Enable getting delta time in OnResize and OnMove

src/OpenTK.Windowing.Desktop/GameWindow.cs

@@ -412,5 +412,24 @@ protected virtual void OnRenderFrame(FrameEventArgs args)
         {
             RenderFrame?.Invoke(args);
         }
+
+        /// <summary>
+        /// The current time since the last update.
+        /// This function is useful when implementing updates on resize using windows.
+        /// </summary>
+        /// <returns>The time since the last update.</returns>
+        public double TimeSinceLastUpdate()
+        {
+            return (float)_watchUpdate.Elapsed.TotalSeconds;
+        }
+
+        /// <summary>
+        /// Resets the time since the last update.
+        /// This function is useful when implementing updates on resize using windows.
+        /// </summary>
+        public void ResetTimeSinceLastUpdate()
+        {
+            _watchUpdate.Restart();
+        }
     }
 }

tests/LocalTest/Program.cs

@@ -51,21 +51,37 @@ protected override void OnLoad()
 
         }
 
+        float time = 0;
+
         protected override void OnRenderFrame(FrameEventArgs args)
         {
             base.OnRenderFrame(args);
 
-            GL.ClearColor(Color4.Coral);
+            time += (float)args.Time;
+            if (time > 8) time = 0;
+
+            Color4 color = Color4.FromHsv(new Vector4(time / 8f, 1, 1, 1));
+
+            GL.ClearColor(color);
             GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
 
+
             SwapBuffers();
         }
 
         protected override void OnUpdateFrame(FrameEventArgs args)
         {
             base.OnUpdateFrame(args);
+        }
 
+        protected override void OnResize(ResizeEventArgs e)
+        {
+            base.OnResize(e);
+        }
 
+        protected override void OnMove(WindowPositionEventArgs e)
+        {
+            base.OnMove(e);
         }
     }
 }