Only keep preferred format as the first element

wgpu/src/backend/web.rs

@@ -1114,14 +1114,20 @@ impl crate::context::Context for Context {
  _adapter_data: &Self::AdapterData,
  ) -> wgt::SurfaceCapabilities {
  let format = self.0.get_preferred_canvas_format();
- let preferred_format = if map_texture_format(wgt::TextureFormat::Bgra8Unorm) == format {
- wgt::TextureFormat::Bgra8Unorm
+ let (preferred, second) = if map_texture_format(wgt::TextureFormat::Bgra8Unorm) == format {
+ (
+ wgt::TextureFormat::Bgra8Unorm,
+ wgt::TextureFormat::Rgba8Unorm,
+ )
  } else {
- wgt::TextureFormat::Rgba8Unorm
+ (
+ wgt::TextureFormat::Rgba8Unorm,
+ wgt::TextureFormat::Bgra8Unorm,
+ )
  };
  wgt::SurfaceCapabilities {
  // https://gpuweb.github.io/gpuweb/#supported-context-formats
- formats: vec![preferred_format, wgt::TextureFormat::Rgba16Float],
+ formats: vec![preferred, second, wgt::TextureFormat::Rgba16Float],
  // Doesn't really have meaning on the web.
  present_modes: vec![wgt::PresentMode::Fifo],
  alpha_modes: vec![wgt::CompositeAlphaMode::Opaque],