How to pass in a Vec<BindGroupLayout> to create_pipeline_layout?

[Pauan]

The signature for PipelineLayoutDescriptor is bind_group_layouts: &'a [&'a BindGroupLayout]

But I have a Vec<BindGroupLayout>, how do I pass it in?

let bind_group_layouts = vec![
    device.create_bind_group_layout(&BindGroupLayoutDescriptor {
        label: None,
        entries: &[
            ...
        ],
    }),
];

device.create_pipeline_layout(&PipelineLayoutDescriptor {
    label: None,
    bind_group_layouts: bind_group_layouts.as_slice(),
    immediate_size: 0,
});

That doesn't work, because it's a &[BindGroupLayout] but it needs to be a &[&BindGroupLayout].

I need it to be a Vec because I'm dynamically creating the bind groups.

[andyleiserson]

Something like &bind_group_layouts.iter().collect::<Vec<_>>() should work, no?

[Pauan]

Yes, using bind_group_layouts.iter().collect::<Vec<_>>().as_slice() does work, is there any way to avoid the extra Vec allocation?

[andyleiserson]

Maybe put the layouts in an array and use each_ref?

(The cost of the allocation will be negligible relative to the cost of creating the pipeline, though.)

[Pauan]

That's a neat idea, I don't think it'll work for my use case though. I'll just have to eat the cost of the Vec, thanks for your help!