fix(desktop): recover from unusable native GL on Windows startup

Some Windows 11 machines flash-exit on launch: their WGL OpenGL is the
GDI-generic 1.1 software renderer (no/old GPU driver, VMs, RDP), which
Skia's GL backend rejects. The old WglThenEgl preference never fell
through to EGL because WGL *did* create a (1.1) context; the failure
only surfaced downstream in make_gl, after which new_desktop merely
eprintln'd (invisible under windows_subsystem="windows") and exited —
a silent crash. Not all machines: ones with a real GPU driver get
GL 3.0+ and work, which is why only some users saw it.

- native: new_desktop retries once via forced EGL (ANGLE) when the
  native context can't drive Skia; machines that already work keep the
  WGL path byte-for-byte unchanged.
- desktop: pop a native error dialog on GL-init failure instead of a
  silent exit, so a GPU/driver problem is visible not mysterious.
- packaging/CI: ship arch-matched ANGLE runtime DLLs (libEGL /
  libGLESv2 / d3dcompiler_47) next to the exe, staged from an Electron
  release zip, so glutin's EGL fallback can load them.

.github/workflows/rust-release.yml

@@ -119,6 +119,17 @@ jobs:
       HAS_APPLE_CERTIFICATE: ${{ secrets.CSC_LINK != '' && secrets.CSC_KEY_PASSWORD != '' && secrets.APPLE_ID != '' && secrets.APPLE_TEAM_ID != '' && secrets.APPLE_APP_SPECIFIC_PASSWORD != '' && 'true' || 'false' }}
       HAS_WINDOWS_CERTIFICATE: ${{ secrets.WIN_CSC_LINK != '' && secrets.WIN_CSC_KEY_PASSWORD != '' && 'true' || 'false' }}
       TAP_GITHUB_TOKEN: ${{ secrets.TAP_GITHUB_TOKEN }}
+      # ANGLE runtime DLLs (libEGL / libGLESv2 / d3dcompiler_47) shipped
+      # in the Windows installer so glutin's EGL fallback can drive Skia
+      # on machines whose native WGL OpenGL is the GDI-generic 1.1
+      # software renderer (no/old GPU driver, VMs, RDP) — those were the
+      # startup flash-exits. We don't build ANGLE from source (heavy,
+      # brittle); we lift the prebuilt, arch-matched DLLs out of an
+      # Electron release zip (BSD-licensed ANGLE + MS-redistributable
+      # d3dcompiler, published at the zip root for x64 + arm64).
+      # Bump freely; verify the tag exists at
+      # https://github.com/electron/electron/releases before changing.
+      ANGLE_ELECTRON_VERSION: v33.0.0
     strategy:
       fail-fast: false
       matrix:
@@ -396,6 +407,32 @@ jobs:
           }
           Split-Path $makensis | Out-File -FilePath $env:GITHUB_PATH -Append
           & $makensis /VERSION
+      - name: Stage ANGLE DLLs (windows)
+        if: runner.os == 'Windows'
+        shell: pwsh
+        run: |
+          $ErrorActionPreference = 'Stop'
+          # Electron's win32 arch token matches our matrix arch (x64 / arm64).
+          $arch = "${{ matrix.arch }}"
+          $ver = "$env:ANGLE_ELECTRON_VERSION"
+          $url = "https://github.com/electron/electron/releases/download/$ver/electron-$ver-win32-$arch.zip"
+          $zip = Join-Path $env:RUNNER_TEMP "electron-$arch.zip"
+          $extract = Join-Path $env:RUNNER_TEMP "electron-$arch"
+          Write-Host "Fetching ANGLE DLLs from $url"
+          Invoke-WebRequest -Uri $url -OutFile $zip
+          Expand-Archive -Path $zip -DestinationPath $extract -Force
+          $dest = "$env:GITHUB_WORKSPACE\target\${{ matrix.target }}\release"
+          # d3dcompiler_47.dll ships in Win10/11 System32, but bundling it
+          # keeps ANGLE self-contained across all environments.
+          $dlls = @("libEGL.dll", "libGLESv2.dll", "d3dcompiler_47.dll")
+          foreach ($dll in $dlls) {
+            $src = Join-Path $extract $dll
+            if (-not (Test-Path $src)) {
+              throw "ANGLE DLL '$dll' not found in $url — the fallback would ship broken; failing the release."
+            }
+            Copy-Item -Path $src -Destination $dest -Force
+            Write-Host "Staged $dll -> $dest"
+          }
       - name: Package NSIS installer (windows)
         if: runner.os == 'Windows'
         shell: pwsh

crates/op-host-desktop/src/app_handler.rs

@@ -545,7 +545,7 @@ impl ApplicationHandler<DesktopEvent> for DesktopApp {
                     }
                 } else {
                     eprintln!(
-                        "openpencil-desktop: ignored dropped file (not .op / .pen / .fig / .html): {}",
+                        "openpencil-desktop: ignored dropped file (not .op / .pen / .fig / .html / .zip): {}",
                         path.display()
                     );
                 }
@@ -1020,7 +1020,9 @@ impl ApplicationHandler<DesktopEvent> for DesktopApp {
             WindowEvent::CursorMoved { position, .. } => {
                 self.cursor_x = position.x as f32 / self.dpi;
                 self.cursor_y = position.y as f32 / self.dpi;
-                let over_layer_panel = self.host.cursor_over_layer_panel(
+                let model_picker_open = self.host.editor_state().editor_ui.chat_model_picker.open;
+                let over_layer_panel = !model_picker_open
+                    && self.host.cursor_over_layer_panel(
                         self.cursor_x,
                         self.cursor_y,
                         self.viewport_width,
@@ -1316,8 +1318,8 @@ impl ApplicationHandler<DesktopEvent> for DesktopApp {
                                     Some(figma_import_session::spawn(&mut self.host, path));
                                 self.request_redraw(true);
                             }
-                            // User picked a saved page; same background
-                            // session discipline as the Figma branch.
+                            // User picked a saved page or ZIP project; same
+                            // background session discipline as the Figma branch.
                             op_host_services::doc_io::ActionOutcome::HtmlImportStarted(path) => {
                                 figma_import_session::cancel(
                                     &mut self.host,
@@ -1589,6 +1591,34 @@ fn render_surface_not_ready(err: &SharedSkiaError) -> bool {
     )
 }
 
+/// Pop a native error dialog when the GL/Skia render context can't be
+/// built, so a fatal graphics-init failure is visible instead of a
+/// silent flash-exit. This matters most on Windows: the binary is a GUI
+/// subsystem app (`windows_subsystem = "windows"`) with no attached
+/// console, so `eprintln!` / tracing-to-stderr produce no output on a
+/// double-click launch. Bilingual EN/中文 body — the failure happens
+/// before the editor locale is meaningfully in play, and it must read
+/// for the affected users (typically machines with a missing/old GPU
+/// driver or a software-only OpenGL renderer).
+fn show_gpu_init_error_dialog(err: &SharedSkiaError) {
+    let body = format!(
+        "OpenPencil could not initialize the graphics (OpenGL) backend and has to close.\n\
+         无法初始化图形 (OpenGL) 渲染引擎，程序即将退出。\n\n\
+         This usually means the GPU driver is missing or too old, or the machine only \
+         has a software renderer (common on virtual machines / remote desktop).\n\
+         通常是显卡驱动缺失或过旧，或运行在只有软件渲染的环境（虚拟机 / 远程桌面）。\n\n\
+         Please update your graphics driver and try again.\n\
+         请更新显卡驱动后重试。\n\n\
+         Details: {err}"
+    );
+    rfd::MessageDialog::new()
+        .set_title("OpenPencil — Graphics initialization failed / 图形初始化失败")
+        .set_description(&body)
+        .set_level(rfd::MessageLevel::Error)
+        .set_buttons(rfd::MessageButtons::Ok)
+        .show();
+}
+
 impl DesktopApp {
     fn refresh_host_clock(&mut self) {
         let now_ms = self.clock_start.elapsed().as_millis() as u64;
@@ -1675,6 +1705,13 @@ impl DesktopApp {
             }
             Err(err) => {
                 eprintln!("openpencil-desktop: SharedSkiaContext::new_desktop failed: {err}");
+                // The GUI subsystem has no console (`windows_subsystem =
+                // "windows"`), so the `eprintln!` above goes nowhere on a
+                // double-click launch — the app would just flash and
+                // vanish. Surface the failure in a native dialog so the
+                // user sees a real reason (GPU driver / OpenGL) instead of
+                // a mystery crash.
+                show_gpu_init_error_dialog(&err);
                 self.error = Some(err);
                 event_loop.exit();
                 false

crates/op-host-native/src/context/provider.rs

@@ -158,6 +158,41 @@ impl GlutinProvider {
     /// matches the window's pixel format and stencil bits.
     #[tracing::instrument(skip_all)]
     pub fn from_window(window: &winit::window::Window) -> ProviderResult<Self> {
+        Self::from_window_impl(window, None)
+    }
+
+    /// Windows-only fallback constructor: force glutin onto the EGL
+    /// display path so it loads ANGLE's `libEGL.dll` (GL ES backed by
+    /// D3D11) instead of the native WGL ICD.
+    ///
+    /// `SharedSkiaContext::new_desktop` calls this ONLY after the primary
+    /// WGL attempt produced a context Skia's GL backend can't drive —
+    /// i.e. machines whose WGL exposes just the Microsoft GDI-generic
+    /// OpenGL 1.1 software renderer (no / stale GPU driver, VMs, RDP).
+    /// On those machines the earlier `WglThenEgl` preference never fell
+    /// through to EGL because WGL *did* create a (1.1) context
+    /// successfully; the failure only surfaces downstream in
+    /// `skia::direct_contexts::make_gl`. Forcing EGL here routes through
+    /// ANGLE instead, which reports a usable GL ES 3.0 context.
+    ///
+    /// Requires `libEGL.dll` + `libGLESv2.dll` shipped next to the
+    /// executable (glutin `LoadLibrary`s them from the exe directory);
+    /// if they are absent EGL display creation fails and this returns
+    /// `Err`, leaving the caller to surface the original WGL failure.
+    #[cfg(target_os = "windows")]
+    #[tracing::instrument(skip_all)]
+    pub fn from_window_forcing_egl(window: &winit::window::Window) -> ProviderResult<Self> {
+        Self::from_window_impl(window, Some(glutin::display::DisplayApiPreference::Egl))
+    }
+
+    /// Shared builder for [`from_window`] and (Windows) the EGL/ANGLE
+    /// fallback. `preference_override` bypasses [`pick_display_api`] so
+    /// the fallback can pin the display API.
+    #[tracing::instrument(skip_all)]
+    fn from_window_impl(
+        window: &winit::window::Window,
+        preference_override: Option<glutin::display::DisplayApiPreference>,
+    ) -> ProviderResult<Self> {
         use glutin::config::ConfigTemplateBuilder;
         use glutin::context::ContextAttributesBuilder;
         use glutin::display::{Display, GetGlDisplay};
@@ -176,7 +211,9 @@ impl GlutinProvider {
 
         // Per-platform display preference (glutin-winit applies the same
         // matrix internally, but we go direct to avoid the sealed trait).
-        let preference = pick_display_api(raw_window_handle);
+        // A caller-supplied override wins so the Windows ANGLE fallback
+        // can pin EGL.
+        let preference = preference_override.unwrap_or_else(|| pick_display_api(raw_window_handle));
 
         let gl_display = unsafe {
             Display::new(raw_display_handle, preference).map_err(ProviderError::from_error)?

crates/op-host-native/src/context/shared.rs

@@ -121,8 +121,60 @@ impl SharedSkiaContext {
     /// matches the window's framebuffer dimensions.
     #[tracing::instrument(skip_all)]
     pub fn new_desktop(window: &winit::window::Window) -> SharedSkiaResult<Self> {
+        // Primary path: the per-platform default display API (native WGL
+        // on Windows). Machines with a real GPU driver keep this exact
+        // render path — no behaviour change.
         let provider = GlutinProvider::from_window(window)?;
-        Self::new(provider)
+        match Self::new(provider) {
+            Ok(ctx) => Ok(ctx),
+            Err(err) => {
+                // On Windows a "successful" WGL context can still be the
+                // GDI-generic OpenGL 1.1 software renderer, which Skia's
+                // GL backend rejects (`make_gl` → None). The old
+                // `WglThenEgl` preference never caught this because WGL
+                // *did* create a context; the failure is downstream in
+                // Skia. Retry once forcing EGL so glutin routes through
+                // ANGLE (GL ES / D3D11), which those machines can drive.
+                //
+                // NOTE (unverified on Windows from this workstation): the
+                // HWND pixel format is set once by the first WGL surface;
+                // ANGLE's D3D11 backend does not consume the GL pixel
+                // format, so reusing the same window is expected to work,
+                // but must be smoke-tested on an affected machine. If it
+                // proves flaky the fallback is window re-creation.
+                #[cfg(target_os = "windows")]
+                {
+                    if Self::gl_backend_unavailable(&err) {
+                        tracing::warn!(
+                            ?err,
+                            "native WGL context cannot drive Skia; retrying via EGL/ANGLE"
+                        );
+                        if let Ok(egl_provider) = GlutinProvider::from_window_forcing_egl(window) {
+                            return Self::new(egl_provider);
+                        }
+                        tracing::warn!(
+                            "EGL/ANGLE fallback unavailable (libEGL.dll missing?); \
+                             surfacing original WGL failure"
+                        );
+                    }
+                }
+                Err(err)
+            }
+        }
+    }
+
+    /// Whether a context-construction error stems from the GL backend
+    /// being unusable (as opposed to a transient not-ready surface),
+    /// making an EGL/ANGLE retry worthwhile. Windows-only — the retry
+    /// site is `#[cfg(target_os = "windows")]`.
+    #[cfg(target_os = "windows")]
+    fn gl_backend_unavailable(err: &SharedSkiaError) -> bool {
+        matches!(
+            err,
+            SharedSkiaError::GlInterface
+                | SharedSkiaError::DirectContext
+                | SharedSkiaError::Surface
+        )
     }
 
     /// Begin a frame. Pure marker hook for now — chrome / canvas viewport

scripts/package-windows.nsi

@@ -97,6 +97,21 @@ Section "OpenPencil" SecMain
   File "${BIN_DIR}\${CLI_NAME}"
   File "/oname=openpencil.ico" "${ICON_FILE}"
 
+  ; ANGLE fallback DLLs (libEGL.dll + libGLESv2.dll, optionally
+  ; d3dcompiler_47.dll). Installed next to the exe so glutin's EGL path
+  ; loads them when the native WGL OpenGL context can't drive Skia — the
+  ; machines that were flash-exiting on startup (no/old GPU driver,
+  ; software-only OpenGL, VMs, RDP). See
+  ; `SharedSkiaContext::new_desktop` for the fallback wiring.
+  ;
+  ; `/nonfatal`: the release/CI build must stage these DLLs into
+  ; ${BIN_DIR} (matching the target arch) before running makensis. Until
+  ; that step exists the installer still builds (just without the
+  ; fallback), so packaging never hard-breaks on a missing DLL.
+  File /nonfatal "${BIN_DIR}\libEGL.dll"
+  File /nonfatal "${BIN_DIR}\libGLESv2.dll"
+  File /nonfatal "${BIN_DIR}\d3dcompiler_47.dll"
+
   WriteUninstaller "$INSTDIR\Uninstall.exe"
   WriteRegStr HKLM "${REG_APP_KEY}" "InstallDir" "$INSTDIR"