Add needs_reconfigure

crates/eframe/src/web/web_painter_wgpu.rs

@@ -22,6 +22,7 @@ pub(crate) struct WebPainterWgpu {
     capture_tx: CaptureSender,
     capture_rx: CaptureReceiver,
     ctx: egui::Context,
+    needs_reconfigure: bool,
 }
 
 impl WebPainterWgpu {
@@ -110,6 +111,7 @@ impl WebPainterWgpu {
             capture_tx,
             capture_rx,
             ctx,
+            needs_reconfigure: false,
         })
     }
 }
@@ -195,11 +197,16 @@ impl WebPainter for WebPainterWgpu {
                 );
             }
 
+            if self.needs_reconfigure {
+                self.surface
+                    .configure(&render_state.device, &self.surface_configuration);
+                self.needs_reconfigure = false;
+            }
+
             let output_frame = match self.surface.get_current_texture() {
                 wgpu::CurrentSurfaceTexture::Success(frame) => frame,
                 wgpu::CurrentSurfaceTexture::Suboptimal(frame) => {
-                    self.surface
+                    self.needs_reconfigure = true;
-                        .configure(&render_state.device, &self.surface_configuration);
                     frame
                 }
                 other => {

crates/egui-wgpu/src/lib.rs

@@ -307,8 +307,9 @@ pub struct WgpuConfiguration {
     ///
     /// Called with the [`wgpu::CurrentSurfaceTexture`] result whenever acquiring a frame
     /// does not return [`wgpu::CurrentSurfaceTexture::Success`]. For
-    /// [`wgpu::CurrentSurfaceTexture::Suboptimal`], egui automatically reconfigures the
+    /// [`wgpu::CurrentSurfaceTexture::Suboptimal`], egui uses the frame as-is and
-    /// surface and uses the frame — the callback is not invoked in that case.
+    /// defers surface reconfiguration to the next frame — the callback is not invoked
+    /// in that case either.
     pub on_surface_status:
         Arc<dyn Fn(&wgpu::CurrentSurfaceTexture) -> SurfaceErrorAction + Send + Sync>,
 }

crates/egui-wgpu/src/winit.rs

@@ -17,6 +17,7 @@ struct SurfaceState {
     width: u32,
     height: u32,
     resizing: bool,
+    needs_reconfigure: bool,
 }
 
 /// Everything you need to paint egui with [`wgpu`] on [`winit`].
@@ -234,6 +235,7 @@ impl Painter {
                 height: size.height,
                 alpha_mode,
                 resizing: false,
+                needs_reconfigure: false,
             },
         );
         let Some(width) = NonZeroU32::new(size.width) else {
@@ -454,7 +456,7 @@ impl Painter {
             commands_submitted: false,
         };
 
-        let Some(surface_state) = self.surfaces.get(&viewport_id) else {
+        let Some(surface_state) = self.surfaces.get_mut(&viewport_id) else {
             return vsync_sec;
         };
 
@@ -491,6 +493,11 @@ impl Painter {
             )
         };
 
+        if surface_state.needs_reconfigure {
+            Self::configure_surface(surface_state, render_state, &self.configuration);
+            surface_state.needs_reconfigure = false;
+        }
+
         let output_frame = {
             profiling::scope!("get_current_texture");
             // This is what vsync-waiting happens on my Mac.
@@ -503,7 +510,7 @@ impl Painter {
         let output_frame = match output_frame {
             wgpu::CurrentSurfaceTexture::Success(frame) => frame,
             wgpu::CurrentSurfaceTexture::Suboptimal(frame) => {
-                Self::configure_surface(surface_state, render_state, &self.configuration);
+                surface_state.needs_reconfigure = true;
                 frame
             }
             other => {