Remove backend_bits from initialize_adapter_from_env (#3904)

Remove backend_bits from initialize_adapter_from_env, backends can
be specified using the backends field in InstanceDescriptor instead.

CHANGELOG.md

@@ -45,6 +45,7 @@ Bottom level categories:
 #### Misc Breaking Changes
 
 - Change `AdapterInfo::{device,vendor}` to be `u32` instead of `usize`. By @ameknite in [#3760](https://github.com/gfx-rs/wgpu/pull/3760)
+- Remove the `backend_bits` parameter in `initialize_adapter_from_env` and `initialize_adapter_from_env_or_default` - use [InstanceDescriptor::backends](https://docs.rs/wgpu/latest/wgpu/struct.InstanceDescriptor.html#structfield.backends) instead. By @fornwall in [#3904](https://github.com/gfx-rs/wgpu/pull/3904)
 
 #### DX12
 

examples/common/src/framework.rs

@@ -180,10 +180,9 @@ async fn setup<E: Example>(title: &str) -> Setup {
 
         (size, surface)
     };
-    let adapter =
-        wgpu::util::initialize_adapter_from_env_or_default(&instance, backends, Some(&surface))
-            .await
-            .expect("No suitable GPU adapters found on the system!");
+    let adapter = wgpu::util::initialize_adapter_from_env_or_default(&instance, Some(&surface))
+        .await
+        .expect("No suitable GPU adapters found on the system!");
 
     #[cfg(not(target_arch = "wasm32"))]
     {

tests/src/lib.rs

@@ -392,7 +392,6 @@ fn initialize_adapter() -> (Adapter, SurfaceGuard) {
     let compatible_surface: Option<&Surface> = compatible_surface.as_ref();
     let adapter = pollster::block_on(wgpu::util::initialize_adapter_from_env_or_default(
         &instance,
-        backends,
         compatible_surface,
     ))
     .expect("could not find suitable adapter on the system");

wgpu/src/util/init.rs

@@ -37,13 +37,13 @@ pub fn power_preference_from_env() -> Option<PowerPreference> {
 
 /// Initialize the adapter obeying the WGPU_ADAPTER_NAME environment variable.
 #[cfg(not(target_arch = "wasm32"))]
-pub fn initialize_adapter_from_env(instance: &Instance, backend_bits: Backends) -> Option<Adapter> {
+pub fn initialize_adapter_from_env(instance: &Instance) -> Option<Adapter> {
     let desired_adapter_name = std::env::var("WGPU_ADAPTER_NAME")
         .as_deref()
         .map(str::to_lowercase)
         .ok()?;
 
-    let adapters = instance.enumerate_adapters(backend_bits);
+    let adapters = instance.enumerate_adapters(Backends::all());
 
     let mut chosen_adapter = None;
     for adapter in adapters {
@@ -60,20 +60,16 @@ pub fn initialize_adapter_from_env(instance: &Instance, backend_bits: Backends)
 
 /// Initialize the adapter obeying the WGPU_ADAPTER_NAME environment variable.
 #[cfg(target_arch = "wasm32")]
-pub fn initialize_adapter_from_env(
-    _instance: &Instance,
-    _backend_bits: Backends,
-) -> Option<Adapter> {
+pub fn initialize_adapter_from_env(_instance: &Instance) -> Option<Adapter> {
     None
 }
 
 /// Initialize the adapter obeying the WGPU_ADAPTER_NAME environment variable and if it doesn't exist fall back on a default adapter.
 pub async fn initialize_adapter_from_env_or_default(
     instance: &Instance,
-    backend_bits: wgt::Backends,
     compatible_surface: Option<&Surface>,
 ) -> Option<Adapter> {
-    match initialize_adapter_from_env(instance, backend_bits) {
+    match initialize_adapter_from_env(instance) {
         Some(a) => Some(a),
         None => {
             instance