construct shader & WHITE_TEXTURE at Game constructor time

Program.cs

@@ -4,9 +4,6 @@ using OpenTK.Windowing.Common;
 using OpenTK.Windowing.Desktop;
 using OpenTK.Windowing.GraphicsLibraryFramework;
 // https://docs.sixlabors.com/api/ImageSharp/SixLabors.ImageSharp.Image.html
-using SixLabors.ImageSharp;
-using SixLabors.ImageSharp.Metadata.Profiles.Exif;
-using System;
 using System.Runtime.CompilerServices;
 using Image = SixLabors.ImageSharp.Image;
 
@@ -24,9 +21,13 @@ public class CameraInfo {
 }
 
 public class Shader : IDisposable {
-  int Handle;
+  public int Handle;
+  private bool init = false;
 
-  public Shader() {
+  public Shader() {}
+
+  public void Init() {
+    init = true;
     int VertexShader;
     int FragmentShader;
 
@@ -99,6 +100,9 @@ void main() {
   }
 
   public void Use() {
+    if (!init) {
+      Console.WriteLine("Shader.Use(): must call Init() first");
+    }
     GL.UseProgram(Handle);
   }
 
@@ -218,7 +222,8 @@ public static class Util {
 public class Game : GameWindow {
   public Game(GameWindowSettings gwSettings, NativeWindowSettings nwSettings) : base(gwSettings, nwSettings) { }
 
-  static Texture TEXTURE_WHITE;
+  private static Image<Rgba32> white1x1 = new(1, 1, new Rgba32(255, 255, 255));
+  private static Texture TEXTURE_WHITE = new Texture(white1x1);
 
   UiGeometry geometry = new();
 
@@ -236,7 +241,7 @@ public class Game : GameWindow {
   int VertexArrayObject;
   List<Texture> textures = new();
   int textureIndex = 0;
-  Shader shader;
+  Shader shader = new Shader();
   Matrix4 projection;
 
   protected override void OnUpdateFrame(FrameEventArgs e) {
@@ -276,7 +281,7 @@ public class Game : GameWindow {
     GL.BindBuffer(BufferTarget.ElementArrayBuffer, ElementBufferObject);
     GL.BufferData(BufferTarget.ElementArrayBuffer, indices.Length * sizeof(uint), indices, BufferUsageHint.DynamicDraw);
 
-    shader = new Shader();
+    shader.Init();
     shader.Use();
 
     // Because there's 5 floats between the start of the first vertex and the start of the second,
@@ -294,8 +299,7 @@ public class Game : GameWindow {
     GL.VertexAttribPointer(texCoordLocation, 2, VertexAttribPointerType.Float, false, 5 * sizeof(float), 3 * sizeof(float));
 
     // Create a blank white texture.
-    Image<Rgba32> white1x1 = new(1, 1, new Rgba32(255, 255, 255));
-    TEXTURE_WHITE = new Texture(white1x1);
+
 
     // Load textures from JPEGs.
     string[] files = Directory.GetFiles(@"c:\users\colin\pictures\photos\2023\06\27\");