jb: touch debounce (#798)

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

## Description of change
Debouce option for touch input. Applies to all touch handlers (rawinput,
win8, win7) since it sits at the touch layer, and then consumed by jb
touch logic.

## Testing

src/spice2x/games/jb/jb_touch.cpp

@@ -12,6 +12,7 @@
 #include "touch/touch.h"
 #include "rawinput/touch.h"
 #include "util/logging.h"
+#include "util/time.h"
 #include "util/utils.h"
 
 // touch layout: a 4x4 grid of 160px buttons separated by 37 / 38 / 37 px gaps
@@ -36,6 +37,7 @@ namespace games::jb {
     // touch state
     JubeatTouchAlgorithm TOUCH_ALGORITHM = Improved;
     JubeatTouchDebugMode TOUCH_DEBUG_OVERLAY = JbTouchDebugAuto;
+    uint32_t TOUCH_DEBOUNCE_MS = 0;
     static std::atomic_bool TOUCH_ENABLE = false;
     static bool TOUCH_ATTACHED = false;
     static bool IS_PORTRAIT = true;
@@ -52,22 +54,31 @@ namespace games::jb {
 
     static void clear_touch_points() {
         for (auto &point : TOUCH_POINTS) {
-            point.store(JB_INVALID_TOUCH_POINT, std::memory_order_relaxed);
+            point.store(JB_INVALID_TOUCH_POINT, std::memory_order_release);
         }
     }
 
-    static void publish_touch_points(const std::vector<TouchPoint> &touch_points) {
+    // false when a contact is younger than the debounce window and should be ignored
+    static bool touch_matured(const TouchPoint &tp, double now_ms, double threshold_ms) {
+        return now_ms - tp.down_ms >= threshold_ms;
+    }
+
+    // snapshot for the debug overlay: each slot atomically holds one matured contact or
+    // the invalid sentinel. immature and absent contacts are published as invalid, so the
+    // overlay never shows a suppressed tap and a single atomic per slot cannot tear
+    static void publish_touch_points(const std::vector<TouchPoint> &touch_points,
+                                     double now_ms, double threshold_ms) {
         size_t count = touch_points.size();
         if (count > JB_MAX_TOUCH_POINTS) {
             count = JB_MAX_TOUCH_POINTS;
         }
 
-        for (size_t i = count; i < JB_MAX_TOUCH_POINTS; i++) {
-            TOUCH_POINTS[i].store(JB_INVALID_TOUCH_POINT, std::memory_order_relaxed);
-        }
-        for (size_t i = 0; i < count; i++) {
-            POINT point { touch_points[i].x, touch_points[i].y };
-            TOUCH_POINTS[i].store(point, std::memory_order_relaxed);
+        for (size_t i = 0; i < JB_MAX_TOUCH_POINTS; i++) {
+            POINT point = JB_INVALID_TOUCH_POINT;
+            if (i < count && touch_matured(touch_points[i], now_ms, threshold_ms)) {
+                point = { touch_points[i].x, touch_points[i].y };
+            }
+            TOUCH_POINTS[i].store(point, std::memory_order_release);
         }
     }
 
@@ -207,7 +218,19 @@ namespace games::jb {
         uint16_t next_state = 0;
         std::vector<TouchPoint> touch_points;
         touch_get_points(touch_points);
-        publish_touch_points(touch_points);
+
+        // debounce: the landing time is stamped by the touch layer, so this is
+        // independent of how often the game polls for input (0 = off)
+        double now_ms = get_performance_milliseconds();
+        double threshold_ms = TOUCH_DEBOUNCE_MS;
+
+        // publish every raw contact (with its maturity) for the debug overlay, then drop
+        // the ones still inside the debounce window so no algorithm sees them
+        publish_touch_points(touch_points, now_ms, threshold_ms);
+        std::erase_if(touch_points, [&](const TouchPoint &tp) {
+            return !touch_matured(tp, now_ms, threshold_ms);
+        });
+
         if (TOUCH_ALGORITHM == Legacy) {
 
             // legacy: evenly divide the play area into a 4x4 grid
@@ -355,18 +378,21 @@ namespace games::jb {
         int radius = touch_radius();
         int draw_radius = radius > 0 ? radius : JB_TOUCH_RADIUS;
 
+        // each slot holds a matured contact or the invalid sentinel; immature and absent
+        // contacts were already filtered out by publish_touch_points
         for (auto &touch_point : TOUCH_POINTS) {
-            POINT point = touch_point.load(std::memory_order_relaxed);
+            POINT point = touch_point.load(std::memory_order_acquire);
             if (point.x == JB_INVALID_TOUCH_COORD) {
                 continue;
             }
+
             bool pressed = touch_presses_button(point.x, point.y, gx, gy, legacy, radius);
 
             SelectObject(hdc, pressed ? pen_white : pen_gray);
             Ellipse(hdc, point.x - draw_radius, point.y - draw_radius,
                          point.x + draw_radius, point.y + draw_radius);
 
-            // the arc would point at a single snapped-to button; plus can trigger several at
+            // the arc points at a single snapped-to button; plus can trigger several at
             // once, so skip it there
             if (pressed || TOUCH_ALGORITHM == Plus) {
                 continue;

src/spice2x/games/jb/jb_touch.h

@@ -26,6 +26,10 @@ namespace games::jb {
     extern JubeatTouchAlgorithm TOUCH_ALGORITHM;
     extern JubeatTouchDebugMode TOUCH_DEBUG_OVERLAY;
 
+    // minimum contact age in milliseconds before a touch registers (0 = off);
+    // filters momentary phantom touches from noisy panels
+    extern uint32_t TOUCH_DEBOUNCE_MS;
+
     // atomically published panel state, read by the I/O layer
     std::bitset<16> touch_state();
 

src/spice2x/launcher/launcher.cpp

@@ -1333,6 +1333,11 @@ int main_implementation(int argc, char *argv[]) {
         }
     }
 
+    if (options[launcher::Options::JubeatTouchDebounce].is_active()) {
+        games::jb::TOUCH_DEBOUNCE_MS =
+            options[launcher::Options::JubeatTouchDebounce].value_uint32();
+    }
+
     // reflec beat touch emulation
     if (options[launcher::Options::spice2x_RBTouchScale].is_active()) {
         games::rb::TOUCH_SCALING = options[launcher::Options::spice2x_RBTouchScale].value_uint32();

src/spice2x/launcher/options.cpp

@@ -2725,6 +2725,20 @@ static const std::vector<OptionDefinition> OPTION_DEFINITIONS = {
         },
         .quick_setting_category = "Game",
     },
+    {
+        // JubeatTouchDebounce
+        .title = "JB Touch Debounce",
+        .name = "jubeattouchdebounce",
+        .desc = "For touch screen players: ignore extremely quick touches by requiring a "
+            "touch to be held for at least this many milliseconds before it registers.\n\n"
+            "Useful for filtering phantom touches on a noisy touch screen. A higher value "
+            "adds input latency, so keep it small. Default: off (0).",
+        .type = OptionType::Integer,
+        .setting_name = "8",
+        .game_name = "Jubeat",
+        .category = "Game Options",
+        .quick_setting_category = "Game",
+    },
     {
         // spice2x_RBTouchScale
         .title = "RB Touch Emulation Scale",

src/spice2x/launcher/options.h

@@ -264,6 +264,7 @@ namespace launcher {
             spice2x_JubeatLegacyTouch,
             JubeatTouchAlgo,
             JubeatTouchDebug,
+            JubeatTouchDebounce,
             spice2x_RBTouchScale,
             RBTouchSize,
             RBTouchPollRate,

src/spice2x/touch/touch.cpp

@@ -20,6 +20,7 @@
 #include "util/detour.h"
 #include "util/libutils.h"
 #include "util/logging.h"
+#include "util/time.h"
 #include "util/utils.h"
 
 #include "handler.h"
@@ -538,6 +539,7 @@ static LRESULT CALLBACK SpiceTouchWndProc(HWND hWnd, UINT msg, WPARAM wParam, LP
                         .x = GET_X_LPARAM(lParam),
                         .y = GET_Y_LPARAM(lParam),
                         .mouse = true,
+                        .down_ms = get_performance_milliseconds(),
                     };
                     TOUCH_POINTS.push_back(tp);
 
@@ -851,6 +853,9 @@ void touch_write_points(std::vector<TouchPoint> *touch_points) {
         // create new touch point when not found
         if (!found) {
 
+            // stamp the landing time so debounce can measure the contact's age
+            tp.down_ms = get_performance_milliseconds();
+
             // add touch point
             TOUCH_POINTS.push_back(tp);
 

src/spice2x/touch/touch.h

@@ -7,6 +7,7 @@ struct TouchPoint {
     DWORD id;
     LONG x, y;
     bool mouse;
+    double down_ms = 0.0; // performance-counter milliseconds when the contact first landed
 };
 enum TouchEventType {
     TOUCH_DOWN,

src/spice2x/touch/win7.cpp

@@ -11,6 +11,7 @@
 
 #include "util/libutils.h"
 #include "util/logging.h"
+#include "util/time.h"
 #include "rawinput/touch.h"
 
 // mingw issue #2205 workaround
@@ -177,6 +178,7 @@ void Win7Handler::handle_message(msg_handler_result &result, HWND hWnd, UINT msg
                             .x = point.x,
                             .y = point.y,
                             .mouse = false,
+                            .down_ms = get_performance_milliseconds(),
                         };
                         TOUCH_POINTS.push_back(tp);
 

src/spice2x/touch/win8.cpp

@@ -12,6 +12,7 @@
 
 #include "util/libutils.h"
 #include "util/logging.h"
+#include "util/time.h"
 #include "rawinput/touch.h"
 
 // mingw does not seem to have this either
@@ -220,6 +221,7 @@ void Win8Handler::handle_message(msg_handler_result &result, HWND hWnd, UINT msg
                         .x = point.x,
                         .y = point.y,
                         .mouse = false,
+                        .down_ms = get_performance_milliseconds(),
                     };
                     TOUCH_POINTS.push_back(tp);