NSWindowCollectionBehaviorCanJoinAllSpaces with Ebitengine

[crgimenes]

I created a program that aims to place a transparent, floating, and borderless window covering the entire screen. Then, I can send commands via Unix Domain Socket and draw on the screen (imitating the behavior of drawing on the screen with BASIC as we did in the 8-bit era.). It would be effortless to do this using Ebitengine, but I ran into a problem; I want the program to be visible in all "spaces", and that's the only thing I couldn't do in Ebitengine.

So, I wrote a small snippet of code in Objective-C to test the concept, which worked perfectly.
The only property I need is NSWindowCollectionBehavior with the value NSWindowCollectionBehaviorCanJoinAllSpaces, which makes the window visible in all spaces.

Here is a link to this property in my prototype:

https://github.com/crgimenes/NeoFrame/blob/master/screen/screen_macos.go#L31

If anyone has any idea how to do this in Ebitengine, it will help me a lot; writing the program in Go will be much simpler than in Objective-C.

[TotallyGamerJet]

In order to call the macOS libraries without OBJC you’ll need to use purego. However, I don’t think ebitengine exposes the native macOS window to be able to change that property.

[crgimenes]

I believe I need to interact with GLFW, which as far as I know is who creates the window. I haven't found a painless way to do this yet.

[TotallyGamerJet]

Yes in ebitengine GLFW is used to create the window. GLFW has glfwGetCocoaWindow. However, ebitengine doesn't expose this function so you can't call it.

[crgimenes]

It may be possible to capture the main window and then change the property.

[NSApplication sharedApplication];
[[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantPast]];
NSWindow *window = [NSApplication sharedApplication].mainWindow;
[window setCollectionBehavior:NSWindowCollectionBehaviorCanJoinAllSpaces];

I'll try this approach and see if it works.

[crgimenes]

I tried capturing the window using Objective-C and changing the property with the function below and several variations of it; I can get the window, but changing the property does not have any effect.

#cgo CFLAGS: -x objective-c
#cgo LDFLAGS: -framework Cocoa

#import <Cocoa/Cocoa.h>

void setWindowCollectionBehavior() {
	dispatch_async(dispatch_get_main_queue(), ^{
		NSApplication *app = [NSApplication sharedApplication];
		NSWindow *window = app.mainWindow;
		[window setCollectionBehavior:NSWindowCollectionBehaviorCanJoinAllSpaces];
	});
}

Does anyone have any different suggestions?