Controller: Add emulation of Namco GunCon

src/core/namco_guncon.h

@@ -0,0 +1,66 @@
+#pragma once
+#include "controller.h"
+#include <memory>
+#include <optional>
+#include <string_view>
+
+class NamcoGunCon final : public Controller
+{
+public:
+  enum class Button : u8
+  {
+    Trigger = 0,
+    A = 1,
+    B = 2,
+    Count
+  };
+
+  NamcoGunCon(System* system);
+  ~NamcoGunCon() override;
+
+  static std::unique_ptr<NamcoGunCon> Create(System* system);
+  static std::optional<s32> StaticGetAxisCodeByName(std::string_view button_name);
+  static std::optional<s32> StaticGetButtonCodeByName(std::string_view button_name);
+  static AxisList StaticGetAxisNames();
+  static ButtonList StaticGetButtonNames();
+  static u32 StaticGetVibrationMotorCount();
+
+  ControllerType GetType() const override;
+  std::optional<s32> GetAxisCodeByName(std::string_view axis_name) const override;
+  std::optional<s32> GetButtonCodeByName(std::string_view button_name) const override;
+
+  void Reset() override;
+  bool DoState(StateWrapper& sw) override;
+
+  void SetAxisState(s32 axis_code, float value) override;
+  void SetButtonState(s32 button_code, bool pressed) override;
+
+  void ResetTransferState() override;
+  bool Transfer(const u8 data_in, u8* data_out) override;
+
+  void SetButtonState(Button button, bool pressed);
+
+private:
+  void UpdatePosition();
+
+  enum class TransferState : u8
+  {
+    Idle,
+    IDMSB,
+    ButtonsLSB,
+    ButtonsMSB,
+    XLSB,
+    XMSB,
+    YLSB,
+    YMSB
+  };
+
+  System* m_system;
+
+  // buttons are active low
+  u16 m_button_state = UINT16_C(0xFFFF);
+  u16 m_position_x = 0;
+  u16 m_position_y = 0;
+
+  TransferState m_transfer_state = TransferState::Idle;
+};