Make Surface::get_default_config return an Option.

CHANGELOG.md

@@ -56,6 +56,13 @@ The various surface capability functions were combined into a single call that g
 + let alpha_modes = caps.alpha_modes;
 ```
 
+Additionally `Surface::get_default_config` now returns an Option and returns None if the surface isn't supported by the adapter.
+
+```diff
+- let config = surface.get_default_config(&adapter);
++ let config = surface.get_default_config(&adapter).expect("Surface unsupported by adapter");
+```
+
 ### Changes
 
 #### General
@@ -65,6 +72,7 @@ The various surface capability functions were combined into a single call that g
 - Improve compute shader validation error message. By @haraldreingruber in [#3139](https://github.com/gfx-rs/wgpu/pull/3139)
 - New downlevel feature `UNRESTRICTED_INDEX_BUFFER` to indicate support for using `INDEX` together with other non-copy/map usages (unsupported on WebGL). By @Wumpf in [#3157](https://github.com/gfx-rs/wgpu/pull/3157)
 - Combine `Surface::get_supported_formats`, `Surface::get_supported_present_modes`, and `Surface::get_supported_alpha_modes` into `Surface::get_capabilities` and `SurfaceCapabilities`. By @cwfitzgerald in [#3157](https://github.com/gfx-rs/wgpu/pull/3157)
+- Make `Surface::get_default_config` return an Option to prevent panics. By @cwfitzgerald in [#3157](https://github.com/gfx-rs/wgpu/pull/3157)
 
 #### WebGPU
 

wgpu/examples/framework.rs

@@ -267,7 +267,9 @@ fn start<E: Example>(
     }: Setup,
 ) {
     let spawner = Spawner::new();
-    let mut config = surface.get_default_config(&adapter, size.width, size.height);
+    let mut config = surface
+        .get_default_config(&adapter, size.width, size.height)
+        .expect("Surface isn't supported by the adapter.");
     surface.configure(&device, &config);
 
     log::info!("Initializing the example...");

wgpu/src/lib.rs

@@ -3705,28 +3705,30 @@ impl Drop for SurfaceTexture {
 
 impl Surface {
     /// Returns the capabilities of the surface when used with the given adapter.
-    /// 
+    ///
     /// Returns specified values (see [`SurfaceCapabilities`]) if surface is incompatible with the adapter.
     pub fn get_capabilities(&self, adapter: &Adapter) -> SurfaceCapabilities {
         Context::surface_get_capabilities(&*self.context, &self.id, &adapter.id)
     }
 
     /// Return a default `SurfaceConfiguration` from width and height to use for the [`Surface`] with this adapter.
+    ///
+    /// Returns None if the surface isn't supported by this adapter
     pub fn get_default_config(
         &self,
         adapter: &Adapter,
         width: u32,
         height: u32,
-    ) -> wgt::SurfaceConfiguration {
+    ) -> Option<wgt::SurfaceConfiguration> {
         let caps = self.get_capabilities(adapter);
-        wgt::SurfaceConfiguration {
+        Some(wgt::SurfaceConfiguration {
             usage: wgt::TextureUsages::RENDER_ATTACHMENT,
-            format: caps.formats[0],
+            format: *caps.formats.get(0)?,
             width,
             height,
-            present_mode: caps.present_modes[0],
+            present_mode: *caps.present_modes.get(0)?,
             alpha_mode: wgt::CompositeAlphaMode::Auto,
-        }
+        })
     }
 
     /// Initializes [`Surface`] for presentation.