start to load images async

Program.cs

@@ -139,20 +139,14 @@ void main() {
 }
 
 public class Photo {
-  public Texture Texture;
-  public bool Loaded = false;
-  private readonly string filename;
+  private Texture texture;
+  private Texture placeholder;
+  private Image<Rgba32> image;
 
-  public Photo(string filename, Texture unloadedTexture) {
-    this.filename = filename;
-    Texture = unloadedTexture;
-  }
-
-  public void Load() {
-    Image<Rgba32> image = Image.Load<Rgba32>(filename);
-
-    Console.WriteLine("----------------------------------");
-    Console.WriteLine($"image loaded: {image.Width}x{image.Height}");
+  public Photo(Image<Rgba32> image, Texture placeholder) {
+    this.image = image;
+    this.placeholder = placeholder;
+    texture = placeholder;
 
     ExifProfile? exifs = image.Metadata.ExifProfile;
     if (exifs != null) {
@@ -162,9 +156,15 @@ public class Photo {
         }
       }
     }
-    Texture = new Texture(image);
-    Loaded = true;
   }
+
+  public Texture Texture() {
+   if (texture == placeholder) {
+    texture = new Texture(image);
+    image.Dispose();
+   }
+   return texture;
+ }
 }
 
 public class Texture : IDisposable {
@@ -175,7 +175,6 @@ public class Texture : IDisposable {
     Size = new Vector2i(image.Width, image.Height);
     byte[] pixelBytes = new byte[Size.X * Size.Y * Unsafe.SizeOf<Rgba32>()];
     image.CopyPixelDataTo(pixelBytes);
-    image.Dispose();
 
     Handle = GL.GenTexture();
     GL.ActiveTexture(TextureUnit.Texture0);
@@ -262,6 +261,7 @@ public class Game : GameWindow {
     1, 2, 3    // second triangle
   };
 
+  bool doneLoading = false;
   int VertexBufferObject;
   int ElementBufferObject;
   int VertexArrayObject;
@@ -293,7 +293,6 @@ public class Game : GameWindow {
       }
     }
 
-
     // Track keyboard repeat times for advancing up/down.
     if (!input.IsKeyDown(Keys.Down)) {
       downTimer = Int64.MaxValue;
@@ -318,7 +317,7 @@ public class Game : GameWindow {
     }
   }
 
-  protected override void OnLoad() {
+  protected override async void OnLoad() {
     base.OnLoad();
 
     GL.ClearColor(0f, 0f, 0f, 1f);
@@ -354,19 +353,24 @@ public class Game : GameWindow {
     // Load textures from JPEGs.
     // 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\2018\06\23");
+
+    List<Task<Image<Rgba32>>> imageTasks = new();
     for (int i = 0; i < files.Count(); i++) {
       string file = files[i];
       if (file.ToLower().EndsWith(".jpg")) {
-        Photo photo = new(file, TEXTURE_WHITE);
-        if (i == 0) {
-          photo.Load();
-        }
-        photos.Add(photo);
-        if (photos.Count > 10) {
-          break;
-        }
+        imageTasks.Add(Image.LoadAsync<Rgba32>(file));
       }
     }
+    Console.WriteLine(DateTime.Now);
+    await Task.WhenAll(imageTasks);
+    Console.WriteLine(DateTime.Now);
+
+    foreach (Task<Image<Rgba32>> task in imageTasks) {
+      Photo photo = new(task.Result, TEXTURE_WHITE);
+      photos.Add(photo);
+    }
+    doneLoading = true;
   }
 
   protected override void OnUnload() {
@@ -375,11 +379,15 @@ public class Game : GameWindow {
 
   protected override void OnRenderFrame(FrameEventArgs e) {
     base.OnRenderFrame(e);
+    if (!doneLoading) {
+      return;
+    }
+
     GL.Clear(ClearBufferMask.ColorBufferBit);
     GL.BindBuffer(BufferTarget.ArrayBuffer, VertexBufferObject);
     GL.ActiveTexture(TextureUnit.Texture0);
 
-    Texture active = photos[photoIndex].Texture;
+    Texture active = photos[photoIndex].Texture();
 
     // FIXME: make a function for scaling & centering one box on another.
     float scaleX = 1f * geometry.PhotoBox.Size.X / active.Size.X;
@@ -390,9 +398,9 @@ public class Game : GameWindow {
     Vector2i center = (Vector2i) geometry.PhotoBox.Center;
     Box2i photoBox = Util.makeBox(center.X - renderSize.X / 2, center.Y - renderSize.Y / 2, renderSize.X, renderSize.Y);
     DrawTexture(active, photoBox); 
-    for (int i = 0; i < photos.Count; i++) {
+    for (int i = 0; i < photos.Count && i < geometry.ThumbnailBoxes.Count(); i++) {
       Box2i box = geometry.ThumbnailBoxes[i];
-      DrawTexture(photos[i].Texture, box);
+      DrawTexture(photos[i].Texture(), box);
       if (i == photoIndex) {
         DrawBox(box, 5, Color4.Black);
         DrawBox(box, 3, Color4.White);
@@ -402,7 +410,6 @@ public class Game : GameWindow {
     SwapBuffers();
   }
 
-  // FIXME: pull these out into a Util class and let photos be able to draw themselves?
   void DrawTexture(Texture texture, Box2i box) {
     DrawTexture(texture, box, Color4.White);
   }