7 files changed, 648 insertions, 2 deletions

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index ccbe7a9ce..3621449b3 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -29,6 +29,8 @@ set(SRCS
             file_sys/ivfc_archive.cpp
             file_sys/path_parser.cpp
             file_sys/savedata_archive.cpp
+            frontend/emu_window.cpp
+            frontend/key_map.cpp
             gdbstub/gdbstub.cpp
             hle/config_mem.cpp
             hle/applets/applet.cpp
@@ -198,6 +200,8 @@ set(HEADERS
             file_sys/ivfc_archive.h
             file_sys/path_parser.h
             file_sys/savedata_archive.h
+            frontend/emu_window.h
+            frontend/key_map.h
             gdbstub/gdbstub.h
             hle/config_mem.h
             hle/function_wrappers.h
diff --git a/src/core/frontend/emu_window.cpp b/src/core/frontend/emu_window.cpp
new file mode 100644
index 000000000..f6f90f9e1
--- /dev/null
+++ b/src/core/frontend/emu_window.cpp
@@ -0,0 +1,107 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <algorithm>
+#include <cmath>
+#include "common/assert.h"
+#include "core/frontend/emu_window.h"
+#include "core/frontend/key_map.h"
+#include "video_core/video_core.h"
+
+void EmuWindow::ButtonPressed(Service::HID::PadState pad) {
+    pad_state.hex |= pad.hex;
+}
+
+void EmuWindow::ButtonReleased(Service::HID::PadState pad) {
+    pad_state.hex &= ~pad.hex;
+}
+
+void EmuWindow::CirclePadUpdated(float x, float y) {
+    constexpr int MAX_CIRCLEPAD_POS = 0x9C; // Max value for a circle pad position
+
+    // Make sure the coordinates are in the unit circle,
+    // otherwise normalize it.
+    float r = x * x + y * y;
+    if (r > 1) {
+        r = std::sqrt(r);
+        x /= r;
+        y /= r;
+    }
+
+    circle_pad_x = static_cast<s16>(x * MAX_CIRCLEPAD_POS);
+    circle_pad_y = static_cast<s16>(y * MAX_CIRCLEPAD_POS);
+}
+
+/**
+ * Check if the given x/y coordinates are within the touchpad specified by the framebuffer layout
+ * @param layout FramebufferLayout object describing the framebuffer size and screen positions
+ * @param framebuffer_x Framebuffer x-coordinate to check
+ * @param framebuffer_y Framebuffer y-coordinate to check
+ * @return True if the coordinates are within the touchpad, otherwise false
+ */
+static bool IsWithinTouchscreen(const Layout::FramebufferLayout& layout, unsigned framebuffer_x,
+                                unsigned framebuffer_y) {
+    return (
+        framebuffer_y >= layout.bottom_screen.top && framebuffer_y < layout.bottom_screen.bottom &&
+        framebuffer_x >= layout.bottom_screen.left && framebuffer_x < layout.bottom_screen.right);
+}
+
+std::tuple<unsigned, unsigned> EmuWindow::ClipToTouchScreen(unsigned new_x, unsigned new_y) {
+    new_x = std::max(new_x, framebuffer_layout.bottom_screen.left);
+    new_x = std::min(new_x, framebuffer_layout.bottom_screen.right - 1);
+
+    new_y = std::max(new_y, framebuffer_layout.bottom_screen.top);
+    new_y = std::min(new_y, framebuffer_layout.bottom_screen.bottom - 1);
+
+    return std::make_tuple(new_x, new_y);
+}
+
+void EmuWindow::TouchPressed(unsigned framebuffer_x, unsigned framebuffer_y) {
+    if (!IsWithinTouchscreen(framebuffer_layout, framebuffer_x, framebuffer_y))
+        return;
+
+    touch_x = VideoCore::kScreenBottomWidth *
+              (framebuffer_x - framebuffer_layout.bottom_screen.left) /
+              (framebuffer_layout.bottom_screen.right - framebuffer_layout.bottom_screen.left);
+    touch_y = VideoCore::kScreenBottomHeight *
+              (framebuffer_y - framebuffer_layout.bottom_screen.top) /
+              (framebuffer_layout.bottom_screen.bottom - framebuffer_layout.bottom_screen.top);
+
+    touch_pressed = true;
+    pad_state.touch.Assign(1);
+}
+
+void EmuWindow::TouchReleased() {
+    touch_pressed = false;
+    touch_x = 0;
+    touch_y = 0;
+    pad_state.touch.Assign(0);
+}
+
+void EmuWindow::TouchMoved(unsigned framebuffer_x, unsigned framebuffer_y) {
+    if (!touch_pressed)
+        return;
+
+    if (!IsWithinTouchscreen(framebuffer_layout, framebuffer_x, framebuffer_y))
+        std::tie(framebuffer_x, framebuffer_y) = ClipToTouchScreen(framebuffer_x, framebuffer_y);
+
+    TouchPressed(framebuffer_x, framebuffer_y);
+}
+
+void EmuWindow::UpdateCurrentFramebufferLayout(unsigned width, unsigned height) {
+    Layout::FramebufferLayout layout;
+    switch (Settings::values.layout_option) {
+    case Settings::LayoutOption::SingleScreen:
+        layout = Layout::SingleFrameLayout(width, height, Settings::values.swap_screen);
+        break;
+    case Settings::LayoutOption::LargeScreen:
+        layout = Layout::LargeFrameLayout(width, height, Settings::values.swap_screen);
+        break;
+    case Settings::LayoutOption::Default:
+    default:
+        layout = Layout::DefaultFrameLayout(width, height, Settings::values.swap_screen);
+        break;
+    }
+    NotifyFramebufferLayoutChanged(layout);
+}
diff --git a/src/core/frontend/emu_window.h b/src/core/frontend/emu_window.h
new file mode 100644
index 000000000..835c4d500
--- /dev/null
+++ b/src/core/frontend/emu_window.h
@@ -0,0 +1,290 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <tuple>
+#include <utility>
+#include "common/common_types.h"
+#include "common/framebuffer_layout.h"
+#include "common/math_util.h"
+#include "core/hle/service/hid/hid.h"
+
+/**
+ * Abstraction class used to provide an interface between emulation code and the frontend
+ * (e.g. SDL, QGLWidget, GLFW, etc...).
+ *
+ * Design notes on the interaction between EmuWindow and the emulation core:
+ * - Generally, decisions on anything visible to the user should be left up to the GUI.
+ *   For example, the emulation core should not try to dictate some window title or size.
+ *   This stuff is not the core's business and only causes problems with regards to thread-safety
+ *   anyway.
+ * - Under certain circumstances, it may be desirable for the core to politely request the GUI
+ *   to set e.g. a minimum window size. However, the GUI should always be free to ignore any
+ *   such hints.
+ * - EmuWindow may expose some of its state as read-only to the emulation core, however care
+ *   should be taken to make sure the provided information is self-consistent. This requires
+ *   some sort of synchronization (most of this is still a TODO).
+ * - DO NOT TREAT THIS CLASS AS A GUI TOOLKIT ABSTRACTION LAYER. That's not what it is. Please
+ *   re-read the upper points again and think about it if you don't see this.
+ */
+class EmuWindow {
+public:
+    /// Data structure to store emuwindow configuration
+    struct WindowConfig {
+        bool fullscreen;
+        int res_width;
+        int res_height;
+        std::pair<unsigned, unsigned> min_client_area_size;
+    };
+
+    /// Swap buffers to display the next frame
+    virtual void SwapBuffers() = 0;
+
+    /// Polls window events
+    virtual void PollEvents() = 0;
+
+    /// Makes the graphics context current for the caller thread
+    virtual void MakeCurrent() = 0;
+
+    /// Releases (dunno if this is the "right" word) the GLFW context from the caller thread
+    virtual void DoneCurrent() = 0;
+
+    virtual void ReloadSetKeymaps() = 0;
+
+    /**
+     * Signals a button press action to the HID module.
+     * @param pad_state indicates which button to press
+     * @note only handles real buttons (A/B/X/Y/...), excluding analog inputs like the circle pad.
+     */
+    void ButtonPressed(Service::HID::PadState pad_state);
+
+    /**
+     * Signals a button release action to the HID module.
+     * @param pad_state indicates which button to press
+     * @note only handles real buttons (A/B/X/Y/...), excluding analog inputs like the circle pad.
+     */
+    void ButtonReleased(Service::HID::PadState pad_state);
+
+    /**
+     * Signals a circle pad change action to the HID module.
+     * @param x new x-coordinate of the circle pad, in the range [-1.0, 1.0]
+     * @param y new y-coordinate of the circle pad, in the range [-1.0, 1.0]
+     * @note the coordinates will be normalized if the radius is larger than 1
+     */
+    void CirclePadUpdated(float x, float y);
+
+    /**
+     * Signal that a touch pressed event has occurred (e.g. mouse click pressed)
+     * @param framebuffer_x Framebuffer x-coordinate that was pressed
+     * @param framebuffer_y Framebuffer y-coordinate that was pressed
+     */
+    void TouchPressed(unsigned framebuffer_x, unsigned framebuffer_y);
+
+    /// Signal that a touch released event has occurred (e.g. mouse click released)
+    void TouchReleased();
+
+    /**
+     * Signal that a touch movement event has occurred (e.g. mouse was moved over the emu window)
+     * @param framebuffer_x Framebuffer x-coordinate
+     * @param framebuffer_y Framebuffer y-coordinate
+     */
+    void TouchMoved(unsigned framebuffer_x, unsigned framebuffer_y);
+
+    /**
+     * Gets the current pad state (which buttons are pressed).
+     * @note This should be called by the core emu thread to get a state set by the window thread.
+     * @note This doesn't include analog input like circle pad direction
+     * @todo Fix this function to be thread-safe.
+     * @return PadState object indicating the current pad state
+     */
+    Service::HID::PadState GetPadState() const {
+        return pad_state;
+    }
+
+    /**
+     * Gets the current circle pad state.
+     * @note This should be called by the core emu thread to get a state set by the window thread.
+     * @todo Fix this function to be thread-safe.
+     * @return std::tuple of (x, y), where `x` and `y` are the circle pad coordinates
+     */
+    std::tuple<s16, s16> GetCirclePadState() const {
+        return std::make_tuple(circle_pad_x, circle_pad_y);
+    }
+
+    /**
+     * Gets the current touch screen state (touch X/Y coordinates and whether or not it is pressed).
+     * @note This should be called by the core emu thread to get a state set by the window thread.
+     * @todo Fix this function to be thread-safe.
+     * @return std::tuple of (x, y, pressed) where `x` and `y` are the touch coordinates and
+     *         `pressed` is true if the touch screen is currently being pressed
+     */
+    std::tuple<u16, u16, bool> GetTouchState() const {
+        return std::make_tuple(touch_x, touch_y, touch_pressed);
+    }
+
+    /**
+     * Gets the current accelerometer state (acceleration along each three axis).
+     * Axis explained:
+     *   +x is the same direction as LEFT on D-pad.
+     *   +y is normal to the touch screen, pointing outward.
+     *   +z is the same direction as UP on D-pad.
+     * Units:
+     *   1 unit of return value = 1/512 g (measured by hw test),
+     *   where g is the gravitational acceleration (9.8 m/sec2).
+     * @note This should be called by the core emu thread to get a state set by the window thread.
+     * @todo Implement accelerometer input in front-end.
+     * @return std::tuple of (x, y, z)
+     */
+    std::tuple<s16, s16, s16> GetAccelerometerState() const {
+        // stubbed
+        return std::make_tuple(0, -512, 0);
+    }
+
+    /**
+     * Gets the current gyroscope state (angular rates about each three axis).
+     * Axis explained:
+     *   +x is the same direction as LEFT on D-pad.
+     *   +y is normal to the touch screen, pointing outward.
+     *   +z is the same direction as UP on D-pad.
+     * Orientation is determined by right-hand rule.
+     * Units:
+     *   1 unit of return value = (1/coef) deg/sec,
+     *   where coef is the return value of GetGyroscopeRawToDpsCoefficient().
+     * @note This should be called by the core emu thread to get a state set by the window thread.
+     * @todo Implement gyroscope input in front-end.
+     * @return std::tuple of (x, y, z)
+     */
+    std::tuple<s16, s16, s16> GetGyroscopeState() const {
+        // stubbed
+        return std::make_tuple(0, 0, 0);
+    }
+
+    /**
+     * Gets the coefficient for units conversion of gyroscope state.
+     * The conversion formula is r = coefficient * v,
+     * where v is angular rate in deg/sec,
+     * and r is the gyroscope state.
+     * @return float-type coefficient
+     */
+    f32 GetGyroscopeRawToDpsCoefficient() const {
+        return 14.375f; // taken from hw test, and gyroscope's document
+    }
+
+    /**
+     * Returns currently active configuration.
+     * @note Accesses to the returned object need not be consistent because it may be modified in
+     * another thread
+     */
+    const WindowConfig& GetActiveConfig() const {
+        return active_config;
+    }
+
+    /**
+     * Requests the internal configuration to be replaced by the specified argument at some point in
+     * the future.
+     * @note This method is thread-safe, because it delays configuration changes to the GUI event
+     * loop. Hence there is no guarantee on when the requested configuration will be active.
+     */
+    void SetConfig(const WindowConfig& val) {
+        config = val;
+    }
+
+    /**
+      * Gets the framebuffer layout (width, height, and screen regions)
+      * @note This method is thread-safe
+      */
+    const Layout::FramebufferLayout& GetFramebufferLayout() const {
+        return framebuffer_layout;
+    }
+
+    /**
+     * Convenience method to update the current frame layout
+     * Read from the current settings to determine which layout to use.
+     */
+    void UpdateCurrentFramebufferLayout(unsigned width, unsigned height);
+
+protected:
+    EmuWindow() {
+        // TODO: Find a better place to set this.
+        config.min_client_area_size = std::make_pair(400u, 480u);
+        active_config = config;
+        pad_state.hex = 0;
+        touch_x = 0;
+        touch_y = 0;
+        circle_pad_x = 0;
+        circle_pad_y = 0;
+        touch_pressed = false;
+    }
+    virtual ~EmuWindow() {}
+
+    /**
+     * Processes any pending configuration changes from the last SetConfig call.
+     * This method invokes OnMinimalClientAreaChangeRequest if the corresponding configuration
+     * field changed.
+     * @note Implementations will usually want to call this from the GUI thread.
+     * @todo Actually call this in existing implementations.
+     */
+    void ProcessConfigurationChanges() {
+        // TODO: For proper thread safety, we should eventually implement a proper
+        // multiple-writer/single-reader queue...
+
+        if (config.min_client_area_size != active_config.min_client_area_size) {
+            OnMinimalClientAreaChangeRequest(config.min_client_area_size);
+            config.min_client_area_size = active_config.min_client_area_size;
+        }
+    }
+
+    /**
+     * Update framebuffer layout with the given parameter.
+     * @note EmuWindow implementations will usually use this in window resize event handlers.
+     */
+    void NotifyFramebufferLayoutChanged(const Layout::FramebufferLayout& layout) {
+        framebuffer_layout = layout;
+    }
+
+    /**
+     * Update internal client area size with the given parameter.
+     * @note EmuWindow implementations will usually use this in window resize event handlers.
+     */
+    void NotifyClientAreaSizeChanged(const std::pair<unsigned, unsigned>& size) {
+        client_area_width = size.first;
+        client_area_height = size.second;
+    }
+
+private:
+    /**
+     * Handler called when the minimal client area was requested to be changed via SetConfig.
+     * For the request to be honored, EmuWindow implementations will usually reimplement this
+     * function.
+     */
+    virtual void OnMinimalClientAreaChangeRequest(
+        const std::pair<unsigned, unsigned>& minimal_size) {
+        // By default, ignore this request and do nothing.
+    }
+
+    Layout::FramebufferLayout framebuffer_layout; ///< Current framebuffer layout
+
+    unsigned client_area_width;  ///< Current client width, should be set by window impl.
+    unsigned client_area_height; ///< Current client height, should be set by window impl.
+
+    WindowConfig config;        ///< Internal configuration (changes pending for being applied in
+                                /// ProcessConfigurationChanges)
+    WindowConfig active_config; ///< Internal active configuration
+
+    bool touch_pressed; ///< True if touchpad area is currently pressed, otherwise false
+
+    u16 touch_x; ///< Touchpad X-position in native 3DS pixel coordinates (0-320)
+    u16 touch_y; ///< Touchpad Y-position in native 3DS pixel coordinates (0-240)
+
+    s16 circle_pad_x; ///< Circle pad X-position in native 3DS pixel coordinates (-156 - 156)
+    s16 circle_pad_y; ///< Circle pad Y-position in native 3DS pixel coordinates (-156 - 156)
+
+    /**
+     * Clip the provided coordinates to be inside the touchscreen area.
+     */
+    std::tuple<unsigned, unsigned> ClipToTouchScreen(unsigned new_x, unsigned new_y);
+
+    Service::HID::PadState pad_state;
+};
diff --git a/src/core/frontend/key_map.cpp b/src/core/frontend/key_map.cpp
new file mode 100644
index 000000000..15f0e079c
--- /dev/null
+++ b/src/core/frontend/key_map.cpp
@@ -0,0 +1,152 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <map>
+#include "core/frontend/emu_window.h"
+#include "core/frontend/key_map.h"
+
+namespace KeyMap {
+
+// TODO (wwylele): currently we treat c-stick as four direction buttons
+//     and map it directly to EmuWindow::ButtonPressed.
+//     It should go the analog input way like circle pad does.
+const std::array<KeyTarget, Settings::NativeInput::NUM_INPUTS> mapping_targets = {{
+    Service::HID::PAD_A,
+    Service::HID::PAD_B,
+    Service::HID::PAD_X,
+    Service::HID::PAD_Y,
+    Service::HID::PAD_L,
+    Service::HID::PAD_R,
+    Service::HID::PAD_ZL,
+    Service::HID::PAD_ZR,
+    Service::HID::PAD_START,
+    Service::HID::PAD_SELECT,
+    Service::HID::PAD_NONE,
+    Service::HID::PAD_UP,
+    Service::HID::PAD_DOWN,
+    Service::HID::PAD_LEFT,
+    Service::HID::PAD_RIGHT,
+    Service::HID::PAD_C_UP,
+    Service::HID::PAD_C_DOWN,
+    Service::HID::PAD_C_LEFT,
+    Service::HID::PAD_C_RIGHT,
+
+    IndirectTarget::CirclePadUp,
+    IndirectTarget::CirclePadDown,
+    IndirectTarget::CirclePadLeft,
+    IndirectTarget::CirclePadRight,
+    IndirectTarget::CirclePadModifier,
+}};
+
+static std::map<HostDeviceKey, KeyTarget> key_map;
+static int next_device_id = 0;
+
+static bool circle_pad_up = false;
+static bool circle_pad_down = false;
+static bool circle_pad_left = false;
+static bool circle_pad_right = false;
+static bool circle_pad_modifier = false;
+
+static void UpdateCirclePad(EmuWindow& emu_window) {
+    constexpr float SQRT_HALF = 0.707106781f;
+    int x = 0, y = 0;
+
+    if (circle_pad_right)
+        ++x;
+    if (circle_pad_left)
+        --x;
+    if (circle_pad_up)
+        ++y;
+    if (circle_pad_down)
+        --y;
+
+    float modifier = circle_pad_modifier ? Settings::values.pad_circle_modifier_scale : 1.0f;
+    emu_window.CirclePadUpdated(x * modifier * (y == 0 ? 1.0f : SQRT_HALF),
+                                y * modifier * (x == 0 ? 1.0f : SQRT_HALF));
+}
+
+int NewDeviceId() {
+    return next_device_id++;
+}
+
+void SetKeyMapping(HostDeviceKey key, KeyTarget target) {
+    key_map[key] = target;
+}
+
+void ClearKeyMapping(int device_id) {
+    auto iter = key_map.begin();
+    while (iter != key_map.end()) {
+        if (iter->first.device_id == device_id)
+            key_map.erase(iter++);
+        else
+            ++iter;
+    }
+}
+
+void PressKey(EmuWindow& emu_window, HostDeviceKey key) {
+    auto target = key_map.find(key);
+    if (target == key_map.end())
+        return;
+
+    if (target->second.direct) {
+        emu_window.ButtonPressed({{target->second.target.direct_target_hex}});
+    } else {
+        switch (target->second.target.indirect_target) {
+        case IndirectTarget::CirclePadUp:
+            circle_pad_up = true;
+            UpdateCirclePad(emu_window);
+            break;
+        case IndirectTarget::CirclePadDown:
+            circle_pad_down = true;
+            UpdateCirclePad(emu_window);
+            break;
+        case IndirectTarget::CirclePadLeft:
+            circle_pad_left = true;
+            UpdateCirclePad(emu_window);
+            break;
+        case IndirectTarget::CirclePadRight:
+            circle_pad_right = true;
+            UpdateCirclePad(emu_window);
+            break;
+        case IndirectTarget::CirclePadModifier:
+            circle_pad_modifier = true;
+            UpdateCirclePad(emu_window);
+            break;
+        }
+    }
+}
+
+void ReleaseKey(EmuWindow& emu_window, HostDeviceKey key) {
+    auto target = key_map.find(key);
+    if (target == key_map.end())
+        return;
+
+    if (target->second.direct) {
+        emu_window.ButtonReleased({{target->second.target.direct_target_hex}});
+    } else {
+        switch (target->second.target.indirect_target) {
+        case IndirectTarget::CirclePadUp:
+            circle_pad_up = false;
+            UpdateCirclePad(emu_window);
+            break;
+        case IndirectTarget::CirclePadDown:
+            circle_pad_down = false;
+            UpdateCirclePad(emu_window);
+            break;
+        case IndirectTarget::CirclePadLeft:
+            circle_pad_left = false;
+            UpdateCirclePad(emu_window);
+            break;
+        case IndirectTarget::CirclePadRight:
+            circle_pad_right = false;
+            UpdateCirclePad(emu_window);
+            break;
+        case IndirectTarget::CirclePadModifier:
+            circle_pad_modifier = false;
+            UpdateCirclePad(emu_window);
+            break;
+        }
+    }
+}
+}
diff --git a/src/core/frontend/key_map.h b/src/core/frontend/key_map.h
new file mode 100644
index 000000000..040794578
--- /dev/null
+++ b/src/core/frontend/key_map.h
@@ -0,0 +1,93 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <array>
+#include <tuple>
+#include "core/hle/service/hid/hid.h"
+
+class EmuWindow;
+
+namespace KeyMap {
+
+/**
+ * Represents key mapping targets that are not real 3DS buttons.
+ * They will be handled by KeyMap and translated to 3DS input.
+ */
+enum class IndirectTarget {
+    CirclePadUp,
+    CirclePadDown,
+    CirclePadLeft,
+    CirclePadRight,
+    CirclePadModifier,
+};
+
+/**
+ * Represents a key mapping target. It can be a PadState that represents real 3DS buttons,
+ * or an IndirectTarget.
+ */
+struct KeyTarget {
+    bool direct;
+    union {
+        u32 direct_target_hex;
+        IndirectTarget indirect_target;
+    } target;
+
+    KeyTarget() : direct(true) {
+        target.direct_target_hex = 0;
+    }
+
+    KeyTarget(Service::HID::PadState pad) : direct(true) {
+        target.direct_target_hex = pad.hex;
+    }
+
+    KeyTarget(IndirectTarget i) : direct(false) {
+        target.indirect_target = i;
+    }
+};
+
+/**
+ * Represents a key for a specific host device.
+ */
+struct HostDeviceKey {
+    int key_code;
+    int device_id; ///< Uniquely identifies a host device
+
+    bool operator<(const HostDeviceKey& other) const {
+        return std::tie(key_code, device_id) < std::tie(other.key_code, other.device_id);
+    }
+
+    bool operator==(const HostDeviceKey& other) const {
+        return std::tie(key_code, device_id) == std::tie(other.key_code, other.device_id);
+    }
+};
+
+extern const std::array<KeyTarget, Settings::NativeInput::NUM_INPUTS> mapping_targets;
+
+/**
+ * Generates a new device id, which uniquely identifies a host device within KeyMap.
+ */
+int NewDeviceId();
+
+/**
+ * Maps a device-specific key to a target (a PadState or an IndirectTarget).
+ */
+void SetKeyMapping(HostDeviceKey key, KeyTarget target);
+
+/**
+ * Clears all key mappings belonging to one device.
+ */
+void ClearKeyMapping(int device_id);
+
+/**
+ * Maps a key press action and call the corresponding function in EmuWindow
+ */
+void PressKey(EmuWindow& emu_window, HostDeviceKey key);
+
+/**
+ * Maps a key release action and call the corresponding function in EmuWindow
+ */
+void ReleaseKey(EmuWindow& emu_window, HostDeviceKey key);
+}
diff --git a/src/core/hle/service/hid/hid.cpp b/src/core/hle/service/hid/hid.cpp
index 18a1b6a16..676154bd4 100644
--- a/src/core/hle/service/hid/hid.cpp
+++ b/src/core/hle/service/hid/hid.cpp
@@ -3,9 +3,9 @@
 // Refer to the license.txt file included.
 
 #include <cmath>
-#include "common/emu_window.h"
 #include "common/logging/log.h"
 #include "core/core_timing.h"
+#include "core/frontend/emu_window.h"
 #include "core/hle/kernel/event.h"
 #include "core/hle/kernel/shared_memory.h"
 #include "core/hle/service/hid/hid.h"
diff --git a/src/core/settings.cpp b/src/core/settings.cpp
index 626e06cd9..5d23c52f9 100644
--- a/src/core/settings.cpp
+++ b/src/core/settings.cpp
@@ -7,7 +7,7 @@
 #include "settings.h"
 #include "video_core/video_core.h"
 
-#include "common/emu_window.h"
+#include "core/frontend/emu_window.h"
 
 namespace Settings {