OpenGLView & OpenGL ES Support

[ibluesun]

Supporting OpenGL is crucial .. and I think relying on ANGLE project to support all underlying OS Platforms is a very desirable feature.

While the OpenGLView still exists in Maui but testing it didn't succeed and it gave an error of handler doesn't exist.

Is there an intention of enabling OpenGLView in MAUI ?? anyone knows about that?

[Paegasus]

Same here, tried it out today and got an unhandled exception. I would like to know as well when we can expect it to work.

[najak3d]

PING! August 2023 -- and we're wanting to port our .NET 4.7 app to .NET 7 (then 8), but we make use of OpenTK, which doesn't even support .NET 5 yet... and now seeing OpenGLView for .NET 7 is deprecated/broke.

Our app makes significant use of OpenGL for 3D world/map rendering, so without OpenGL support, our plans to migrate to .NET 7/8, are sunk.

We also make heavy use of SkiaSharp for 2D map rendering -- but here again, it looks like the latest SkiaSharp 2.88.5 only supports up to .NET 6, not 7 or 8.

What are the plans here? Is there some critical reason that .NET 7/8 are unsupported for OpenGL and SkiaSharp?

[xtuzy]

• skiasharp support net6, so it also support net7/8, but on windows, maui use winui3, skiasharp use google's angle to support gpu backend run on windows, current angle not work on winui3, need fix by Support for GPU Acceleration for WinUI3 mono/SkiaSharp#1893 , on ios, i believe it run well, because Avalonia use it
• official opentk may drop support for mobile, which fork you use? i see this fork also drop support https://github.com/ppy/osuTK, but it use net6-ios/android, so you can try use it

[najak3d]

We're on a very old version of OpenTK 1.2 that runs fine on .NET 4.7.2 Our usage of OpenGL is on the light side (3D rendering is basic).

Thanks for the update on all of this. We're able to push off this migration for 7 more months, so will be putting this idea on-hold for the time, and will be coming back April 2024, to try again, and re-assess this situation. Perhaps by then, MAUI will simply have a widely used OpenGL Control replacement.

[ibluesun]

if this can help .. I made a solution for the android part to use opentk .. found on this repo
https://github.com/ibluesun/MauiOpenGL

I also communicated this with the opentk community .. so they may come up with a standard control after that "

however .. there will be challenge for the IOS, and windows desktop.

[ibluesun]

existence of all three would be very usefull .. actually I was trying to use ANGLE with winui 3 a while ago .. with no luck as I should build some Direct3D 12 knowledge to use the SwapChainPanel.

I guess iOS will be more challenging .. Apple uses their new Metal API .. that should be on the same conceptual level of DX12 and Vulkan

I have my eyes on purchasing M2 mini for this specific thing .. hopefully after finishing my other stuff first.

but again .. if the MAUI team can support that control from their side .. it would be a massive game changer .. as it can truly leverage the idea of OS native support ..

to my little knowledge .. not even flutter can be used for talking with GPU.

[najak3d]

... Yet Xamarin Studio on the Mac, running equivalent of .NET 4.7 - works with OpenTK just fine for giving full GPU access for iOS. I don't understand why the concept of MAUI/.NET7+ can't achieve this same thing, without too much work.

[xtuzy]

@ibluesun

• use gpu in MAUI you can try https://github.com/veldrid/veldrid , game OSU using it. i have some sample about it https://github.com/xtuzy/Veldrid.Samples.
• run ANGLE in winui3 you need this Support for GPU Acceleration for WinUI3 mono/SkiaSharp#1893 to fix it

[ibluesun]

@xtuzy

looking to the ANGLE patch .. seems like microsoft didn't upgrade its code to care for winui3 elements .. interesting patch .. as it replaces the WinRT interfaces with the WinUi3 ones

the veldrid api seems interesting .. somehow .. it follows the commandlist pattern (which is new to me still)

I am actually implementing a new CAD application .. web/mobile .. so I was using xamarin forms .. but it is going to be discontinued soon .. and actually MAUI implementation is more cleaner than xamarin (if it works 100% for sure)

interesting stuff .. I will try to get the opengl runs with the patched EGL .. then merge that in my other project if possible.

[najak3d]

That would be GREAT! ^^^^

Our usage of Xamarin Forms is nominal - we currently just have one full-window picture box, that we blit to. Our entire UI/app is rendered via SKIA to this bitmap, and so the UI is graphics-based (not native-controls). We currently interface directly to OpenTK, rendering to a screen buffer (bitmap equivalent) which we then copy out of the GPU onto our SKBitmap, before blitting this to the picture box.

Our intent with MAUI is to:

1. Move from .NET 4.7 to .NET 8+, and remain mainstream for .NET
2. Switch over to using a SKIA CanvasView control, rather that our PictureBox.
3. Switch over to using a Maui-based OpenGL Control, rather than manually copying the screenbuffer to Skia bitmap.

[gmgallo]

Almost 7 month have passed since the last post here.
Has anyone since found a woraround to get an OpenGL window hosted in a WinUI3 desktop app?

[najak3d]

You might want to check out SkiaSharp -- they have a SKGLSurfaceView concept (for each platform) - that wraps an OpenGL context, that I think you can get at, and do your own ops on the surface.

Not sure if they've completed their Maui support yet, but if they haven't, pretty sure it's high on their short list.

The beauty here, is that you can ALSO use SKIA drawing commands for this Surface (good for UI elements that sit on top).

[ibluesun]

Hello guys .,. I managed to get the windows part working with OpenGL .. using the patched ANGLE dll

please check the repository again https://github.com/ibluesun/MauiOpenGL

[gmgallo]

After much delving and googling for answers, the way around I find to host OpenGL in WinUI3 is to grab the underlying HWND handle of WidowCore and create a child Win32 window for it with CreateWindowEx() that can then be overlay over a WinUI3 Border or GRID control. If someone wants to know the implementation details send me a note.

[SinnersSum]

Does this solution require 'air space' like WPF does?

[gmgallo]

Hi @SinnersSum, I'm not familiar with 'air space'. What I did is create a Win32 child window of the hosting window in a c++/CLI DLL.
The DLL declares a class derived from a WinUI3 Canvas that can be hosted inside any XAML. It took me some time to figure out all the details to make this Canvas fit and resize inside its container as the windows is resized. The other thing to know is that all OpenGL calls must be made from the same thread, UI or other, otherwise weird things happen.

[SinnersSum]

Airspace was a limitation of WPF where WPF controls couldn't be displayed atop the embedded Win32 control (E.g. you couldn't put a WPF text control above an opengl control without a filled background.) I was just wondering if this limitation exists in MAUI too.

[gmgallo]

I see, thanks for the info. If you need to display text or other controls on top of the Win32 child window I think that you will need Air Space or similar. But if you are in control of the OpenGL client better use Angle or similar approaches. I've seen one that shares the render surface with OpenGL and DirectX. My OpenGL window is for display live images from a 360 panoramic camera without any overlay. If you only need to overlay text you can use OpenGL calls for it.

Just a clarification, my application is only for Windows desktop, not MAUI. I happen to land here in search for a solution.