No mipmap interpolation, mipmap level 0 fetched by default.

[jkb0o]

Bevy version

8.1

Relevant system information

AdapterInfo { name: "Apple M1", vendor: 0, device: 0, device_type: IntegratedGpu, backend: Metal }

What you did

I render single image with mipmaps (circle.basis) multiple times with different sizes using bevy ui:

bevy_issue_mipmaps.zip

What went wrong

Looks like mipmaps doesn't respected. There is a screenshot. Top row is basis image with mipmaps. The bottom row is png image without mipmaps. It looks the same, pixelated:

I'm expecting the correct interpolation between mipmap levels based on image size. Something like this:

Additional information

I found this happens because bevy::render::texture::ImageSettings::linear_descriptior() do not set mipmap_filter option:

bevy/crates/bevy_render/src/texture/image.rs

Lines 142 to 148 in 7989cb2

	pub fn linear_descriptor() -> wgpu::SamplerDescriptor<'static> {
	wgpu::SamplerDescriptor {
	mag_filter: wgpu::FilterMode::Linear,
	min_filter: wgpu::FilterMode::Linear,
	..Default::default()
	}
	}

It is FilterMode::Nearest by default. With this setting I was even unable to fetch color with textureSampleLevel in wgsl shader, it always return data from mip level 0.

Changing ImageSettings didn't help, possibly because of #5744.
The only workaround i found is to set mipmap_filter manually, as suggested in #5744:

fn patch_default_mipmap_filter(
    mut texture_events: EventReader<AssetEvent<Image>>,
    mut textures: ResMut<Assets<Image>>,
) {
    let filter = FilterMode::Linear;
    for event in texture_events.iter() {
        if let AssetEvent::Created { handle } = event {
            if let Some(mut texture) = textures.get_mut(handle) {
                texture.sampler_descriptor = ImageSampler::Descriptor(SamplerDescriptor {
                    mag_filter: filter,
                    min_filter: filter,
                    mipmap_filter: filter,
                    ..default()
                });
            };
        }
    }
}

While researching I found the same behaviour in 3d as well: by default mipmap level 0 fetched.