Tweaks to video driver handling

- Use a separate `gldriver6` file for configuring Qt6 so we don't
pick up old settings, or cause problems when switching back and forth.
- Default to OpenGL/auto instead of software, as that was what we
were using throughout the beta period.
- Try to detect driver failure on startup. Untested.
- Hide the selector in the preferences again, as if Anki is unable
to automatically switch drivers, the user could change the setting
and then not be able to get back into Anki.

qt/aqt/__init__.py

@@ -34,7 +34,7 @@ import locale
 import os
 import tempfile
 import traceback
-from typing import Any, Callable, Optional, cast
+from typing import TYPE_CHECKING, Any, Callable, Optional, cast
 
 import anki.lang
 from anki._backend import RustBackend
@@ -46,6 +46,9 @@ from aqt import gui_hooks
 from aqt.qt import *
 from aqt.utils import TR, tr
 
+if TYPE_CHECKING:
+    import aqt.profiles
+
 # compat aliases
 anki.version = _version  # type: ignore
 anki.Collection = Collection  # type: ignore
@@ -394,7 +397,12 @@ def setupGL(pm: aqt.profiles.ProfileManager) -> None:
             context += f"{ctx.function}"
         if context:
             context = f"'{context}'"
-        if "Failed to create OpenGL context" in msg:
+        if (
+            "Failed to create OpenGL context" in msg
+            # Based on the message Qt6 shows to the user; have not tested whether
+            # we can actually capture this or not.
+            or "Failed to initialize graphics backend" in msg
+        ):
             QMessageBox.critical(
                 None,
                 tr.qt_misc_error(),

qt/aqt/preferences.py

@@ -290,6 +290,7 @@ class Preferences(QDialog):
         self.form.video_driver.setCurrentIndex(
             self.video_drivers.index(self.mw.pm.video_driver())
         )
+        self.form.video_driver.setVisible(qtmajor == 5)
 
     def update_video_driver(self) -> None:
         new_driver = self.video_drivers[self.form.video_driver.currentIndex()]

qt/aqt/profiles.py

@@ -38,7 +38,7 @@ class VideoDriver(Enum):
 
     @staticmethod
     def default_for_platform() -> VideoDriver:
-        if is_mac:
+        if is_mac or qtmajor > 5:
             return VideoDriver.OpenGL
         else:
             return VideoDriver.Software
@@ -479,7 +479,11 @@ create table if not exists profiles
     ######################################################################
 
     def _gldriver_path(self) -> str:
-        return os.path.join(self.base, "gldriver")
+        if qtmajor < 6:
+            fname = "gldriver"
+        else:
+            fname = "gldriver6"
+        return os.path.join(self.base, fname)
 
     def video_driver(self) -> VideoDriver:
         path = self._gldriver_path()