Vendor things

third-party/vendor/wgpu/src/util/init.rs

@@ -0,0 +1,116 @@
+use wgt::{Backends, PowerPreference, RequestAdapterOptions};
+
+use crate::{Adapter, Instance, Surface};
+
+#[cfg(any(not(target_arch = "wasm32"), feature = "wgc"))]
+pub use wgc::instance::parse_backends_from_comma_list;
+/// Always returns WEBGPU on wasm over webgpu.
+#[cfg(all(target_arch = "wasm32", not(feature = "wgc")))]
+pub fn parse_backends_from_comma_list(_string: &str) -> Backends {
+    Backends::BROWSER_WEBGPU
+}
+
+/// Get a set of backend bits from the environment variable WGPU_BACKEND.
+pub fn backend_bits_from_env() -> Option<Backends> {
+    std::env::var("WGPU_BACKEND")
+        .as_deref()
+        .map(str::to_lowercase)
+        .ok()
+        .as_deref()
+        .map(parse_backends_from_comma_list)
+}
+
+/// Get a power preference from the environment variable WGPU_POWER_PREF
+pub fn power_preference_from_env() -> Option<PowerPreference> {
+    Some(
+        match std::env::var("WGPU_POWER_PREF")
+            .as_deref()
+            .map(str::to_lowercase)
+            .as_deref()
+        {
+            Ok("low") => PowerPreference::LowPower,
+            Ok("high") => PowerPreference::HighPerformance,
+            _ => return None,
+        },
+    )
+}
+
+/// Initialize the adapter obeying the WGPU_ADAPTER_NAME environment variable.
+#[cfg(not(target_arch = "wasm32"))]
+pub fn initialize_adapter_from_env(
+    instance: &Instance,
+    compatible_surface: Option<&Surface>,
+) -> Option<Adapter> {
+    let desired_adapter_name = std::env::var("WGPU_ADAPTER_NAME")
+        .as_deref()
+        .map(str::to_lowercase)
+        .ok()?;
+
+    let adapters = instance.enumerate_adapters(Backends::all());
+
+    let mut chosen_adapter = None;
+    for adapter in adapters {
+        let info = adapter.get_info();
+
+        if let Some(surface) = compatible_surface {
+            if !adapter.is_surface_supported(surface) {
+                continue;
+            }
+        }
+
+        if info.name.to_lowercase().contains(&desired_adapter_name) {
+            chosen_adapter = Some(adapter);
+            break;
+        }
+    }
+
+    Some(chosen_adapter.expect("WGPU_ADAPTER_NAME set but no matching adapter found!"))
+}
+
+/// Initialize the adapter obeying the WGPU_ADAPTER_NAME environment variable.
+#[cfg(target_arch = "wasm32")]
+pub fn initialize_adapter_from_env(
+    _instance: &Instance,
+    _compatible_surface: Option<&Surface>,
+) -> 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,
+    compatible_surface: Option<&Surface>,
+) -> Option<Adapter> {
+    match initialize_adapter_from_env(instance, compatible_surface) {
+        Some(a) => Some(a),
+        None => {
+            instance
+                .request_adapter(&RequestAdapterOptions {
+                    power_preference: power_preference_from_env().unwrap_or_default(),
+                    force_fallback_adapter: false,
+                    compatible_surface,
+                })
+                .await
+        }
+    }
+}
+
+/// Choose which DX12 shader compiler to use from the environment variable `WGPU_DX12_COMPILER`.
+///
+/// Possible values are `dxc` and `fxc`. Case insensitive.
+pub fn dx12_shader_compiler_from_env() -> Option<wgt::Dx12Compiler> {
+    Some(
+        match std::env::var("WGPU_DX12_COMPILER")
+            .as_deref()
+            .map(str::to_lowercase)
+            .as_deref()
+        {
+            Ok("dxc") => wgt::Dx12Compiler::Dxc {
+                dxil_path: None,
+                dxc_path: None,
+            },
+            Ok("fxc") => wgt::Dx12Compiler::Fxc,
+            _ => return None,
+        },
+    )
+}