Immediate-Mode-UI.Nuklear/example/overview.c

/* nuklear - v1.00 - public domain */
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdarg.h>
#include <string.h>
#include <math.h>
#include <assert.h>
#include <math.h>
#include <time.h>
#include <limits.h>

#include <GL/glew.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include <GLFW/glfw3.h>

#define NK_INCLUDE_FIXED_TYPES
#define NK_INCLUDE_STANDARD_IO
#define NK_INCLUDE_DEFAULT_ALLOCATOR
#define NK_INCLUDE_VERTEX_BUFFER_OUTPUT
#define NK_INCLUDE_FONT_BAKING
#define NK_INCLUDE_DEFAULT_FONT
#define NK_IMPLEMENTATION
#include "../nuklear.h"

/* macros */
#define WINDOW_WIDTH 800
#define WINDOW_HEIGHT 600

#define MAX_VERTEX_MEMORY 512 * 1024
#define MAX_ELEMENT_MEMORY 128 * 1024

#define UNUSED(a) (void)a
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#define MAX(a,b) ((a) < (b) ? (b) : (a))
#define LEN(a) (sizeof(a)/sizeof(a)[0])

/* ===============================================================
 *
 *                          GUI
 *
 * ===============================================================*/
static int
overview_window(struct nk_context *ctx)
{
    struct nk_panel menu;

    /* window flags */
    static int show_menu = nk_true;
    static int titlebar = nk_true;
    static int border = nk_true;
    static int resize = nk_true;
    static int moveable = nk_true;
    static int no_scrollbar = nk_false;
    static nk_flags window_flags = 0;
    static int minimizable = nk_true;
    static int close = nk_true;

    /* popups */
    static enum nk_style_header_align header_align = NK_HEADER_RIGHT;
    static int show_app_about = nk_false;
    struct nk_panel layout;

    /* window flags */
    window_flags = 0;
    ctx->style.window.header.align = header_align;
    if (border) window_flags |= NK_WINDOW_BORDER;
    if (resize) window_flags |= NK_WINDOW_SCALABLE;
    if (moveable) window_flags |= NK_WINDOW_MOVABLE;
    if (no_scrollbar) window_flags |= NK_WINDOW_NO_SCROLLBAR;
    if (minimizable) window_flags |= NK_WINDOW_MINIMIZABLE;
    if (close) window_flags |= NK_WINDOW_CLOSABLE;

    if (nk_begin(ctx, &layout, "Demo", nk_rect(10, 10, 400, 750), window_flags))
    {
        if (show_menu)
        {
            /* menubar */
            enum menu_states {MENU_DEFAULT, MENU_WINDOWS};
            static enum menu_states menu_state = MENU_DEFAULT;
            static nk_size mprog = 60;
            static int mslider = 10;
            static int mcheck = nk_true;

            nk_menubar_begin(ctx);
            nk_layout_row_begin(ctx, NK_STATIC, 25, 2);
            nk_layout_row_push(ctx, 45);
            if (nk_menu_begin_label(ctx, &menu, "MENU", NK_TEXT_LEFT, 120))
            {
                static size_t prog = 40;
                static int slider = 10;
                static int check = nk_true;
                nk_layout_row_dynamic(ctx, 25, 1);
                if (nk_menu_item_label(ctx, "Hide", NK_TEXT_LEFT))
                    show_menu = nk_false;
                if (nk_menu_item_label(ctx, "About", NK_TEXT_LEFT))
                    show_app_about = nk_true;
                nk_progress(ctx, &prog, 100, NK_MODIFIABLE);
                nk_slider_int(ctx, 0, &slider, 16, 1);
                nk_checkbox_label(ctx, "check", &check);
                nk_menu_end(ctx);
            }
            nk_layout_row_push(ctx, 70);
            nk_progress(ctx, &mprog, 100, NK_MODIFIABLE);
            nk_slider_int(ctx, 0, &mslider, 16, 1);
            nk_checkbox_label(ctx, "check", &mcheck);
            nk_menubar_end(ctx);
        }

        if (show_app_about)
        {
            /* about popup */
            struct nk_panel popup;
            static struct nk_rect s = {20, 100, 300, 190};
            if (nk_popup_begin(ctx, &popup, NK_POPUP_STATIC, "About", NK_WINDOW_CLOSABLE, s))
            {
                nk_layout_row_dynamic(ctx, 20, 1);
                nk_label(ctx, "Nuklear", NK_TEXT_LEFT);
                nk_label(ctx, "By Micha Mettke", NK_TEXT_LEFT);
                nk_label(ctx, "nuklear is licensed under the public domain License.",  NK_TEXT_LEFT);
                nk_popup_end(ctx);
            } else show_app_about = nk_false;
        }

        /* window flags */
        if (nk_tree_push(ctx, NK_TREE_TAB, "Window", NK_MINIMIZED)) {
            nk_layout_row_dynamic(ctx, 30, 2);
            nk_checkbox_label(ctx, "Titlebar", &titlebar);
            nk_checkbox_label(ctx, "Menu", &show_menu);
            nk_checkbox_label(ctx, "Border", &border);
            nk_checkbox_label(ctx, "Resizable", &resize);
            nk_checkbox_label(ctx, "Moveable", &moveable);
            nk_checkbox_label(ctx, "No Scrollbar", &no_scrollbar);
            nk_checkbox_label(ctx, "Minimizable", &minimizable);
            nk_checkbox_label(ctx, "Closeable", &close);
            nk_tree_pop(ctx);
        }

        if (nk_tree_push(ctx, NK_TREE_TAB, "Widgets", NK_MINIMIZED))
        {
            enum options {A,B,C};
            static int checkbox;
            static int option;
            if (nk_tree_push(ctx, NK_TREE_NODE, "Text", NK_MINIMIZED))
            {
                /* Text Widgets */
                nk_layout_row_dynamic(ctx, 20, 1);
                nk_label(ctx, "Label aligned left", NK_TEXT_LEFT);
                nk_label(ctx, "Label aligned centered", NK_TEXT_CENTERED);
                nk_label(ctx, "Label aligned right", NK_TEXT_RIGHT);
                nk_label_colored(ctx, "Blue text", NK_TEXT_LEFT, nk_rgb(0,0,255));
                nk_label_colored(ctx, "Yellow text", NK_TEXT_LEFT, nk_rgb(255,255,0));
                nk_text(ctx, "Text without /0", 15, NK_TEXT_RIGHT);

                nk_layout_row_static(ctx, 100, 200, 1);
                nk_label_wrap(ctx, "This is a very long line to hopefully get this text to be wrapped into multiple lines to show line wrapping");
                nk_layout_row_dynamic(ctx, 100, 1);
                nk_label_wrap(ctx, "This is another long text to show dynamic window changes on multiline text");
                nk_tree_pop(ctx);
            }

            if (nk_tree_push(ctx, NK_TREE_NODE, "Button", NK_MINIMIZED))
            {
                /* Buttons Widgets */
                nk_layout_row_static(ctx, 30, 100, 3);
                if (nk_button_label(ctx, "Button", NK_BUTTON_DEFAULT))
                    fprintf(stdout, "Button pressed!\n");
                if (nk_button_label(ctx, "Repeater", NK_BUTTON_REPEATER))
                    fprintf(stdout, "Repeater is being pressed!\n");
                nk_button_color(ctx, nk_rgb(0,0,255), NK_BUTTON_DEFAULT);

                nk_layout_row_static(ctx, 20, 20, 8);
                nk_button_symbol(ctx, NK_SYMBOL_CIRCLE, NK_BUTTON_DEFAULT);
                nk_button_symbol(ctx, NK_SYMBOL_CIRCLE_FILLED, NK_BUTTON_DEFAULT);
                nk_button_symbol(ctx, NK_SYMBOL_RECT, NK_BUTTON_DEFAULT);
                nk_button_symbol(ctx, NK_SYMBOL_RECT_FILLED, NK_BUTTON_DEFAULT);
                nk_button_symbol(ctx, NK_SYMBOL_TRIANGLE_UP, NK_BUTTON_DEFAULT);
                nk_button_symbol(ctx, NK_SYMBOL_TRIANGLE_DOWN, NK_BUTTON_DEFAULT);
                nk_button_symbol(ctx, NK_SYMBOL_TRIANGLE_LEFT, NK_BUTTON_DEFAULT);
                nk_button_symbol(ctx, NK_SYMBOL_TRIANGLE_RIGHT, NK_BUTTON_DEFAULT);

                nk_layout_row_static(ctx, 30, 100, 2);
                nk_button_symbol_label(ctx, NK_SYMBOL_TRIANGLE_LEFT, "prev", NK_TEXT_RIGHT, NK_BUTTON_DEFAULT);
                nk_button_symbol_label(ctx, NK_SYMBOL_TRIANGLE_RIGHT, "next", NK_TEXT_LEFT, NK_BUTTON_DEFAULT);
                nk_tree_pop(ctx);
            }

            if (nk_tree_push(ctx, NK_TREE_NODE, "Basic", NK_MINIMIZED))
            {
                /* Basic widgets */
                static int int_slider = 5;
                static float float_slider = 2.5f;
                static size_t prog_value = 40;
                static float property_float = 2;
                static int property_int = 10;
                static int property_neg = 10;

                static float range_float_min = 0;
                static float range_float_max = 100;
                static float range_float_value = 50;
                static int range_int_min = 0;
                static int range_int_value = 2048;
                static int range_int_max = 4096;
                static const float ratio[] = {120, 150};

                nk_layout_row_static(ctx, 30, 100, 1);
                nk_checkbox_label(ctx, "Checkbox", &checkbox);

                nk_layout_row_static(ctx, 30, 80, 3);
                option = nk_option_label(ctx, "optionA", option == A) ? A : option;
                option = nk_option_label(ctx, "optionB", option == B) ? B : option;
                option = nk_option_label(ctx, "optionC", option == C) ? C : option;


                nk_layout_row(ctx, NK_STATIC, 30, 2, ratio);
                nk_labelf(ctx, NK_TEXT_LEFT, "Slider int");
                nk_slider_int(ctx, 0, &int_slider, 10, 1);

                nk_label(ctx, "Slider float", NK_TEXT_LEFT);
                nk_slider_float(ctx, 0, &float_slider, 5.0, 0.5f);
                nk_labelf(ctx, NK_TEXT_LEFT, "Progressbar" , prog_value);
                nk_progress(ctx, &prog_value, 100, NK_MODIFIABLE);

                nk_layout_row(ctx, NK_STATIC, 25, 2, ratio);
                nk_label(ctx, "Property float:", NK_TEXT_LEFT);
                nk_property_float(ctx, "Float:", 0, &property_float, 64.0f, 0.1f, 0.2f);
                nk_label(ctx, "Property int:", NK_TEXT_LEFT);
                nk_property_int(ctx, "Int:", 0, &property_int, 100.0f, 1, 1);
                nk_label(ctx, "Property neg:", NK_TEXT_LEFT);
                nk_property_int(ctx, "Neg:", -10, &property_neg, 10, 1, 1);

                nk_layout_row_dynamic(ctx, 25, 1);
                nk_label(ctx, "Range:", NK_TEXT_LEFT);
                nk_layout_row_dynamic(ctx, 25, 3);
                nk_property_float(ctx, "#min:", 0, &range_float_min, range_float_max, 1.0f, 0.2f);
                nk_property_float(ctx, "#float:", range_float_min, &range_float_value, range_float_max, 1.0f, 0.2f);
                nk_property_float(ctx, "#max:", range_float_min, &range_float_max, 100, 1.0f, 0.2f);

                nk_property_int(ctx, "#min:", INT_MIN, &range_int_min, range_int_max, 1, 10);
                nk_property_int(ctx, "#neg:", range_int_min, &range_int_value, range_int_max, 1, 10);
                nk_property_int(ctx, "#max:", range_int_min, &range_int_max, INT_MAX, 1, 10);

                nk_tree_pop(ctx);
            }

            if (nk_tree_push(ctx, NK_TREE_NODE, "Selectable", NK_MINIMIZED))
            {
                if (nk_tree_push(ctx, NK_TREE_NODE, "List", NK_MINIMIZED))
                {
                    static int selected[4] = {nk_false, nk_false, nk_true, nk_false};
                    nk_layout_row_static(ctx, 18, 100, 1);
                    nk_selectable_label(ctx, "Selectable", NK_TEXT_LEFT, &selected[0]);
                    nk_selectable_label(ctx, "Selectable", NK_TEXT_LEFT, &selected[1]);
                    nk_label(ctx, "Not Selectable", NK_TEXT_LEFT);
                    nk_selectable_label(ctx, "Selectable", NK_TEXT_LEFT, &selected[2]);
                    nk_selectable_label(ctx, "Selectable", NK_TEXT_LEFT, &selected[3]);
                    nk_tree_pop(ctx);
                }
                if (nk_tree_push(ctx, NK_TREE_NODE, "Grid", NK_MINIMIZED))
                {
                    int i;
                    static int selected[16] = {1,0,0,0, 0,1,0,0, 0,0,1,0, 0,0,0,1};
                    nk_layout_row_static(ctx, 50, 50, 4);
                    for (i = 0; i < 16; ++i) {
                        if (nk_selectable_label(ctx, "Z", NK_TEXT_CENTERED, &selected[i])) {
                            int x = (i % 4), y = i / 4;
                            if (x > 0) selected[i - 1] ^= 1;
                            if (x < 3) selected[i + 1] ^= 1;
                            if (y > 0) selected[i - 4] ^= 1;
                            if (y < 3) selected[i + 4] ^= 1;
                        }
                    }
                    nk_tree_pop(ctx);
                }
                nk_tree_pop(ctx);
            }

            if (nk_tree_push(ctx, NK_TREE_NODE, "Combo", NK_MINIMIZED))
            {
                /* Combobox Widgets
                 * In this library comboboxes are not limited to being a popup
                 * list of selectable text. Instead it is a abstract concept of
                 * having something that is *selected* or displayed, a popup window
                 * which opens if something needs to be modified and the content
                 * of the popup which causes the *selected* or displayed value to
                 * change or if wanted close the combobox.
                 *
                 * While strange at first handling comboboxes in a abstract way
                 * solves the problem of overloaded window content. For example
                 * changing a color value requires 4 value modifier (slider, property,...)
                 * for RGBA then you need a label and ways to display the current color.
                 * If you want to go fancy you even add rgb and hsv ratio boxes.
                 * While fine for one color if you have a lot of them it because
                 * tedious to look at and quite wasteful in space. You could add
                 * a popup which modifies the color but this does not solve the
                 * fact that it still requires a lot of cluttered space to do.
                 *
                 * In these kind of instance abstract comboboxes are quite handy. All
                 * value modifiers are hidden inside the combobox popup and only
                 * the color is shown if not open. This combines the clarity of the
                 * popup with the ease of use of just using the space for modifiers.
                 *
                 * Other instances are for example time and especially date picker,
                 * which only show the currently activated time/data and hide the
                 * selection logic inside the combobox popup.
                 */
                static float chart_selection = 8.0f;
                static int current_weapon = 0;
                static int check_values[5];
                static float position[3];
                static struct nk_color combo_color = {130, 50, 50, 255};
                static struct nk_color combo_color2 = {130, 180, 50, 255};
                static size_t prog_a =  20, prog_b = 40, prog_c = 10, prog_d = 90;
                static const char *weapons[] = {"Fist","Pistol","Shotgun","Plasma","BFG"};

                char buffer[64];
                size_t sum = 0;
                struct nk_panel combo;

                /* default combobox */
                nk_layout_row_static(ctx, 25, 200, 1);
                current_weapon = nk_combo(ctx, weapons, LEN(weapons), current_weapon, 25);

                /* slider color combobox */
                if (nk_combo_begin_color(ctx, &combo, combo_color, 200)) {
                    float ratios[] = {0.15f, 0.85f};
                    nk_layout_row(ctx, NK_DYNAMIC, 30, 2, ratios);
                    nk_label(ctx, "R:", NK_TEXT_LEFT);
                    combo_color.r = (nk_byte)nk_slide_int(ctx, 0, combo_color.r, 255, 5);
                    nk_label(ctx, "G:", NK_TEXT_LEFT);
                    combo_color.g = (nk_byte)nk_slide_int(ctx, 0, combo_color.g, 255, 5);
                    nk_label(ctx, "B:", NK_TEXT_LEFT);
                    combo_color.b = (nk_byte)nk_slide_int(ctx, 0, combo_color.b, 255, 5);
                    nk_label(ctx, "A:", NK_TEXT_LEFT);
                    combo_color.a = (nk_byte)nk_slide_int(ctx, 0, combo_color.a , 255, 5);
                    nk_combo_end(ctx);
                }

                /* complex color combobox */
                if (nk_combo_begin_color(ctx, &combo, combo_color2, 400)) {
                    enum color_mode {COL_RGB, COL_HSV};
                    static int col_mode = COL_RGB;
                    #ifndef DEMO_DO_NOT_USE_COLOR_PICKER
                    nk_layout_row_dynamic(ctx, 120, 1);
                    combo_color2 = nk_color_picker(ctx, combo_color2, NK_RGBA);
                    #endif

                    nk_layout_row_dynamic(ctx, 25, 2);
                    col_mode = nk_option_label(ctx, "RGB", col_mode == COL_RGB) ? COL_RGB : col_mode;
                    col_mode = nk_option_label(ctx, "HSV", col_mode == COL_HSV) ? COL_HSV : col_mode;

                    nk_layout_row_dynamic(ctx, 25, 1);
                    if (col_mode == COL_RGB) {
                        combo_color2.r = (nk_byte)nk_propertyi(ctx, "#R:", 0, combo_color2.r, 255, 1,1);
                        combo_color2.g = (nk_byte)nk_propertyi(ctx, "#G:", 0, combo_color2.g, 255, 1,1);
                        combo_color2.b = (nk_byte)nk_propertyi(ctx, "#B:", 0, combo_color2.b, 255, 1,1);
                        combo_color2.a = (nk_byte)nk_propertyi(ctx, "#A:", 0, combo_color2.a, 255, 1,1);
                    } else {
                        nk_byte tmp[4];
                        nk_color_hsva_bv(tmp, combo_color2);
                        tmp[0] = (nk_byte)nk_propertyi(ctx, "#H:", 0, tmp[0], 255, 1,1);
                        tmp[1] = (nk_byte)nk_propertyi(ctx, "#S:", 0, tmp[1], 255, 1,1);
                        tmp[2] = (nk_byte)nk_propertyi(ctx, "#V:", 0, tmp[2], 255, 1,1);
                        tmp[3] = (nk_byte)nk_propertyi(ctx, "#A:", 0, tmp[3], 255, 1,1);
                        combo_color2 = nk_hsva_bv(tmp);
                    }
                    nk_combo_end(ctx);
                }

                /* progressbar combobox */
                sum = prog_a + prog_b + prog_c + prog_d;
                sprintf(buffer, "%lu", sum);
                if (nk_combo_begin_label(ctx, &combo, buffer, 200)) {
                    nk_layout_row_dynamic(ctx, 30, 1);
                    nk_progress(ctx, &prog_a, 100, NK_MODIFIABLE);
                    nk_progress(ctx, &prog_b, 100, NK_MODIFIABLE);
                    nk_progress(ctx, &prog_c, 100, NK_MODIFIABLE);
                    nk_progress(ctx, &prog_d, 100, NK_MODIFIABLE);
                    nk_combo_end(ctx);
                }

                /* checkbox combobox */
                sum = (size_t)(check_values[0] + check_values[1] + check_values[2] + check_values[3] + check_values[4]);
                sprintf(buffer, "%lu", sum);
                if (nk_combo_begin_label(ctx, &combo, buffer, 200)) {
                    nk_layout_row_dynamic(ctx, 30, 1);
                    nk_checkbox_label(ctx, weapons[0], &check_values[0]);
                    nk_checkbox_label(ctx, weapons[1], &check_values[1]);
                    nk_checkbox_label(ctx, weapons[2], &check_values[2]);
                    nk_checkbox_label(ctx, weapons[3], &check_values[3]);
                    nk_combo_end(ctx);
                }

                /* complex text combobox */
                sprintf(buffer, "%.2f, %.2f, %.2f", position[0], position[1],position[2]);
                if (nk_combo_begin_label(ctx, &combo, buffer, 200)) {
                    nk_layout_row_dynamic(ctx, 25, 1);
                    nk_property_float(ctx, "#X:", -1024.0f, &position[0], 1024.0f, 1,0.5f);
                    nk_property_float(ctx, "#Y:", -1024.0f, &position[1], 1024.0f, 1,0.5f);
                    nk_property_float(ctx, "#Z:", -1024.0f, &position[2], 1024.0f, 1,0.5f);
                    nk_combo_end(ctx);
                }

                /* chart combobox */
                sprintf(buffer, "%.1f", chart_selection);
                if (nk_combo_begin_label(ctx, &combo, buffer, 250)) {
                    size_t i = 0;
                    static const float values[]={26.0f,13.0f,30.0f,15.0f,25.0f,10.0f,20.0f,40.0f, 12.0f, 8.0f, 22.0f, 28.0f, 5.0f};
                    nk_layout_row_dynamic(ctx, 150, 1);
                    nk_chart_begin(ctx, NK_CHART_COLUMN, LEN(values), 0, 50);
                    for (i = 0; i < LEN(values); ++i) {
                        nk_flags res = nk_chart_push(ctx, values[i]);
                        if (res & NK_CHART_CLICKED) {
                            chart_selection = values[i];
                            nk_combo_close(ctx);
                        }
                    }
                    nk_chart_end(ctx);
                    nk_combo_end(ctx);
                }

                {
                    static int time_selected = 0;
                    static int date_selected = 0;
                    static struct tm sel_time;
                    static struct tm sel_date;
                    if (!time_selected || !date_selected) {
                        /* keep time and date updated if nothing is selected */
                        time_t cur_time = time(0);
                        struct tm *n = localtime(&cur_time);
                        if (!time_selected)
                            memcpy(&sel_time, n, sizeof(struct tm));
                        if (!date_selected)
                            memcpy(&sel_date, n, sizeof(struct tm));
                    }

                    /* time combobox */
                    sprintf(buffer, "%02d:%02d:%02d", sel_time.tm_hour, sel_time.tm_min, sel_time.tm_sec);
                    if (nk_combo_begin_label(ctx, &combo, buffer, 250)) {
                        time_selected = 1;
                        nk_layout_row_dynamic(ctx, 25, 1);
                        sel_time.tm_sec = nk_propertyi(ctx, "#S:", 0, sel_time.tm_sec, 60, 1, 1);
                        sel_time.tm_min = nk_propertyi(ctx, "#M:", 0, sel_time.tm_min, 60, 1, 1);
                        sel_time.tm_hour = nk_propertyi(ctx, "#H:", 0, sel_time.tm_hour, 23, 1, 1);
                        nk_combo_end(ctx);
                    }

                    /* date combobox */
                    nk_layout_row_static(ctx, 25, 350, 1);
                    sprintf(buffer, "%02d-%02d-%02d", sel_date.tm_mday, sel_date.tm_mon+1, sel_date.tm_year+1900);
                    if (nk_combo_begin_label(ctx, &combo, buffer, 400))
                    {
                        int i = 0;
                        const char *month[] = {"January", "February", "March", "Apil", "May", "June", "July", "August", "September", "Ocotober", "November", "December"};
                        const char *week_days[] = {"SUN", "MON", "TUE", "WED", "THU", "FRI", "SAT"};
                        const int month_days[] = {31,28,31,30,31,30,31,31,30,31,30,31};
                        int year = sel_date.tm_year+1900;
                        int leap_year = (!(year % 4) && ((year % 100))) || !(year % 400);
                        int days = (sel_date.tm_mon == 1) ?
                            month_days[sel_date.tm_mon] + leap_year:
                            month_days[sel_date.tm_mon];

                        /* header with month and year */
                        date_selected = 1;
                        nk_layout_row_begin(ctx, NK_DYNAMIC, 20, 3);
                        nk_layout_row_push(ctx, 0.05f);
                        if (nk_button_symbol(ctx, NK_SYMBOL_TRIANGLE_LEFT, NK_BUTTON_DEFAULT)) {
                            if (sel_date.tm_mon == 0) {
                                sel_date.tm_mon = 11;
                                sel_date.tm_year = MAX(0, sel_date.tm_year-1);
                            } else sel_date.tm_mon--;
                        }
                        nk_layout_row_push(ctx, 0.9f);
                        sprintf(buffer, "%s %d", month[sel_date.tm_mon], year);
                        nk_label(ctx, buffer, NK_TEXT_CENTERED);
                        nk_layout_row_push(ctx, 0.05f);
                        if (nk_button_symbol(ctx, NK_SYMBOL_TRIANGLE_RIGHT, NK_BUTTON_DEFAULT)) {
                            if (sel_date.tm_mon == 11) {
                                sel_date.tm_mon = 0;
                                sel_date.tm_year++;
                            } else sel_date.tm_mon++;
                        }
                        nk_layout_row_end(ctx);

                        /* good old week day formula (double because precision) */
                        {int year_n = (sel_date.tm_mon < 2) ? year-1: year;
                        int y = year_n % 100;
                        int c = year_n / 100;
                        int y4 = (int)((float)y / 4);
                        int c4 = (int)((float)c / 4);
                        int m = (int)(2.6 * (double)(((sel_date.tm_mon + 10) % 12) + 1) - 0.2);
                        int week_day = (((1 + m + y + y4 + c4 - 2 * c) % 7) + 7) % 7;

                        /* weekdays  */
                        nk_layout_row_dynamic(ctx, 35, 7);
                        for (i = 0; i < (int)LEN(week_days); ++i)
                            nk_label(ctx, week_days[i], NK_TEXT_CENTERED);

                        /* days  */
                        if (week_day > 0) nk_spacing(ctx, week_day);
                        for (i = 1; i <= days; ++i) {
                            sprintf(buffer, "%d", i);
                            if (nk_button_label(ctx, buffer, NK_BUTTON_DEFAULT)) {
                                sel_date.tm_mday = i;
                                nk_combo_close(ctx);
                            }
                        }}
                        nk_combo_end(ctx);
                    }
                }

                nk_tree_pop(ctx);
            }

            if (nk_tree_push(ctx, NK_TREE_NODE, "Input", NK_MINIMIZED))
            {
                static const float ratio[] = {120, 150};
                static char field_buffer[64];
                static char text[9][64];
                static int text_len[9];
                static char box_buffer[512];
                static int field_len;
                static int box_len;
                nk_flags active;

                nk_layout_row(ctx, NK_STATIC, 25, 2, ratio);
                nk_label(ctx, "Default:", NK_TEXT_LEFT);

                nk_edit_string(ctx, NK_EDIT_SIMPLE, text[0], &text_len[0], 64, nk_filter_default);
                nk_label(ctx, "Int:", NK_TEXT_LEFT);
                nk_edit_string(ctx, NK_EDIT_SIMPLE, text[1], &text_len[1], 64, nk_filter_decimal);
                nk_label(ctx, "Float:", NK_TEXT_LEFT);
                nk_edit_string(ctx, NK_EDIT_SIMPLE, text[2], &text_len[2], 64, nk_filter_float);
                nk_label(ctx, "Hex:", NK_TEXT_LEFT);
                nk_edit_string(ctx, NK_EDIT_SIMPLE, text[4], &text_len[4], 64, nk_filter_hex);
                nk_label(ctx, "Octal:", NK_TEXT_LEFT);
                nk_edit_string(ctx, NK_EDIT_SIMPLE, text[5], &text_len[5], 64, nk_filter_oct);
                nk_label(ctx, "Binary:", NK_TEXT_LEFT);
                nk_edit_string(ctx, NK_EDIT_SIMPLE, text[6], &text_len[6], 64, nk_filter_binary);

                nk_label(ctx, "Password:", NK_TEXT_LEFT);
                {
                    int i = 0;
                    int old_len = text_len[8];
                    char buffer[64];
                    for (i = 0; i < text_len[8]; ++i) buffer[i] = '*';
                    nk_edit_string(ctx, NK_EDIT_FIELD, buffer, &text_len[8], 64, nk_filter_default);
                    if (old_len < text_len[8])
                        memcpy(&text[8][old_len], &buffer[old_len], (nk_size)(text_len[8] - old_len));
                }

                nk_label(ctx, "Field:", NK_TEXT_LEFT);
                nk_edit_string(ctx, NK_EDIT_FIELD, field_buffer, &field_len, 64, nk_filter_default);

                nk_label(ctx, "Box:", NK_TEXT_LEFT);
                nk_layout_row_static(ctx, 180, 278, 1);
                nk_edit_string(ctx, NK_EDIT_BOX, box_buffer, &box_len, 512, nk_filter_default);

                nk_layout_row(ctx, NK_STATIC, 25, 2, ratio);
                active = nk_edit_string(ctx, NK_EDIT_FIELD|NK_EDIT_SIG_ENTER, text[7], &text_len[7], 64,  nk_filter_ascii);
                if (nk_button_label(ctx, "Submit", NK_BUTTON_DEFAULT) ||
                    (active & NK_EDIT_COMMITED))
                {
                    text[7][text_len[7]] = '\n';
                    text_len[7]++;
                    memcpy(&box_buffer[box_len], &text[7], (nk_size)text_len[7]);
                    box_len += text_len[7];
                    text_len[7] = 0;
                }
                nk_layout_row_end(ctx);
                nk_tree_pop(ctx);
            }
            nk_tree_pop(ctx);
        }

        if (nk_tree_push(ctx, NK_TREE_TAB, "Chart", NK_MINIMIZED))
        {
            /* Chart Widgets
             * This library has two different rather simple charts. The line and the
             * column chart. Both provide a simple way of visualizing values and
             * have a retain mode and immedidate mode API version. For the retain
             * mode version `nk_plot` and `nk_plot_function` you either provide
             * an array or a callback to call to handle drawing the graph.
             * For the immediate mode version you start by calling `nk_chart_begin`
             * and need to provide min and max values for scaling on the Y-axis.
             * and then call `nk_chart_push` to push values into the chart.
             * Finally `nk_chart_end` needs to be called to end the process. */
            float id = 0;
            static int col_index = -1;
            static int line_index = -1;
            float step = (2*3.141592654f) / 32;

            int i;
            int index = -1;
            struct nk_rect bounds;

            /* line chart */
            id = 0;
            index = -1;
            nk_layout_row_dynamic(ctx, 100, 1);
            bounds = nk_widget_bounds(ctx);
            if (nk_chart_begin(ctx, NK_CHART_LINES, 32, -1.0f, 1.0f)) {
                for (i = 0; i < 32; ++i) {
                    nk_flags res = nk_chart_push(ctx, (float)cos(id));
                    if (res & NK_CHART_HOVERING)
                        index = (int)i;
                    if (res & NK_CHART_CLICKED)
                        line_index = (int)i;
                    id += step;
                }
                nk_chart_end(ctx);
            }

            if (index != -1) {
                char buffer[NK_MAX_NUMBER_BUFFER];
                float val = (float)cos((float)index*step);
                sprintf(buffer, "Value: %.2f", val);
                nk_tooltip(ctx, buffer);
            }
            if (line_index != -1) {
                nk_layout_row_dynamic(ctx, 20, 1);
                nk_labelf(ctx, NK_TEXT_LEFT, "Selected value: %.2f", (float)cos((float)index*step));
            }

            /* column chart */
            nk_layout_row_dynamic(ctx, 100, 1);
            bounds = nk_widget_bounds(ctx);
            if (nk_chart_begin(ctx, NK_CHART_COLUMN, 32, 0.0f, 1.0f)) {
                for (i = 0; i < 32; ++i) {
                    nk_flags res = nk_chart_push(ctx, (float)fabs(sin(id)));
                    if (res & NK_CHART_HOVERING)
                        index = (int)i;
                    if (res & NK_CHART_CLICKED)
                        col_index = (int)i;
                    id += step;
                }
                nk_chart_end(ctx);
            }
            if (index != -1) {
                char buffer[NK_MAX_NUMBER_BUFFER];
                sprintf(buffer, "Value: %.2f", (float)fabs(sin(step * (float)index)));
                nk_tooltip(ctx, buffer);
            }
            if (col_index != -1) {
                nk_layout_row_dynamic(ctx, 20, 1);
                nk_labelf(ctx, NK_TEXT_LEFT, "Selected value: %.2f", (float)fabs(sin(step * (float)col_index)));
            }
            nk_tree_pop(ctx);
        }

        if (nk_tree_push(ctx, NK_TREE_TAB, "Popup", NK_MINIMIZED))
        {
            static struct nk_color color = {255,0,0, 255};
            static int select[4];
            static int popup_active;
            const struct nk_input *in = &ctx->input;
            struct nk_rect bounds;

            /* menu contextual */
            nk_layout_row_static(ctx, 30, 150, 1);
            bounds = nk_widget_bounds(ctx);
            nk_label(ctx, "Right click me for menu", NK_TEXT_LEFT);

            if (nk_contextual_begin(ctx, &menu, 0, nk_vec2(100, 300), bounds)) {
                static size_t prog = 40;
                static int slider = 10;

                nk_layout_row_dynamic(ctx, 25, 1);
                nk_checkbox_label(ctx, "Menu", &show_menu);
                nk_progress(ctx, &prog, 100, NK_MODIFIABLE);
                nk_slider_int(ctx, 0, &slider, 16, 1);
                if (nk_contextual_item_label(ctx, "About", NK_TEXT_CENTERED))
                    show_app_about = nk_true;
                nk_selectable_label(ctx, select[0]?"Unselect":"Select", NK_TEXT_LEFT, &select[0]);
                nk_selectable_label(ctx, select[1]?"Unselect":"Select", NK_TEXT_LEFT, &select[1]);
                nk_selectable_label(ctx, select[2]?"Unselect":"Select", NK_TEXT_LEFT, &select[2]);
                nk_selectable_label(ctx, select[3]?"Unselect":"Select", NK_TEXT_LEFT, &select[3]);
                nk_contextual_end(ctx);
            }

            /* color contextual */
            nk_layout_row_begin(ctx, NK_STATIC, 30, 2);
            nk_layout_row_push(ctx, 100);
            nk_label(ctx, "Right Click here:", NK_TEXT_LEFT);
            nk_layout_row_push(ctx, 50);
            bounds = nk_widget_bounds(ctx);
            nk_button_color(ctx, color, NK_BUTTON_DEFAULT);
            nk_layout_row_end(ctx);

            if (nk_contextual_begin(ctx, &menu, 0, nk_vec2(350, 60), bounds)) {
                nk_layout_row_dynamic(ctx, 30, 4);
                color.r = (nk_byte)nk_propertyi(ctx, "#r", 0, color.r, 255, 1, 1);
                color.g = (nk_byte)nk_propertyi(ctx, "#g", 0, color.g, 255, 1, 1);
                color.b = (nk_byte)nk_propertyi(ctx, "#b", 0, color.b, 255, 1, 1);
                color.a = (nk_byte)nk_propertyi(ctx, "#a", 0, color.a, 255, 1, 1);
                nk_contextual_end(ctx);
            }

            /* popup */
            nk_layout_row_begin(ctx, NK_STATIC, 30, 2);
            nk_layout_row_push(ctx, 100);
            nk_label(ctx, "Popup:", NK_TEXT_LEFT);
            nk_layout_row_push(ctx, 50);
            if (nk_button_label(ctx, "Popup", NK_BUTTON_DEFAULT))
                popup_active = 1;
            nk_layout_row_end(ctx);

            if (popup_active)
            {
                static struct nk_rect s = {20, 100, 220, 150};
                if (nk_popup_begin(ctx, &menu, NK_POPUP_STATIC, "Error", NK_WINDOW_DYNAMIC, s))
                {
                    nk_layout_row_dynamic(ctx, 25, 1);
                    nk_label(ctx, "A terrible error as occured", NK_TEXT_LEFT);
                    nk_layout_row_dynamic(ctx, 25, 2);
                    if (nk_button_label(ctx, "OK", NK_BUTTON_DEFAULT)) {
                        popup_active = 0;
                        nk_popup_close(ctx);
                    }
                    if (nk_button_label(ctx, "Cancel", NK_BUTTON_DEFAULT)) {
                        popup_active = 0;
                        nk_popup_close(ctx);
                    }
                    nk_popup_end(ctx);
                } else popup_active = nk_false;
            }

            /* tooltip */
            nk_layout_row_static(ctx, 30, 150, 1);
            bounds = nk_widget_bounds(ctx);
            nk_label(ctx, "Hover me for tooltip", NK_TEXT_LEFT);
            if (nk_input_is_mouse_hovering_rect(in, bounds))
                nk_tooltip(ctx, "This is a tooltip");

            nk_tree_pop(ctx);
        }

        if (nk_tree_push(ctx, NK_TREE_TAB, "Layout", NK_MINIMIZED))
        {
            if (nk_tree_push(ctx, NK_TREE_NODE, "Widget", NK_MINIMIZED))
            {
                float ratio_two[] = {0.2f, 0.6f, 0.2f};
                float width_two[] = {100, 200, 50};

                nk_layout_row_dynamic(ctx, 30, 1);
                nk_label(ctx, "Dynamic fixed column layout with generated position and size:", NK_TEXT_LEFT);
                nk_layout_row_dynamic(ctx, 30, 3);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);

                nk_layout_row_dynamic(ctx, 30, 1);
                nk_label(ctx, "static fixed column layout with generated position and size:", NK_TEXT_LEFT);
                nk_layout_row_static(ctx, 30, 100, 3);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);

                nk_layout_row_dynamic(ctx, 30, 1);
                nk_label(ctx, "Dynamic array-based custom column layout with generated position and custom size:",NK_TEXT_LEFT);
                nk_layout_row(ctx, NK_DYNAMIC, 30, 3, ratio_two);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);

                nk_layout_row_dynamic(ctx, 30, 1);
                nk_label(ctx, "Static array-based custom column layout with generated position and custom size:",NK_TEXT_LEFT );
                nk_layout_row(ctx, NK_STATIC, 30, 3, width_two);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);

                nk_layout_row_dynamic(ctx, 30, 1);
                nk_label(ctx, "Dynamic immediate mode custom column layout with generated position and custom size:",NK_TEXT_LEFT);
                nk_layout_row_begin(ctx, NK_DYNAMIC, 30, 3);
                nk_layout_row_push(ctx, 0.2f);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_layout_row_push(ctx, 0.6f);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_layout_row_push(ctx, 0.2f);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_layout_row_end(ctx);

                nk_layout_row_dynamic(ctx, 30, 1);
                nk_label(ctx, "Static immmediate mode custom column layout with generated position and custom size:", NK_TEXT_LEFT);
                nk_layout_row_begin(ctx, NK_STATIC, 30, 3);
                nk_layout_row_push(ctx, 100);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_layout_row_push(ctx, 200);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_layout_row_push(ctx, 50);
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_layout_row_end(ctx);

                nk_layout_row_dynamic(ctx, 30, 1);
                nk_label(ctx, "Static free space with custom position and custom size:", NK_TEXT_LEFT);
                nk_layout_space_begin(ctx, NK_STATIC, 120, 4);
                nk_layout_space_push(ctx, nk_rect(100, 0, 100, 30));
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_layout_space_push(ctx, nk_rect(0, 15, 100, 30));
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_layout_space_push(ctx, nk_rect(200, 15, 100, 30));
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_layout_space_push(ctx, nk_rect(100, 30, 100, 30));
                nk_button_label(ctx, "button", NK_BUTTON_DEFAULT);
                nk_layout_space_end(ctx);
                nk_tree_pop(ctx);
            }

            if (nk_tree_push(ctx, NK_TREE_NODE, "Group", NK_MINIMIZED))
            {
                static int group_titlebar = nk_false;
                static int group_border = nk_true;
                static int group_no_scrollbar = nk_false;
                static int group_width = 320;
                static int group_height = 200;
                struct nk_panel tab;

                nk_flags group_flags = 0;
                if (group_border) group_flags |= NK_WINDOW_BORDER;
                if (group_no_scrollbar) group_flags |= NK_WINDOW_NO_SCROLLBAR;
                if (group_titlebar) group_flags |= NK_WINDOW_TITLE;

                nk_layout_row_dynamic(ctx, 30, 3);
                nk_checkbox_label(ctx, "Titlebar", &group_titlebar);
                nk_checkbox_label(ctx, "Border", &group_border);
                nk_checkbox_label(ctx, "No Scrollbar", &group_no_scrollbar);

                nk_layout_row_begin(ctx, NK_STATIC, 22, 2);
                nk_layout_row_push(ctx, 50);
                nk_label(ctx, "size:", NK_TEXT_LEFT);
                nk_layout_row_push(ctx, 130);
                nk_property_int(ctx, "#Width:", 100, &group_width, 500, 10, 1);
                nk_layout_row_push(ctx, 130);
                nk_property_int(ctx, "#Height:", 100, &group_height, 500, 10, 1);
                nk_layout_row_end(ctx);

                nk_layout_row_static(ctx, (float)group_height, group_width, 2);
                if (nk_group_begin(ctx, &tab, "Group", group_flags)) {
                    int i = 0;
                    static int selected[16];
                    nk_layout_row_static(ctx, 18, 100, 1);
                    for (i = 0; i < 16; ++i)
                        nk_selectable_label(ctx, (selected[i]) ? "Selected": "Unselected", NK_TEXT_CENTERED, &selected[i]);
                    nk_group_end(ctx);
                }
                nk_tree_pop(ctx);
            }

            if (nk_tree_push(ctx, NK_TREE_NODE, "Simple", NK_MINIMIZED))
            {
                struct nk_panel tab;
                nk_layout_row_dynamic(ctx, 300, 2);
                if (nk_group_begin(ctx, &tab, "Group_Without_Border", 0)) {
                    int i = 0;
                    char buffer[64];
                    nk_layout_row_static(ctx, 18, 150, 1);
                    for (i = 0; i < 64; ++i) {
                        sprintf(buffer, "0x%02x", i);
                        nk_labelf(ctx, NK_TEXT_LEFT, "%s: scrollable region", buffer);
                    }
                    nk_group_end(ctx);
                }
                if (nk_group_begin(ctx, &tab, "Group_With_Border", NK_WINDOW_BORDER)) {
                    int i = 0;
                    char buffer[64];
                    nk_layout_row_dynamic(ctx, 25, 2);
                    for (i = 0; i < 64; ++i) {
                        sprintf(buffer, "%08d", ((((i%7)*10)^32))+(64+(i%2)*2));
                        nk_button_label(ctx, buffer, NK_BUTTON_DEFAULT);
                    }
                    nk_group_end(ctx);
                }
                nk_tree_pop(ctx);
            }

            if (nk_tree_push(ctx, NK_TREE_NODE, "Complex", NK_MINIMIZED))
            {
                int i;
                struct nk_panel tab;
                nk_layout_space_begin(ctx, NK_STATIC, 500, 64);
                nk_layout_space_push(ctx, nk_rect(0,0,150,500));
                if (nk_group_begin(ctx, &tab, "Group_left", NK_WINDOW_BORDER)) {
                    static int selected[32];
                    nk_layout_row_static(ctx, 18, 100, 1);
                    for (i = 0; i < 32; ++i)
                        nk_selectable_label(ctx, (selected[i]) ? "Selected": "Unselected", NK_TEXT_CENTERED, &selected[i]);
                    nk_group_end(ctx);
                }

                nk_layout_space_push(ctx, nk_rect(160,0,150,240));
                if (nk_group_begin(ctx, &tab, "Group_top", NK_WINDOW_BORDER)) {
                    nk_layout_row_dynamic(ctx, 25, 1);
                    nk_button_label(ctx, "#FFAA", NK_BUTTON_DEFAULT);
                    nk_button_label(ctx, "#FFBB", NK_BUTTON_DEFAULT);
                    nk_button_label(ctx, "#FFCC", NK_BUTTON_DEFAULT);
                    nk_button_label(ctx, "#FFDD", NK_BUTTON_DEFAULT);
                    nk_button_label(ctx, "#FFEE", NK_BUTTON_DEFAULT);
                    nk_button_label(ctx, "#FFFF", NK_BUTTON_DEFAULT);
                    nk_group_end(ctx);
                }

                nk_layout_space_push(ctx, nk_rect(160,250,150,250));
                if (nk_group_begin(ctx, &tab, "Group_buttom", NK_WINDOW_BORDER)) {
                    nk_layout_row_dynamic(ctx, 25, 1);
                    nk_button_label(ctx, "#FFAA", NK_BUTTON_DEFAULT);
                    nk_button_label(ctx, "#FFBB", NK_BUTTON_DEFAULT);
                    nk_button_label(ctx, "#FFCC", NK_BUTTON_DEFAULT);
                    nk_button_label(ctx, "#FFDD", NK_BUTTON_DEFAULT);
                    nk_button_label(ctx, "#FFEE", NK_BUTTON_DEFAULT);
                    nk_button_label(ctx, "#FFFF", NK_BUTTON_DEFAULT);
                    nk_group_end(ctx);
                }

                nk_layout_space_push(ctx, nk_rect(320,0,150,150));
                if (nk_group_begin(ctx, &tab, "Group_right_top", NK_WINDOW_BORDER)) {
                    static int selected[4];
                    nk_layout_row_static(ctx, 18, 100, 1);
                    for (i = 0; i < 4; ++i)
                        nk_selectable_label(ctx, (selected[i]) ? "Selected": "Unselected", NK_TEXT_CENTERED, &selected[i]);
                    nk_group_end(ctx);
                }

                nk_layout_space_push(ctx, nk_rect(320,160,150,150));
                if (nk_group_begin(ctx, &tab, "Group_right_center", NK_WINDOW_BORDER)) {
                    static int selected[4];
                    nk_layout_row_static(ctx, 18, 100, 1);
                    for (i = 0; i < 4; ++i)
                        nk_selectable_label(ctx, (selected[i]) ? "Selected": "Unselected", NK_TEXT_CENTERED, &selected[i]);
                    nk_group_end(ctx);
                }

                nk_layout_space_push(ctx, nk_rect(320,320,150,150));
                if (nk_group_begin(ctx, &tab, "Group_right_bottom", NK_WINDOW_BORDER)) {
                    static int selected[4];
                    nk_layout_row_static(ctx, 18, 100, 1);
                    for (i = 0; i < 4; ++i)
                        nk_selectable_label(ctx, (selected[i]) ? "Selected": "Unselected", NK_TEXT_CENTERED, &selected[i]);
                    nk_group_end(ctx);
                }
                nk_layout_space_end(ctx);
                nk_tree_pop(ctx);
            }

            if (nk_tree_push(ctx, NK_TREE_NODE, "Splitter", NK_MINIMIZED))
            {
                const struct nk_input *in = &ctx->input;
                nk_layout_row_static(ctx, 20, 320, 1);
                nk_label(ctx, "Use slider and spinner to change tile size", NK_TEXT_LEFT);
                nk_label(ctx, "Drag the space between tiles to change tile ratio", NK_TEXT_LEFT);

                if (nk_tree_push(ctx, NK_TREE_NODE, "Vertical", NK_MINIMIZED))
                {
                    static float a = 100, b = 100, c = 100;
                    struct nk_rect bounds;
                    struct nk_panel sub;

                    float row_layout[5];
                    row_layout[0] = a;
                    row_layout[1] = 8;
                    row_layout[2] = b;
                    row_layout[3] = 8;
                    row_layout[4] = c;

                    /* header */
                    nk_layout_row_static(ctx, 30, 100, 2);
                    nk_label(ctx, "left:", NK_TEXT_LEFT);
                    nk_slider_float(ctx, 10.0f, &a, 200.0f, 10.0f);

                    nk_label(ctx, "middle:", NK_TEXT_LEFT);
                    nk_slider_float(ctx, 10.0f, &b, 200.0f, 10.0f);

                    nk_label(ctx, "right:", NK_TEXT_LEFT);
                    nk_slider_float(ctx, 10.0f, &c, 200.0f, 10.0f);

                    /* tiles */
                    nk_layout_row(ctx, NK_STATIC, 200, 5, row_layout);

                    /* left space */
                    if (nk_group_begin(ctx, &sub, "left", NK_WINDOW_NO_SCROLLBAR|NK_WINDOW_BORDER|NK_WINDOW_NO_SCROLLBAR)) {
                        nk_layout_row_dynamic(ctx, 25, 1);
                        nk_button_label(ctx, "#FFAA", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFBB", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFCC", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFDD", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFEE", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFFF", NK_BUTTON_DEFAULT);
                        nk_group_end(ctx);
                    }

                    /* scaler */
                    bounds = nk_widget_bounds(ctx);
                    nk_spacing(ctx, 1);
                    if ((nk_input_is_mouse_hovering_rect(in, bounds) ||
                        nk_input_is_mouse_prev_hovering_rect(in, bounds)) &&
                        nk_input_is_mouse_down(in, NK_BUTTON_LEFT))
                    {
                        a = row_layout[0] + in->mouse.delta.x;
                        b = row_layout[2] - in->mouse.delta.x;
                    }

                    /* middle space */
                    if (nk_group_begin(ctx, &sub, "center", NK_WINDOW_BORDER|NK_WINDOW_NO_SCROLLBAR)) {
                        nk_layout_row_dynamic(ctx, 25, 1);
                        nk_button_label(ctx, "#FFAA", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFBB", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFCC", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFDD", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFEE", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFFF", NK_BUTTON_DEFAULT);
                        nk_group_end(ctx);
                    }

                    /* scaler */
                    bounds = nk_widget_bounds(ctx);
                    nk_spacing(ctx, 1);
                    if ((nk_input_is_mouse_hovering_rect(in, bounds) ||
                        nk_input_is_mouse_prev_hovering_rect(in, bounds)) &&
                        nk_input_is_mouse_down(in, NK_BUTTON_LEFT))
                    {
                        b = (row_layout[2] + in->mouse.delta.x);
                        c = (row_layout[4] - in->mouse.delta.x);
                    }

                    /* right space */
                    if (nk_group_begin(ctx, &sub, "right", NK_WINDOW_BORDER|NK_WINDOW_NO_SCROLLBAR)) {
                        nk_layout_row_dynamic(ctx, 25, 1);
                        nk_button_label(ctx, "#FFAA", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFBB", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFCC", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFDD", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFEE", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFFF", NK_BUTTON_DEFAULT);
                        nk_group_end(ctx);
                    }

                    nk_tree_pop(ctx);
                }

                if (nk_tree_push(ctx, NK_TREE_NODE, "Horizontal", NK_MINIMIZED))
                {
                    static float a = 100, b = 100, c = 100;
                    struct nk_panel sub;
                    struct nk_rect bounds;

                    /* header */
                    nk_layout_row_static(ctx, 30, 100, 2);
                    nk_label(ctx, "top:", NK_TEXT_LEFT);
                    nk_slider_float(ctx, 10.0f, &a, 200.0f, 10.0f);

                    nk_label(ctx, "middle:", NK_TEXT_LEFT);
                    nk_slider_float(ctx, 10.0f, &b, 200.0f, 10.0f);

                    nk_label(ctx, "bottom:", NK_TEXT_LEFT);
                    nk_slider_float(ctx, 10.0f, &c, 200.0f, 10.0f);

                    /* top space */
                    nk_layout_row_dynamic(ctx, a, 1);
                    if (nk_group_begin(ctx, &sub, "top", NK_WINDOW_NO_SCROLLBAR|NK_WINDOW_BORDER)) {
                        nk_layout_row_dynamic(ctx, 25, 3);
                        nk_button_label(ctx, "#FFAA", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFBB", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFCC", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFDD", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFEE", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFFF", NK_BUTTON_DEFAULT);
                        nk_group_end(ctx);
                    }

                    /* scaler */
                    nk_layout_row_dynamic(ctx, 8, 1);
                    bounds = nk_widget_bounds(ctx);
                    nk_spacing(ctx, 1);
                    if ((nk_input_is_mouse_hovering_rect(in, bounds) ||
                        nk_input_is_mouse_prev_hovering_rect(in, bounds)) &&
                        nk_input_is_mouse_down(in, NK_BUTTON_LEFT))
                    {
                        a = a + in->mouse.delta.y;
                        b = b - in->mouse.delta.y;
                    }

                    /* middle space */
                    nk_layout_row_dynamic(ctx, b, 1);
                    if (nk_group_begin(ctx, &sub, "middle", NK_WINDOW_NO_SCROLLBAR|NK_WINDOW_BORDER)) {
                        nk_layout_row_dynamic(ctx, 25, 3);
                        nk_button_label(ctx, "#FFAA", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFBB", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFCC", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFDD", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFEE", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFFF", NK_BUTTON_DEFAULT);
                        nk_group_end(ctx);
                    }

                    {
                        /* scaler */
                        nk_layout_row_dynamic(ctx, 8, 1);
                        bounds = nk_widget_bounds(ctx);
                        if ((nk_input_is_mouse_hovering_rect(in, bounds) ||
                            nk_input_is_mouse_prev_hovering_rect(in, bounds)) &&
                            nk_input_is_mouse_down(in, NK_BUTTON_LEFT))
                        {
                            b = b + in->mouse.delta.y;
                            c = c - in->mouse.delta.y;
                        }
                    }

                    /* bottom space */
                    nk_layout_row_dynamic(ctx, c, 1);
                    if (nk_group_begin(ctx, &sub, "bottom", NK_WINDOW_NO_SCROLLBAR|NK_WINDOW_BORDER)) {
                        nk_layout_row_dynamic(ctx, 25, 3);
                        nk_button_label(ctx, "#FFAA", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFBB", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFCC", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFDD", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFEE", NK_BUTTON_DEFAULT);
                        nk_button_label(ctx, "#FFFF", NK_BUTTON_DEFAULT);
                        nk_group_end(ctx);
                    }
                    nk_tree_pop(ctx);
                }
                nk_tree_pop(ctx);
            }
            nk_tree_pop(ctx);
        }
    }
    nk_end(ctx);
    return !nk_window_is_closed(ctx, "Demo");
}

/* ===============================================================
 *
 *                          DEVICE
 *
 * ===============================================================*/
struct device {
    struct nk_buffer cmds;
    struct nk_draw_null_texture null;
    GLuint vbo, vao, ebo;
    GLuint prog;
    GLuint vert_shdr;
    GLuint frag_shdr;
    GLint attrib_pos;
    GLint attrib_uv;
    GLint attrib_col;
    GLint uniform_tex;
    GLint uniform_proj;
    GLuint font_tex;
};

static void
device_init(struct device *dev)
{
    GLint status;
    static const GLchar *vertex_shader =
        "#version 300 es\n"
        "uniform mat4 ProjMtx;\n"
        "in vec2 Position;\n"
        "in vec2 TexCoord;\n"
        "in vec4 Color;\n"
        "out vec2 Frag_UV;\n"
        "out vec4 Frag_Color;\n"
        "void main() {\n"
        "   Frag_UV = TexCoord;\n"
        "   Frag_Color = Color;\n"
        "   gl_Position = ProjMtx * vec4(Position.xy, 0, 1);\n"
        "}\n";
    static const GLchar *fragment_shader =
        "#version 300 es\n"
        "precision mediump float;\n"
        "uniform sampler2D Texture;\n"
        "in vec2 Frag_UV;\n"
        "in vec4 Frag_Color;\n"
        "out vec4 Out_Color;\n"
        "void main(){\n"
        "   Out_Color = Frag_Color * texture(Texture, Frag_UV.st);\n"
        "}\n";

    nk_buffer_init_default(&dev->cmds);
    dev->prog = glCreateProgram();
    dev->vert_shdr = glCreateShader(GL_VERTEX_SHADER);
    dev->frag_shdr = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(dev->vert_shdr, 1, &vertex_shader, 0);
    glShaderSource(dev->frag_shdr, 1, &fragment_shader, 0);
    glCompileShader(dev->vert_shdr);
    glCompileShader(dev->frag_shdr);
    glGetShaderiv(dev->vert_shdr, GL_COMPILE_STATUS, &status);
    assert(status == GL_TRUE);
    glGetShaderiv(dev->frag_shdr, GL_COMPILE_STATUS, &status);
    assert(status == GL_TRUE);
    glAttachShader(dev->prog, dev->vert_shdr);
    glAttachShader(dev->prog, dev->frag_shdr);
    glLinkProgram(dev->prog);
    glGetProgramiv(dev->prog, GL_LINK_STATUS, &status);
    assert(status == GL_TRUE);

    dev->uniform_tex = glGetUniformLocation(dev->prog, "Texture");
    dev->uniform_proj = glGetUniformLocation(dev->prog, "ProjMtx");
    dev->attrib_pos = glGetAttribLocation(dev->prog, "Position");
    dev->attrib_uv = glGetAttribLocation(dev->prog, "TexCoord");
    dev->attrib_col = glGetAttribLocation(dev->prog, "Color");

    {
        /* buffer setup */
        GLsizei vs = sizeof(struct nk_draw_vertex);
        size_t vp = offsetof(struct nk_draw_vertex, position);
        size_t vt = offsetof(struct nk_draw_vertex, uv);
        size_t vc = offsetof(struct nk_draw_vertex, col);

        glGenBuffers(1, &dev->vbo);
        glGenBuffers(1, &dev->ebo);
        glGenVertexArrays(1, &dev->vao);

        glBindVertexArray(dev->vao);
        glBindBuffer(GL_ARRAY_BUFFER, dev->vbo);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, dev->ebo);

        glEnableVertexAttribArray((GLuint)dev->attrib_pos);
        glEnableVertexAttribArray((GLuint)dev->attrib_uv);
        glEnableVertexAttribArray((GLuint)dev->attrib_col);

        glVertexAttribPointer((GLuint)dev->attrib_pos, 2, GL_FLOAT, GL_FALSE, vs, (void*)vp);
        glVertexAttribPointer((GLuint)dev->attrib_uv, 2, GL_FLOAT, GL_FALSE, vs, (void*)vt);
        glVertexAttribPointer((GLuint)dev->attrib_col, 4, GL_UNSIGNED_BYTE, GL_TRUE, vs, (void*)vc);
    }

    glBindTexture(GL_TEXTURE_2D, 0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
    glBindVertexArray(0);
}

static void
device_upload_atlas(struct device *dev, const void *image, int width, int height)
{
    glGenTextures(1, &dev->font_tex);
    glBindTexture(GL_TEXTURE_2D, dev->font_tex);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, (GLsizei)width, (GLsizei)height, 0,
                GL_RGBA, GL_UNSIGNED_BYTE, image);
}

static void
device_shutdown(struct device *dev)
{
    glDetachShader(dev->prog, dev->vert_shdr);
    glDetachShader(dev->prog, dev->frag_shdr);
    glDeleteShader(dev->vert_shdr);
    glDeleteShader(dev->frag_shdr);
    glDeleteProgram(dev->prog);
    glDeleteTextures(1, &dev->font_tex);
    glDeleteBuffers(1, &dev->vbo);
    glDeleteBuffers(1, &dev->ebo);
    nk_buffer_free(&dev->cmds);
}

static void
device_draw(struct device *dev, struct nk_context *ctx, int width, int height,
    enum nk_anti_aliasing AA)
{
    GLint last_prog, last_tex;
    GLint last_ebo, last_vbo, last_vao;
    GLfloat ortho[4][4] = {
        {2.0f, 0.0f, 0.0f, 0.0f},
        {0.0f,-2.0f, 0.0f, 0.0f},
        {0.0f, 0.0f,-1.0f, 0.0f},
        {-1.0f,1.0f, 0.0f, 1.0f},
    };
    ortho[0][0] /= (GLfloat)width;
    ortho[1][1] /= (GLfloat)height;

    /* save previous opengl state */
    glGetIntegerv(GL_CURRENT_PROGRAM, &last_prog);
    glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_tex);
    glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_vao);
    glGetIntegerv(GL_ELEMENT_ARRAY_BUFFER_BINDING, &last_ebo);
    glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vbo);

    /* setup global state */
    glEnable(GL_BLEND);
    glBlendEquation(GL_FUNC_ADD);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glDisable(GL_CULL_FACE);
    glDisable(GL_DEPTH_TEST);
    glEnable(GL_SCISSOR_TEST);
    glActiveTexture(GL_TEXTURE0);

    /* setup program */
    glUseProgram(dev->prog);
    glUniform1i(dev->uniform_tex, 0);
    glUniformMatrix4fv(dev->uniform_proj, 1, GL_FALSE, &ortho[0][0]);
    {
        /* convert from command queue into draw list and draw to screen */
        const struct nk_draw_command *cmd;
        void *vertices, *elements;
        const nk_draw_index *offset = NULL;

        /* allocate vertex and element buffer */
        glBindVertexArray(dev->vao);
        glBindBuffer(GL_ARRAY_BUFFER, dev->vbo);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, dev->ebo);

        glBufferData(GL_ARRAY_BUFFER, MAX_VERTEX_MEMORY, NULL, GL_STREAM_DRAW);
        glBufferData(GL_ELEMENT_ARRAY_BUFFER, MAX_ELEMENT_MEMORY, NULL, GL_STREAM_DRAW);

        /* load draw vertices & elements directly into vertex + element buffer */
        vertices = glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY);
        elements = glMapBuffer(GL_ELEMENT_ARRAY_BUFFER, GL_WRITE_ONLY);
        {
            /* fill converting configuration */
            struct nk_convert_config config;
            memset(&config, 0, sizeof(config));
            config.global_alpha = 1.0f;
            config.shape_AA = AA;
            config.line_AA = AA;
            config.circle_segment_count = 22;
            config.curve_segment_count = 22;
            config.arc_segment_count = 22;
            config.null = dev->null;

            /* setup buffers to load vertices and elements */
            {struct nk_buffer vbuf, ebuf;
            nk_buffer_init_fixed(&vbuf, vertices, MAX_VERTEX_MEMORY);
            nk_buffer_init_fixed(&ebuf, elements, MAX_ELEMENT_MEMORY);
            nk_convert(ctx, &dev->cmds, &vbuf, &ebuf, &config);}
        }
        glUnmapBuffer(GL_ARRAY_BUFFER);
        glUnmapBuffer(GL_ELEMENT_ARRAY_BUFFER);

        /* iterate over and execute each draw command */
        nk_draw_foreach(cmd, ctx, &dev->cmds) {
            if (!cmd->elem_count) continue;
            glBindTexture(GL_TEXTURE_2D, (GLuint)cmd->texture.id);
            glScissor((GLint)cmd->clip_rect.x,
                height - (GLint)(cmd->clip_rect.y + cmd->clip_rect.h),
                (GLint)cmd->clip_rect.w, (GLint)cmd->clip_rect.h);
            glDrawElements(GL_TRIANGLES, (GLsizei)cmd->elem_count, GL_UNSIGNED_SHORT, offset);
            offset += cmd->elem_count;
        }
        nk_clear(ctx);
    }

    /* restore old state */
    glUseProgram((GLuint)last_prog);
    glBindTexture(GL_TEXTURE_2D, (GLuint)last_tex);
    glBindBuffer(GL_ARRAY_BUFFER, (GLuint)last_vbo);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, (GLuint)last_ebo);
    glBindVertexArray((GLuint)last_vao);
    glDisable(GL_SCISSOR_TEST);
}


/* glfw callbacks (I don't know if there is a easier way to access text and scroll )*/
static void error_callback(int e, const char *d){printf("Error %d: %s\n", e, d);}
static void text_input(GLFWwindow *win, unsigned int codepoint)
{nk_input_unicode((struct nk_context*)glfwGetWindowUserPointer(win), codepoint);}
static void scroll_input(GLFWwindow *win, double _, double yoff)
{UNUSED(_);nk_input_scroll((struct nk_context*)glfwGetWindowUserPointer(win), (float)yoff);}

int main(int argc, char *argv[])
{
    /* Platform */
    static GLFWwindow *win;
    int width = 0, height = 0;

    /* GUI */
    struct device device;
    struct nk_context ctx;
    struct nk_font *font;
    struct nk_font_atlas atlas;

    /* GLFW */
    glfwSetErrorCallback(error_callback);
    if (!glfwInit()) {
        fprintf(stdout, "[GFLW] failed to init!\n");
        exit(1);
    }
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
#ifdef __APPLE__
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endif
    win = glfwCreateWindow(WINDOW_WIDTH, WINDOW_HEIGHT, "Demo", NULL, NULL);
    glfwMakeContextCurrent(win);
    glfwSetWindowUserPointer(win, &ctx);
    glfwSetCharCallback(win, text_input);
    glfwSetScrollCallback(win, scroll_input);

    /* OpenGL */
    glViewport(0, 0, WINDOW_WIDTH, WINDOW_HEIGHT);
    glewExperimental = 1;
    if (glewInit() != GLEW_OK) {
        fprintf(stderr, "Failed to setup GLEW\n");
        exit(1);
    }

    {/* GUI */
    device_init(&device);
    {const void *image; int w, h;
    const char *font_path = (argc > 1) ? argv[1]: 0;
    nk_font_atlas_init_default(&atlas);
    nk_font_atlas_begin(&atlas);
    if (font_path) font = nk_font_atlas_add_from_file(&atlas, font_path, 14.0f, NULL);
    else font = nk_font_atlas_add_default(&atlas, 14.0f, NULL);
    image = nk_font_atlas_bake(&atlas, &w, &h, NK_FONT_ATLAS_RGBA32);
    device_upload_atlas(&device, image, w, h);
    nk_font_atlas_end(&atlas, nk_handle_id((int)device.font_tex), &device.null);}
    nk_init_default(&ctx, &font->handle);}

    while (!glfwWindowShouldClose(win))
    {
        /* Input */
        {double x, y;
        nk_input_begin(&ctx);
        glfwPollEvents();
        nk_input_key(&ctx, NK_KEY_DEL, glfwGetKey(win, GLFW_KEY_DELETE) == GLFW_PRESS);
        nk_input_key(&ctx, NK_KEY_ENTER, glfwGetKey(win, GLFW_KEY_ENTER) == GLFW_PRESS);
        nk_input_key(&ctx, NK_KEY_TAB, glfwGetKey(win, GLFW_KEY_TAB) == GLFW_PRESS);
        nk_input_key(&ctx, NK_KEY_BACKSPACE, glfwGetKey(win, GLFW_KEY_BACKSPACE) == GLFW_PRESS);
        nk_input_key(&ctx, NK_KEY_LEFT, glfwGetKey(win, GLFW_KEY_LEFT) == GLFW_PRESS);
        nk_input_key(&ctx, NK_KEY_RIGHT, glfwGetKey(win, GLFW_KEY_RIGHT) == GLFW_PRESS);
        nk_input_key(&ctx, NK_KEY_UP, glfwGetKey(win, GLFW_KEY_UP) == GLFW_PRESS);
        nk_input_key(&ctx, NK_KEY_DOWN, glfwGetKey(win, GLFW_KEY_DOWN) == GLFW_PRESS);
        if (glfwGetKey(win, GLFW_KEY_LEFT_CONTROL) == GLFW_PRESS ||
            glfwGetKey(win, GLFW_KEY_RIGHT_CONTROL)) {
            nk_input_key(&ctx, NK_KEY_COPY, glfwGetKey(win, GLFW_KEY_C) == GLFW_PRESS);
            nk_input_key(&ctx, NK_KEY_PASTE, glfwGetKey(win, GLFW_KEY_P) == GLFW_PRESS);
            nk_input_key(&ctx, NK_KEY_CUT, glfwGetKey(win, GLFW_KEY_X) == GLFW_PRESS);
            nk_input_key(&ctx, NK_KEY_CUT, glfwGetKey(win, GLFW_KEY_E) == GLFW_PRESS);
            nk_input_key(&ctx, NK_KEY_SHIFT, 1);
        } else {
            nk_input_key(&ctx, NK_KEY_COPY, 0);
            nk_input_key(&ctx, NK_KEY_PASTE, 0);
            nk_input_key(&ctx, NK_KEY_CUT, 0);
            nk_input_key(&ctx, NK_KEY_SHIFT, 0);
        }
        glfwGetCursorPos(win, &x, &y);
        nk_input_motion(&ctx, (int)x, (int)y);
        nk_input_button(&ctx, NK_BUTTON_LEFT, (int)x, (int)y, glfwGetMouseButton(win, GLFW_MOUSE_BUTTON_LEFT) == GLFW_PRESS);
        nk_input_button(&ctx, NK_BUTTON_MIDDLE, (int)x, (int)y, glfwGetMouseButton(win, GLFW_MOUSE_BUTTON_MIDDLE) == GLFW_PRESS);
        nk_input_button(&ctx, NK_BUTTON_RIGHT, (int)x, (int)y, glfwGetMouseButton(win, GLFW_MOUSE_BUTTON_RIGHT) == GLFW_PRESS);
        nk_input_end(&ctx);}

        /* GUI */
        if (!overview_window(&ctx)) break;

        /* Draw */
        glfwGetWindowSize(win, &width, &height);
        glViewport(0, 0, width, height);
        glClear(GL_COLOR_BUFFER_BIT);
        glClearColor(0.2f, 0.2f, 0.2f, 1.0f);
        device_draw(&device, &ctx, width, height, NK_ANTI_ALIASING_ON);
        glfwSwapBuffers(win);
    }

    nk_font_atlas_clear(&atlas);
    nk_free(&ctx);
    device_shutdown(&device);
    glfwTerminate();
    return 0;
}