imgui/backends/imgui_impl_glfw.cpp

// dear imgui: Platform Backend for GLFW
// This needs to be used along with a Renderer (e.g. OpenGL3, Vulkan, WebGPU..)
// (Info: GLFW is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan graphics context creation, etc.)
// (Requires: GLFW 3.1+)

// Implemented features:
//  [X] Platform: Clipboard support.
//  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy GLFW_KEY_* values will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
//  [X] Platform: Gamepad support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
//  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange' (note: the resizing cursors requires GLFW 3.4+).

// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
// Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
// If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
// Read online: https://github.com/ocornut/imgui/tree/master/docs

// CHANGELOG
// (minor and older changes stripped away, please see git history for details)
//  2022-02-07: Added ImGui_ImplGlfw_InstallCallbacks()/ImGui_ImplGlfw_RestoreCallbacks() helpers to facilitate user installing callbacks after iniitializing backend.
//  2022-01-26: Inputs: replaced short-lived io.AddKeyModsEvent() (added two weeks ago)with io.AddKeyEvent() using ImGuiKey_ModXXX flags. Sorry for the confusion.
//  2021-01-20: Inputs: calling new io.AddKeyAnalogEvent() for gamepad support, instead of writing directly to io.NavInputs[].
//  2022-01-17: Inputs: calling new io.AddMousePosEvent(), io.AddMouseButtonEvent(), io.AddMouseWheelEvent() API (1.87+).
//  2022-01-17: Inputs: always update key mods next and before key event (not in NewFrame) to fix input queue with very low framerates.
//  2022-01-12: *BREAKING CHANGE*: Now using glfwSetCursorPosCallback(). If you called ImGui_ImplGlfw_InitXXX() with install_callbacks = false, you MUST install glfwSetCursorPosCallback() and forward it to the backend via ImGui_ImplGlfw_CursorPosCallback().
//  2022-01-10: Inputs: calling new io.AddKeyEvent(), io.AddKeyModsEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
//  2022-01-05: Inputs: Converting GLFW untranslated keycodes back to translated keycodes (in the ImGui_ImplGlfw_KeyCallback() function) in order to match the behavior of every other backend, and facilitate the use of GLFW with lettered-shortcuts API.
//  2021-08-17: *BREAKING CHANGE*: Now using glfwSetWindowFocusCallback() to calling io.AddFocusEvent(). If you called ImGui_ImplGlfw_InitXXX() with install_callbacks = false, you MUST install glfwSetWindowFocusCallback() and forward it to the backend via ImGui_ImplGlfw_WindowFocusCallback().
//  2021-07-29: *BREAKING CHANGE*: Now using glfwSetCursorEnterCallback(). MousePos is correctly reported when the host platform window is hovered but not focused. If you called ImGui_ImplGlfw_InitXXX() with install_callbacks = false, you MUST install glfwSetWindowFocusCallback() callback and forward it to the backend via ImGui_ImplGlfw_CursorEnterCallback().
//  2021-06-29: Reorganized backend to pull data from a single structure to facilitate usage with multiple-contexts (all g_XXXX access changed to bd->XXXX).
//  2020-01-17: Inputs: Disable error callback while assigning mouse cursors because some X11 setup don't have them and it generates errors.
//  2019-12-05: Inputs: Added support for new mouse cursors added in GLFW 3.4+ (resizing cursors, not allowed cursor).
//  2019-10-18: Misc: Previously installed user callbacks are now restored on shutdown.
//  2019-07-21: Inputs: Added mapping for ImGuiKey_KeyPadEnter.
//  2019-05-11: Inputs: Don't filter value from character callback before calling AddInputCharacter().
//  2019-03-12: Misc: Preserve DisplayFramebufferScale when main window is minimized.
//  2018-11-30: Misc: Setting up io.BackendPlatformName so it can be displayed in the About Window.
//  2018-11-07: Inputs: When installing our GLFW callbacks, we save user's previously installed ones - if any - and chain call them.
//  2018-08-01: Inputs: Workaround for Emscripten which doesn't seem to handle focus related calls.
//  2018-06-29: Inputs: Added support for the ImGuiMouseCursor_Hand cursor.
//  2018-06-08: Misc: Extracted imgui_impl_glfw.cpp/.h away from the old combined GLFW+OpenGL/Vulkan examples.
//  2018-03-20: Misc: Setup io.BackendFlags ImGuiBackendFlags_HasMouseCursors flag + honor ImGuiConfigFlags_NoMouseCursorChange flag.
//  2018-02-20: Inputs: Added support for mouse cursors (ImGui::GetMouseCursor() value, passed to glfwSetCursor()).
//  2018-02-06: Misc: Removed call to ImGui::Shutdown() which is not available from 1.60 WIP, user needs to call CreateContext/DestroyContext themselves.
//  2018-02-06: Inputs: Added mapping for ImGuiKey_Space.
//  2018-01-25: Inputs: Added gamepad support if ImGuiConfigFlags_NavEnableGamepad is set.
//  2018-01-25: Inputs: Honoring the io.WantSetMousePos by repositioning the mouse (when using navigation and ImGuiConfigFlags_NavMoveMouse is set).
//  2018-01-20: Inputs: Added Horizontal Mouse Wheel support.
//  2018-01-18: Inputs: Added mapping for ImGuiKey_Insert.
//  2017-08-25: Inputs: MousePos set to -FLT_MAX,-FLT_MAX when mouse is unavailable/missing (instead of -1,-1).
//  2016-10-15: Misc: Added a void* user_data parameter to Clipboard function handlers.

#include "imgui.h"
#include "imgui_impl_glfw.h"

// Clang warnings with -Weverything
#if defined(__clang__)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wold-style-cast"     // warning: use of old-style cast
#pragma clang diagnostic ignored "-Wsign-conversion"    // warning: implicit conversion changes signedness
#if __has_warning("-Wzero-as-null-pointer-constant")
#pragma clang diagnostic ignored "-Wzero-as-null-pointer-constant"
#endif
#endif

// GLFW
#include <GLFW/glfw3.h>
#ifdef _WIN32
#undef APIENTRY
#define GLFW_EXPOSE_NATIVE_WIN32
#include <GLFW/glfw3native.h>   // for glfwGetWin32Window
#endif
#ifdef GLFW_RESIZE_NESW_CURSOR        // Let's be nice to people who pulled GLFW between 2019-04-16 (3.4 define) and 2019-11-29 (cursors defines) // FIXME: Remove when GLFW 3.4 is released?
#define GLFW_HAS_NEW_CURSORS          (GLFW_VERSION_MAJOR * 1000 + GLFW_VERSION_MINOR * 100 >= 3400) // 3.4+ GLFW_RESIZE_ALL_CURSOR, GLFW_RESIZE_NESW_CURSOR, GLFW_RESIZE_NWSE_CURSOR, GLFW_NOT_ALLOWED_CURSOR
#else
#define GLFW_HAS_NEW_CURSORS          (0)
#endif
#define GLFW_HAS_GAMEPAD_API          (GLFW_VERSION_MAJOR * 1000 + GLFW_VERSION_MINOR * 100 >= 3300) // 3.3+ glfwGetGamepadState() new api
#define GLFW_HAS_GET_KEY_NAME         (GLFW_VERSION_MAJOR * 1000 + GLFW_VERSION_MINOR * 100 >= 3200) // 3.2+ glfwGetKeyName()

// GLFW data
enum GlfwClientApi
{
    GlfwClientApi_Unknown,
    GlfwClientApi_OpenGL,
    GlfwClientApi_Vulkan
};

struct ImGui_ImplGlfw_Data
{
    GLFWwindow*             Window;
    GlfwClientApi           ClientApi;
    double                  Time;
    GLFWwindow*             MouseWindow;
    GLFWcursor*             MouseCursors[ImGuiMouseCursor_COUNT];
    ImVec2                  LastValidMousePos;
    bool                    InstalledCallbacks;

    // Chain GLFW callbacks: our callbacks will call the user's previously installed callbacks, if any.
    GLFWwindowfocusfun      PrevUserCallbackWindowFocus;
    GLFWcursorposfun        PrevUserCallbackCursorPos;
    GLFWcursorenterfun      PrevUserCallbackCursorEnter;
    GLFWmousebuttonfun      PrevUserCallbackMousebutton;
    GLFWscrollfun           PrevUserCallbackScroll;
    GLFWkeyfun              PrevUserCallbackKey;
    GLFWcharfun             PrevUserCallbackChar;
    GLFWmonitorfun          PrevUserCallbackMonitor;

    ImGui_ImplGlfw_Data()   { memset(this, 0, sizeof(*this)); }
};

// Backend data stored in io.BackendPlatformUserData to allow support for multiple Dear ImGui contexts
// It is STRONGLY preferred that you use docking branch with multi-viewports (== single Dear ImGui context + multiple windows) instead of multiple Dear ImGui contexts.
// FIXME: multi-context support is not well tested and probably dysfunctional in this backend.
// - Because glfwPollEvents() process all windows and some events may be called outside of it, you will need to register your own callbacks
//   (passing install_callbacks=false in ImGui_ImplGlfw_InitXXX functions), set the current dear imgui context and then call our callbacks.
// - Otherwise we may need to store a GLFWWindow* -> ImGuiContext* map and handle this in the backend, adding a little bit of extra complexity to it.
// FIXME: some shared resources (mouse cursor shape, gamepad) are mishandled when using multi-context.
static ImGui_ImplGlfw_Data* ImGui_ImplGlfw_GetBackendData()
{
    return ImGui::GetCurrentContext() ? (ImGui_ImplGlfw_Data*)ImGui::GetIO().BackendPlatformUserData : NULL;
}

// Functions
static const char* ImGui_ImplGlfw_GetClipboardText(void* user_data)
{
    return glfwGetClipboardString((GLFWwindow*)user_data);
}

static void ImGui_ImplGlfw_SetClipboardText(void* user_data, const char* text)
{
    glfwSetClipboardString((GLFWwindow*)user_data, text);
}

static ImGuiKey ImGui_ImplGlfw_KeyToImGuiKey(int key)
{
    switch (key)
    {
        case GLFW_KEY_TAB: return ImGuiKey_Tab;
        case GLFW_KEY_LEFT: return ImGuiKey_LeftArrow;
        case GLFW_KEY_RIGHT: return ImGuiKey_RightArrow;
        case GLFW_KEY_UP: return ImGuiKey_UpArrow;
        case GLFW_KEY_DOWN: return ImGuiKey_DownArrow;
        case GLFW_KEY_PAGE_UP: return ImGuiKey_PageUp;
        case GLFW_KEY_PAGE_DOWN: return ImGuiKey_PageDown;
        case GLFW_KEY_HOME: return ImGuiKey_Home;
        case GLFW_KEY_END: return ImGuiKey_End;
        case GLFW_KEY_INSERT: return ImGuiKey_Insert;
        case GLFW_KEY_DELETE: return ImGuiKey_Delete;
        case GLFW_KEY_BACKSPACE: return ImGuiKey_Backspace;
        case GLFW_KEY_SPACE: return ImGuiKey_Space;
        case GLFW_KEY_ENTER: return ImGuiKey_Enter;
        case GLFW_KEY_ESCAPE: return ImGuiKey_Escape;
        case GLFW_KEY_APOSTROPHE: return ImGuiKey_Apostrophe;
        case GLFW_KEY_COMMA: return ImGuiKey_Comma;
        case GLFW_KEY_MINUS: return ImGuiKey_Minus;
        case GLFW_KEY_PERIOD: return ImGuiKey_Period;
        case GLFW_KEY_SLASH: return ImGuiKey_Slash;
        case GLFW_KEY_SEMICOLON: return ImGuiKey_Semicolon;
        case GLFW_KEY_EQUAL: return ImGuiKey_Equal;
        case GLFW_KEY_LEFT_BRACKET: return ImGuiKey_LeftBracket;
        case GLFW_KEY_BACKSLASH: return ImGuiKey_Backslash;
        case GLFW_KEY_RIGHT_BRACKET: return ImGuiKey_RightBracket;
        case GLFW_KEY_GRAVE_ACCENT: return ImGuiKey_GraveAccent;
        case GLFW_KEY_CAPS_LOCK: return ImGuiKey_CapsLock;
        case GLFW_KEY_SCROLL_LOCK: return ImGuiKey_ScrollLock;
        case GLFW_KEY_NUM_LOCK: return ImGuiKey_NumLock;
        case GLFW_KEY_PRINT_SCREEN: return ImGuiKey_PrintScreen;
        case GLFW_KEY_PAUSE: return ImGuiKey_Pause;
        case GLFW_KEY_KP_0: return ImGuiKey_Keypad0;
        case GLFW_KEY_KP_1: return ImGuiKey_Keypad1;
        case GLFW_KEY_KP_2: return ImGuiKey_Keypad2;
        case GLFW_KEY_KP_3: return ImGuiKey_Keypad3;
        case GLFW_KEY_KP_4: return ImGuiKey_Keypad4;
        case GLFW_KEY_KP_5: return ImGuiKey_Keypad5;
        case GLFW_KEY_KP_6: return ImGuiKey_Keypad6;
        case GLFW_KEY_KP_7: return ImGuiKey_Keypad7;
        case GLFW_KEY_KP_8: return ImGuiKey_Keypad8;
        case GLFW_KEY_KP_9: return ImGuiKey_Keypad9;
        case GLFW_KEY_KP_DECIMAL: return ImGuiKey_KeypadDecimal;
        case GLFW_KEY_KP_DIVIDE: return ImGuiKey_KeypadDivide;
        case GLFW_KEY_KP_MULTIPLY: return ImGuiKey_KeypadMultiply;
        case GLFW_KEY_KP_SUBTRACT: return ImGuiKey_KeypadSubtract;
        case GLFW_KEY_KP_ADD: return ImGuiKey_KeypadAdd;
        case GLFW_KEY_KP_ENTER: return ImGuiKey_KeypadEnter;
        case GLFW_KEY_KP_EQUAL: return ImGuiKey_KeypadEqual;
        case GLFW_KEY_LEFT_SHIFT: return ImGuiKey_LeftShift;
        case GLFW_KEY_LEFT_CONTROL: return ImGuiKey_LeftCtrl;
        case GLFW_KEY_LEFT_ALT: return ImGuiKey_LeftAlt;
        case GLFW_KEY_LEFT_SUPER: return ImGuiKey_LeftSuper;
        case GLFW_KEY_RIGHT_SHIFT: return ImGuiKey_RightShift;
        case GLFW_KEY_RIGHT_CONTROL: return ImGuiKey_RightCtrl;
        case GLFW_KEY_RIGHT_ALT: return ImGuiKey_RightAlt;
        case GLFW_KEY_RIGHT_SUPER: return ImGuiKey_RightSuper;
        case GLFW_KEY_MENU: return ImGuiKey_Menu;
        case GLFW_KEY_0: return ImGuiKey_0;
        case GLFW_KEY_1: return ImGuiKey_1;
        case GLFW_KEY_2: return ImGuiKey_2;
        case GLFW_KEY_3: return ImGuiKey_3;
        case GLFW_KEY_4: return ImGuiKey_4;
        case GLFW_KEY_5: return ImGuiKey_5;
        case GLFW_KEY_6: return ImGuiKey_6;
        case GLFW_KEY_7: return ImGuiKey_7;
        case GLFW_KEY_8: return ImGuiKey_8;
        case GLFW_KEY_9: return ImGuiKey_9;
        case GLFW_KEY_A: return ImGuiKey_A;
        case GLFW_KEY_B: return ImGuiKey_B;
        case GLFW_KEY_C: return ImGuiKey_C;
        case GLFW_KEY_D: return ImGuiKey_D;
        case GLFW_KEY_E: return ImGuiKey_E;
        case GLFW_KEY_F: return ImGuiKey_F;
        case GLFW_KEY_G: return ImGuiKey_G;
        case GLFW_KEY_H: return ImGuiKey_H;
        case GLFW_KEY_I: return ImGuiKey_I;
        case GLFW_KEY_J: return ImGuiKey_J;
        case GLFW_KEY_K: return ImGuiKey_K;
        case GLFW_KEY_L: return ImGuiKey_L;
        case GLFW_KEY_M: return ImGuiKey_M;
        case GLFW_KEY_N: return ImGuiKey_N;
        case GLFW_KEY_O: return ImGuiKey_O;
        case GLFW_KEY_P: return ImGuiKey_P;
        case GLFW_KEY_Q: return ImGuiKey_Q;
        case GLFW_KEY_R: return ImGuiKey_R;
        case GLFW_KEY_S: return ImGuiKey_S;
        case GLFW_KEY_T: return ImGuiKey_T;
        case GLFW_KEY_U: return ImGuiKey_U;
        case GLFW_KEY_V: return ImGuiKey_V;
        case GLFW_KEY_W: return ImGuiKey_W;
        case GLFW_KEY_X: return ImGuiKey_X;
        case GLFW_KEY_Y: return ImGuiKey_Y;
        case GLFW_KEY_Z: return ImGuiKey_Z;
        case GLFW_KEY_F1: return ImGuiKey_F1;
        case GLFW_KEY_F2: return ImGuiKey_F2;
        case GLFW_KEY_F3: return ImGuiKey_F3;
        case GLFW_KEY_F4: return ImGuiKey_F4;
        case GLFW_KEY_F5: return ImGuiKey_F5;
        case GLFW_KEY_F6: return ImGuiKey_F6;
        case GLFW_KEY_F7: return ImGuiKey_F7;
        case GLFW_KEY_F8: return ImGuiKey_F8;
        case GLFW_KEY_F9: return ImGuiKey_F9;
        case GLFW_KEY_F10: return ImGuiKey_F10;
        case GLFW_KEY_F11: return ImGuiKey_F11;
        case GLFW_KEY_F12: return ImGuiKey_F12;
        default: return ImGuiKey_None;
    }
}

static void ImGui_ImplGlfw_UpdateKeyModifiers(int mods)
{
    ImGuiIO& io = ImGui::GetIO();
    io.AddKeyEvent(ImGuiKey_ModCtrl, (mods & GLFW_MOD_CONTROL) != 0);
    io.AddKeyEvent(ImGuiKey_ModShift, (mods & GLFW_MOD_SHIFT) != 0);
    io.AddKeyEvent(ImGuiKey_ModAlt, (mods & GLFW_MOD_ALT) != 0);
    io.AddKeyEvent(ImGuiKey_ModSuper, (mods & GLFW_MOD_SUPER) != 0);
}

void ImGui_ImplGlfw_MouseButtonCallback(GLFWwindow* window, int button, int action, int mods)
{
    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
    if (bd->PrevUserCallbackMousebutton != NULL && window == bd->Window)
        bd->PrevUserCallbackMousebutton(window, button, action, mods);

    ImGui_ImplGlfw_UpdateKeyModifiers(mods);

    ImGuiIO& io = ImGui::GetIO();
    if (button >= 0 && button < ImGuiMouseButton_COUNT)
        io.AddMouseButtonEvent(button, action == GLFW_PRESS);
}

void ImGui_ImplGlfw_ScrollCallback(GLFWwindow* window, double xoffset, double yoffset)
{
    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
    if (bd->PrevUserCallbackScroll != NULL && window == bd->Window)
        bd->PrevUserCallbackScroll(window, xoffset, yoffset);

    ImGuiIO& io = ImGui::GetIO();
    io.AddMouseWheelEvent((float)xoffset, (float)yoffset);
}

static int ImGui_ImplGlfw_TranslateUntranslatedKey(int key, int scancode)
{
#if GLFW_HAS_GET_KEY_NAME && !defined(__EMSCRIPTEN__)
    // GLFW 3.1+ attempts to "untranslate" keys, which goes the opposite of what every other framework does, making using lettered shortcuts difficult.
    // (It had reasons to do so: namely GLFW is/was more likely to be used for WASD-type game controls rather than lettered shortcuts, but IHMO the 3.1 change could have been done differently)
    // See https://github.com/glfw/glfw/issues/1502 for details.
    // Adding a workaround to undo this (so our keys are translated->untranslated->translated, likely a lossy process).
    // This won't cover edge cases but this is at least going to cover common cases.
    if (key >= GLFW_KEY_KP_0 && key <= GLFW_KEY_KP_EQUAL)
        return key;
    const char* key_name = glfwGetKeyName(key, scancode);
    if (key_name && key_name[0] != 0 && key_name[1] == 0)
    {
        const char char_names[] = "`-=[]\\,;\'./";
        const int char_keys[] = { GLFW_KEY_GRAVE_ACCENT, GLFW_KEY_MINUS, GLFW_KEY_EQUAL, GLFW_KEY_LEFT_BRACKET, GLFW_KEY_RIGHT_BRACKET, GLFW_KEY_BACKSLASH, GLFW_KEY_COMMA, GLFW_KEY_SEMICOLON, GLFW_KEY_APOSTROPHE, GLFW_KEY_PERIOD, GLFW_KEY_SLASH, 0 };
        IM_ASSERT(IM_ARRAYSIZE(char_names) == IM_ARRAYSIZE(char_keys));
        if (key_name[0] >= '0' && key_name[0] <= '9')               { key = GLFW_KEY_0 + (key_name[0] - '0'); }
        else if (key_name[0] >= 'A' && key_name[0] <= 'Z')          { key = GLFW_KEY_A + (key_name[0] - 'A'); }
        else if (const char* p = strchr(char_names, key_name[0]))   { key = char_keys[p - char_names]; }
    }
    // if (action == GLFW_PRESS) printf("key %d scancode %d name '%s'\n", key, scancode, key_name);
#else
    IM_UNUSED(scancode);
#endif
    return key;
}

void ImGui_ImplGlfw_KeyCallback(GLFWwindow* window, int keycode, int scancode, int action, int mods)
{
    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
    if (bd->PrevUserCallbackKey != NULL && window == bd->Window)
        bd->PrevUserCallbackKey(window, keycode, scancode, action, mods);

    if (action != GLFW_PRESS && action != GLFW_RELEASE)
        return;

    ImGui_ImplGlfw_UpdateKeyModifiers(mods);

    keycode = ImGui_ImplGlfw_TranslateUntranslatedKey(keycode, scancode);

    ImGuiIO& io = ImGui::GetIO();
    ImGuiKey imgui_key = ImGui_ImplGlfw_KeyToImGuiKey(keycode);
    io.AddKeyEvent(imgui_key, (action == GLFW_PRESS));
    io.SetKeyEventNativeData(imgui_key, keycode, scancode); // To support legacy indexing (<1.87 user code)
}

void ImGui_ImplGlfw_WindowFocusCallback(GLFWwindow* window, int focused)
{
    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
    if (bd->PrevUserCallbackWindowFocus != NULL && window == bd->Window)
        bd->PrevUserCallbackWindowFocus(window, focused);

    ImGuiIO& io = ImGui::GetIO();
    io.AddFocusEvent(focused != 0);
}

void ImGui_ImplGlfw_CursorPosCallback(GLFWwindow* window, double x, double y)
{
    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
    if (bd->PrevUserCallbackCursorPos != NULL && window == bd->Window)
        bd->PrevUserCallbackCursorPos(window, x, y);

    ImGuiIO& io = ImGui::GetIO();
    io.AddMousePosEvent((float)x, (float)y);
    bd->LastValidMousePos = ImVec2((float)x, (float)y);
}

// Workaround: X11 seems to send spurious Leave/Enter events which would make us lose our position,
// so we back it up and restore on Leave/Enter (see https://github.com/ocornut/imgui/issues/4984)
void ImGui_ImplGlfw_CursorEnterCallback(GLFWwindow* window, int entered)
{
    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
    if (bd->PrevUserCallbackCursorEnter != NULL && window == bd->Window)
        bd->PrevUserCallbackCursorEnter(window, entered);

    ImGuiIO& io = ImGui::GetIO();
    if (entered)
    {
        bd->MouseWindow = window;
        io.AddMousePosEvent(bd->LastValidMousePos.x, bd->LastValidMousePos.y);
    }
    else if (!entered && bd->MouseWindow == window)
    {
        bd->LastValidMousePos = io.MousePos;
        bd->MouseWindow = NULL;
        io.AddMousePosEvent(-FLT_MAX, -FLT_MAX);
    }
}

void ImGui_ImplGlfw_CharCallback(GLFWwindow* window, unsigned int c)
{
    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
    if (bd->PrevUserCallbackChar != NULL && window == bd->Window)
        bd->PrevUserCallbackChar(window, c);

    ImGuiIO& io = ImGui::GetIO();
    io.AddInputCharacter(c);
}

void ImGui_ImplGlfw_MonitorCallback(GLFWmonitor*, int)
{
	// Unused in 'master' branch but 'docking' branch will use this, so we declare it ahead of it so if you have to install callbacks you can install this one too.
}

void ImGui_ImplGlfw_InstallCallbacks(GLFWwindow* window)
{
    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
    IM_ASSERT(bd->InstalledCallbacks == false && "Callbacks already installed!");
    IM_ASSERT(bd->Window == window);

    bd->PrevUserCallbackWindowFocus = glfwSetWindowFocusCallback(window, ImGui_ImplGlfw_WindowFocusCallback);
    bd->PrevUserCallbackCursorEnter = glfwSetCursorEnterCallback(window, ImGui_ImplGlfw_CursorEnterCallback);
    bd->PrevUserCallbackCursorPos = glfwSetCursorPosCallback(window, ImGui_ImplGlfw_CursorPosCallback);
    bd->PrevUserCallbackMousebutton = glfwSetMouseButtonCallback(window, ImGui_ImplGlfw_MouseButtonCallback);
    bd->PrevUserCallbackScroll = glfwSetScrollCallback(window, ImGui_ImplGlfw_ScrollCallback);
    bd->PrevUserCallbackKey = glfwSetKeyCallback(window, ImGui_ImplGlfw_KeyCallback);
    bd->PrevUserCallbackChar = glfwSetCharCallback(window, ImGui_ImplGlfw_CharCallback);
    bd->PrevUserCallbackMonitor = glfwSetMonitorCallback(ImGui_ImplGlfw_MonitorCallback);
    bd->InstalledCallbacks = true;
}

void ImGui_ImplGlfw_RestoreCallbacks(GLFWwindow* window)
{
    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
    IM_ASSERT(bd->InstalledCallbacks == true && "Callbacks not installed!");
    IM_ASSERT(bd->Window == window);

    glfwSetWindowFocusCallback(window, bd->PrevUserCallbackWindowFocus);
    glfwSetCursorEnterCallback(window, bd->PrevUserCallbackCursorEnter);
    glfwSetCursorPosCallback(window, bd->PrevUserCallbackCursorPos);
    glfwSetMouseButtonCallback(window, bd->PrevUserCallbackMousebutton);
    glfwSetScrollCallback(window, bd->PrevUserCallbackScroll);
    glfwSetKeyCallback(window, bd->PrevUserCallbackKey);
    glfwSetCharCallback(window, bd->PrevUserCallbackChar);
    glfwSetMonitorCallback(bd->PrevUserCallbackMonitor);
    bd->InstalledCallbacks = false;
    bd->PrevUserCallbackWindowFocus = NULL;
    bd->PrevUserCallbackCursorEnter = NULL;
    bd->PrevUserCallbackCursorPos = NULL;
    bd->PrevUserCallbackMousebutton = NULL;
    bd->PrevUserCallbackScroll = NULL;
    bd->PrevUserCallbackKey = NULL;
    bd->PrevUserCallbackChar = NULL;
    bd->PrevUserCallbackMonitor = NULL;
}

static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, GlfwClientApi client_api)
{
    ImGuiIO& io = ImGui::GetIO();
    IM_ASSERT(io.BackendPlatformUserData == NULL && "Already initialized a platform backend!");

    // Setup backend capabilities flags
    ImGui_ImplGlfw_Data* bd = IM_NEW(ImGui_ImplGlfw_Data)();
    io.BackendPlatformUserData = (void*)bd;
    io.BackendPlatformName = "imgui_impl_glfw";
    io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;         // We can honor GetMouseCursor() values (optional)
    io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;          // We can honor io.WantSetMousePos requests (optional, rarely used)

    bd->Window = window;
    bd->Time = 0.0;

    io.SetClipboardTextFn = ImGui_ImplGlfw_SetClipboardText;
    io.GetClipboardTextFn = ImGui_ImplGlfw_GetClipboardText;
    io.ClipboardUserData = bd->Window;

    // Set platform dependent data in viewport
#if defined(_WIN32)
    ImGui::GetMainViewport()->PlatformHandleRaw = (void*)glfwGetWin32Window(bd->Window);
#endif

    // Create mouse cursors
    // (By design, on X11 cursors are user configurable and some cursors may be missing. When a cursor doesn't exist,
    // GLFW will emit an error which will often be printed by the app, so we temporarily disable error reporting.
    // Missing cursors will return NULL and our _UpdateMouseCursor() function will use the Arrow cursor instead.)
    GLFWerrorfun prev_error_callback = glfwSetErrorCallback(NULL);
    bd->MouseCursors[ImGuiMouseCursor_Arrow] = glfwCreateStandardCursor(GLFW_ARROW_CURSOR);
    bd->MouseCursors[ImGuiMouseCursor_TextInput] = glfwCreateStandardCursor(GLFW_IBEAM_CURSOR);
    bd->MouseCursors[ImGuiMouseCursor_ResizeNS] = glfwCreateStandardCursor(GLFW_VRESIZE_CURSOR);
    bd->MouseCursors[ImGuiMouseCursor_ResizeEW] = glfwCreateStandardCursor(GLFW_HRESIZE_CURSOR);
    bd->MouseCursors[ImGuiMouseCursor_Hand] = glfwCreateStandardCursor(GLFW_HAND_CURSOR);
#if GLFW_HAS_NEW_CURSORS
    bd->MouseCursors[ImGuiMouseCursor_ResizeAll] = glfwCreateStandardCursor(GLFW_RESIZE_ALL_CURSOR);
    bd->MouseCursors[ImGuiMouseCursor_ResizeNESW] = glfwCreateStandardCursor(GLFW_RESIZE_NESW_CURSOR);
    bd->MouseCursors[ImGuiMouseCursor_ResizeNWSE] = glfwCreateStandardCursor(GLFW_RESIZE_NWSE_CURSOR);
    bd->MouseCursors[ImGuiMouseCursor_NotAllowed] = glfwCreateStandardCursor(GLFW_NOT_ALLOWED_CURSOR);
#else
    bd->MouseCursors[ImGuiMouseCursor_ResizeAll] = glfwCreateStandardCursor(GLFW_ARROW_CURSOR);
    bd->MouseCursors[ImGuiMouseCursor_ResizeNESW] = glfwCreateStandardCursor(GLFW_ARROW_CURSOR);
    bd->MouseCursors[ImGuiMouseCursor_ResizeNWSE] = glfwCreateStandardCursor(GLFW_ARROW_CURSOR);
    bd->MouseCursors[ImGuiMouseCursor_NotAllowed] = glfwCreateStandardCursor(GLFW_ARROW_CURSOR);
#endif
    glfwSetErrorCallback(prev_error_callback);

    // Chain GLFW callbacks: our callbacks will call the user's previously installed callbacks, if any.
    if (install_callbacks)
        ImGui_ImplGlfw_InstallCallbacks(window);

    bd->ClientApi = client_api;
    return true;
}

bool ImGui_ImplGlfw_InitForOpenGL(GLFWwindow* window, bool install_callbacks)
{
    return ImGui_ImplGlfw_Init(window, install_callbacks, GlfwClientApi_OpenGL);
}

bool ImGui_ImplGlfw_InitForVulkan(GLFWwindow* window, bool install_callbacks)
{
    return ImGui_ImplGlfw_Init(window, install_callbacks, GlfwClientApi_Vulkan);
}

bool ImGui_ImplGlfw_InitForOther(GLFWwindow* window, bool install_callbacks)
{
    return ImGui_ImplGlfw_Init(window, install_callbacks, GlfwClientApi_Unknown);
}

void ImGui_ImplGlfw_Shutdown()
{
    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
    IM_ASSERT(bd != NULL && "No platform backend to shutdown, or already shutdown?");
    ImGuiIO& io = ImGui::GetIO();

    if (bd->InstalledCallbacks)
        ImGui_ImplGlfw_RestoreCallbacks(bd->Window);

    for (ImGuiMouseCursor cursor_n = 0; cursor_n < ImGuiMouseCursor_COUNT; cursor_n++)
        glfwDestroyCursor(bd->MouseCursors[cursor_n]);

    io.BackendPlatformName = NULL;
    io.BackendPlatformUserData = NULL;
    IM_DELETE(bd);
}

static void ImGui_ImplGlfw_UpdateMouseData()
{
    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
    ImGuiIO& io = ImGui::GetIO();

#ifdef __EMSCRIPTEN__
    const bool is_app_focused = true;
#else
    const bool is_app_focused = glfwGetWindowAttrib(bd->Window, GLFW_FOCUSED) != 0;
#endif
    if (is_app_focused)
    {
        // (Optional) Set OS mouse position from Dear ImGui if requested (rarely used, only when ImGuiConfigFlags_NavEnableSetMousePos is enabled by user)
        if (io.WantSetMousePos)
            glfwSetCursorPos(bd->Window, (double)io.MousePos.x, (double)io.MousePos.y);

        // (Optional) Fallback to provide mouse position when focused (ImGui_ImplGlfw_CursorPosCallback already provides this when hovered or captured)
        if (is_app_focused && bd->MouseWindow == NULL)
        {
            double mouse_x, mouse_y;
            glfwGetCursorPos(bd->Window, &mouse_x, &mouse_y);
            io.AddMousePosEvent((float)mouse_x, (float)mouse_y);
            bd->LastValidMousePos = ImVec2((float)mouse_x, (float)mouse_y);
        }
    }
}

static void ImGui_ImplGlfw_UpdateMouseCursor()
{
    ImGuiIO& io = ImGui::GetIO();
    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
    if ((io.ConfigFlags & ImGuiConfigFlags_NoMouseCursorChange) || glfwGetInputMode(bd->Window, GLFW_CURSOR) == GLFW_CURSOR_DISABLED)
        return;

    ImGuiMouseCursor imgui_cursor = ImGui::GetMouseCursor();
    if (imgui_cursor == ImGuiMouseCursor_None || io.MouseDrawCursor)
    {
        // Hide OS mouse cursor if imgui is drawing it or if it wants no cursor
        glfwSetInputMode(bd->Window, GLFW_CURSOR, GLFW_CURSOR_HIDDEN);
    }
    else
    {
        // Show OS mouse cursor
        // FIXME-PLATFORM: Unfocused windows seems to fail changing the mouse cursor with GLFW 3.2, but 3.3 works here.
        glfwSetCursor(bd->Window, bd->MouseCursors[imgui_cursor] ? bd->MouseCursors[imgui_cursor] : bd->MouseCursors[ImGuiMouseCursor_Arrow]);
        glfwSetInputMode(bd->Window, GLFW_CURSOR, GLFW_CURSOR_NORMAL);
    }
}

// Update gamepad inputs
static inline float Saturate(float v) { return v < 0.0f ? 0.0f : v  > 1.0f ? 1.0f : v; }
static void ImGui_ImplGlfw_UpdateGamepads()
{
    ImGuiIO& io = ImGui::GetIO();
    if ((io.ConfigFlags & ImGuiConfigFlags_NavEnableGamepad) == 0)
        return;

    io.BackendFlags &= ~ImGuiBackendFlags_HasGamepad;
#if GLFW_HAS_GAMEPAD_API
    GLFWgamepadstate gamepad;
    if (!glfwGetGamepadState(GLFW_JOYSTICK_1, &gamepad))
        return;
    #define MAP_BUTTON(KEY_NO, BUTTON_NO, _UNUSED)          do { io.AddKeyEvent(KEY_NO, gamepad.buttons[BUTTON_NO] != 0); } while (0)
    #define MAP_ANALOG(KEY_NO, AXIS_NO, _UNUSED, V0, V1)    do { float v = gamepad.axes[AXIS_NO]; v = (v - V0) / (V1 - V0); io.AddKeyAnalogEvent(KEY_NO, v > 0.10f, Saturate(v)); } while (0)
#else
    int axes_count = 0, buttons_count = 0;
    const float* axes = glfwGetJoystickAxes(GLFW_JOYSTICK_1, &axes_count);
    const unsigned char* buttons = glfwGetJoystickButtons(GLFW_JOYSTICK_1, &buttons_count);
    if (axes_count == 0 || buttons_count == 0)
        return;
    #define MAP_BUTTON(KEY_NO, _UNUSED, BUTTON_NO)          do { io.AddKeyEvent(KEY_NO, (buttons_count > BUTTON_NO && buttons[BUTTON_NO] == GLFW_PRESS)); } while (0)
    #define MAP_ANALOG(KEY_NO, _UNUSED, AXIS_NO, V0, V1)    do { float v = (axes_count > AXIS_NO) ? axes[AXIS_NO] : V0; v = (v - V0) / (V1 - V0); io.AddKeyAnalogEvent(KEY_NO, v > 0.10f, Saturate(v)); } while (0)
#endif
    io.BackendFlags |= ImGuiBackendFlags_HasGamepad;
    MAP_BUTTON(ImGuiKey_GamepadStart,       GLFW_GAMEPAD_BUTTON_START,          7);
    MAP_BUTTON(ImGuiKey_GamepadBack,        GLFW_GAMEPAD_BUTTON_BACK,           6);
    MAP_BUTTON(ImGuiKey_GamepadFaceDown,    GLFW_GAMEPAD_BUTTON_A,              0);     // Xbox A, PS Cross
    MAP_BUTTON(ImGuiKey_GamepadFaceRight,   GLFW_GAMEPAD_BUTTON_B,              1);     // Xbox B, PS Circle
    MAP_BUTTON(ImGuiKey_GamepadFaceLeft,    GLFW_GAMEPAD_BUTTON_X,              2);     // Xbox X, PS Square
    MAP_BUTTON(ImGuiKey_GamepadFaceUp,      GLFW_GAMEPAD_BUTTON_Y,              3);     // Xbox Y, PS Triangle
    MAP_BUTTON(ImGuiKey_GamepadDpadLeft,    GLFW_GAMEPAD_BUTTON_DPAD_LEFT,      13);
    MAP_BUTTON(ImGuiKey_GamepadDpadRight,   GLFW_GAMEPAD_BUTTON_DPAD_RIGHT,     11);
    MAP_BUTTON(ImGuiKey_GamepadDpadUp,      GLFW_GAMEPAD_BUTTON_DPAD_UP,        10);
    MAP_BUTTON(ImGuiKey_GamepadDpadDown,    GLFW_GAMEPAD_BUTTON_DPAD_DOWN,      12);
    MAP_BUTTON(ImGuiKey_GamepadL1,          GLFW_GAMEPAD_BUTTON_LEFT_BUMPER,    4);
    MAP_BUTTON(ImGuiKey_GamepadR1,          GLFW_GAMEPAD_BUTTON_RIGHT_BUMPER,   5);
    MAP_ANALOG(ImGuiKey_GamepadL2,          GLFW_GAMEPAD_AXIS_LEFT_TRIGGER,     4,      -0.75f,  +1.0f);
    MAP_ANALOG(ImGuiKey_GamepadR2,          GLFW_GAMEPAD_AXIS_RIGHT_TRIGGER,    5,      -0.75f,  +1.0f);
    MAP_BUTTON(ImGuiKey_GamepadL3,          GLFW_GAMEPAD_BUTTON_LEFT_THUMB,     8);
    MAP_BUTTON(ImGuiKey_GamepadR3,          GLFW_GAMEPAD_BUTTON_RIGHT_THUMB,    9);
    MAP_ANALOG(ImGuiKey_GamepadLStickLeft,  GLFW_GAMEPAD_AXIS_LEFT_X,           0,      -0.25f,  -1.0f);
    MAP_ANALOG(ImGuiKey_GamepadLStickRight, GLFW_GAMEPAD_AXIS_LEFT_X,           0,      +0.25f,  +1.0f);
    MAP_ANALOG(ImGuiKey_GamepadLStickUp,    GLFW_GAMEPAD_AXIS_LEFT_Y,           1,      -0.25f,  -1.0f);
    MAP_ANALOG(ImGuiKey_GamepadLStickDown,  GLFW_GAMEPAD_AXIS_LEFT_Y,           1,      +0.25f,  +1.0f);
    MAP_ANALOG(ImGuiKey_GamepadRStickLeft,  GLFW_GAMEPAD_AXIS_RIGHT_X,          2,      -0.25f,  -1.0f);
    MAP_ANALOG(ImGuiKey_GamepadRStickRight, GLFW_GAMEPAD_AXIS_RIGHT_X,          2,      +0.25f,  +1.0f);
    MAP_ANALOG(ImGuiKey_GamepadRStickUp,    GLFW_GAMEPAD_AXIS_RIGHT_Y,          3,      -0.25f,  -1.0f);
    MAP_ANALOG(ImGuiKey_GamepadRStickDown,  GLFW_GAMEPAD_AXIS_RIGHT_Y,          3,      +0.25f,  +1.0f);
    #undef MAP_BUTTON
    #undef MAP_ANALOG
}

void ImGui_ImplGlfw_NewFrame()
{
    ImGuiIO& io = ImGui::GetIO();
    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
    IM_ASSERT(bd != NULL && "Did you call ImGui_ImplGlfw_InitForXXX()?");

    // Setup display size (every frame to accommodate for window resizing)
    int w, h;
    int display_w, display_h;
    glfwGetWindowSize(bd->Window, &w, &h);
    glfwGetFramebufferSize(bd->Window, &display_w, &display_h);
    io.DisplaySize = ImVec2((float)w, (float)h);
    if (w > 0 && h > 0)
        io.DisplayFramebufferScale = ImVec2((float)display_w / (float)w, (float)display_h / (float)h);

    // Setup time step
    double current_time = glfwGetTime();
    io.DeltaTime = bd->Time > 0.0 ? (float)(current_time - bd->Time) : (float)(1.0f / 60.0f);
    bd->Time = current_time;

    ImGui_ImplGlfw_UpdateMouseData();
    ImGui_ImplGlfw_UpdateMouseCursor();

    // Update game controllers (if enabled and available)
    ImGui_ImplGlfw_UpdateGamepads();
}

#if defined(__clang__)
#pragma clang diagnostic pop
#endif