cache images by string (filename) rather than index; disable unloading for now

Program.cs

@@ -565,7 +565,7 @@ public class Game : GameWindow {
   int VertexArrayObject;
   List<Photo> allPhotos = new();
   List<Photo> photos = new();
-  HashSet<int> loadedImages = new();
+  HashSet<string> loadedImages = new();
   int photoIndex = 0;
   int ribbonIndex = 0;
   Shader shader = new();
@@ -710,6 +710,8 @@ public class Game : GameWindow {
 
   void FilterByRating(int rating) {
     Console.WriteLine("filter to " + rating);
+    photos = allPhotos.Where(p => p.Rating >= rating).ToList();
+    photoIndex = 0;
   }
 
   protected override void OnLoad() {
@@ -750,11 +752,11 @@ public class Game : GameWindow {
 
     // Load photos from a directory.
     // string[] files = Directory.GetFiles(@"c:\users\colin\desktop\photos-test\");
-    // string[] files = Directory.GetFiles(@"c:\users\colin\pictures\photos\2023\07\14\");
+    string[] files = Directory.GetFiles(@"c:\users\colin\pictures\photos\2023\07\14\");
     // string[] files = Directory.GetFiles(@"G:\DCIM\100EOSR6\");
     // string[] files = Directory.GetFiles(@"C:\Users\colin\Pictures\photos\2018\06\23");
     // string[] files = Directory.GetFiles(@"C:\Users\colin\Desktop\Germany all\104D7000");
-    string[] files = Directory.GetFiles(@"C:\Users\colin\Desktop\many-birds\");
+    // string[] files = Directory.GetFiles(@"C:\Users\colin\Desktop\many-birds\");
 
     for (int i = 0; i < files.Count(); i++) {
       string file = files[i];
@@ -789,8 +791,9 @@ public class Game : GameWindow {
     int maxLoadedImage = Math.Min(photoIndex + 20, photos.Count - 1);
     // First, unload images that are far outside our window.
     // FIXME: also cancel any in-progress loading tasks that have moved outside our window.
-    // FIXME: maybe use an LRU cache for evicting images?
     // FIXME: keep around thumbnail-sized textures?
+    // FIXME: turn unloading back on, using an LRU cache for evicting images.
+    /*
     foreach (int i in loadedImages) {
       if (i < minUnloadedImage || i > maxUnloadedImage) {
         // Console.WriteLine("unloading " + i);
@@ -798,12 +801,12 @@ public class Game : GameWindow {
         photos[i].UnloadAsync();
       }
     }
-
+    */
     // Then, start loading any images that aren't in our window.
     for (int i = minLoadedImage; i <= maxLoadedImage; i++) {
-      if (!loadedImages.Contains(i)) {
+      if (!loadedImages.Contains(photos[i].Filename)) {
         // Console.WriteLine("loading " + i);
-        loadedImages.Add(i);
+        loadedImages.Add(photos[i].Filename);
         await Task.Run( () => { photos[i].LoadAsync(); });
       }
     }
@@ -816,7 +819,7 @@ public class Game : GameWindow {
     LoadAndUnloadImagesAsync();
 
     GL.Clear(ClearBufferMask.ColorBufferBit);
-    GL.BindBuffer(BufferTarget.ArrayBuffer, VertexBufferObject);  HashSet<int> loadedImages = new();
+    GL.BindBuffer(BufferTarget.ArrayBuffer, VertexBufferObject);
     GL.ActiveTexture(TextureUnit.Texture0);
 
     Photo activePhoto = photos[photoIndex];