more attention to disposing unmanaged memory

src/Drawables/Camera.cs

@@ -48,6 +48,11 @@ public void Load()
             // nothing to do
         }
 
+        public void Dispose()
+        {
+            // nothing to do
+        }
+
         public void Update(FrameEventArgs e)
         {
             KeyboardState ks = Showcase.Current.KeyState;

src/Drawables/Connection.cs

@@ -81,6 +81,13 @@ public void SetProperties(Vector3 pointA, Vector3 pointB)
             translation = Matrix4.CreateTranslation(pointB);
             sphereB.WorldMatrix = scale * translation;
         }
+
+        public void Dispose()
+        {
+            tube.Dispose();
+            sphereA.Dispose();
+            sphereB.Dispose();
+        }
     }
 
     public class Tube : Primitive

src/Drawables/Primitive.cs

@@ -29,7 +29,7 @@
 
 namespace GJKEPADemo
 {
-    public class Primitive : IDrawableComponent, IDisposable
+    public class Primitive : IDrawableComponent
     {
         private BufferHandle VBO, EBO;
         private VertexArrayHandle VAO;
@@ -114,6 +114,7 @@ public virtual void Update(FrameEventArgs e)
 
         public virtual void Dispose()
         {
+            GL.DeleteVertexArray(VAO);
             GL.DeleteBuffer(EBO);
             GL.DeleteBuffer(VBO);
         }

src/Drawables/Showcase.cs

@@ -40,7 +40,7 @@ public class Showcase : IDrawableComponent
 
         public MainWindow Window { get; private set; }
 
-        private List<IDrawableComponent> drawableComponents = new List<IDrawableComponent>();
+        private List<IDrawableComponent> drawableComponents = new ();
 
         public ImplicitShape PrimitiveLeft { private set; get; }
         public ImplicitShape PrimitiveRight { private set; get; }
@@ -51,7 +51,7 @@ public class Showcase : IDrawableComponent
         private bool autorotate = true;
         private bool advancerotation = false;
 
-        private Random random = new Random();
+        private Random random = new ();
 
         public List<Type> AllShapes { get; private set; }
 
@@ -203,5 +203,13 @@ public void Update(FrameEventArgs e)
 
             foreach (var component in drawableComponents) component.Update(e);
         }
+
+        public void Dispose()
+        {
+            foreach (var component in drawableComponents)
+            {
+                component.Dispose();
+            }
+        }
     }
 }

src/Drawables/TextOverlay.cs

@@ -181,6 +181,15 @@ public void Update(FrameEventArgs e)
         {
             // nothing to do
         }
+
+        public void Dispose()
+        {
+            shader.Dispose();
+            GL.DeleteTexture(texture);
+            GL.DeleteVertexArray(VAO);
+            GL.DeleteBuffer(VBO);
+            GL.DeleteBuffer(EBO);
+        }
     }
 
     public static class Monospace12

src/Program.cs

@@ -28,7 +28,7 @@
 
 namespace GJKEPADemo
 {
-    public interface IDrawableComponent
+    public interface IDrawableComponent : IDisposable
     {
         public void Draw(FrameEventArgs e);
         public void Update(FrameEventArgs e);
@@ -50,6 +50,12 @@ protected override void OnLoad()
             showcase.Load();
         }
 
+        protected override void OnUnload()
+        {
+            showcase.Dispose();
+            base.OnUnload();
+        }
+
         protected override void OnResize(ResizeEventArgs e)
         {
             base.OnResize(e);