[HID/Linux] Implement cross platform controller input using SDL2 library.

src/xenia/hid/sdl/sdl_input_driver.h

@@ -0,0 +1,72 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2020 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#ifndef XENIA_HID_SDL_SDL_INPUT_DRIVER_H_
+#define XENIA_HID_SDL_SDL_INPUT_DRIVER_H_
+
+#include <SDL2/SDL.h>
+
+#include <array>
+#include <atomic>
+#include <mutex>
+
+#include "xenia/hid/input_driver.h"
+
+#define HID_SDL_USER_COUNT (4)
+
+namespace xe {
+namespace hid {
+namespace sdl {
+
+class SDLInputDriver : public InputDriver {
+ public:
+  explicit SDLInputDriver(xe::ui::Window* window);
+  ~SDLInputDriver() override;
+
+  X_STATUS Setup() override;
+
+  X_RESULT GetCapabilities(uint32_t user_index, uint32_t flags,
+                           X_INPUT_CAPABILITIES* out_caps) override;
+  X_RESULT GetState(uint32_t user_index, X_INPUT_STATE* out_state) override;
+  X_RESULT SetState(uint32_t user_index, X_INPUT_VIBRATION* vibration) override;
+  X_RESULT GetKeystroke(uint32_t user_index, uint32_t flags,
+                        X_INPUT_KEYSTROKE* out_keystroke) override;
+
+ protected:
+  struct ControllerState {
+    SDL_GameController* sdl;
+    bool state_changed;
+    X_INPUT_STATE state;
+  };
+
+ protected:
+  void OnControllerDeviceAdded(SDL_Event* event);
+  void OnControllerDeviceRemoved(SDL_Event* event);
+  void OnControllerDeviceAxisMotion(SDL_Event* event);
+  void OnControllerDeviceButtonChanged(SDL_Event* event);
+  std::pair<bool, size_t> GetControllerIndexFromInstanceID(
+      SDL_JoystickID instance_id);
+  ControllerState* GetControllerState(uint32_t user_index);
+  bool TestSDLVersion();
+  void QueueControllerUpdate();
+
+ protected:
+  bool sdl_events_initialized_;
+  bool sdl_gamecontroller_initialized_;
+  int sdl_events_unflushed_;
+  std::atomic<bool> sdl_pumpevents_queued_;
+  std::array<ControllerState, HID_SDL_USER_COUNT> controllers_;
+  std::mutex controllers_mutex_;
+};
+
+}  // namespace sdl
+}  // namespace hid
+}  // namespace xe
+
+#endif  // XENIA_HID_SDL_SDL_INPUT_DRIVER_H_