Toggle the first-person camera with a right thumbstick click

Clicking the right thumbstick flips first person exactly as the F10
checkbox does, and saves it the same way. It works on the VR controllers
in either presentation (with a short tick on the right controller) and on
any other gamepad while VR is running. It never reached the game: SDL's
stick click only lands in Aurora's extended buttons.

A click counts on release, and only if the left thumbstick stayed up and
the headset settings panel stayed closed throughout, so the two-thumbstick
panel chord in gamepad mode never toggles the camera. A gamepad whose
right stick click is bound to a GameCube control on its port, as a button
or in an input expression, keeps it for the game. The XR side only posts
a request; the toggle itself runs on the game thread with the checkbox.

[vr] first_person_toggle_click (default true) and a checkbox under the
camera toggle turn the click off. mkw_vr_camera_toggle_tests covers the
click rule.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

runtime/src/settings_overlay.cpp

@@ -11,6 +11,7 @@
 #include "music_attenuation.h"
 #include "runtime_config.h"
 #include "runtime_log.h"
+#include "vr/camera_toggle.h"
 #include "vr/mkw_vr_first_person.h"
 #include "vr/mkw_vr_policy.h"
 #include "vr/openxr_diagnostics.h"
@@ -33,6 +34,7 @@
 #include <array>
 #include <algorithm>
 #include <atomic>
+#include <unordered_map>
 #include <cctype>
 #include <cfloat>
 #include <charconv>
@@ -140,6 +142,11 @@ bool g_vrStopAtDisplayCopy = RuntimeConfigFile::VrStopAtDisplayCopy(true);
 bool g_vrSkipCopyClears = RuntimeConfigFile::VrSkipCopyClears(true);
 bool g_vrHudVirtualScreen = RuntimeConfigFile::VrHudVirtualScreen(true);
 bool g_vrFirstPerson = RuntimeConfigFile::VrFirstPerson(false);
+bool g_vrFirstPersonToggleClick = RuntimeConfigFile::VrFirstPersonToggleClick();
+// Set from any thread by the right-thumbstick click, applied on the game thread.
+std::atomic<bool> g_firstPersonToggleRequested{false};
+// Per physical gamepad; the VR controllers keep theirs on the XR side.
+std::unordered_map<SDL_JoystickID, mkw::vr::ClickToggle> g_gamepadFirstPersonClicks;
 float g_vrFirstPersonUnitsPerMeter = RuntimeConfigFile::VrFirstPersonUnitsPerMeter();
 // 0 = cockpit, 1 = custom, matching kVrFirstPersonSeatNames.
 constexpr std::array<const char*, 2> kVrFirstPersonSeatNames{"cockpit", "custom"};
@@ -1477,6 +1484,12 @@ void DrawVrSettings() {
         RuntimeConfigFile::SetVrFirstPerson(g_vrFirstPerson);
         mkw::vr::MkwVRFirstPersonApplyConfiguredSettings();
     }
+    if (ImGui::IsItemHovered()) {
+        ImGui::SetTooltip("Also toggled by clicking the right thumbstick, on the VR controllers or on a gamepad.");
+    }
+    if (ImGui::Checkbox("Right thumbstick click toggles it", &g_vrFirstPersonToggleClick)) {
+        RuntimeConfigFile::SetVrFirstPersonToggleClick(g_vrFirstPersonToggleClick);
+    }
     if (ImGui::IsItemHovered()) {
         ImGui::SetTooltip(
             "Moves the camera to the Player 1 driver's head and keeps the horizon level, "
@@ -1614,6 +1627,65 @@ void DrawVrSettings() {
     }
 }
 
+// The right-thumbstick click: flips the first-person camera exactly as its
+// checkbox does. Game thread.
+void ToggleFirstPersonCamera() {
+    g_vrFirstPerson = !g_vrFirstPerson;
+    RuntimeConfigFile::SetVrFirstPerson(g_vrFirstPerson);
+    mkw::vr::MkwVRFirstPersonApplyConfiguredSettings();
+    RT_LOG(RT_TAG_RUNTIME) << "[mkw-vr] first-person camera " << (g_vrFirstPerson ? "on" : "off")
+                           << " (right thumbstick click)" << std::endl;
+}
+
+// A gamepad whose right thumbstick click reaches the game (bound to a
+// GameCube control on its port) keeps it; toggling the camera as well would
+// fire both.
+bool RightStickDrivesGame(SDL_Gamepad* gamepad) {
+    if (gamepad == nullptr) {
+        return false;
+    }
+    for (uint32_t port = 0; port < PAD_MAX_CONTROLLERS; ++port) {
+        const s32 index = PADGetIndexForPort(port);
+        if (index < 0 || PADGetSDLGamepadForIndex(static_cast<u32>(index)) != gamepad) {
+            continue;
+        }
+        for (auto* mappings : {&PADGetButtonMappings, &PADGetAltButtonMappings}) {
+            u32 count = 0;
+            const PADButtonMapping* list = (*mappings)(port, &count);
+            for (u32 i = 0; list != nullptr && i < count; ++i) {
+                if (list[i].nativeButton == SDL_GAMEPAD_BUTTON_RIGHT_STICK) {
+                    return true;
+                }
+            }
+        }
+        for (size_t control = 0; control < InputBindings::kControls.size(); ++control) {
+            const std::string expression = InputBindings::GetExpression(port, control);
+            if (expression.find("Thumb R") != std::string::npos || expression.find("Button 11") != std::string::npos) {
+                return true;
+            }
+        }
+    }
+    return false;
+}
+
+// A physical gamepad's right-thumbstick click, while VR runs.
+void HandleGamepadFirstPersonClick(const SDL_GamepadButtonEvent& event) {
+    const bool right = event.button == SDL_GAMEPAD_BUTTON_RIGHT_STICK;
+    const bool left = event.button == SDL_GAMEPAD_BUTTON_LEFT_STICK;
+    if ((!right && !left) || mkw::vr::OpenXRIsControllerGamepad(event.which)) {
+        return;
+    }
+    SDL_Gamepad* gamepad = SDL_GetGamepadFromID(event.which);
+    auto& click = g_gamepadFirstPersonClicks[event.which];
+    const bool held = right ? event.down : click.Held();
+    const bool partner = left ? event.down : gamepad != nullptr && SDL_GetGamepadButton(gamepad, SDL_GAMEPAD_BUTTON_LEFT_STICK);
+    const bool blocked = g_rebind.active || InputBindings::InputBlocked();
+    if (click.Update(held, partner, blocked) && g_vrFirstPersonToggleClick && mkw::vr::OpenXRIsRunning() &&
+        !RightStickDrivesGame(gamepad)) {
+        ToggleFirstPersonCamera();
+    }
+}
+
 // Export Logs. SDL shows the folder picker without blocking the game and calls
 // back on a thread of its choosing (its own dialog thread on Windows), where the
 // copy then runs; the menu only reads the outcome through this state.
@@ -2217,6 +2289,8 @@ void InitializeRuntimeSettings() noexcept {
 
 void RefreshVrHudVirtualScreen() noexcept { ApplyVrHudVirtualScreen(); }
 
+void RequestFirstPersonToggle() noexcept { g_firstPersonToggleRequested.store(true, std::memory_order_release); }
+
 void HandleEvents(const AuroraEvent* events) noexcept {
     if (!events) {
         return;
@@ -2237,6 +2311,9 @@ void HandleEvents(const AuroraEvent* events) noexcept {
             CompleteRebind(g_rebind.kind == RebindKind::Controller ? PAD_NATIVE_BUTTON_DISABLED
                                                                   : static_cast<uint32_t>(PAD_KEY_INVALID));
         }
+        if (ev->sdl.type == SDL_EVENT_GAMEPAD_BUTTON_DOWN || ev->sdl.type == SDL_EVENT_GAMEPAD_BUTTON_UP) {
+            HandleGamepadFirstPersonClick(ev->sdl.gbutton);
+        }
         if (!g_rebind.active && IsToggleKey(ev->sdl, SDL_SCANCODE_F10)) {
             SetTopBarVisible(!g_topBarVisible);
         }
@@ -2312,6 +2389,9 @@ void Draw() noexcept {
     // its "communications interrupted" prompt without polling pads). Same guest
     // thread as PADRead, so no concurrent access to the scanner's state.
     WiiRemoteInput::Poll();
+    if (g_firstPersonToggleRequested.exchange(false, std::memory_order_acq_rel)) {
+        ToggleFirstPersonCamera();
+    }
     ApplyConfiguredMappings();
     PersistDisplayModeIfChanged();
     UpdateCursorAutoHide();