support xbox triggers

Author: emutavchi

src/gamepad/linux_gamepad.cpp

@@ -80,16 +80,16 @@ static int32_t mapButtonId(int32_t code)
   // buttons[3]	Top button in right cluster
   // buttons[4]	Top left front button
   // buttons[5]	Top right front button
-  // buttons[6]	Bottom left front button
-  // buttons[7]	Bottom right front button
+  // buttons[6]	Bottom left front button (trigger)
+  // buttons[7]	Bottom right front button (trigger)
   // buttons[8]	Left button in center cluster
   // buttons[9]	Right button in center cluster
   // buttons[10]	Left stick pressed button
   // buttons[11]	Right stick pressed button
   // buttons[12]	Top button in left cluster
   // buttons[13]	Bottom button in left cluster
-  // buttons[14]	Right button in left cluster
-  // buttons[15]	Left button in left cluster
+  // buttons[14]	Right  button in left cluster
+  // buttons[15]	Left   button in left cluster
 
   struct MapEntry {
     const int32_t code;
@@ -107,18 +107,28 @@ static int32_t mapButtonId(int32_t code)
     { BTN_TR2,    7 },
     { BTN_SELECT, 8 },
     { BTN_START,  9 },
-    { BTN_THUMBL, 10 },
-    { BTN_THUMBR, 11 },
+    { BTN_THUMBL, 10 }, // stick pressed button
+    { BTN_THUMBR, 11 }, // stick pressed button
     { ABS_HAT0Y,  12 },
-    { ABS_HAT0X,  14 }
+    { ABS_HAT0X,  14 },
+
+    // TODO: Add configurable re-mapping for any controller
+    //
+    // Append:  XBOX Wireless Controller
+    //
+    { ABS_BRAKE,   6 },  // trigger
+    { ABS_GAS,     7 },  // trigger
+    { KEY_BACK,    8 }   // Left center "menu/start" button
+
   };
 
   static const size_t mapSize = sizeof(map)/sizeof(map[0]);
 
   for (int i = 0; i < mapSize; ++i)
+  {
     if (code == map[i].code)
       return map[i].id;
-
+  }
   return -1;
 }
 
@@ -137,7 +147,7 @@ static int mapAxisId(int32_t code)
     { ABS_X,  0 },
     { ABS_Y,  1 },
     { ABS_Z,  2 },
-    { ABS_RZ, 3 }
+    { ABS_RZ, 3 },
   };
 
   static const size_t mapSize = sizeof(map)/sizeof(map[0]);
@@ -164,8 +174,10 @@ static double mapAxisValue(int32_t val, int32_t min, int32_t max)
     double offset = (max + min) / (kMappedMax - kMappedMin) * scale * kMappedMin;
     double mappedVal = val * scale + offset;
     mappedVal = clamp(mappedVal, kMappedMin, kMappedMax);
+
     if (mappedVal < 0.009 && mappedVal > -0.009)
-        return 0.0;
+        mappedVal = 0.0;
+
     return mappedVal;
 }
 
@@ -304,7 +316,7 @@ struct GamepadProvider
     if (fd < 0)
       return false;
 
-    unsigned long ev_bits[NBITS(EV_CNT)]   = {0};
+    unsigned long  ev_bits[NBITS( EV_CNT)] = {0};
     unsigned long key_bits[NBITS(KEY_CNT)] = {0};
     unsigned long abs_bits[NBITS(ABS_CNT)] = {0};
 
@@ -369,6 +381,7 @@ struct GamepadProvider
       {
         SourceData *sourcedata = static_cast<SourceData*>(data);
         GamepadProvider& self = *(sourcedata->first);
+
         int32_t gamepad_id = sourcedata->second;
         if (condition & (G_IO_HUP | G_IO_ERR)) {
           self.closeGamepad(gamepad_id);
@@ -572,8 +585,9 @@ void GamepadProvider::updateGamepad(GamepadInfo& info, std::vector<input_event>
   const auto updateButtonValue = [&info, &buttonValuesChanged] (int32_t code, int32_t value)
   {
     const int32_t button_id = mapButtonId(code);
+
     if (button_id < 0 || button_id >= info.buttonValues.size()) {
-      g_warning("unmapped button code: %d \n", code);
+      g_warning("unmapped button code: %d    0x%04X\n", code, code);
       return;
     }
     info.buttonValues[button_id] = value == 0 ? 0.0 : 1.0;
@@ -584,12 +598,12 @@ void GamepadProvider::updateGamepad(GamepadInfo& info, std::vector<input_event>
   {
     // todo: figure out a better to handle dpad
     if (code != ABS_HAT0X && code != ABS_HAT0Y) {
-      g_warning("not supported code: %d \n", code);
+      g_warning("not supported code: %d    0x%04X\n", code, code);
       return;
     }
     const int32_t idx_base = mapButtonId(code);
     if ((idx_base < 0) || (idx_base + 1 >= info.buttonValues.size())) {
-      g_warning("unmapped button code: %d \n", code);
+      g_warning("unmapped button code: %d    0x%04X\n", code, code);
       return;
     }
     info.buttonValues[idx_base]     = 0.0;
@@ -599,6 +613,32 @@ void GamepadProvider::updateGamepad(GamepadInfo& info, std::vector<input_event>
     buttonValuesChanged = true;
   };
 
+  const auto updateTriggerValue = [&info, &buttonValuesChanged] (int32_t code, int32_t value)
+  {
+    const int32_t idx_base = mapButtonId(code);
+    if ((idx_base < 0) || (idx_base + 1 >= info.buttonValues.size())) {
+      g_warning("unmapped trigger code: %d    0x%04X\n", code, code);
+      return;
+    }
+
+    auto info_iter = info.axisInfo.find(code);
+    if (info_iter == info.axisInfo.end()) {
+      g_warning("no trigger info: %d \n", code);
+      return;
+    }
+
+    const input_absinfo& axisInfo = info_iter->second;
+    double mapped = mapAxisValue(value, axisInfo.minimum, axisInfo.maximum);
+
+    // Need to Normalize values in [ -1 <-> 1 ] to [ 0 <-> 1 ]
+    //
+    // First [ -1 <-> 1 ] / 2      =  [ -0.5 <-> 0.5 ]
+    // Then  [ -0.5 <-> 0.5] + 0.5 =  [  0.0 <-> 1.0 ]
+    //
+    info.buttonValues[idx_base] = (mapped/2) + 0.5;
+    buttonValuesChanged = true;
+  };
+
   const auto updateAxisValue = [&info, &axisValuesChanged] (int32_t code, int32_t value)
   {
     auto info_iter = info.axisInfo.find(code);
@@ -611,8 +651,10 @@ void GamepadProvider::updateGamepad(GamepadInfo& info, std::vector<input_event>
       g_warning("unmapped axis code: %d \n", code);
       return;
     }
+
     const input_absinfo& axisInfo = info_iter->second;
     double mapped = mapAxisValue(value, axisInfo.minimum, axisInfo.maximum);
+
     info.axisValues[axis_id] = mapped;
     axisValuesChanged = true;
   };
@@ -628,6 +670,9 @@ void GamepadProvider::updateGamepad(GamepadInfo& info, std::vector<input_event>
       }
       case EV_ABS:
       {
+        if (event.code == ABS_GAS || event.code == ABS_BRAKE) // L/R triggers
+          updateTriggerValue(event.code, event.value);
+        else
         if (event.code == ABS_HAT0X || event.code == ABS_HAT0Y)
           updateDpadButtonValue(event.code, event.value);
         else