overlay: create a dedicated thread for polling hotkeys (#864)

## Link to GitHub Issue or related Pull Request, if one exists
n/a

## Description of change
Create a new thread that polls for the following hotkeys:

* super exit (both alt+f4 and bound key)
* coin insert
* screenshot

The goal is to make the capture of these more reliable, because before
this PR it wasn't.

## Testing

src/spice2x/misc/eamuse.cpp

@@ -25,10 +25,8 @@ static double CARD_INSERT_TIME[2] = {0, 0};
 static double CARD_INSERT_TIMEOUT = 2.0;
 static char CARD_INSERT_UID[2][8] = {{0}, {0}};
 static char CARD_INSERT_UID_ENABLE[2] = {false, false};
-static int COIN_STOCK = 0;
-static bool COIN_BLOCK = false;
-static std::thread *COIN_INPUT_THREAD;
-static bool COIN_INPUT_THREAD_ACTIVE = false;
+static std::atomic_int COIN_STOCK {0};
+static std::atomic_bool COIN_BLOCK {false};
 static uint16_t KEYPAD_STATE[] = {0, 0};
 static uint16_t KEYPAD_STATE_OVERRIDES[] = {0, 0};
 static uint16_t KEYPAD_STATE_OVERRIDES_BT5[] = {0, 0};
@@ -292,78 +290,49 @@ bool eamuse_card_insert_consume(int active_count, int unit_id) {
 }
 
 bool eamuse_coin_get_block() {
-    return COIN_BLOCK;
+    return COIN_BLOCK.load(std::memory_order_relaxed);
 }
 
 void eamuse_coin_set_block(bool block) {
-    COIN_BLOCK = block;
+    COIN_BLOCK.store(block, std::memory_order_relaxed);
 }
 
 int eamuse_coin_get_stock() {
-    return COIN_STOCK;
+    return COIN_STOCK.load(std::memory_order_relaxed);
 }
 
 void eamuse_coin_set_stock(int amount) {
-    COIN_STOCK = amount;
+    COIN_STOCK.store(amount, std::memory_order_relaxed);
 }
 
 bool eamuse_coin_consume(int amount) {
-    if (COIN_STOCK < amount) {
-        return false;
-    } else {
-        COIN_STOCK -= amount;
-        return true;
+    auto stock = COIN_STOCK.load(std::memory_order_relaxed);
+    while (stock >= amount) {
+        if (COIN_STOCK.compare_exchange_weak(
+                stock,
+                stock - amount,
+                std::memory_order_relaxed)) {
+            return true;
+        }
     }
+    return false;
 }
 
 int eamuse_coin_consume_stock() {
-    int stock = COIN_STOCK;
-    COIN_STOCK = 0;
-    return stock;
+    return COIN_STOCK.exchange(0, std::memory_order_relaxed);
 }
 
 int eamuse_coin_add() {
-    return ++COIN_STOCK;
+    return COIN_STOCK.fetch_add(1, std::memory_order_relaxed) + 1;
 }
 
-void eamuse_coin_start_thread() {
-
-    // set active
-    COIN_INPUT_THREAD_ACTIVE = true;
-
-    // create thread
-    COIN_INPUT_THREAD = new std::thread([]() {
-        auto overlay_buttons = games::get_buttons_overlay(eamuse_get_game());
-        static bool COIN_INPUT_KEY_STATE = false;
-        while (COIN_INPUT_THREAD_ACTIVE) {
-
-            // check input key
-            if (overlay_buttons && GameAPI::Buttons::getState(RI_MGR, overlay_buttons->at(
-                    games::OverlayButtons::InsertCoin))) {
-                if (!COIN_INPUT_KEY_STATE) {
-                    if (COIN_BLOCK)
-                        log_info("eamuse", "coin inserted while blocked");
-                    else {
-                        log_info("eamuse", "coin insert");
-                        COIN_STOCK++;
-                    }
-                }
-                COIN_INPUT_KEY_STATE = true;
-            } else {
-                COIN_INPUT_KEY_STATE = false;
-            }
-
-            // once every two frames
-            std::this_thread::sleep_for(std::chrono::milliseconds(1000 / 30));
-        }
-    });
-}
-
-void eamuse_coin_stop_thread() {
-    COIN_INPUT_THREAD_ACTIVE = false;
-    COIN_INPUT_THREAD->join();
-    delete COIN_INPUT_THREAD;
-    COIN_INPUT_THREAD = nullptr;
+void eamuse_coin_insert() {
+    if (COIN_BLOCK.load(std::memory_order_relaxed)) {
+        log_info("eamuse", "coin inserted while blocked");
+    } else {
+        log_info("eamuse", "coin insert");
+        COIN_STOCK.fetch_add(1, std::memory_order_relaxed);
+    }
 }
 
 void eamuse_pin_macro_start_thread() {

src/spice2x/misc/eamuse.h

@@ -58,9 +58,7 @@ bool eamuse_coin_consume(int amount);
 int eamuse_coin_consume_stock();
 
 int eamuse_coin_add();
-
-void eamuse_coin_start_thread();
-void eamuse_coin_stop_thread();
+void eamuse_coin_insert();
 
 void eamuse_pin_macro_start_thread();
 void eamuse_pin_macro_stop_thread();

src/spice2x/misc/hotkeys.cpp

@@ -0,0 +1,154 @@
+#include "hotkeys.h"
+
+#include <atomic>
+#include <chrono>
+#include <mutex>
+#include <stop_token>
+#include <thread>
+#include <vector>
+
+#include <windows.h>
+
+#include "games/io.h"
+#include "launcher/superexit.h"
+#include "misc/eamuse.h"
+#include "overlay/overlay.h"
+#include "rawinput/rawinput.h"
+#include "util/logging.h"
+
+namespace hotkeys {
+
+    namespace {
+
+        // 8 ms targets short screenshot pulses; sleep_for may use a coarser scheduler
+        // interval during early boot or when process timer adjustments are disabled
+        constexpr auto MIN_SAMPLE_INTERVAL = std::chrono::milliseconds(8);
+
+        std::atomic_bool SCREENSHOT_PENDING {false};
+        std::mutex INPUT_MUTEX;
+        bool INPUT_ENABLED = false;
+        bool RAW_INPUT_ENABLED = false;
+        std::jthread WORKER;
+
+        bool read_button(std::vector<Button> *buttons, size_t index) {
+            // getState retains each binding's focus, modifier, inversion, and debounce policy
+            return RI_MGR && buttons && index < buttons->size() &&
+                GameAPI::Buttons::getState(RI_MGR, buttons->at(index));
+        }
+
+        bool read_alt_f4() {
+            // preserve both legacy detection paths whenever raw input is available
+            bool pressed = (GetAsyncKeyState(VK_MENU) & 0x8000) != 0 &&
+                (GetAsyncKeyState(VK_F4) & 0x8000) != 0;
+            if (!RAW_INPUT_ENABLED || !RI_MGR) {
+                return pressed;
+            }
+            return pressed || RI_MGR->keyboard_combo_pressed(VK_MENU, VK_F4);
+        }
+
+        bool rising_edge(bool current, bool &previous) {
+            const bool edge = current && !previous;
+            previous = current;
+            return edge;
+        }
+
+        void run(std::stop_token stop_token) {
+            bool screenshot_previous = false;
+            bool coin_previous = false;
+
+            while (!stop_token.stop_requested()) {
+                bool coin_edge = false;
+                bool super_exit_current = false;
+                bool alt_f4_current = false;
+
+                {
+                    // lifecycle functions hold this mutex until raw-input polling is complete
+                    std::lock_guard<std::mutex> lock(INPUT_MUTEX);
+                    if (INPUT_ENABLED || RAW_INPUT_ENABLED) {
+                        auto *buttons = games::get_buttons_overlay(eamuse_get_game());
+                        const bool screenshot_down = INPUT_ENABLED && read_button(
+                            buttons, games::OverlayButtons::Screenshot);
+                        const bool coin_current = INPUT_ENABLED && read_button(
+                                buttons, games::OverlayButtons::InsertCoin);
+                        const bool super_exit_down = RAW_INPUT_ENABLED && read_button(
+                                buttons, games::OverlayButtons::SuperExit);
+
+                        // global_hotkeys_triggered takes OVERLAY_MUTEX, then the overlay's
+                        // hotkeys_mutex; its button reads may then take device mutexes. polling
+                        // every mapped-input tick is intentional so HotkeyToggle releases cannot
+                        // be missed when the render thread stalls.
+                        const bool gate_active = overlay::global_hotkeys_triggered();
+                        const bool screenshot_current = screenshot_down && gate_active;
+                        super_exit_current = super_exit_down && gate_active;
+
+                        if (rising_edge(screenshot_current, screenshot_previous)) {
+                            SCREENSHOT_PENDING.store(true, std::memory_order_relaxed);
+                        }
+                        coin_edge = rising_edge(coin_current, coin_previous);
+                    } else {
+                        screenshot_previous = false;
+                        coin_previous = false;
+                    }
+
+                    alt_f4_current = read_alt_f4();
+                }
+
+                if (coin_edge) {
+                    eamuse_coin_insert();
+                }
+
+                // pass held state so returning focus can exit without another key press
+                superexit::handle_hotkeys(alt_f4_current, super_exit_current);
+
+                std::this_thread::sleep_for(MIN_SAMPLE_INTERVAL);
+            }
+        }
+    }
+
+    void start() {
+        if (WORKER.joinable()) {
+            return;
+        }
+
+        SCREENSHOT_PENDING.store(false, std::memory_order_relaxed);
+        WORKER = std::jthread(run);
+        log_info("hotkeys", "sampler started");
+    }
+
+    void enable_raw_input() {
+        std::lock_guard<std::mutex> lock(INPUT_MUTEX);
+        RAW_INPUT_ENABLED = true;
+    }
+
+    void enable_input() {
+        std::lock_guard<std::mutex> lock(INPUT_MUTEX);
+        SCREENSHOT_PENDING.store(false, std::memory_order_relaxed);
+        INPUT_ENABLED = true;
+        log_info("hotkeys", "configured input enabled");
+    }
+
+    void disable_input() {
+        std::lock_guard<std::mutex> lock(INPUT_MUTEX);
+        INPUT_ENABLED = false;
+        SCREENSHOT_PENDING.store(false, std::memory_order_relaxed);
+        log_info("hotkeys", "configured input disabled");
+    }
+
+    void disable_raw_input() {
+        std::lock_guard<std::mutex> lock(INPUT_MUTEX);
+        RAW_INPUT_ENABLED = false;
+    }
+
+    void stop() {
+        if (!WORKER.joinable()) {
+            return;
+        }
+        WORKER.request_stop();
+        WORKER.join();
+        log_info("hotkeys", "sampler stopped");
+    }
+
+    bool consume_screenshot() {
+        return SCREENSHOT_PENDING.exchange(false, std::memory_order_relaxed);
+    }
+}

src/spice2x/misc/hotkeys.h

@@ -0,0 +1,13 @@
+#pragma once
+
+namespace hotkeys {
+
+    // ALT+F4 monitoring spans boot and teardown; configured actions are enabled separately
+    void start();
+    void enable_raw_input();
+    void enable_input();
+    void disable_input();
+    void disable_raw_input();
+    void stop();
+    bool consume_screenshot();
+}