Added SDL2 optional checks to CMake + barebones SDL2 input

src/input_common/CMakeLists.txt

@@ -1,3 +1,7 @@
-set(SRCS	input_common.cpp)
+set(SRCS input_common.cpp)
+
+if(SDL2_FOUND)
+    set(SRCS sdl_input/sdl_input.cpp)
+endif()
 
 add_library(input_common STATIC ${SRCS})

src/input_common/sdl_input/sdl_input.cpp

@@ -0,0 +1,46 @@
+// Copyright 2015 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "input_common/sdl_input/sdl_input.h"
+
+namespace InputCommon {
+
+SDLController::SDLController() {
+    name = "SDL2::NONE";
+    j_pad = nullptr;
+    index = 0;
+}
+
+SDLController::~SDLController() {
+    ShutDown();
+}
+
+bool SDLController::Init() {
+
+    //Attempt to initialize SDL with joystick only
+    if(SDL_Init(SDL_INIT_JOYSTICK) != 0) {
+        return false;
+    }
+
+    //Attempt to open joystick with SDL
+    //TODO - Use DiscoverDevice to generate a list of available joysticks, then open the correct index
+    j_pad = SDL_JoystickOpen(index);
+
+    if(j_pad == nullptr) {
+        return false;
+    }
+}
+
+void SDLController::DiscoverDevices() {}
+
+void SDLController::ShutDown() {
+    //Attempt to close joystick with SDL
+    if(j_pad != nullptr) {
+        SDL_JoystickClose(j_pad);
+    }
+}
+
+void SDLController::Poll() {}
+
+}//namespace

src/input_common/sdl_input/sdl_input.h

@@ -0,0 +1,43 @@
+// Copyright 2015 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <SDL2/SDL.h>
+#include <iostream>
+#include "input_common/input_common.h"
+
+namespace InputCommon {
+
+class SDLController  : virtual public ControllerBase {
+public:
+    SDLController();
+    ~SDLController();
+
+    ///Initializes input via SDL2
+    bool Init();
+
+    ///Grabs a list of devices supported by the backend
+    void DiscoverDevices();
+
+    ///Grab and process input via SDL2
+    void Poll();
+
+    ///Shuts down all joysticks opened by SDL2
+    void ShutDown();
+
+    ///SDL event used for polling
+    SDL_Event input_event;
+
+private:
+    std::string name;
+    SDL_Joystick* j_pad;
+
+    ///Index of joystick, used for opening/closing a joystick
+    int index;
+};
+
+} //namespace
+
+