* Removed unnecessary dependency in `wgpu` on `hashbrown`.
* Removed unused dependencies in `naga-test`.
* Moved some dependencies in `wgpu-test` to `[dev-dependencies]`
(see comment for why this is worth doing).
Candidates were discovered by `cargo clippy -- -Wunused-crate-dependencies`.
This command reports whether each dependency is unused in each *crate*,
so it has false positives when a dependency is used by only some crates
in a package, but it is still useful as a short-list.
In order to support external textures, we must be able to map a single
external texture resource binding to multiple Vulkan descriptors. This
means we must be able to override the `Binding` and `DescriptorSet`
values for global variables when generating SPIR-V, rather than simply
passing through the group and binding values from Naga IR.
This patch extends the existing SPIR-V Naga backend's `BindingMap` to
contain a descriptor set and binding value in addition to the existing
array size. When creating BindGroupLayouts/BindGroups we use a
sequentially incrementing value for each entry's binding value,
continuing to just use the bind group index as the descriptor set
value.
The Naga backend looks up each resource in the map when emitting its
`Binding` and `DescriptorSet` decorations. If the entry cannot be
found in the map, it will either error or emit fake bindings based on
its configuration.
