Unify Surface Capabilities APIs under one function call

CHANGELOG.md

@@ -40,6 +40,22 @@ Bottom level categories:
 
 ## Unreleased
 
+### Major Changes
+
+#### Surface Capabilities API
+
+The various surface capability functions were combined into a single call that gives you all the capabilities.
+
+```diff
+- let formats = surface.get_supported_formats(&adapter);
+- let present_modes = surface.get_supported_present_modes(&adapter);
+- let alpha_modes = surface.get_supported_alpha_modes(&adapter);
++ let caps = surface.get_capabilities(&adapter);
++ let formats = caps.formats;
++ let present_modes = caps.present_modes;
++ let alpha_modes = caps.alpha_modes;
+```
+
 ### Changes
 
 #### General
@@ -48,6 +64,7 @@ Bottom level categories:
 - Implement `Default` for `CompositeAlphaMode`
 - 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)
 
 #### WebGPU
 

wgpu-core/src/device/mod.rs

@@ -3225,43 +3225,21 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
         Ok(adapter.is_surface_supported(surface))
     }
 
-    pub fn surface_get_supported_formats<A: HalApi>(
+    pub fn surface_get_capabilities<A: HalApi>(
         &self,
         surface_id: id::SurfaceId,
         adapter_id: id::AdapterId,
-    ) -> Result<Vec<TextureFormat>, instance::GetSurfaceSupportError> {
-        profiling::scope!("Surface::get_supported_formats");
-        self.fetch_adapter_and_surface::<A, _, Vec<TextureFormat>>(
-            surface_id,
-            adapter_id,
-            |adapter, surface| surface.get_supported_formats(adapter),
-        )
-    }
-
-    pub fn surface_get_supported_present_modes<A: HalApi>(
-        &self,
-        surface_id: id::SurfaceId,
-        adapter_id: id::AdapterId,
-    ) -> Result<Vec<wgt::PresentMode>, instance::GetSurfaceSupportError> {
-        profiling::scope!("Surface::get_supported_present_modes");
-        self.fetch_adapter_and_surface::<A, _, Vec<wgt::PresentMode>>(
-            surface_id,
-            adapter_id,
-            |adapter, surface| surface.get_supported_present_modes(adapter),
-        )
-    }
-
-    pub fn surface_get_supported_alpha_modes<A: HalApi>(
-        &self,
-        surface_id: id::SurfaceId,
-        adapter_id: id::AdapterId,
-    ) -> Result<Vec<wgt::CompositeAlphaMode>, instance::GetSurfaceSupportError> {
-        profiling::scope!("Surface::get_supported_alpha_modes");
-        self.fetch_adapter_and_surface::<A, _, Vec<wgt::CompositeAlphaMode>>(
-            surface_id,
-            adapter_id,
-            |adapter, surface| surface.get_supported_alpha_modes(adapter),
-        )
+    ) -> Result<wgt::SurfaceCapabilities, instance::GetSurfaceSupportError> {
+        profiling::scope!("Surface::get_capabilities");
+        self.fetch_adapter_and_surface::<A, _, _>(surface_id, adapter_id, |adapter, surface| {
+            let hal_caps = surface.get_capabilities(adapter)?;
+
+            Ok(wgt::SurfaceCapabilities {
+                formats: hal_caps.formats,
+                present_modes: hal_caps.present_modes,
+                alpha_modes: hal_caps.composite_alpha_modes,
+            })
+        })
     }
 
     fn fetch_adapter_and_surface<

wgpu-core/src/instance.rs

@@ -8,7 +8,7 @@ use crate::{
 
 use wgt::{Backend, Backends, PowerPreference};
 
-use hal::{Adapter as _, Instance as _, SurfaceCapabilities};
+use hal::{Adapter as _, Instance as _};
 use thiserror::Error;
 
 pub type RequestAdapterOptions = wgt::RequestAdapterOptions<SurfaceId>;
@@ -152,37 +152,10 @@ impl crate::hub::Resource for Surface {
 }
 
 impl Surface {
-    pub fn get_supported_formats<A: HalApi>(
+    pub fn get_capabilities<A: HalApi>(
         &self,
         adapter: &Adapter<A>,
-    ) -> Result<Vec<wgt::TextureFormat>, GetSurfaceSupportError> {
-        self.get_capabilities(adapter).map(|mut caps| {
-            // TODO: maybe remove once we support texture view changing srgb-ness
-            caps.formats.sort_by_key(|f| !f.describe().srgb);
-            caps.formats
-        })
-    }
-
-    pub fn get_supported_present_modes<A: HalApi>(
-        &self,
-        adapter: &Adapter<A>,
-    ) -> Result<Vec<wgt::PresentMode>, GetSurfaceSupportError> {
-        self.get_capabilities(adapter)
-            .map(|caps| caps.present_modes)
-    }
-
-    pub fn get_supported_alpha_modes<A: HalApi>(
-        &self,
-        adapter: &Adapter<A>,
-    ) -> Result<Vec<wgt::CompositeAlphaMode>, GetSurfaceSupportError> {
-        self.get_capabilities(adapter)
-            .map(|caps| caps.composite_alpha_modes)
-    }
-
-    fn get_capabilities<A: HalApi>(
-        &self,
-        adapter: &Adapter<A>,
-    ) -> Result<SurfaceCapabilities, GetSurfaceSupportError> {
+    ) -> Result<hal::SurfaceCapabilities, GetSurfaceSupportError> {
         let suf = A::get_surface(self).ok_or(GetSurfaceSupportError::Unsupported)?;
         profiling::scope!("surface_capabilities");
         let caps = unsafe {

wgpu-types/src/lib.rs

@@ -3883,6 +3883,33 @@ bitflags::bitflags! {
 
 impl_bitflags!(TextureUsages);
 
+/// Defines the capabilities of a given surface and adapter.
+#[derive(Debug)]
+pub struct SurfaceCapabilities {
+    /// List of supported formats to use with the given adapter. The first format in the vector is preferred.
+    ///
+    /// Returns an empty vector if the surface is incompatible with the adapter.
+    pub formats: Vec<TextureFormat>,
+    /// List of supported presentation modes to use with the given adapter.
+    ///
+    /// Returns an empty vector if the surface is incompatible with the adapter.
+    pub present_modes: Vec<PresentMode>,
+    /// List of supported alpha modes to use with the given adapter.
+    ///
+    /// Will return at least one element, CompositeAlphaMode::Opaque or CompositeAlphaMode::Inherit.
+    pub alpha_modes: Vec<CompositeAlphaMode>,
+}
+
+impl Default for SurfaceCapabilities {
+    fn default() -> Self {
+        Self {
+            formats: Vec::new(),
+            present_modes: Vec::new(),
+            alpha_modes: vec![CompositeAlphaMode::Opaque],
+        }
+    }
+}
+
 /// Configures a [`Surface`] for presentation.
 ///
 /// [`Surface`]: ../wgpu/struct.Surface.html

wgpu/examples/hello-triangle/main.rs

@@ -46,7 +46,8 @@ async fn run(event_loop: EventLoop<()>, window: Window) {
         push_constant_ranges: &[],
     });
 
-    let swapchain_format = surface.get_supported_formats(&adapter)[0];
+    let swapchain_capabilities = surface.get_capabilities(&adapter);
+    let swapchain_format = swapchain_capabilities.formats[0];
 
     let render_pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
         label: None,
@@ -73,7 +74,7 @@ async fn run(event_loop: EventLoop<()>, window: Window) {
         width: size.width,
         height: size.height,
         present_mode: wgpu::PresentMode::Fifo,
-        alpha_mode: surface.get_supported_alpha_modes(&adapter)[0],
+        alpha_mode: swapchain_capabilities.alpha_modes[0],
     };
 
     surface.configure(&device, &config);

wgpu/examples/hello-windows/main.rs

@@ -31,13 +31,14 @@ impl ViewportDesc {
     fn build(self, adapter: &wgpu::Adapter, device: &wgpu::Device) -> Viewport {
         let size = self.window.inner_size();
 
+        let caps = self.surface.get_capabilities(adapter);
         let config = wgpu::SurfaceConfiguration {
             usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
-            format: self.surface.get_supported_formats(adapter)[0],
+            format: caps.formats[0],
             width: size.width,
             height: size.height,
             present_mode: wgpu::PresentMode::Fifo,
-            alpha_mode: self.surface.get_supported_alpha_modes(adapter)[0],
+            alpha_mode: caps.alpha_modes[0],
         };
 
         self.surface.configure(device, &config);

wgpu/src/backend/direct.rs

@@ -4,7 +4,7 @@ use crate::{
     DownlevelCapabilities, Features, Label, Limits, LoadOp, MapMode, Operations,
     PipelineLayoutDescriptor, RenderBundleEncoderDescriptor, RenderPipelineDescriptor,
     SamplerDescriptor, ShaderModuleDescriptor, ShaderModuleDescriptorSpirV, ShaderSource,
-    SurfaceStatus, TextureDescriptor, TextureFormat, TextureViewDescriptor,
+    SurfaceStatus, TextureDescriptor, TextureViewDescriptor,
 };
 
 use arrayvec::ArrayVec;
@@ -19,7 +19,6 @@ use std::{
     slice,
     sync::Arc,
 };
-use wgt::{CompositeAlphaMode, PresentMode};
 
 const LABEL: &str = "label";
 
@@ -1064,47 +1063,18 @@ impl crate::Context for Context {
         }
     }
 
-    fn surface_get_supported_formats(
+    fn surface_get_capabilities(
         &self,
         surface: &Self::SurfaceId,
         adapter: &Self::AdapterId,
-    ) -> Vec<TextureFormat> {
+    ) -> wgt::SurfaceCapabilities {
         let global = &self.0;
-        match wgc::gfx_select!(adapter => global.surface_get_supported_formats(surface.id, *adapter))
-        {
-            Ok(formats) => formats,
-            Err(wgc::instance::GetSurfaceSupportError::Unsupported) => vec![],
-            Err(err) => self.handle_error_fatal(err, "Surface::get_supported_formats"),
-        }
-    }
-
-    fn surface_get_supported_present_modes(
-        &self,
-        surface: &Self::SurfaceId,
-        adapter: &Self::AdapterId,
-    ) -> Vec<PresentMode> {
-        let global = &self.0;
-        match wgc::gfx_select!(adapter => global.surface_get_supported_present_modes(surface.id, *adapter))
-        {
-            Ok(modes) => modes,
-            Err(wgc::instance::GetSurfaceSupportError::Unsupported) => vec![],
-            Err(err) => self.handle_error_fatal(err, "Surface::get_supported_present_modes"),
-        }
-    }
-
-    fn surface_get_supported_alpha_modes(
-        &self,
-        surface: &Self::SurfaceId,
-        adapter: &Self::AdapterId,
-    ) -> Vec<CompositeAlphaMode> {
-        let global = &self.0;
-        match wgc::gfx_select!(adapter => global.surface_get_supported_alpha_modes(surface.id, *adapter))
-        {
-            Ok(modes) => modes,
+        match wgc::gfx_select!(adapter => global.surface_get_capabilities(surface.id, *adapter)) {
+            Ok(caps) => caps,
             Err(wgc::instance::GetSurfaceSupportError::Unsupported) => {
-                vec![CompositeAlphaMode::Opaque]
+                wgt::SurfaceCapabilities::default()
             }
-            Err(err) => self.handle_error_fatal(err, "Surface::get_supported_alpha_modes"),
+            Err(err) => self.handle_error_fatal(err, "Surface::get_supported_formats"),
         }
     }
 

wgpu/src/backend/web.rs

@@ -1322,33 +1322,22 @@ impl crate::Context for Context {
         format.describe().guaranteed_format_features
     }
 
-    fn surface_get_supported_formats(
+    fn surface_get_capabilities(
         &self,
         _surface: &Self::SurfaceId,
         _adapter: &Self::AdapterId,
-    ) -> Vec<wgt::TextureFormat> {
-        // https://gpuweb.github.io/gpuweb/#supported-context-formats
-        vec![
-            wgt::TextureFormat::Bgra8Unorm,
-            wgt::TextureFormat::Rgba8Unorm,
-            wgt::TextureFormat::Rgba16Float,
-        ]
-    }
-
-    fn surface_get_supported_present_modes(
-        &self,
-        _surface: &Self::SurfaceId,
-        _adapter: &Self::AdapterId,
-    ) -> Vec<wgt::PresentMode> {
-        vec![wgt::PresentMode::Fifo]
-    }
-
-    fn surface_get_supported_alpha_modes(
-        &self,
-        _surface: &Self::SurfaceId,
-        _adapter: &Self::AdapterId,
-    ) -> Vec<wgt::CompositeAlphaMode> {
-        vec![wgt::CompositeAlphaMode::Opaque]
+    ) -> wgt::SurfaceCapabilities {
+        wgt::SurfaceCapabilities {
+            // https://gpuweb.github.io/gpuweb/#supported-context-formats
+            formats: vec![
+                wgt::TextureFormat::Bgra8Unorm,
+                wgt::TextureFormat::Rgba8Unorm,
+                wgt::TextureFormat::Rgba16Float,
+            ],
+            // Doesn't really have meaning on the web.
+            present_modes: vec![wgt::PresentMode::Fifo],
+            alpha_modes: vec![wgt::CompositeAlphaMode::Opaque],
+        }
     }
 
     fn surface_configure(