Fix scale_factor_override not used in window creation

[chompaa]

Objective

Fixes #17188. When scale_factor_override is set on WindowResolution, the resulting WindowResolution is incorrect for the first frame. This is because when windows are first created in bevy::winit::create_windows, the resolution is set without respect to WindowResolution::scale_factor_override:

window
    .resolution
    .set_scale_factor_and_apply_to_physical_size(winit_window.scale_factor() as f32);

Afterwards, bevy::winit::changed_windows updates the resolution at the end of the first frame.

Solution

Check if scale_factor_override is set before using OS resolution settings on window creation.

Testing

Tested using the code from the linked issue.

[BenjaminBrienen]

Should there be an else that sets it using the scale_factor_override? I know you mentioned it gets set later in the first frame, but maybe it makes sense to set it here?

[chompaa]

Should there be an else that sets it using the scale_factor_override? I know you mentioned it gets set later in the first frame, but maybe it makes sense to set it here?

I don't think so. By getting set later, I meant that the initially (incorrect) set `physical_width` and `physical_height` of the `WindowResolution` is corrected. Now it is initially set correctly.

As an aside, I am a bit confused as to why set_scale_factor_and_apply_to_physical_size exists. From my understanding:

$$\text{logical\_size} = \text{physical\_size} \times \text{scale\_factor}$$

Maybe someone else can shed light on this, but from my point of view it should just set scale_factor and not the physical size.

Edit: I was wrong, fixing now

[BenjaminBrienen]

example works