How do I use the raw_window_handle() method from winit rust crate?

Question

I'm trying to create my first Vulkan application using Rust following adrien ben's vulkan-tutorial.

As I progressed to commit 1.2.1 I noticed he is creating the winit-window for Windows.

Because I'm developing the application on my Linux-system I decided to leave the pre-scripted path, and try to implement the windowing-part on my own.

So I stumbled across the ash-window-crate which gives me a create-surface() method that needs a window-handle as a parameter.

My problem is as follows:

I'm not able to call the raw-window-handle function from my winit-window although the docs of winit suggest the Window-Struct implements the HasRawWindowHandle-Trait, which to my understanding would expose the aforementioned function.

I'm trying to create the KHRSurface like this:

let window = WindowBuilder::new().build(&events_loop).unwrap();;
let surface_khr = unsafe { create_surface(&entry, &instance, &window.raw_window_handle(), None).unwrap(); };

and the rust-compiler complains:

error[E0277]: the trait bound `RawWindowHandle: HasRawWindowHandle` is not satisfied
  --> src/main.rs:46:70
   |
46 |         let surface_khr = unsafe { create_surface(&entry, &instance, &window.raw_window_handle(), None).unwrap(); };
   |                                                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `HasRawWindowHandle` is not implemented for `RawWindowHandle`
   |
   = note: required for the cast to the object type `dyn HasRawWindowHandle`

As I'm quite new to the Rust programming language I'm not very familiar with the concept of traits and therefore any help would be very appreciated.

Answer 1

welcome to StackOverflow.

The window does indeed implement the HasRawWindowHandle trait, and the create_surface function wants to be passed a window object that implements this trait.

That tells us that, somewhere inside of create_surface, it will call raw_window_handle on that object.

But in your code, you are already grabbing the window's raw_window_handle and passing that into the function.

So now create_surface would want to get the raw_window_handle of your raw_window_handle.

Long story short, just try passing in &window instead of &window.raw_window_handle().