Mac OS Compatibility Issues

[AveryNorris]

I've had a few issues running this in Mac OS

First of all, the program will crash with no error unless you remove the line

"GL.DebugMessageCallback(DebugProcCallback, IntPtr.Zero);"
at 32:Window.cs

I'm not really sure why, there is no error message that I could find.

Additionally, once the program starts up, ImGUI only occupies the bottom left corner

I've found that changing two lines fixes this,

(449: ImguiImplOpenTK4.cs)
should be
io.DisplaySize = new(clientSize.X, clientSize.Y);

and

(452: ImguiImplOpenTK4.cs)
should be
io.DisplayFramebufferScale = new(fbSize.X / clientSize.X, fbSize.Y / clientSize.Y);

I am sure this solution is merely a bandaid, but I thought it was an important clue to give the fix I found.

[NogginBops]

First of all, the program will crash with no error unless you remove the line
"GL.DebugMessageCallback(DebugProcCallback, IntPtr.Zero);" at 32:Window.cs

This is because macOS doesn't support the KHR_debug extension so that function will not work. It should be guarded by the same condition as here:

ImGui.NET_OpenTK_Sample/Dear ImGui Sample/Backends/ImguiImplOpenGL3.cs

Line 86 in f019250

bd->KHRDebugAvailable = (major == 4 && minor >= 3) || IsExtensionSupported("KHR_debug");

ImGui.NET_OpenTK_Sample/Dear ImGui Sample/Backends/ImguiImplOpenGL3.cs

Lines 188 to 191 in f019250

	if (bd->KHRDebugAvailable)
	{
	GL.ObjectLabel(ObjectLabelIdentifier.VertexArray, vao, -1, "OpenTK_ImGui: VAO");
	}

For the scaling stuff I think you are correct. I just mixed up which size goes where. It would be great if you could open a PR to fix it, otherwise I'll fix it when I get time.