add DrawTexture() and DrawBox() functions

Program.cs

@@ -189,7 +189,7 @@ public class Game : GameWindow {
   public Game(GameWindowSettings gwSettings, NativeWindowSettings nwSettings) : base(gwSettings, nwSettings) { }
 
   static CameraInfo activeCamera = CameraInfo.NIKON_D7000;
-  static int thumbnailHeight = 100;
+  static int thumbnailHeight = 150;
   static int thumbnailWidth = (int) 1.0 * thumbnailHeight * activeCamera.Resolution.X / activeCamera.Resolution.Y;
   static Texture TEXTURE_WHITE;
 
@@ -294,34 +294,44 @@ public class Game : GameWindow {
   protected override void OnRenderFrame(FrameEventArgs e) {
     base.OnRenderFrame(e);
     GL.Clear(ClearBufferMask.ColorBufferBit);
+    GL.BindBuffer(BufferTarget.ArrayBuffer, VertexBufferObject);
+    GL.ActiveTexture(TextureUnit.Texture0);
 
-    int borderWidth = 2;
+    int borderWidth = 0;
     int maxPhotoWidth = windowWidth - thumbnailWidth - borderWidth;
 
     Texture active = textures[textureIndex];
     // TODO: handle the case where we need to letterbox vertically instead.
+    // TODO: pull these geometry calculations out into an object.
     int photoWidth = (int) (1.0 * windowHeight / active.Height * active.Width);
     int letterboxWidth = (maxPhotoWidth - photoWidth) / 2;
 
-    SetVertices(letterboxWidth, 0, photoWidth, windowHeight);
-    GL.BindBuffer(BufferTarget.ArrayBuffer, VertexBufferObject);
-    GL.BufferData(BufferTarget.ArrayBuffer, vertices.Length * sizeof(float), vertices, BufferUsageHint.DynamicDraw);
-    GL.ActiveTexture(TextureUnit.Texture0);
-    GL.BindTexture(TextureTarget.Texture2D, active.Handle);
-    GL.DrawElements(PrimitiveType.Triangles, indices.Length, DrawElementsType.UnsignedInt, 0);
-
+    DrawTexture(active, letterboxWidth, 0, photoWidth, windowHeight);
     for (int i = 0; i < textures.Count; i++) {
-      SetVertices(windowWidth - thumbnailWidth, i * thumbnailHeight, thumbnailWidth, thumbnailHeight - borderWidth);
-      GL.BindBuffer(BufferTarget.ArrayBuffer, VertexBufferObject);
-      GL.BufferData(BufferTarget.ArrayBuffer, vertices.Length * sizeof(float), vertices, BufferUsageHint.DynamicDraw);
-      GL.ActiveTexture(TextureUnit.Texture0);
-      GL.BindTexture(TextureTarget.Texture2D, textures[i].Handle);
-      GL.DrawElements(PrimitiveType.Triangles, indices.Length, DrawElementsType.UnsignedInt, 0);
+      // FIXME: make this a rect or something
+      DrawTexture(textures[i], windowWidth - thumbnailWidth, i * thumbnailHeight, thumbnailWidth, thumbnailHeight - borderWidth);
+      if (i == textureIndex) {
+        DrawBox(windowWidth - thumbnailWidth, i * thumbnailHeight, thumbnailWidth, thumbnailHeight - borderWidth, 2);
+      }
     }
 
     SwapBuffers();
   }
 
+  void DrawTexture(Texture texture, int left, int top, int width, int height) {
+    SetVertices(left, top, width, height);
+    GL.BufferData(BufferTarget.ArrayBuffer, vertices.Length * sizeof(float), vertices, BufferUsageHint.DynamicDraw);
+    GL.BindTexture(TextureTarget.Texture2D, texture.Handle);
+    GL.DrawElements(PrimitiveType.Triangles, indices.Length, DrawElementsType.UnsignedInt, 0);
+  }
+
+  void DrawBox(int left, int top, int width, int height, int thickness) {
+    DrawTexture(TEXTURE_WHITE, left, top, width, thickness);
+    DrawTexture(TEXTURE_WHITE, left, top, thickness, height);
+    DrawTexture(TEXTURE_WHITE, left, top + height - thickness, width, thickness);
+    DrawTexture(TEXTURE_WHITE, left + width - thickness, top, thickness, height);
+  }
+
   protected override void OnResize(ResizeEventArgs e) {
     base.OnResize(e);
     Console.WriteLine($"OnResize: {e.Width}x{e.Height}");