From 38e800f70d122051e12ac9f22e23d84b97fec424 Mon Sep 17 00:00:00 2001
From: wwylele <wwylele@gmail.com>
Date: Sat, 21 Jan 2017 11:53:03 +0200
Subject: InputCommon: add Keyboard

---
 src/input_common/CMakeLists.txt | 15 ++++++++
 src/input_common/keyboard.cpp   | 82 +++++++++++++++++++++++++++++++++++++++++
 src/input_common/keyboard.h     | 45 ++++++++++++++++++++++
 src/input_common/main.cpp       | 35 ++++++++++++++++++
 src/input_common/main.h         | 25 +++++++++++++
 5 files changed, 202 insertions(+)
 create mode 100644 src/input_common/CMakeLists.txt
 create mode 100644 src/input_common/keyboard.cpp
 create mode 100644 src/input_common/keyboard.h
 create mode 100644 src/input_common/main.cpp
 create mode 100644 src/input_common/main.h

(limited to 'src/input_common')

diff --git a/src/input_common/CMakeLists.txt b/src/input_common/CMakeLists.txt
new file mode 100644
index 000000000..ac1ad45a9
--- /dev/null
+++ b/src/input_common/CMakeLists.txt
@@ -0,0 +1,15 @@
+set(SRCS
+            keyboard.cpp
+            main.cpp
+            )
+
+set(HEADERS
+            keyboard.h
+            main.h
+            )
+
+create_directory_groups(${SRCS} ${HEADERS})
+
+add_library(input_common STATIC ${SRCS} ${HEADERS})
+target_link_libraries(input_common common core)
+
diff --git a/src/input_common/keyboard.cpp b/src/input_common/keyboard.cpp
new file mode 100644
index 000000000..a8fc01f2e
--- /dev/null
+++ b/src/input_common/keyboard.cpp
@@ -0,0 +1,82 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <atomic>
+#include <list>
+#include <mutex>
+#include "input_common/keyboard.h"
+
+namespace InputCommon {
+
+class KeyButton final : public Input::ButtonDevice {
+public:
+    explicit KeyButton(std::shared_ptr<KeyButtonList> key_button_list_)
+        : key_button_list(key_button_list_) {}
+
+    ~KeyButton();
+
+    bool GetStatus() const override {
+        return status.load();
+    }
+
+    friend class KeyButtonList;
+
+private:
+    std::shared_ptr<KeyButtonList> key_button_list;
+    std::atomic<bool> status{false};
+};
+
+struct KeyButtonPair {
+    int key_code;
+    KeyButton* key_button;
+};
+
+class KeyButtonList {
+public:
+    void AddKeyButton(int key_code, KeyButton* key_button) {
+        std::lock_guard<std::mutex> guard(mutex);
+        list.push_back(KeyButtonPair{key_code, key_button});
+    }
+
+    void RemoveKeyButton(const KeyButton* key_button) {
+        std::lock_guard<std::mutex> guard(mutex);
+        list.remove_if(
+            [key_button](const KeyButtonPair& pair) { return pair.key_button == key_button; });
+    }
+
+    void ChangeKeyStatus(int key_code, bool pressed) {
+        std::lock_guard<std::mutex> guard(mutex);
+        for (const KeyButtonPair& pair : list) {
+            if (pair.key_code == key_code)
+                pair.key_button->status.store(pressed);
+        }
+    }
+
+private:
+    std::mutex mutex;
+    std::list<KeyButtonPair> list;
+};
+
+Keyboard::Keyboard() : key_button_list{std::make_shared<KeyButtonList>()} {}
+
+KeyButton::~KeyButton() {
+    key_button_list->RemoveKeyButton(this);
+}
+
+std::unique_ptr<Input::ButtonDevice> Keyboard::Create(const Common::ParamPackage& params) {
+    int key_code = params.Get("code", 0);
+    std::unique_ptr<KeyButton> button = std::make_unique<KeyButton>(key_button_list);
+    key_button_list->AddKeyButton(key_code, button.get());
+    return std::move(button);
+}
+
+void Keyboard::PressKey(int key_code) {
+    key_button_list->ChangeKeyStatus(key_code, true);
+}
+
+void Keyboard::ReleaseKey(int key_code) {
+    key_button_list->ChangeKeyStatus(key_code, false);
+}
+
+} // namespace InputCommon
diff --git a/src/input_common/keyboard.h b/src/input_common/keyboard.h
new file mode 100644
index 000000000..76359aa30
--- /dev/null
+++ b/src/input_common/keyboard.h
@@ -0,0 +1,45 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include "core/frontend/input.h"
+
+namespace InputCommon {
+
+class KeyButtonList;
+
+/**
+ * A button device factory representing a keyboard. It receives keyboard events and forward them
+ * to all button devices it created.
+ */
+class Keyboard final : public Input::Factory<Input::ButtonDevice> {
+public:
+    Keyboard();
+
+    /**
+     * Creates a button device from a keyboard key
+     * @param params contains parameters for creating the device:
+     *     - "code": the code of the key to bind with the button
+     */
+    std::unique_ptr<Input::ButtonDevice> Create(const Common::ParamPackage& params) override;
+
+    /**
+     * Sets the status of all buttons bound with the key to pressed
+     * @param key_code the code of the key to press
+     */
+    void PressKey(int key_code);
+
+    /**
+     * Sets the status of all buttons bound with the key to released
+     * @param key_code the code of the key to release
+     */
+    void ReleaseKey(int key_code);
+
+private:
+    std::shared_ptr<KeyButtonList> key_button_list;
+};
+
+} // namespace InputCommon
diff --git a/src/input_common/main.cpp b/src/input_common/main.cpp
new file mode 100644
index 000000000..ff25220b4
--- /dev/null
+++ b/src/input_common/main.cpp
@@ -0,0 +1,35 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <memory>
+#include "common/param_package.h"
+#include "input_common/keyboard.h"
+#include "input_common/main.h"
+
+namespace InputCommon {
+
+static std::shared_ptr<Keyboard> keyboard;
+
+void Init() {
+    keyboard = std::make_shared<InputCommon::Keyboard>();
+    Input::RegisterFactory<Input::ButtonDevice>("keyboard", keyboard);
+}
+
+void Shutdown() {
+    Input::UnregisterFactory<Input::ButtonDevice>("keyboard");
+    keyboard.reset();
+}
+
+Keyboard* GetKeyboard() {
+    return keyboard.get();
+}
+
+std::string GenerateKeyboardParam(int key_code) {
+    Common::ParamPackage param{
+        {"engine", "keyboard"}, {"code", std::to_string(key_code)},
+    };
+    return param.Serialize();
+}
+
+} // namespace InputCommon
diff --git a/src/input_common/main.h b/src/input_common/main.h
new file mode 100644
index 000000000..a490dd829
--- /dev/null
+++ b/src/input_common/main.h
@@ -0,0 +1,25 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <string>
+
+namespace InputCommon {
+
+/// Initializes and registers all built-in input device factories.
+void Init();
+
+/// Unresisters all build-in input device factories and shut them down.
+void Shutdown();
+
+class Keyboard;
+
+/// Gets the keyboard button device factory.
+Keyboard* GetKeyboard();
+
+/// Generates a serialized param package for creating a keyboard button device
+std::string GenerateKeyboardParam(int key_code);
+
+} // namespace InputCommon
-- 
cgit v1.2.3


From a6bd7917cbc06f9b8f5a7ae24e75db776dc1cd6a Mon Sep 17 00:00:00 2001
From: wwylele <wwylele@gmail.com>
Date: Sat, 21 Jan 2017 13:04:00 +0200
Subject: InputCommon: add AnalogFromButton

---
 src/input_common/CMakeLists.txt         |  2 ++
 src/input_common/analog_from_button.cpp | 58 +++++++++++++++++++++++++++++++++
 src/input_common/analog_from_button.h   | 31 ++++++++++++++++++
 src/input_common/main.cpp               | 18 ++++++++++
 src/input_common/main.h                 |  4 +++
 5 files changed, 113 insertions(+)
 create mode 100755 src/input_common/analog_from_button.cpp
 create mode 100755 src/input_common/analog_from_button.h

(limited to 'src/input_common')

diff --git a/src/input_common/CMakeLists.txt b/src/input_common/CMakeLists.txt
index ac1ad45a9..9f4422269 100644
--- a/src/input_common/CMakeLists.txt
+++ b/src/input_common/CMakeLists.txt
@@ -1,9 +1,11 @@
 set(SRCS
+            analog_from_button.cpp
             keyboard.cpp
             main.cpp
             )
 
 set(HEADERS
+            analog_from_button.h
             keyboard.h
             main.h
             )
diff --git a/src/input_common/analog_from_button.cpp b/src/input_common/analog_from_button.cpp
new file mode 100755
index 000000000..e1a260762
--- /dev/null
+++ b/src/input_common/analog_from_button.cpp
@@ -0,0 +1,58 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "input_common/analog_from_button.h"
+
+namespace InputCommon {
+
+class Analog final : public Input::AnalogDevice {
+public:
+    using Button = std::unique_ptr<Input::ButtonDevice>;
+
+    Analog(Button up_, Button down_, Button left_, Button right_, Button modifier_,
+           float modifier_scale_)
+        : up(std::move(up_)), down(std::move(down_)), left(std::move(left_)),
+          right(std::move(right_)), modifier(std::move(modifier_)),
+          modifier_scale(modifier_scale_) {}
+
+    std::tuple<float, float> GetStatus() const override {
+        constexpr float SQRT_HALF = 0.707106781f;
+        int x = 0, y = 0;
+
+        if (right->GetStatus())
+            ++x;
+        if (left->GetStatus())
+            --x;
+        if (up->GetStatus())
+            ++y;
+        if (down->GetStatus())
+            --y;
+
+        float coef = modifier->GetStatus() ? modifier_scale : 1.0f;
+        return std::make_tuple(x * coef * (y == 0 ? 1.0f : SQRT_HALF),
+                               y * coef * (x == 0 ? 1.0f : SQRT_HALF));
+    }
+
+private:
+    Button up;
+    Button down;
+    Button left;
+    Button right;
+    Button modifier;
+    float modifier_scale;
+};
+
+std::unique_ptr<Input::AnalogDevice> AnalogFromButton::Create(const Common::ParamPackage& params) {
+    const std::string null_engine = Common::ParamPackage{{"engine", "null"}}.Serialize();
+    auto up = Input::CreateDevice<Input::ButtonDevice>(params.Get("up", null_engine));
+    auto down = Input::CreateDevice<Input::ButtonDevice>(params.Get("down", null_engine));
+    auto left = Input::CreateDevice<Input::ButtonDevice>(params.Get("left", null_engine));
+    auto right = Input::CreateDevice<Input::ButtonDevice>(params.Get("right", null_engine));
+    auto modifier = Input::CreateDevice<Input::ButtonDevice>(params.Get("modifier", null_engine));
+    auto modifier_scale = params.Get("modifier_scale", 0.5f);
+    return std::make_unique<Analog>(std::move(up), std::move(down), std::move(left),
+                                    std::move(right), std::move(modifier), modifier_scale);
+}
+
+} // namespace InputCommon
diff --git a/src/input_common/analog_from_button.h b/src/input_common/analog_from_button.h
new file mode 100755
index 000000000..bbd583dd9
--- /dev/null
+++ b/src/input_common/analog_from_button.h
@@ -0,0 +1,31 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include "core/frontend/input.h"
+
+namespace InputCommon {
+
+/**
+ * An analog device factory that takes direction button devices and combines them into a analog
+ * device.
+ */
+class AnalogFromButton final : public Input::Factory<Input::AnalogDevice> {
+public:
+    /**
+     * Creates an analog device from direction button devices
+     * @param params contains parameters for creating the device:
+     *     - "up": a serialized ParamPackage for creating a button device for up direction
+     *     - "down": a serialized ParamPackage for creating a button device for down direction
+     *     - "left": a serialized ParamPackage for creating a button device for left direction
+     *     - "right": a serialized ParamPackage  for creating a button device for right direction
+     *     - "modifier": a serialized ParamPackage for creating a button device as the modifier
+     *     - "modifier_scale": a float for the multiplier the modifier gives to the position
+     */
+    std::unique_ptr<Input::AnalogDevice> Create(const Common::ParamPackage& params) override;
+};
+
+} // namespace InputCommon
diff --git a/src/input_common/main.cpp b/src/input_common/main.cpp
index ff25220b4..8455fdc17 100644
--- a/src/input_common/main.cpp
+++ b/src/input_common/main.cpp
@@ -4,6 +4,7 @@
 
 #include <memory>
 #include "common/param_package.h"
+#include "input_common/analog_from_button.h"
 #include "input_common/keyboard.h"
 #include "input_common/main.h"
 
@@ -14,11 +15,14 @@ static std::shared_ptr<Keyboard> keyboard;
 void Init() {
     keyboard = std::make_shared<InputCommon::Keyboard>();
     Input::RegisterFactory<Input::ButtonDevice>("keyboard", keyboard);
+    Input::RegisterFactory<Input::AnalogDevice>("analog_from_button",
+                                                std::make_shared<InputCommon::AnalogFromButton>());
 }
 
 void Shutdown() {
     Input::UnregisterFactory<Input::ButtonDevice>("keyboard");
     keyboard.reset();
+    Input::UnregisterFactory<Input::AnalogDevice>("analog_from_button");
 }
 
 Keyboard* GetKeyboard() {
@@ -32,4 +36,18 @@ std::string GenerateKeyboardParam(int key_code) {
     return param.Serialize();
 }
 
+std::string GenerateAnalogParamFromKeys(int key_up, int key_down, int key_left, int key_right,
+                                        int key_modifier, float modifier_scale) {
+    Common::ParamPackage circle_pad_param{
+        {"engine", "analog_from_button"},
+        {"up", GenerateKeyboardParam(key_up)},
+        {"down", GenerateKeyboardParam(key_down)},
+        {"left", GenerateKeyboardParam(key_left)},
+        {"right", GenerateKeyboardParam(key_right)},
+        {"modifier", GenerateKeyboardParam(key_modifier)},
+        {"modifier_scale", std::to_string(modifier_scale)},
+    };
+    return circle_pad_param.Serialize();
+}
+
 } // namespace InputCommon
diff --git a/src/input_common/main.h b/src/input_common/main.h
index a490dd829..140bbd014 100644
--- a/src/input_common/main.h
+++ b/src/input_common/main.h
@@ -22,4 +22,8 @@ Keyboard* GetKeyboard();
 /// Generates a serialized param package for creating a keyboard button device
 std::string GenerateKeyboardParam(int key_code);
 
+/// Generates a serialized param package for creating an analog device taking input from keyboard
+std::string GenerateAnalogParamFromKeys(int key_up, int key_down, int key_left, int key_right,
+                                        int key_modifier, float modifier_scale);
+
 } // namespace InputCommon
-- 
cgit v1.2.3


From 51b1c1f211bf8112eba845256bd52cbd36a5932a Mon Sep 17 00:00:00 2001
From: wwylele <wwylele@gmail.com>
Date: Sat, 21 Jan 2017 17:33:48 +0200
Subject: InputCommon: add SDL joystick support

---
 src/input_common/CMakeLists.txt |  10 ++
 src/input_common/main.cpp       |  10 ++
 src/input_common/sdl/sdl.cpp    | 202 ++++++++++++++++++++++++++++++++++++++++
 src/input_common/sdl/sdl.h      |  19 ++++
 4 files changed, 241 insertions(+)
 create mode 100644 src/input_common/sdl/sdl.cpp
 create mode 100644 src/input_common/sdl/sdl.h

(limited to 'src/input_common')

diff --git a/src/input_common/CMakeLists.txt b/src/input_common/CMakeLists.txt
index 9f4422269..cfe5caaa3 100644
--- a/src/input_common/CMakeLists.txt
+++ b/src/input_common/CMakeLists.txt
@@ -10,8 +10,18 @@ set(HEADERS
             main.h
             )
 
+if(SDL2_FOUND)
+    set(SRCS ${SRCS} sdl/sdl.cpp)
+    set(HEADERS ${HEADERS} sdl/sdl.h)
+    include_directories(${SDL2_INCLUDE_DIR})
+endif()
+
 create_directory_groups(${SRCS} ${HEADERS})
 
 add_library(input_common STATIC ${SRCS} ${HEADERS})
 target_link_libraries(input_common common core)
 
+if(SDL2_FOUND)
+    target_link_libraries(input_common ${SDL2_LIBRARY})
+    set_property(TARGET input_common APPEND PROPERTY COMPILE_DEFINITIONS HAVE_SDL2)
+endif()
diff --git a/src/input_common/main.cpp b/src/input_common/main.cpp
index 8455fdc17..699f41e6b 100644
--- a/src/input_common/main.cpp
+++ b/src/input_common/main.cpp
@@ -7,6 +7,9 @@
 #include "input_common/analog_from_button.h"
 #include "input_common/keyboard.h"
 #include "input_common/main.h"
+#ifdef HAVE_SDL2
+#include "input_common/sdl/sdl.h"
+#endif
 
 namespace InputCommon {
 
@@ -17,12 +20,19 @@ void Init() {
     Input::RegisterFactory<Input::ButtonDevice>("keyboard", keyboard);
     Input::RegisterFactory<Input::AnalogDevice>("analog_from_button",
                                                 std::make_shared<InputCommon::AnalogFromButton>());
+#ifdef HAVE_SDL2
+    SDL::Init();
+#endif
 }
 
 void Shutdown() {
     Input::UnregisterFactory<Input::ButtonDevice>("keyboard");
     keyboard.reset();
     Input::UnregisterFactory<Input::AnalogDevice>("analog_from_button");
+
+#ifdef HAVE_SDL2
+    SDL::Shutdown();
+#endif
 }
 
 Keyboard* GetKeyboard() {
diff --git a/src/input_common/sdl/sdl.cpp b/src/input_common/sdl/sdl.cpp
new file mode 100644
index 000000000..ae0206909
--- /dev/null
+++ b/src/input_common/sdl/sdl.cpp
@@ -0,0 +1,202 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <cmath>
+#include <memory>
+#include <string>
+#include <tuple>
+#include <unordered_map>
+#include <SDL.h>
+#include "common/math_util.h"
+#include "input_common/sdl/sdl.h"
+
+namespace InputCommon {
+
+namespace SDL {
+
+class SDLJoystick;
+class SDLButtonFactory;
+class SDLAnalogFactory;
+static std::unordered_map<int, std::weak_ptr<SDLJoystick>> joystick_list;
+static std::shared_ptr<SDLButtonFactory> button_factory;
+static std::shared_ptr<SDLAnalogFactory> analog_factory;
+
+static bool initialized = false;
+
+class SDLJoystick {
+public:
+    explicit SDLJoystick(int joystick_index)
+        : joystick{SDL_JoystickOpen(joystick_index), SDL_JoystickClose} {
+        if (!joystick) {
+            LOG_ERROR(Input, "failed to open joystick %d", joystick_index);
+        }
+    }
+
+    bool GetButton(int button) const {
+        if (!joystick)
+            return {};
+        SDL_JoystickUpdate();
+        return SDL_JoystickGetButton(joystick.get(), button) == 1;
+    }
+
+    std::tuple<float, float> GetAnalog(int axis_x, int axis_y) const {
+        if (!joystick)
+            return {};
+        SDL_JoystickUpdate();
+        float x = SDL_JoystickGetAxis(joystick.get(), axis_x) / 32767.0f;
+        float y = SDL_JoystickGetAxis(joystick.get(), axis_y) / 32767.0f;
+        y = -y; // 3DS uses an y-axis inverse from SDL
+
+        // Make sure the coordinates are in the unit circle,
+        // otherwise normalize it.
+        float r = x * x + y * y;
+        if (r > 1.0f) {
+            r = std::sqrt(r);
+            x /= r;
+            y /= r;
+        }
+
+        return std::make_tuple(x, y);
+    }
+
+    bool GetHatDirection(int hat, Uint8 direction) const {
+        return (SDL_JoystickGetHat(joystick.get(), hat) & direction) != 0;
+    }
+
+private:
+    std::unique_ptr<SDL_Joystick, decltype(&SDL_JoystickClose)> joystick;
+};
+
+class SDLButton final : public Input::ButtonDevice {
+public:
+    explicit SDLButton(std::shared_ptr<SDLJoystick> joystick_, int button_)
+        : joystick(joystick_), button(button_) {}
+
+    bool GetStatus() const override {
+        return joystick->GetButton(button);
+    }
+
+private:
+    std::shared_ptr<SDLJoystick> joystick;
+    int button;
+};
+
+class SDLDirectionButton final : public Input::ButtonDevice {
+public:
+    explicit SDLDirectionButton(std::shared_ptr<SDLJoystick> joystick_, int hat_, Uint8 direction_)
+        : joystick(joystick_), hat(hat_), direction(direction_) {}
+
+    bool GetStatus() const override {
+        return joystick->GetHatDirection(hat, direction);
+    }
+
+private:
+    std::shared_ptr<SDLJoystick> joystick;
+    int hat;
+    Uint8 direction;
+};
+
+class SDLAnalog final : public Input::AnalogDevice {
+public:
+    SDLAnalog(std::shared_ptr<SDLJoystick> joystick_, int axis_x_, int axis_y_)
+        : joystick(joystick_), axis_x(axis_x_), axis_y(axis_y_) {}
+
+    std::tuple<float, float> GetStatus() const override {
+        return joystick->GetAnalog(axis_x, axis_y);
+    }
+
+private:
+    std::shared_ptr<SDLJoystick> joystick;
+    int axis_x;
+    int axis_y;
+};
+
+static std::shared_ptr<SDLJoystick> GetJoystick(int joystick_index) {
+    std::shared_ptr<SDLJoystick> joystick = joystick_list[joystick_index].lock();
+    if (!joystick) {
+        joystick = std::make_shared<SDLJoystick>(joystick_index);
+        joystick_list[joystick_index] = joystick;
+    }
+    return joystick;
+}
+
+/// A button device factory that creates button devices from SDL joystick
+class SDLButtonFactory final : public Input::Factory<Input::ButtonDevice> {
+public:
+    /**
+     * Creates a button device from a joystick button
+     * @param params contains parameters for creating the device:
+     *     - "joystick": the index of the joystick to bind
+     *     - "button"(optional): the index of the button to bind
+     *     - "hat"(optional): the index of the hat to bind as direction buttons
+     *     - "direction"(only used for hat): the direction name of the hat to bind. Can be "up",
+     *                                     "down", "left" or "right"
+     */
+    std::unique_ptr<Input::ButtonDevice> Create(const Common::ParamPackage& params) override {
+        const int joystick_index = params.Get("joystick", 0);
+
+        if (params.Has("hat")) {
+            const int hat = params.Get("hat", 0);
+            const std::string direction_name = params.Get("direction", "");
+            Uint8 direction;
+            if (direction_name == "up") {
+                direction = SDL_HAT_UP;
+            } else if (direction_name == "down") {
+                direction = SDL_HAT_DOWN;
+            } else if (direction_name == "left") {
+                direction = SDL_HAT_LEFT;
+            } else if (direction_name == "right") {
+                direction = SDL_HAT_RIGHT;
+            } else {
+                direction = 0;
+            }
+            return std::make_unique<SDLDirectionButton>(GetJoystick(joystick_index), hat,
+                                                        direction);
+        }
+
+        const int button = params.Get("button", 0);
+        return std::make_unique<SDLButton>(GetJoystick(joystick_index), button);
+    }
+};
+
+/// An analog device factory that creates analog devices from SDL joystick
+class SDLAnalogFactory final : public Input::Factory<Input::AnalogDevice> {
+public:
+    /**
+     * Creates analog device from joystick axes
+     * @param params contains parameters for creating the device:
+     *     - "joystick": the index of the joystick to bind
+     *     - "axis_x": the index of the axis to be bind as x-axis
+     *     - "axis_y": the index of the axis to be bind as y-axis
+     */
+    std::unique_ptr<Input::AnalogDevice> Create(const Common::ParamPackage& params) override {
+        const int joystick_index = params.Get("joystick", 0);
+        const int axis_x = params.Get("axis_x", 0);
+        const int axis_y = params.Get("axis_y", 1);
+        return std::make_unique<SDLAnalog>(GetJoystick(joystick_index), axis_x, axis_y);
+    }
+};
+
+void Init() {
+    if (SDL_Init(SDL_INIT_JOYSTICK) < 0) {
+        LOG_CRITICAL(Input, "SDL_Init(SDL_INIT_JOYSTICK) failed with: %s", SDL_GetError());
+    } else {
+        using namespace Input;
+        RegisterFactory<ButtonDevice>("sdl", std::make_shared<SDLButtonFactory>());
+        RegisterFactory<AnalogDevice>("sdl", std::make_shared<SDLAnalogFactory>());
+        initialized = true;
+    }
+}
+
+void Shutdown() {
+    if (initialized) {
+        using namespace Input;
+        UnregisterFactory<ButtonDevice>("sdl");
+        UnregisterFactory<AnalogDevice>("sdl");
+        SDL_QuitSubSystem(SDL_INIT_JOYSTICK);
+    }
+}
+
+} // namespace SDL
+} // namespace InputCommon
diff --git a/src/input_common/sdl/sdl.h b/src/input_common/sdl/sdl.h
new file mode 100644
index 000000000..3e72debcc
--- /dev/null
+++ b/src/input_common/sdl/sdl.h
@@ -0,0 +1,19 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "core/frontend/input.h"
+
+namespace InputCommon {
+namespace SDL {
+
+/// Initializes and registers SDL device factories
+void Init();
+
+/// Unresisters SDL device factories and shut them down.
+void Shutdown();
+
+} // namespace SDL
+} // namespace InputCommon
-- 
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