small improvements and test code for manipulating vertices

src/EngineSharp.Core/EngineSharp.Core/OpenGLEngine.cs

@@ -110,6 +110,9 @@ internal class OpenGLEngine : Engine
         {
             _window.Close();
         }
+
+        Time._secondsSinceStart = _window.Time;
+        Time._deltaTime = deltaTime;
         
         TemporaryMovementProcessing((float)deltaTime);
         TemporaryMouseProcessing();

src/EngineSharp.Core/EngineSharp.Core/Time.cs

@@ -0,0 +1,12 @@
+namespace EngineSharp.Core;
+
+public static class Time
+{
+    internal static double _deltaTime;
+    internal static double _secondsSinceStart;
+
+    public static double DeltaTime => _deltaTime;
+    public static float DeltaTimeF => (float)_deltaTime;
+    public static double SecondsSinceStart => _secondsSinceStart;
+    public static float SecondsSinceStartF => (float)_secondsSinceStart;
+}