Desktop: Add rudimentary support for custom WGPU adapter selection (#3201)

* rudimentary custom wgpu adapter selection

* WgpuContextBuilder

* wasm fix

* fix wasm warnings

* Clean up

* Review suggestions

* fix

desktop/src/gpu_context.rs

@@ -0,0 +1,23 @@
+use graphite_desktop_wrapper::{WgpuContext, WgpuContextBuilder, WgpuFeatures};
+
+pub(super) async fn create_wgpu_context() -> WgpuContext {
+	let wgpu_context_builder = WgpuContextBuilder::new().with_features(WgpuFeatures::PUSH_CONSTANTS);
+
+	// TODO: add a cli flag to list adapters and exit instead of always printing
+	println!("\nAvailable WGPU adapters:\n{}", wgpu_context_builder.available_adapters_fmt().await);
+
+	// TODO: make this configurable via cli flags instead
+	let wgpu_context = match std::env::var("GRAPHITE_WGPU_ADAPTER").ok().and_then(|s| s.parse().ok()) {
+		None => wgpu_context_builder.build().await,
+		Some(adapter_index) => {
+			tracing::info!("Overriding WGPU adapter selection with adapter index {adapter_index}");
+			wgpu_context_builder.build_with_adapter_selection(|_| Some(adapter_index)).await
+		}
+	}
+	.expect("Failed to create WGPU context");
+
+	// TODO: add a cli flag to list adapters and exit instead of always printing
+	println!("Using WGPU adapter: {:?}", wgpu_context.adapter.get_info());
+
+	wgpu_context
+}