CODEWITHSUNDEEP
c#wpfwindowsopentkskiasharp
Inglonias
Inglonias

Reputation: 532

How do I create an OpenGL GrContext for SkiaSharp?

I'm trying to render a SkiaSharp element in my WPF application using an OpenGL backend in the hopes of making it faster. I found this documentation explaining how to work with the resulting surface created, but it has this extremely unhelpful sentence in it:

Skia does not create a OpenGL context or Vulkan device for you. In OpenGL mode it also assumes that the correct OpenGL context has been made current to the current thread when Skia calls are made.

The documentation then proceeds to also assume that I know how to create said OpenGL or Vulkan device. After Googling this for an hour or so, I can tell you there are a few ways to do this (apparently), involving OpenTK, or creating the context manually, or using a WindowsFormsHost to host my drawing element, but I have been completely unable to find any specific information on what I need to do to make these things happen. If I have found this info in my Google searches, I lack the knowledge to recognize it as the answer.

To be 100% clear, what I'm asking is this: What do I need to do before the following lines of code will work?

var context = GRContext.CreateGl();
var gpuSurface = SKSurface.Create(context, true, new SKImageInfo(PageData.Instance.GetTotalWidth(), PageData.Instance.GetTotalHeight()));

Upvotes: 4

Views: 2351

Answers (1)

Inglonias
Inglonias

Reputation: 532

Still looking for alternatives that don't require adding a 5 MB DLL just to use one object, but this is what I have for now.

I ended up going with this after installing OpenTK and OpenTK.GLControl from NuGet:

public SKSurface GetOpenGlSurface(int width, int height)
        {
            if (GPUContext == null)
            {
                GLControl control = new GLControl(new GraphicsMode(32, 24, 8, 4));
                control.MakeCurrent();
                GPUContext = GRContext.CreateGl();
            }
            var gpuSurface = SKSurface.Create(GPUContext, true, new SKImageInfo(width, height));
            return gpuSurface;
        }

It's worth noting that doing this and rendering various images using the GPU instead actually drastically cut performance, even with a decent video card. This is probably because I'm terrible at this, and I'm introducing bottlenecks. I suspect someone who knows what they're doing can avoid these pitfalls just fine.

Upvotes: 2

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