custom_gamepad.h

#pragma once

#define PICADE_HID_GAMEPAD(...) \
  HID_USAGE_PAGE ( HID_USAGE_PAGE_DESKTOP     )                 ,\
  HID_USAGE      ( HID_USAGE_DESKTOP_GAMEPAD  )                 ,\
  HID_COLLECTION ( HID_COLLECTION_APPLICATION )                 ,\
    /* Report ID if any */\
    __VA_ARGS__ \
    /* 8 bit X, Y (min -127, max 127 ) */ \
    HID_USAGE_PAGE     ( HID_USAGE_PAGE_DESKTOP                 ) ,\
    HID_USAGE          ( HID_USAGE_DESKTOP_X                    ) ,\
    HID_USAGE          ( HID_USAGE_DESKTOP_Y                    ) ,\
    HID_LOGICAL_MIN    ( 0x81                                   ) ,\
    HID_LOGICAL_MAX    ( 0x7f                                   ) ,\
    HID_REPORT_COUNT   ( 2                                      ) ,\
    HID_REPORT_SIZE    ( 8                                      ) ,\
    HID_INPUT          ( HID_DATA | HID_VARIABLE | HID_ABSOLUTE ) ,\
    /* 15 bit Button Map */ \
    HID_USAGE_PAGE     ( HID_USAGE_PAGE_BUTTON                  ) ,\
    HID_USAGE_MIN      ( 1                                      ) ,\
    HID_USAGE_MAX      ( 15                                     ) ,\
    HID_LOGICAL_MIN    ( 0                                      ) ,\
    HID_LOGICAL_MAX    ( 1                                      ) ,\
    HID_REPORT_COUNT   ( 15                                     ) ,\
    HID_REPORT_SIZE    ( 1                                      ) ,\
    HID_INPUT          ( HID_DATA | HID_VARIABLE | HID_ABSOLUTE ) ,\
    /* 1 bit reserved */ \
    HID_REPORT_COUNT ( 1                                      )  ,\
    HID_REPORT_SIZE  ( 1                                      )  ,\
    HID_INPUT        ( HID_CONSTANT                           )  ,\
  HID_COLLECTION_END \

typedef struct TU_ATTR_PACKED
{
  int8_t  x;         ///< Delta x  movement of left analog-stick
  int8_t  y;         ///< Delta y  movement of left analog-stick
  uint16_t buttons;  ///< Buttons mask for currently pressed buttons
} picade_gamepad_report_t;

bool picade_gamepad_report(uint8_t instance, int8_t x, int8_t y, uint16_t buttons)
{
  picade_gamepad_report_t report =
  {
    .x       = x,
    .y       = y,
    .buttons = buttons,
  };

  return tud_hid_n_report(instance, 0, &report, sizeof(report));
}