Improve screen brightness by also using camera gain (#20357)

selfdrive/ui/ui.cc

@@ -237,7 +237,9 @@ static void update_sockets(UIState *s) {
   }
 #ifdef QCOM2
   if (sm.updated("roadCameraState")) {
-    scene.light_sensor = std::clamp<float>(1023.0 - sm["roadCameraState"].getRoadCameraState().getIntegLines(), 0.0, 1023.0);
+    auto camera_state = sm["roadCameraState"].getRoadCameraState();
+    float gain = camera_state.getGainFrac() * (camera_state.getGlobalGain() > 100 ? 2.5 : 1.0) / 10.0;
+    scene.light_sensor = std::clamp<float>((1023.0 / 1757.0) * (1757.0 - camera_state.getIntegLines()) * (1.0 - gain), 0.0, 1023.0);
   }
 #endif
   scene.started = scene.deviceState.getStarted() || scene.driver_view;