Is this library functional?

[mikau16]

Hello,

I tried compiling and building the example but there appears to be no performance advantage - moreover, the frame rate tanks and the CPU and memory usage skyrockets when I set to 4k resolution which suggests to me the image is not being transferred by the GPU. Are there some additional dependencies I need to install for this to work? Can you comment?

Thank you!
-Michael

[yk35]

Hello,
This library needs graphics device that supported NV_DX_interop.
https://www.khronos.org/registry/OpenGL/extensions/NV/WGL_NV_DX_interop.txt

If your devices not supported NV_DX_interop, example code is fallback to WritableBitmapUpdater that works ReadPixels and copy to WritableBitmap buffer.
Above mode is slow.

Did you your device support NV_DX_interop?
(Please check OnLoaded() functio in MainWindow.xaml.cs that not cause exception.)

Thank you for your report.

[mikau16]

Hello,
Thank you for your response. Made a little progress but still some issues.

I dug into it and found that support for NV_DX_interop was not the problem. The following lines of code were not finding the appropriate methods and it was producing null reference exceptions, which caused it to revert to CPU rendering.

In Helpers/WGL_NV_DX_interop.cs I had to replace lines 68-74 with the following:

var wglSupportsExtension = (Func<string, bool>)wgl.GetMethods().Where(m => m.Name == "SupportsExtension" && m.GetParameters().Length == 1).Single().CreateDelegate(typeof(Func<string, bool>));
var wglSupportsFunction = (Func<string, bool>)wgl.GetMethods().Where(m => m.Name == "SupportsFunction" && m.GetParameters().Length == 1).Single().CreateDelegate(typeof(Func<string, bool>));
// Private
wglIsValid = (Func<IntPtr, bool>)wgl.GetMethod("IsValid", BindingFlags.NonPublic | BindingFlags.Static).CreateDelegate(typeof(Func<IntPtr, bool>));
// INSTANCE (still invisible!) METHODS
// Protected
wglGetAddress = (Func<string, IntPtr>)wgl.GetMethod("GetAddress", BindingFlags.NonPublic | BindingFlags.Instance).CreateDelegate(typeof(Func<string, IntPtr>), wglInstance);

This was able to run and it passed the wglSupportsExtension("WGL_NV_DX_interop") check. I confirmed that when executing the CPU usage went way way down, but the issue is it was twice as slow as rendering with CPU (Particularly when rendering at 4k) which seems like something must be wrong.

My laptop specs:

Processor: Intel Core i7-8750H CPU @ 2.20 Ghz, 2208 Mhz, 6 Cores, 12 Logical Processors.
Physical memory: 32 GB ram.
Graphics card: NVIDIA GeForce GTX 1050 Ti with Max-Q Design

Do you agree that there must be some issue?