Mesh view bind group layout is changed

MeshPipelineViewLayouts no longer stores all possible view layouts. Now it only stores necessary parameters for creating bind group layouts on demand. And MeshPipelineViewLayouts::get_view_layout returns MeshPipelineViewLayout by value instead of by reference.

generate_view_layouts is removed and layout_entries is private now. Please use MeshPipelineViewLayouts::get_view_layout.

Mesh view bind group layout has more variants now and some dynamic uniforms such as distance fog, ssr, contact shadows, and environment map are not guaranteed to exist. Please use MeshViewBindGroup::main_offsets to get the dynamic offsets.

In 0.18:

    let mut offsets: SmallVec<[u32; 8]> = smallvec![
        view_uniform_offset.offset,
        view_lights_offset.offset,
        view_fog_offset.offset,
        **view_light_probes_offset,
        **view_ssr_offset,
        **view_contact_shadows_offset,
        **view_environment_map_offset,
    ];
    if let Some(oit_settings_offset) = maybe_oit_settings_offset {
        offsets.push(oit_settings_offset.offset);
    }
    pass.set_bind_group(I, &mesh_view_bind_group.main, &offsets);

In 0.19:

    pass.set_bind_group(
        I,
        &mesh_view_bind_group.main,
        &mesh_view_bind_group.main_offsets,
    );