hid_gamepad.hpp

#pragma once
#include <cmath>
#include <cstdint>
#include <cstring>
 
#include "hid.hpp"
 
namespace LibXR::USB
{
 
// 模板化 4 轴 + 8 按钮 HID 手柄报告描述符（见类内 GetReportDesc）
// Templated 4-axes + 8-buttons HID gamepad report descriptor (see GetReportDesc in class)
 
template <int16_t LOG_MIN = 0, int16_t LOG_MAX = 2047, uint8_t IN_EP_INTERVAL_MS = 1>
class HIDGamepadT
    : public HID<50 /* desc size */, 9 /* report len */, 0 /* feature len */>
{
  static_assert(LOG_MIN <= LOG_MAX, "LOG_MIN must be <= LOG_MAX");
  static_assert(LOG_MIN >= -32768 && LOG_MAX <= 32767,
                "Axis logical range must fit in int16_t");
 
 public:
  explicit HIDGamepadT(Endpoint::EPNumber in_ep_num = Endpoint::EPNumber::EP_AUTO)
      : HID<50, 9, 0>(false, IN_EP_INTERVAL_MS, /*out_ep_interval*/ 1, in_ep_num,
                      Endpoint::EPNumber::EP_AUTO)
  {
    // 初始化上一帧：轴置中，按钮清零 / Initialize last report: axes to mid, buttons
    // cleared
    last_.x = Mid();
    last_.y = Mid();
    last_.z = Mid();
    last_.rx = Mid();
    last_.buttons = 0;
  }
 
  enum Button : uint8_t
  {
    BTN1 = 0x01,
    BTN2 = 0x02,
    BTN3 = 0x04,
    BTN4 = 0x08,
    BTN5 = 0x10,
    BTN6 = 0x20,
    BTN7 = 0x40,
    BTN8 = 0x80,
  };
 
#pragma pack(push, 1)
  struct Report
  {
    int16_t x;        
    int16_t y;        
    int16_t z;        
    int16_t rx;       
    uint8_t buttons;  
  };
#pragma pack(pop)
 
  static_assert(sizeof(Report) == 9, "Report size must be 9 bytes");
 
  ErrorCode Send(int x, int y, int z, int rx, uint8_t buttons)
  {
    last_.x = Clamp(x);
    last_.y = Clamp(y);
    last_.z = Clamp(z);
    last_.rx = Clamp(rx);
    last_.buttons = buttons;
    return SendInputReport(ConstRawData{&last_, sizeof(last_)});
  }
 
  ErrorCode SendButtons(uint8_t buttons)
  {
    last_.buttons = buttons;
    return SendInputReport(ConstRawData{&last_, sizeof(last_)});
  }
 
  ErrorCode SendAxes(int x, int y, int z, int rx)
  {
    last_.x = Clamp(x);
    last_.y = Clamp(y);
    last_.z = Clamp(z);
    last_.rx = Clamp(rx);
    return SendInputReport(ConstRawData{&last_, sizeof(last_)});
  }
 
 protected:
  ErrorCode WriteDeviceDescriptor(DeviceDescriptor& header) override
  {
    header.data_.bDeviceClass = DeviceDescriptor::ClassID::PER_INTERFACE;  // 0x00
    header.data_.bDeviceSubClass = 0;
    header.data_.bDeviceProtocol = 0;
    return ErrorCode::OK;
  }
 
  ConstRawData GetReportDesc() override { return ConstRawData{desc_, sizeof(desc_)}; }
 
 private:
  // 报告描述符（编译期常量 50 字节） / HID report descriptor (compile-time 50 bytes)
  // 轴：X/Y/Z/Rx，16 位容器；按钮：8 个 / Axes: X/Y/Z/Rx, 16-bit containers; Buttons: 8
  static constexpr uint8_t U8(uint16_t v) { return static_cast<uint8_t>(v & 0xFF); }
  static constexpr uint8_t U8H(uint16_t v)
  {
    return static_cast<uint8_t>((v >> 8) & 0xFF);
  }
 
  static constexpr uint8_t desc_[/*50*/] = {
      0x05, 0x01,  // Usage Page (Generic Desktop)
      0x09, 0x05,  // Usage (Game Pad)
      0xA1, 0x01,  // Collection (Application)
 
      // Axes collection
      0x09, 0x01,  //   Usage (Pointer)
      0xA1, 0x00,  //   Collection (Physical)
      0x05, 0x01,  //     Usage Page (Generic Desktop)
      0x09, 0x30,  //     Usage (X)
      0x09, 0x31,  //     Usage (Y)
      0x09, 0x32,  //     Usage (Z)
      0x09, 0x33,  //     Usage (Rx)
 
      // Logical Min/Max (16-bit)
      0x16, U8(static_cast<uint16_t>(LOG_MIN)),
      U8H(static_cast<uint16_t>(LOG_MIN)),  // Logical Minimum
      0x26, U8(static_cast<uint16_t>(LOG_MAX)),
      U8H(static_cast<uint16_t>(LOG_MAX)),  // Logical Maximum
 
      0x75, 0x10,  //     Report Size (16)
      0x95, 0x04,  //     Report Count (4)
      0x81, 0x02,  //     Input (Data, Variable, Absolute)
      0xC0,        //   End Collection (Physical)
 
      // Buttons
      0x05, 0x09,  //   Usage Page (Button)
      0x19, 0x01,  //   Usage Minimum (Button 1)
      0x29, 0x08,  //   Usage Maximum (Button 8)
      0x15, 0x00,  //   Logical Minimum (0)
      0x25, 0x01,  //   Logical Maximum (1)
      0x95, 0x08,  //   Report Count (8)
      0x75, 0x01,  //   Report Size (1)
      0x81, 0x02,  //   Input (Data, Variable, Absolute)
 
      0xC0  // End Collection (Application)
  };
 
  static_assert(sizeof(desc_) == 50,
                "HID report descriptor size changed; update base template arg!");
 
  static constexpr int16_t Clamp(int v)
  {
    return (v < LOG_MIN) ? LOG_MIN : (v > LOG_MAX ? LOG_MAX : static_cast<int16_t>(v));
  }
 
  static constexpr int16_t Mid()
  {
    return static_cast<int16_t>(
        (static_cast<int32_t>(LOG_MIN) + static_cast<int32_t>(LOG_MAX)) / 2);
  }
 
  Report last_{};  
};
 
using HIDGamepad = HIDGamepadT<0, 2047, 1>;
 
using HIDGamepadBipolar = HIDGamepadT<-2048, 2047, 1>;
 
}  // namespace LibXR::USB