OpenTK, SharpGL and WPF

Question

I am about to begin a new project. Some decisions are out of my control: Using WPF and OpenGL are some of them.

However, I have narrowed down my OpenGL options to two: Either OpenTK or SharpGL. SharpGL has a WPF control, while OpenTK only has a Windows Forms control, which makes it that I have to embed it in a Windows Forms Host :-/ While I don't mind the airspace restrictions, I do wish to have decent performance, since I am building a real time application. Not a game, but still, real time.

How much of a performance hit would my program take for using OpenTK over a Windows Forms Host, vs using SharpGL with a "pure" WPF control?

Answer 1

When it comes to performance, I can actually only give you a single answer: Do a benchmark yourself! But as you are asking for an elaborate guess:

SharpGl should require an indirection step less, as it leaves out the Windows Forms host control as an "intermediate" blitting target. Take this with a grain of salt though, I have neither looked at the source nor tested it myself.

But practically speaking: The performance should be very similar. At the end of the day the computational heavy operations will probably be the rendering itself, which is done by OpenGL. Blitting the finished result should only take a fraction of that time. So I hope that, however you decide, none of these options would really hurt your performance.

For the sake of the argument: Lets assume the rendering itself (the OpenGL part) takes 16 ms, so we would have a theoretical perfomance of about 60 FPS. Framework A adds an overhead of 1 ms, Framework B an overhead of 4 ms. Even with this quite gross difference in the overhead, Framework a would render at ~ 58 FPS and Framework B at ~ 50 FPS. So in both cases, the application should remain usable.

But what puzzles me is how much you are wondering about this aspect. In the end you are doing work with OpenGL and it shouldn't be too much of a hassle to simply switch the underlying implementation in case things go bad? The interfaces don't seem too different to me.

Answer 2

I would say go with OpenTK, or if it's more comfortable for you to use SharpGL, then go with it in Winforms mode and embed it inside a WPF application.

The reason is that the OpenGL driver knows how to work with a window handle, provided with every winforms control. In a WPF application there is only one window handle, the one of the main window. You may try to use it, but I think it will pose too many problems.

If you don't want things to get rendered directly to screen, and you think of using a PixelBufferObject or a RenderBufferObject, than you will probably be okay with SharpGL in WPF mode (it renders to a RenderBufferObject, than places the resulting buffer in an image, probably using a WritableBitmap or so), or you can do the same thing yourself.