Add get_default_configure to simplify user creation of `SurfaceConf…

…iguration`

CHANGELOG.md

@@ -115,6 +115,7 @@ SurfaceConfiguration {
 - Address Clippy 0.1.63 complaints. By @jimblandy in [#2977](https://github.com/gfx-rs/wgpu/pull/2977)
 - Don't use `PhantomData` for `IdentityManager`'s `Input` type. By @jimblandy in [#2972](https://github.com/gfx-rs/wgpu/pull/2972)
 - Changed Naga variant in ShaderSource to `Cow<'static, Module>`, to allow loading global variables by @daxpedda in [#2903](https://github.com/gfx-rs/wgpu/pull/2903)
+- Add `get_default_configure` to simplify user creation of `SurfaceConfiguration`. By @jinleili in [#3034](https://github.com/gfx-rs/wgpu/pull/3034)
 
 #### Metal
 - Extract the generic code into `get_metal_layer` by @jinleili in [#2826](https://github.com/gfx-rs/wgpu/pull/2826)

wgpu-core/src/device/mod.rs

@@ -3206,6 +3206,21 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
         )
     }
 
+    pub fn surface_get_default_configure<A: HalApi>(
+        &self,
+        surface_id: id::SurfaceId,
+        adapter_id: id::AdapterId,
+        width: u32,
+        height: u32,
+    ) -> Result<wgt::SurfaceConfiguration, instance::GetSurfaceSupportError> {
+        profiling::scope!("Surface::get_default_configure");
+        self.fetch_adapter_and_surface::<A, _, wgt::SurfaceConfiguration>(
+            surface_id,
+            adapter_id,
+            |adapter, surface| surface.get_default_configure(adapter, width, height),
+        )
+    }
+
     fn fetch_adapter_and_surface<
         A: HalApi,
         F: FnOnce(&Adapter<A>, &Surface) -> Result<B, instance::GetSurfaceSupportError>,

wgpu-core/src/instance.rs

@@ -195,6 +195,26 @@ impl Surface {
 
         Ok(caps)
     }
+
+    pub fn get_default_configure<A: HalApi>(
+        &self,
+        adapter: &Adapter<A>,
+        width: u32,
+        height: u32,
+    ) -> Result<wgt::SurfaceConfiguration, GetSurfaceSupportError> {
+        let formats = self.get_supported_formats(adapter)?;
+        let present_modes = self.get_supported_present_modes(adapter)?;
+        let alpha_modes = self.get_supported_alpha_modes(adapter)?;
+
+        Ok(wgt::SurfaceConfiguration {
+            usage: wgt::TextureUsages::RENDER_ATTACHMENT,
+            format: formats[0],
+            width,
+            height,
+            present_mode: present_modes[0],
+            alpha_mode: alpha_modes[0],
+        })
+    }
 }
 
 pub struct Adapter<A: hal::Api> {

wgpu/examples/framework.rs

@@ -267,14 +267,7 @@ fn start<E: Example>(
     }: Setup,
 ) {
     let spawner = Spawner::new();
-    let mut config = wgpu::SurfaceConfiguration {
-        usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
-        format: surface.get_supported_formats(&adapter)[0],
-        width: size.width,
-        height: size.height,
-        present_mode: wgpu::PresentMode::Fifo,
-        alpha_mode: surface.get_supported_alpha_modes(&adapter)[0],
-    };
+    let mut config = surface.get_default_configure(&adapter, size.width, size.height);
     surface.configure(&device, &config);
 
     log::info!("Initializing the example...");

wgpu/src/backend/direct.rs

@@ -1004,6 +1004,21 @@ impl crate::Context for Context {
         }
     }
 
+    fn surface_get_default_configure(
+        &self,
+        surface: &Self::SurfaceId,
+        adapter: &Self::AdapterId,
+        width: u32,
+        height: u32,
+    ) -> wgt::SurfaceConfiguration {
+        let global = &self.0;
+        match wgc::gfx_select!(adapter => global.surface_get_default_configure(surface.id, *adapter, width, height))
+        {
+            Ok(config) => config,
+            Err(err) => self.handle_error_fatal(err, "Surface::get_default_configure"),
+        }
+    }
+
     fn surface_configure(
         &self,
         surface: &Self::SurfaceId,

wgpu/src/backend/web.rs

@@ -1229,6 +1229,23 @@ impl crate::Context for Context {
         vec![wgt::CompositeAlphaMode::Opaque]
     }
 
+    fn surface_get_default_configure(
+        &self,
+        _surface: &Self::SurfaceId,
+        _adapter: &Self::AdapterId,
+        width: u32,
+        height: u32,
+    ) -> wgt::SurfaceConfiguration {
+        wgt::SurfaceConfiguration {
+            usage: wgt::TextureUsages::RENDER_ATTACHMENT,
+            format: wgt::TextureFormat::Bgra8Unorm,
+            width,
+            height,
+            present_mode: wgt::PresentMode::Fifo,
+            alpha_mode: wgt::CompositeAlphaMode::Opaque,
+        }
+    }
+
     fn surface_configure(
         &self,
         surface: &Self::SurfaceId,

wgpu/src/lib.rs

@@ -242,6 +242,13 @@ trait Context: Debug + Send + Sized + Sync {
         surface: &Self::SurfaceId,
         adapter: &Self::AdapterId,
     ) -> Vec<CompositeAlphaMode>;
+    fn surface_get_default_configure(
+        &self,
+        surface: &Self::SurfaceId,
+        adapter: &Self::AdapterId,
+        width: u32,
+        height: u32,
+    ) -> wgt::SurfaceConfiguration;
     fn surface_configure(
         &self,
         surface: &Self::SurfaceId,
@@ -3690,6 +3697,18 @@ impl Surface {
         Context::surface_get_supported_alpha_modes(&*self.context, &self.id, &adapter.id)
     }
 
+    /// Return a default `SurfaceConfiguration` from width and height to use for the [`Surface`] with this adapter.
+    ///
+    /// Panic if the surface is incompatible with the adapter.
+    pub fn get_default_configure(
+        &self,
+        adapter: &Adapter,
+        width: u32,
+        height: u32,
+    ) -> wgt::SurfaceConfiguration {
+        Context::surface_get_default_configure(&*self.context, &self.id, &adapter.id, width, height)
+    }
+
     /// Initializes [`Surface`] for presentation.
     ///
     /// # Panics