app/src-tauri/src/main.rs

@@ -1,6 +1,35 @@
 // Prevents additional console window on Windows in release
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
 
+/// WebKitGTK's DMA-BUF renderer (its default accelerated-compositing path
+/// since 2.42) fails outright on some Mesa/driver/compositor combinations
+/// under Wayland, printing `Could not create default EGL display:
+/// EGL_BAD_PARAMETER. Aborting.` straight to stderr from WebKitGTK's own C
+/// code and killing the webview before Triple-C's own logging even starts —
+/// see triple-c#34, reported on CachyOS/Arch with Wayland. There is no
+/// reliable way to detect the affected driver/compositor combination ahead
+/// of time (it is not simply "Wayland vs. X11" — the same failure has been
+/// reported under XWayland too), so this is set unconditionally on Linux
+/// rather than gated on `WAYLAND_DISPLAY`. WebKitGTK falls back to a
+/// software/shared-memory compositing path when this is set, which costs
+/// some rendering performance but nothing this app's UI depends on.
+///
+/// Must be set before `triple_c_lib::run()` — GTK/WebKitGTK reads it at
+/// their own init time, which happens inside the Tauri builder that
+/// function calls into, not at binary load.
+///
+/// A user who has already set this themselves (including to `0`, to force
+/// the DMA-BUF path back on for their own hardware) is left alone.
+#[cfg(target_os = "linux")]
+fn apply_webkit_wayland_workaround() {
+    if std::env::var_os("WEBKIT_DISABLE_DMABUF_RENDERER").is_none() {
+        std::env::set_var("WEBKIT_DISABLE_DMABUF_RENDERER", "1");
+    }
+}
+
 fn main() {
+    #[cfg(target_os = "linux")]
+    apply_webkit_wayland_workaround();
+
     triple_c_lib::run()
 }