Add Flat Screen mode for VR races and update settings accordingly

runtime/include/vr/mkw_vr_policy.h

@@ -71,6 +71,7 @@ inline constexpr uint32_t kMkwVRRequiredImmersiveBindings =
 
 struct MkwVRPolicyConfig {
     bool enabled = false;
+    // False is Flat Screen mode: races stay on the virtual screen the menus use.
     bool immersive_races = true;
     float world_units_per_meter = 500.0f;
     float hud_distance_meters = 2.0f;
@@ -151,6 +152,9 @@ void MkwVRPolicySetFirstPersonEngaged(bool engaged) noexcept;
 // MkwVRPolicyConfigure so the F10 slider can retune it during a race without
 // republishing (and revalidating) the whole configuration.
 void MkwVRPolicySetFirstPersonUnitsPerMeter(float units_per_meter) noexcept;
+// Flat Screen mode, live from the F10 menu. Unlike the scale above this changes
+// which content is safe to present, so it advances the safety generation.
+void MkwVRPolicySetImmersiveRaces(bool enabled) noexcept;
 MkwVRPolicySnapshot MkwVRPolicyGetSnapshot() noexcept;
 
 // This classifier is deliberately structural rather than heuristic: future

runtime/include/vr/openxr_driving.h

@@ -79,10 +79,11 @@ inline float MaxWheelAngle(bool bike, const WheelTuning& tuning) noexcept {
     return clamped * 0.01745329252f;
 }
 
-// Grips only grab. While a hand holds the wheel its squeeze is released for the
-// game, where it would press C on the Nunchuk or a shoulder on the gamepad, and
-// the wheel replaces the left stick's X axis, which both controller modes steer
-// with. The stick's Y axis keeps aiming items forwards and backwards.
+// Grips only grab. As a Wii Remote they press nothing at all (C, the game's
+// look-behind, is right B); as a gamepad they are the shoulders, so a holding
+// hand's squeeze is released for the game. The wheel replaces the left stick's
+// X axis, which both controller modes steer with, and the stick's Y axis keeps
+// aiming items forwards and backwards.
 inline void ApplyHandSteering(std::array<wii_remote::HandInputs, 2>& hands, const WheelState& wheel) noexcept {
     for (size_t hand = 0; hand < hands.size(); ++hand) {
         if (wheel.held[hand]) {

runtime/include/vr/openxr_input.h

@@ -63,7 +63,8 @@ struct OpenXRPointerScreen {
 // the seated frame every frame. With hand steering on, a squeezed grip near the
 // steering wheel or handlebar takes hold of it; while held, the wheel replaces
 // the left stick's X axis in both presentations and that grip no longer reaches
-// the game (C on the Nunchuk, a shoulder on the gamepad).
+// the game (a shoulder on the gamepad; as a Wii Remote the grips are unbound,
+// so a hand on the wheel cannot hold down a button).
 //
 // A right-thumbstick click on its own toggles the first-person camera, as its
 // F10 checkbox does (first_person_toggle_click).

runtime/include/vr/openxr_wii_remote.h

@@ -342,10 +342,12 @@ struct HandInputs {
 
 // Adapted from DolphinXR's default "OpenXR Wii Remote" profile
 // (Data/Sys/Profiles/Wiimote):
-//   right A -> A, right trigger -> B, right stick up/down -> 1/2,
+//   right A -> A, right trigger -> B, right B -> C, right stick up/down -> 1/2,
 //   left X -> -, left menu -> +,
-//   left grip -> C, left trigger -> Z, left stick -> Nunchuk stick.
+//   left trigger -> Z, left stick -> Nunchuk stick.
 // HOME has no button; left Y opens the settings panel (openxr_settings_panel.h).
+// The grips press nothing: they take hold of the wheel (openxr_driving.h), and C
+// is the game's look-behind, which a hand on the wheel would otherwise hold down.
 inline uint32_t RemoteButtons(const HandInputs& left, const HandInputs& right) noexcept {
     uint32_t hold = 0;
     const auto press = [&hold](bool held, uint32_t bit) {
@@ -355,11 +357,11 @@ inline uint32_t RemoteButtons(const HandInputs& left, const HandInputs& right) n
     };
     press(right.primary, kButtonA);
     press(right.trigger > kPressThreshold, kButtonB);
+    press(right.secondary, kButtonC);
     press(right.stick_y > kPressThreshold, kButtonOne);
     press(right.stick_y < -kPressThreshold, kButtonTwo);
     press(left.primary, kButtonMinus);
     press(left.menu, kButtonPlus);
-    press(left.squeeze > kPressThreshold, kButtonC);
     press(left.trigger > kPressThreshold, kButtonZ);
     return hold;
 }