls[i] == urlToFind)
             {
                 return i;
             }
@@ -454,11 +484,11 @@ private int FindMatchingUrlIndex(string urlToFind, int additionalCount = 0)
         string filename = ExtractFilenameFromUrl(urlToFind);
         if (!string.IsNullOrEmpty(filename))
         {
-            for (int i = 0; i < predefinedUrls.Length; i++)
+            for (int i = 0; i < _cachedUrls.Length; i++)
             {
-                if (predefinedUrls[i] != null && 
-                    !string.IsNullOrEmpty(predefinedUrls[i].Get()) && 
-                    predefinedUrls[i].Get().Contains(filename))
+                if (_cachedUrls[i] != null &&
+                    !string.IsNullOrEmpty(_cachedUrls[i]) &&
+                    _cachedUrls[i].Contains(filename))
                 {
                     return i;
                 }
@@ -505,13 +535,18 @@ private int FindUrlSlotForFilename(string filename)
             Debug.LogError("No valid VRCUrl found in predefinedUrls array!");
             return -1;
         }
+
+        if (_cachedUrls == null || _cachedUrls.Length != predefinedUrls.Length)
+        {
+            CacheUrls();
+        }
         
         // Find a predefined URL that matches this filename
-        for (int i = 0; i < predefinedUrls.Length; i++)
+        for (int i = 0; i < _cachedUrls.Length; i++)
         {
-            if (predefinedUrls[i] != null && !string.IsNullOrEmpty(predefinedUrls[i].Get()))
+            if (_cachedUrls[i] != null && !string.IsNullOrEmpty(_cachedUrls[i]))
             {
-                if (predefinedUrls[i].Get().Contains(filename))
+                if (_cachedUrls[i].Contains(filename))
                 {
                     return i;
                 }
@@ -598,13 +633,18 @@ public override void OnImageLoadSuccess(IVRCImageDownload result)
         
         string loadedUrl = result.Url.Get();
         Debug.Log($"Image loaded successfully: {loadedUrl}");
+
+        if (_cachedUrls == null || _cachedUrls.Length != predefinedUrls.Length)
+        {
+            CacheUrls();
+        }
         
         // Find which of our URLs this corresponds to
         for (int i = 0; i < _activeUrlIndices.Length; i++)
         {
             int urlIndex = _activeUrlIndices[i];
             if (urlIndex < predefinedUrls.Length && predefinedUrls[urlIndex] != null && 
-                predefinedUrls[urlIndex].Get() == loadedUrl)
+                _cachedUrls[urlIndex] == loadedUrl)
             {
                 // Store the downloaded texture
                 _downloadedTextures[i] = result.Result;
@@ -700,6 +740,8 @@ public void ClearPredefinedUrls()
             }
         }
         
+        CacheUrls();
+
         // Reset URL count
         urlCount = 0;