The Windows app no longer starts OpenGL, which crashed some Intel drivers before the window opened

eframe starts every wgpu backend before an adapter is picked, and starting GL loads the system's OpenGL driver; Intel's ig9icd64.dll crashed in it (0xc0000005), so the app vanished with no window or error box. Windows now starts the primary backends only (DX12 with WARP, Vulkan); WGPU_BACKEND still decides when set.

Fixes #196

apps/craft-anything/src/main.rs

@@ -48,6 +48,10 @@ fn main() -> eframe::Result {
     let mut options = eframe::NativeOptions { viewport, ..Default::default() };
     #[cfg(windows)]
     if let eframe::egui_wgpu::WgpuSetup::CreateNew(setup) = &mut options.wgpu_options.wgpu_setup {
+        // Starting GL loads the system's OpenGL driver before any adapter is picked, and some
+        // Intel drivers crash in it (ig9icd64.dll, #196), so the window never opens. DX12 (with
+        // WARP) and Vulkan always cover Windows; `WGPU_BACKEND=gl` still asks for GL.
+        setup.instance_descriptor.backends = windows_backends(eframe::wgpu::Backends::from_env());
         setup.native_adapter_selector = Some(Arc::new(pick_adapter));
     }
     let run = eframe::run_native(
@@ -102,6 +106,13 @@ fn pick_adapter(adapters: &[eframe::wgpu::Adapter], surface: Option<&eframe::wgp
     }
 }
 
+/// Windows: the graphics backends to start. `WGPU_BACKEND` decides when set; otherwise every
+/// primary backend and not GL (#196).
+#[cfg(windows)]
+fn windows_backends(from_env: Option<eframe::wgpu::Backends>) -> eframe::wgpu::Backends {
+    from_env.unwrap_or(eframe::wgpu::Backends::PRIMARY)
+}
+
 /// Lower is better: GL last, then the fastest kind of device first (wgpu's own high-performance
 /// preference).
 #[cfg(windows)]
@@ -131,6 +142,15 @@ mod tests {
         assert_eq!(best(&[(B::Dx12, T::IntegratedGpu), (B::Vulkan, T::DiscreteGpu), (B::Dx12, T::Cpu)]), Some(1), "fastest GPU first");
         assert_eq!(best(&[(B::Gl, T::Other)]), Some(0), "GL when it's all there is");
     }
+
+    /// #196: an Intel OpenGL driver crashed the app as wgpu started GL, before any window.
+    #[test]
+    fn gl_is_only_started_when_asked_for() {
+        use eframe::wgpu::Backends;
+        let started = windows_backends(None);
+        assert!(!started.contains(Backends::GL) && started.contains(Backends::DX12) && started.contains(Backends::VULKAN));
+        assert_eq!(windows_backends(Some(Backends::GL)), Backends::GL, "WGPU_BACKEND=gl still works");
+    }
 }
 
 /// Kept small: started afresh once it passes this size.

docs/pitfalls.md

@@ -141,6 +141,11 @@ real Deep-mode run (the CLI never shows it: it already has a console). Every chi
 the windowed app gets `CREATE_NO_WINDOW`; check the desktop app, not only the CLI, after adding a
 program.
 
+**A graphics backend that crashed before it was chosen.** We ranked GL last when picking an
+adapter, but eframe starts every backend first, and starting GL loaded an old Intel OpenGL driver
+that crashed the app before any window or error box (#196). Ranking can't protect you from a
+backend that's started at all: start only the backends the app may use.
+
 **A Mac app that couldn't find Claude Code, and offered a GitHub key instead.** An app opened from
 the Dock gets the system's short `PATH`, not the shell's, so `claude` in `~/.local/bin` wasn't
 found; "Built by" then fell back to "Claude Code on github.com-work", an `~/.ssh/config` alias