Add vulkan resources

lib/imgui/imconfig.h

@@ -0,0 +1,108 @@
+//-----------------------------------------------------------------------------
+// COMPILE-TIME OPTIONS FOR DEAR IMGUI
+// Runtime options (clipboard callbacks, enabling various features, etc.) can generally be set via the ImGuiIO structure.
+// You can use ImGui::SetAllocatorFunctions() before calling ImGui::CreateContext() to rewire memory allocation functions.
+//-----------------------------------------------------------------------------
+// A) You may edit imconfig.h (and not overwrite it when updating Dear ImGui, or maintain a patch/branch with your modifications to imconfig.h)
+// B) or add configuration directives in your own file and compile with #define IMGUI_USER_CONFIG "myfilename.h"
+// If you do so you need to make sure that configuration settings are defined consistently _everywhere_ Dear ImGui is used, which include
+// the imgui*.cpp files but also _any_ of your code that uses Dear ImGui. This is because some compile-time options have an affect on data structures.
+// Defining those options in imconfig.h will ensure every compilation unit gets to see the same data structure layouts.
+// Call IMGUI_CHECKVERSION() from your .cpp files to verify that the data structures your files are using are matching the ones imgui.cpp is using.
+//-----------------------------------------------------------------------------
+
+#pragma once
+
+//---- Define assertion handler. Defaults to calling assert().
+// If your macro uses multiple statements, make sure is enclosed in a 'do { .. } while (0)' block so it can be used as a single statement.
+//#define IM_ASSERT(_EXPR)  MyAssert(_EXPR)
+//#define IM_ASSERT(_EXPR)  ((void)(_EXPR))     // Disable asserts
+
+//---- Define attributes of all API symbols declarations, e.g. for DLL under Windows
+// Using dear imgui via a shared library is not recommended, because of function call overhead and because we don't guarantee backward nor forward ABI compatibility.
+//#define IMGUI_API __declspec( dllexport )
+//#define IMGUI_API __declspec( dllimport )
+
+//---- Don't define obsolete functions/enums/behaviors. Consider enabling from time to time after updating to avoid using soon-to-be obsolete function/names.
+//#define IMGUI_DISABLE_OBSOLETE_FUNCTIONS
+
+//---- Disable all of Dear ImGui or don't implement standard windows.
+// It is very strongly recommended to NOT disable the demo windows during development. Please read comments in imgui_demo.cpp.
+//#define IMGUI_DISABLE                                     // Disable everything: all headers and source files will be empty.
+//#define IMGUI_DISABLE_DEMO_WINDOWS                        // Disable demo windows: ShowDemoWindow()/ShowStyleEditor() will be empty. Not recommended.
+//#define IMGUI_DISABLE_METRICS_WINDOW                      // Disable debug/metrics window: ShowMetricsWindow() will be empty.
+
+//---- Don't implement some functions to reduce linkage requirements.
+//#define IMGUI_DISABLE_WIN32_DEFAULT_CLIPBOARD_FUNCTIONS   // [Win32] Don't implement default clipboard handler. Won't use and link with OpenClipboard/GetClipboardData/CloseClipboard etc.
+//#define IMGUI_DISABLE_WIN32_DEFAULT_IME_FUNCTIONS         // [Win32] Don't implement default IME handler. Won't use and link with ImmGetContext/ImmSetCompositionWindow.
+//#define IMGUI_DISABLE_WIN32_FUNCTIONS                     // [Win32] Won't use and link with any Win32 function (clipboard, ime).
+//#define IMGUI_ENABLE_OSX_DEFAULT_CLIPBOARD_FUNCTIONS      // [OSX] Implement default OSX clipboard handler (need to link with '-framework ApplicationServices', this is why this is not the default).
+//#define IMGUI_DISABLE_DEFAULT_FORMAT_FUNCTIONS            // Don't implement ImFormatString/ImFormatStringV so you can implement them yourself (e.g. if you don't want to link with vsnprintf)
+//#define IMGUI_DISABLE_DEFAULT_MATH_FUNCTIONS              // Don't implement ImFabs/ImSqrt/ImPow/ImFmod/ImCos/ImSin/ImAcos/ImAtan2 so you can implement them yourself.
+//#define IMGUI_DISABLE_DEFAULT_FILE_FUNCTIONS              // Don't implement ImFileOpen/ImFileClose/ImFileRead/ImFileWrite so you can implement them yourself if you don't want to link with fopen/fclose/fread/fwrite. This will also disable the LogToTTY() function.
+//#define IMGUI_DISABLE_DEFAULT_ALLOCATORS                  // Don't implement default allocators calling malloc()/free() to avoid linking with them. You will need to call ImGui::SetAllocatorFunctions().
+
+//---- Include imgui_user.h at the end of imgui.h as a convenience
+//#define IMGUI_INCLUDE_IMGUI_USER_H
+
+//---- Pack colors to BGRA8 instead of RGBA8 (to avoid converting from one to another)
+//#define IMGUI_USE_BGRA_PACKED_COLOR
+
+//---- Use 32-bit for ImWchar (default is 16-bit) to support full unicode code points.
+//#define IMGUI_USE_WCHAR32
+
+//---- Avoid multiple STB libraries implementations, or redefine path/filenames to prioritize another version
+// By default the embedded implementations are declared static and not available outside of imgui cpp files.
+//#define IMGUI_STB_TRUETYPE_FILENAME   "my_folder/stb_truetype.h"
+//#define IMGUI_STB_RECT_PACK_FILENAME  "my_folder/stb_rect_pack.h"
+//#define IMGUI_DISABLE_STB_TRUETYPE_IMPLEMENTATION
+//#define IMGUI_DISABLE_STB_RECT_PACK_IMPLEMENTATION
+
+//---- Unless IMGUI_DISABLE_DEFAULT_FORMAT_FUNCTIONS is defined, use the much faster STB sprintf library implementation of vsnprintf instead of the one from the default C library.
+// Note that stb_sprintf.h is meant to be provided by the user and available in the include path at compile time. Also, the compatibility checks of the arguments and formats done by clang and GCC will be disabled in order to support the extra formats provided by STB sprintf.
+// #define IMGUI_USE_STB_SPRINTF
+
+//---- Define constructor and implicit cast operators to convert back<>forth between your math types and ImVec2/ImVec4.
+// This will be inlined as part of ImVec2 and ImVec4 class declarations.
+/*
+#define IM_VEC2_CLASS_EXTRA                                                 \
+        ImVec2(const MyVec2& f) { x = f.x; y = f.y; }                       \
+        operator MyVec2() const { return MyVec2(x,y); }
+
+#define IM_VEC4_CLASS_EXTRA                                                 \
+        ImVec4(const MyVec4& f) { x = f.x; y = f.y; z = f.z; w = f.w; }     \
+        operator MyVec4() const { return MyVec4(x,y,z,w); }
+*/
+
+//---- Use 32-bit vertex indices (default is 16-bit) is one way to allow large meshes with more than 64K vertices.
+// Your renderer back-end will need to support it (most example renderer back-ends support both 16/32-bit indices).
+// Another way to allow large meshes while keeping 16-bit indices is to handle ImDrawCmd::VtxOffset in your renderer.
+// Read about ImGuiBackendFlags_RendererHasVtxOffset for details.
+//#define ImDrawIdx unsigned int
+
+//---- Override ImDrawCallback signature (will need to modify renderer back-ends accordingly)
+//struct ImDrawList;
+//struct ImDrawCmd;
+//typedef void (*MyImDrawCallback)(const ImDrawList* draw_list, const ImDrawCmd* cmd, void* my_renderer_user_data);
+//#define ImDrawCallback MyImDrawCallback
+
+//---- Debug Tools: Macro to break in Debugger
+// (use 'Metrics->Tools->Item Picker' to pick widgets with the mouse and break into them for easy debugging.)
+//#define IM_DEBUG_BREAK  IM_ASSERT(0)
+//#define IM_DEBUG_BREAK  __debugbreak()
+
+//---- Debug Tools: Have the Item Picker break in the ItemAdd() function instead of ItemHoverable(),
+// (which comes earlier in the code, will catch a few extra items, allow picking items other than Hovered one.)
+// This adds a small runtime cost which is why it is not enabled by default.
+//#define IMGUI_DEBUG_TOOL_ITEM_PICKER_EX
+
+//---- Debug Tools: Enable slower asserts
+//#define IMGUI_DEBUG_PARANOID
+
+//---- Tip: You can add extra functions within the ImGui:: namespace, here or in your own headers files.
+/*
+namespace ImGui
+{
+    void MyFunction(const char* name, const MyMatrix44& v);
+}
+*/

lib/imgui/imgui_impl_sdl.cpp

@@ -0,0 +1,367 @@
+// dear imgui: Platform Binding for SDL2
+// This needs to be used along with a Renderer (e.g. DirectX11, OpenGL3, Vulkan..)
+// (Info: SDL2 is a cross-platform general purpose library for handling windows, inputs, graphics context creation, etc.)
+// (Requires: SDL 2.0. Prefer SDL 2.0.4+ for full feature support.)
+
+// Implemented features:
+//  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
+//  [X] Platform: Clipboard support.
+//  [X] Platform: Keyboard arrays indexed using SDL_SCANCODE_* codes, e.g. ImGui::IsKeyPressed(SDL_SCANCODE_SPACE).
+//  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
+// Missing features:
+//  [ ] Platform: SDL2 handling of IME under Windows appears to be broken and it explicitly disable the regular Windows IME. You can restore Windows IME by compiling SDL with SDL_DISABLE_WINDOWS_IME.
+
+// You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
+// If you are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
+// https://github.com/ocornut/imgui
+
+// CHANGELOG
+// (minor and older changes stripped away, please see git history for details)
+//  2020-02-20: Inputs: Fixed mapping for ImGuiKey_KeyPadEnter (using SDL_SCANCODE_KP_ENTER instead of SDL_SCANCODE_RETURN2).
+//  2019-12-17: Inputs: On Wayland, use SDL_GetMouseState (because there is no global mouse state).
+//  2019-12-05: Inputs: Added support for ImGuiMouseCursor_NotAllowed mouse cursor.
+//  2019-07-21: Inputs: Added mapping for ImGuiKey_KeyPadEnter.
+//  2019-04-23: Inputs: Added support for SDL_GameController (if ImGuiConfigFlags_NavEnableGamepad is set by user application).
+//  2019-03-12: Misc: Preserve DisplayFramebufferScale when main window is minimized.
+//  2018-12-21: Inputs: Workaround for Android/iOS which don't seem to handle focus related calls.
+//  2018-11-30: Misc: Setting up io.BackendPlatformName so it can be displayed in the About Window.
+//  2018-11-14: Changed the signature of ImGui_ImplSDL2_ProcessEvent() to take a 'const SDL_Event*'.
+//  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_sdl.cpp/.h away from the old combined SDL2+OpenGL/Vulkan examples.
+//  2018-06-08: Misc: ImGui_ImplSDL2_InitForOpenGL() now takes a SDL_GLContext parameter.
+//  2018-05-09: Misc: Fixed clipboard paste memory leak (we didn't call SDL_FreeMemory on the data returned by SDL_GetClipboardText).
+//  2018-03-20: Misc: Setup io.BackendFlags ImGuiBackendFlags_HasMouseCursors flag + honor ImGuiConfigFlags_NoMouseCursorChange flag.
+//  2018-02-16: Inputs: Added support for mouse cursors, honoring ImGui::GetMouseCursor() value.
+//  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.
+//  2018-02-05: Misc: Using SDL_GetPerformanceCounter() instead of SDL_GetTicks() to be able to handle very high framerate (1000+ FPS).
+//  2018-02-05: Inputs: Keyboard mapping is using scancodes everywhere instead of a confusing mixture of keycodes and scancodes.
+//  2018-01-20: Inputs: Added Horizontal Mouse Wheel support.
+//  2018-01-19: Inputs: When available (SDL 2.0.4+) using SDL_CaptureMouse() to retrieve coordinates outside of client area when dragging. Otherwise (SDL 2.0.3 and before) testing for SDL_WINDOW_INPUT_FOCUS instead of SDL_WINDOW_MOUSE_FOCUS.
+//  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_sdl.h"
+
+// SDL
+#include <SDL.h>
+#include <SDL_syswm.h>
+#if defined(__APPLE__)
+#include "TargetConditionals.h"
+#endif
+
+#define SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE    SDL_VERSION_ATLEAST(2,0,4)
+#define SDL_HAS_VULKAN                      SDL_VERSION_ATLEAST(2,0,6)
+
+// Data
+static SDL_Window*  g_Window = NULL;
+static Uint64       g_Time = 0;
+static bool         g_MousePressed[3] = { false, false, false };
+static SDL_Cursor*  g_MouseCursors[ImGuiMouseCursor_COUNT] = {};
+static char*        g_ClipboardTextData = NULL;
+static bool         g_MouseCanUseGlobalState = true;
+
+static const char* ImGui_ImplSDL2_GetClipboardText(void*)
+{
+    if (g_ClipboardTextData)
+        SDL_free(g_ClipboardTextData);
+    g_ClipboardTextData = SDL_GetClipboardText();
+    return g_ClipboardTextData;
+}
+
+static void ImGui_ImplSDL2_SetClipboardText(void*, const char* text)
+{
+    SDL_SetClipboardText(text);
+}
+
+// You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
+// - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application.
+// - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application.
+// Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
+// If you have multiple SDL events and some of them are not meant to be used by dear imgui, you may need to filter events based on their windowID field.
+bool ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    switch (event->type)
+    {
+    case SDL_MOUSEWHEEL:
+        {
+            if (event->wheel.x > 0) io.MouseWheelH += 1;
+            if (event->wheel.x < 0) io.MouseWheelH -= 1;
+            if (event->wheel.y > 0) io.MouseWheel += 1;
+            if (event->wheel.y < 0) io.MouseWheel -= 1;
+            return true;
+        }
+    case SDL_MOUSEBUTTONDOWN:
+        {
+            if (event->button.button == SDL_BUTTON_LEFT) g_MousePressed[0] = true;
+            if (event->button.button == SDL_BUTTON_RIGHT) g_MousePressed[1] = true;
+            if (event->button.button == SDL_BUTTON_MIDDLE) g_MousePressed[2] = true;
+            return true;
+        }
+    case SDL_TEXTINPUT:
+        {
+            io.AddInputCharactersUTF8(event->text.text);
+            return true;
+        }
+    case SDL_KEYDOWN:
+    case SDL_KEYUP:
+        {
+            int key = event->key.keysym.scancode;
+            IM_ASSERT(key >= 0 && key < IM_ARRAYSIZE(io.KeysDown));
+            io.KeysDown[key] = (event->type == SDL_KEYDOWN);
+            io.KeyShift = ((SDL_GetModState() & KMOD_SHIFT) != 0);
+            io.KeyCtrl = ((SDL_GetModState() & KMOD_CTRL) != 0);
+            io.KeyAlt = ((SDL_GetModState() & KMOD_ALT) != 0);
+#ifdef _WIN32
+            io.KeySuper = false;
+#else
+            io.KeySuper = ((SDL_GetModState() & KMOD_GUI) != 0);
+#endif
+            return true;
+        }
+    }
+    return false;
+}
+
+static bool ImGui_ImplSDL2_Init(SDL_Window* window)
+{
+    g_Window = window;
+
+    // Setup back-end capabilities flags
+    ImGuiIO& io = ImGui::GetIO();
+    io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;       // We can honor GetMouseCursor() values (optional)
+    io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;        // We can honor io.WantSetMousePos requests (optional, rarely used)
+    io.BackendPlatformName = "imgui_impl_sdl";
+
+    // Keyboard mapping. ImGui will use those indices to peek into the io.KeysDown[] array.
+    io.KeyMap[ImGuiKey_Tab] = SDL_SCANCODE_TAB;
+    io.KeyMap[ImGuiKey_LeftArrow] = SDL_SCANCODE_LEFT;
+    io.KeyMap[ImGuiKey_RightArrow] = SDL_SCANCODE_RIGHT;
+    io.KeyMap[ImGuiKey_UpArrow] = SDL_SCANCODE_UP;
+    io.KeyMap[ImGuiKey_DownArrow] = SDL_SCANCODE_DOWN;
+    io.KeyMap[ImGuiKey_PageUp] = SDL_SCANCODE_PAGEUP;
+    io.KeyMap[ImGuiKey_PageDown] = SDL_SCANCODE_PAGEDOWN;
+    io.KeyMap[ImGuiKey_Home] = SDL_SCANCODE_HOME;
+    io.KeyMap[ImGuiKey_End] = SDL_SCANCODE_END;
+    io.KeyMap[ImGuiKey_Insert] = SDL_SCANCODE_INSERT;
+    io.KeyMap[ImGuiKey_Delete] = SDL_SCANCODE_DELETE;
+    io.KeyMap[ImGuiKey_Backspace] = SDL_SCANCODE_BACKSPACE;
+    io.KeyMap[ImGuiKey_Space] = SDL_SCANCODE_SPACE;
+    io.KeyMap[ImGuiKey_Enter] = SDL_SCANCODE_RETURN;
+    io.KeyMap[ImGuiKey_Escape] = SDL_SCANCODE_ESCAPE;
+    io.KeyMap[ImGuiKey_KeyPadEnter] = SDL_SCANCODE_KP_ENTER;
+    io.KeyMap[ImGuiKey_A] = SDL_SCANCODE_A;
+    io.KeyMap[ImGuiKey_C] = SDL_SCANCODE_C;
+    io.KeyMap[ImGuiKey_V] = SDL_SCANCODE_V;
+    io.KeyMap[ImGuiKey_X] = SDL_SCANCODE_X;
+    io.KeyMap[ImGuiKey_Y] = SDL_SCANCODE_Y;
+    io.KeyMap[ImGuiKey_Z] = SDL_SCANCODE_Z;
+
+    io.SetClipboardTextFn = ImGui_ImplSDL2_SetClipboardText;
+    io.GetClipboardTextFn = ImGui_ImplSDL2_GetClipboardText;
+    io.ClipboardUserData = NULL;
+
+    // Load mouse cursors
+    g_MouseCursors[ImGuiMouseCursor_Arrow] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_ARROW);
+    g_MouseCursors[ImGuiMouseCursor_TextInput] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_IBEAM);
+    g_MouseCursors[ImGuiMouseCursor_ResizeAll] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZEALL);
+    g_MouseCursors[ImGuiMouseCursor_ResizeNS] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZENS);
+    g_MouseCursors[ImGuiMouseCursor_ResizeEW] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZEWE);
+    g_MouseCursors[ImGuiMouseCursor_ResizeNESW] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZENESW);
+    g_MouseCursors[ImGuiMouseCursor_ResizeNWSE] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZENWSE);
+    g_MouseCursors[ImGuiMouseCursor_Hand] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_HAND);
+    g_MouseCursors[ImGuiMouseCursor_NotAllowed] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_NO);
+
+    // Check and store if we are on Wayland
+    g_MouseCanUseGlobalState = strncmp(SDL_GetCurrentVideoDriver(), "wayland", 7) != 0;
+
+#ifdef _WIN32
+    SDL_SysWMinfo wmInfo;
+    SDL_VERSION(&wmInfo.version);
+    SDL_GetWindowWMInfo(window, &wmInfo);
+    io.ImeWindowHandle = wmInfo.info.win.window;
+#else
+    (void)window;
+#endif
+
+    return true;
+}
+
+bool ImGui_ImplSDL2_InitForOpenGL(SDL_Window* window, void* sdl_gl_context)
+{
+    (void)sdl_gl_context; // Viewport branch will need this.
+    return ImGui_ImplSDL2_Init(window);
+}
+
+bool ImGui_ImplSDL2_InitForVulkan(SDL_Window* window)
+{
+#if !SDL_HAS_VULKAN
+    IM_ASSERT(0 && "Unsupported");
+#endif
+    return ImGui_ImplSDL2_Init(window);
+}
+
+bool ImGui_ImplSDL2_InitForD3D(SDL_Window* window)
+{
+#if !defined(_WIN32)
+    IM_ASSERT(0 && "Unsupported");
+#endif
+    return ImGui_ImplSDL2_Init(window);
+}
+
+bool ImGui_ImplSDL2_InitForMetal(SDL_Window* window)
+{
+    return ImGui_ImplSDL2_Init(window);
+}
+
+void ImGui_ImplSDL2_Shutdown()
+{
+    g_Window = NULL;
+
+    // Destroy last known clipboard data
+    if (g_ClipboardTextData)
+        SDL_free(g_ClipboardTextData);
+    g_ClipboardTextData = NULL;
+
+    // Destroy SDL mouse cursors
+    for (ImGuiMouseCursor cursor_n = 0; cursor_n < ImGuiMouseCursor_COUNT; cursor_n++)
+        SDL_FreeCursor(g_MouseCursors[cursor_n]);
+    memset(g_MouseCursors, 0, sizeof(g_MouseCursors));
+}
+
+static void ImGui_ImplSDL2_UpdateMousePosAndButtons()
+{
+    ImGuiIO& io = ImGui::GetIO();
+
+    // Set OS mouse position if requested (rarely used, only when ImGuiConfigFlags_NavEnableSetMousePos is enabled by user)
+    if (io.WantSetMousePos)
+        SDL_WarpMouseInWindow(g_Window, (int)io.MousePos.x, (int)io.MousePos.y);
+    else
+        io.MousePos = ImVec2(-FLT_MAX, -FLT_MAX);
+
+    int mx, my;
+    Uint32 mouse_buttons = SDL_GetMouseState(&mx, &my);
+    io.MouseDown[0] = g_MousePressed[0] || (mouse_buttons & SDL_BUTTON(SDL_BUTTON_LEFT)) != 0;  // If a mouse press event came, always pass it as "mouse held this frame", so we don't miss click-release events that are shorter than 1 frame.
+    io.MouseDown[1] = g_MousePressed[1] || (mouse_buttons & SDL_BUTTON(SDL_BUTTON_RIGHT)) != 0;
+    io.MouseDown[2] = g_MousePressed[2] || (mouse_buttons & SDL_BUTTON(SDL_BUTTON_MIDDLE)) != 0;
+    g_MousePressed[0] = g_MousePressed[1] = g_MousePressed[2] = false;
+
+#if SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE && !defined(__EMSCRIPTEN__) && !defined(__ANDROID__) && !(defined(__APPLE__) && TARGET_OS_IOS)
+    SDL_Window* focused_window = SDL_GetKeyboardFocus();
+    if (g_Window == focused_window)
+    {
+        if (g_MouseCanUseGlobalState)
+        {
+            // SDL_GetMouseState() gives mouse position seemingly based on the last window entered/focused(?)
+            // The creation of a new windows at runtime and SDL_CaptureMouse both seems to severely mess up with that, so we retrieve that position globally.
+            // Won't use this workaround when on Wayland, as there is no global mouse position.
+            int wx, wy;
+            SDL_GetWindowPosition(focused_window, &wx, &wy);
+            SDL_GetGlobalMouseState(&mx, &my);
+            mx -= wx;
+            my -= wy;
+        }
+        io.MousePos = ImVec2((float)mx, (float)my);
+    }
+
+    // SDL_CaptureMouse() let the OS know e.g. that our imgui drag outside the SDL window boundaries shouldn't e.g. trigger the OS window resize cursor.
+    // The function is only supported from SDL 2.0.4 (released Jan 2016)
+    bool any_mouse_button_down = ImGui::IsAnyMouseDown();
+    SDL_CaptureMouse(any_mouse_button_down ? SDL_TRUE : SDL_FALSE);
+#else
+    if (SDL_GetWindowFlags(g_Window) & SDL_WINDOW_INPUT_FOCUS)
+        io.MousePos = ImVec2((float)mx, (float)my);
+#endif
+}
+
+static void ImGui_ImplSDL2_UpdateMouseCursor()
+{
+    ImGuiIO& io = ImGui::GetIO();
+    if (io.ConfigFlags & ImGuiConfigFlags_NoMouseCursorChange)
+        return;
+
+    ImGuiMouseCursor imgui_cursor = ImGui::GetMouseCursor();
+    if (io.MouseDrawCursor || imgui_cursor == ImGuiMouseCursor_None)
+    {
+        // Hide OS mouse cursor if imgui is drawing it or if it wants no cursor
+        SDL_ShowCursor(SDL_FALSE);
+    }
+    else
+    {
+        // Show OS mouse cursor
+        SDL_SetCursor(g_MouseCursors[imgui_cursor] ? g_MouseCursors[imgui_cursor] : g_MouseCursors[ImGuiMouseCursor_Arrow]);
+        SDL_ShowCursor(SDL_TRUE);
+    }
+}
+
+static void ImGui_ImplSDL2_UpdateGamepads()
+{
+    ImGuiIO& io = ImGui::GetIO();
+    memset(io.NavInputs, 0, sizeof(io.NavInputs));
+    if ((io.ConfigFlags & ImGuiConfigFlags_NavEnableGamepad) == 0)
+        return;
+
+    // Get gamepad
+    SDL_GameController* game_controller = SDL_GameControllerOpen(0);
+    if (!game_controller)
+    {
+        io.BackendFlags &= ~ImGuiBackendFlags_HasGamepad;
+        return;
+    }
+
+    // Update gamepad inputs
+    #define MAP_BUTTON(NAV_NO, BUTTON_NO)       { io.NavInputs[NAV_NO] = (SDL_GameControllerGetButton(game_controller, BUTTON_NO) != 0) ? 1.0f : 0.0f; }
+    #define MAP_ANALOG(NAV_NO, AXIS_NO, V0, V1) { float vn = (float)(SDL_GameControllerGetAxis(game_controller, AXIS_NO) - V0) / (float)(V1 - V0); if (vn > 1.0f) vn = 1.0f; if (vn > 0.0f && io.NavInputs[NAV_NO] < vn) io.NavInputs[NAV_NO] = vn; }
+    const int thumb_dead_zone = 8000;           // SDL_gamecontroller.h suggests using this value.
+    MAP_BUTTON(ImGuiNavInput_Activate,      SDL_CONTROLLER_BUTTON_A);               // Cross / A
+    MAP_BUTTON(ImGuiNavInput_Cancel,        SDL_CONTROLLER_BUTTON_B);               // Circle / B
+    MAP_BUTTON(ImGuiNavInput_Menu,          SDL_CONTROLLER_BUTTON_X);               // Square / X
+    MAP_BUTTON(ImGuiNavInput_Input,         SDL_CONTROLLER_BUTTON_Y);               // Triangle / Y
+    MAP_BUTTON(ImGuiNavInput_DpadLeft,      SDL_CONTROLLER_BUTTON_DPAD_LEFT);       // D-Pad Left
+    MAP_BUTTON(ImGuiNavInput_DpadRight,     SDL_CONTROLLER_BUTTON_DPAD_RIGHT);      // D-Pad Right
+    MAP_BUTTON(ImGuiNavInput_DpadUp,        SDL_CONTROLLER_BUTTON_DPAD_UP);         // D-Pad Up
+    MAP_BUTTON(ImGuiNavInput_DpadDown,      SDL_CONTROLLER_BUTTON_DPAD_DOWN);       // D-Pad Down
+    MAP_BUTTON(ImGuiNavInput_FocusPrev,     SDL_CONTROLLER_BUTTON_LEFTSHOULDER);    // L1 / LB
+    MAP_BUTTON(ImGuiNavInput_FocusNext,     SDL_CONTROLLER_BUTTON_RIGHTSHOULDER);   // R1 / RB
+    MAP_BUTTON(ImGuiNavInput_TweakSlow,     SDL_CONTROLLER_BUTTON_LEFTSHOULDER);    // L1 / LB
+    MAP_BUTTON(ImGuiNavInput_TweakFast,     SDL_CONTROLLER_BUTTON_RIGHTSHOULDER);   // R1 / RB
+    MAP_ANALOG(ImGuiNavInput_LStickLeft,    SDL_CONTROLLER_AXIS_LEFTX, -thumb_dead_zone, -32768);
+    MAP_ANALOG(ImGuiNavInput_LStickRight,   SDL_CONTROLLER_AXIS_LEFTX, +thumb_dead_zone, +32767);
+    MAP_ANALOG(ImGuiNavInput_LStickUp,      SDL_CONTROLLER_AXIS_LEFTY, -thumb_dead_zone, -32767);
+    MAP_ANALOG(ImGuiNavInput_LStickDown,    SDL_CONTROLLER_AXIS_LEFTY, +thumb_dead_zone, +32767);
+
+    io.BackendFlags |= ImGuiBackendFlags_HasGamepad;
+    #undef MAP_BUTTON
+    #undef MAP_ANALOG
+}
+
+void ImGui_ImplSDL2_NewFrame(SDL_Window* window)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    IM_ASSERT(io.Fonts->IsBuilt() && "Font atlas not built! It is generally built by the renderer back-end. Missing call to renderer _NewFrame() function? e.g. ImGui_ImplOpenGL3_NewFrame().");
+
+    // Setup display size (every frame to accommodate for window resizing)
+    int w, h;
+    int display_w, display_h;
+    SDL_GetWindowSize(window, &w, &h);
+    SDL_GL_GetDrawableSize(window, &display_w, &display_h);
+    io.DisplaySize = ImVec2((float)w, (float)h);
+    if (w > 0 && h > 0)
+        io.DisplayFramebufferScale = ImVec2((float)display_w / w, (float)display_h / h);
+
+    // Setup time step (we don't use SDL_GetTicks() because it is using millisecond resolution)
+    static Uint64 frequency = SDL_GetPerformanceFrequency();
+    Uint64 current_time = SDL_GetPerformanceCounter();
+    io.DeltaTime = g_Time > 0 ? (float)((double)(current_time - g_Time) / frequency) : (float)(1.0f / 60.0f);
+    g_Time = current_time;
+
+    ImGui_ImplSDL2_UpdateMousePosAndButtons();
+    ImGui_ImplSDL2_UpdateMouseCursor();
+
+    // Update game controllers (if enabled and available)
+    ImGui_ImplSDL2_UpdateGamepads();
+}

lib/imgui/imgui_impl_sdl.h

@@ -0,0 +1,29 @@
+// dear imgui: Platform Binding for SDL2
+// This needs to be used along with a Renderer (e.g. DirectX11, OpenGL3, Vulkan..)
+// (Info: SDL2 is a cross-platform general purpose library for handling windows, inputs, graphics context creation, etc.)
+
+// Implemented features:
+//  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
+//  [X] Platform: Clipboard support.
+//  [X] Platform: Keyboard arrays indexed using SDL_SCANCODE_* codes, e.g. ImGui::IsKeyPressed(SDL_SCANCODE_SPACE).
+//  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
+// Missing features:
+//  [ ] Platform: SDL2 handling of IME under Windows appears to be broken and it explicitly disable the regular Windows IME. You can restore Windows IME by compiling SDL with SDL_DISABLE_WINDOWS_IME.
+
+// You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
+// If you are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
+// https://github.com/ocornut/imgui
+
+#pragma once
+#include "imgui.h"      // IMGUI_IMPL_API
+
+struct SDL_Window;
+typedef union SDL_Event SDL_Event;
+
+IMGUI_IMPL_API bool     ImGui_ImplSDL2_InitForOpenGL(SDL_Window* window, void* sdl_gl_context);
+IMGUI_IMPL_API bool     ImGui_ImplSDL2_InitForVulkan(SDL_Window* window);
+IMGUI_IMPL_API bool     ImGui_ImplSDL2_InitForD3D(SDL_Window* window);
+IMGUI_IMPL_API bool     ImGui_ImplSDL2_InitForMetal(SDL_Window* window);
+IMGUI_IMPL_API void     ImGui_ImplSDL2_Shutdown();
+IMGUI_IMPL_API void     ImGui_ImplSDL2_NewFrame(SDL_Window* window);
+IMGUI_IMPL_API bool     ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event);

lib/imgui/imgui_impl_vulkan.h

@@ -0,0 +1,126 @@
+// dear imgui: Renderer for Vulkan
+// This needs to be used along with a Platform Binding (e.g. GLFW, SDL, Win32, custom..)
+
+// Implemented features:
+//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+// Missing features:
+//  [ ] Renderer: User texture binding. Changes of ImTextureID aren't supported by this binding! See https://github.com/ocornut/imgui/pull/914
+
+// You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
+// If you are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
+// https://github.com/ocornut/imgui
+
+// The aim of imgui_impl_vulkan.h/.cpp is to be usable in your engine without any modification.
+// IF YOU FEEL YOU NEED TO MAKE ANY CHANGE TO THIS CODE, please share them and your feedback at https://github.com/ocornut/imgui/
+
+// Important note to the reader who wish to integrate imgui_impl_vulkan.cpp/.h in their own engine/app.
+// - Common ImGui_ImplVulkan_XXX functions and structures are used to interface with imgui_impl_vulkan.cpp/.h.
+//   You will use those if you want to use this rendering back-end in your engine/app.
+// - Helper ImGui_ImplVulkanH_XXX functions and structures are only used by this example (main.cpp) and by
+//   the back-end itself (imgui_impl_vulkan.cpp), but should PROBABLY NOT be used by your own engine/app code.
+// Read comments in imgui_impl_vulkan.h.
+
+#pragma once
+#include "imgui.h"      // IMGUI_IMPL_API
+#include <vulkan/vulkan.h>
+
+// Initialization data, for ImGui_ImplVulkan_Init()
+// [Please zero-clear before use!]
+struct ImGui_ImplVulkan_InitInfo
+{
+    VkInstance          Instance;
+    VkPhysicalDevice    PhysicalDevice;
+    VkDevice            Device;
+    uint32_t            QueueFamily;
+    VkQueue             Queue;
+    VkPipelineCache     PipelineCache;
+    VkDescriptorPool    DescriptorPool;
+    uint32_t            MinImageCount;          // >= 2
+    uint32_t            ImageCount;             // >= MinImageCount
+    VkSampleCountFlagBits        MSAASamples;   // >= VK_SAMPLE_COUNT_1_BIT
+    const VkAllocationCallbacks* Allocator;
+    void                (*CheckVkResultFn)(VkResult err);
+};
+
+// Called by user code
+IMGUI_IMPL_API bool     ImGui_ImplVulkan_Init(ImGui_ImplVulkan_InitInfo* info, VkRenderPass render_pass);
+IMGUI_IMPL_API void     ImGui_ImplVulkan_Shutdown();
+IMGUI_IMPL_API void     ImGui_ImplVulkan_NewFrame();
+IMGUI_IMPL_API void     ImGui_ImplVulkan_RenderDrawData(ImDrawData* draw_data, VkCommandBuffer command_buffer);
+IMGUI_IMPL_API bool     ImGui_ImplVulkan_CreateFontsTexture(VkCommandBuffer command_buffer);
+IMGUI_IMPL_API void     ImGui_ImplVulkan_DestroyFontUploadObjects();
+IMGUI_IMPL_API void     ImGui_ImplVulkan_SetMinImageCount(uint32_t min_image_count); // To override MinImageCount after initialization (e.g. if swap chain is recreated)
+
+
+//-------------------------------------------------------------------------
+// Internal / Miscellaneous Vulkan Helpers
+// (Used by example's main.cpp. Used by multi-viewport features. PROBABLY NOT used by your own engine/app.)
+//-------------------------------------------------------------------------
+// You probably do NOT need to use or care about those functions.
+// Those functions only exist because:
+//   1) they facilitate the readability and maintenance of the multiple main.cpp examples files.
+//   2) the upcoming multi-viewport feature will need them internally.
+// Generally we avoid exposing any kind of superfluous high-level helpers in the bindings,
+// but it is too much code to duplicate everywhere so we exceptionally expose them.
+//
+// Your engine/app will likely _already_ have code to setup all that stuff (swap chain, render pass, frame buffers, etc.).
+// You may read this code to learn about Vulkan, but it is recommended you use you own custom tailored code to do equivalent work.
+// (The ImGui_ImplVulkanH_XXX functions do not interact with any of the state used by the regular ImGui_ImplVulkan_XXX functions)
+//-------------------------------------------------------------------------
+
+struct ImGui_ImplVulkanH_Frame;
+struct ImGui_ImplVulkanH_Window;
+
+// Helpers
+IMGUI_IMPL_API void                 ImGui_ImplVulkanH_CreateWindow(VkInstance instance, VkPhysicalDevice physical_device, VkDevice device, ImGui_ImplVulkanH_Window* wnd, uint32_t queue_family, const VkAllocationCallbacks* allocator, int w, int h, uint32_t min_image_count);
+IMGUI_IMPL_API void                 ImGui_ImplVulkanH_DestroyWindow(VkInstance instance, VkDevice device, ImGui_ImplVulkanH_Window* wnd, const VkAllocationCallbacks* allocator);
+IMGUI_IMPL_API VkSurfaceFormatKHR   ImGui_ImplVulkanH_SelectSurfaceFormat(VkPhysicalDevice physical_device, VkSurfaceKHR surface, const VkFormat* request_formats, int request_formats_count, VkColorSpaceKHR request_color_space);
+IMGUI_IMPL_API VkPresentModeKHR     ImGui_ImplVulkanH_SelectPresentMode(VkPhysicalDevice physical_device, VkSurfaceKHR surface, const VkPresentModeKHR* request_modes, int request_modes_count);
+IMGUI_IMPL_API int                  ImGui_ImplVulkanH_GetMinImageCountFromPresentMode(VkPresentModeKHR present_mode);
+
+// Helper structure to hold the data needed by one rendering frame
+// (Used by example's main.cpp. Used by multi-viewport features. Probably NOT used by your own engine/app.)
+// [Please zero-clear before use!]
+struct ImGui_ImplVulkanH_Frame
+{
+    VkCommandPool       CommandPool;
+    VkCommandBuffer     CommandBuffer;
+    VkFence             Fence;
+    VkImage             Backbuffer;
+    VkImageView         BackbufferView;
+    VkFramebuffer       Framebuffer;
+};
+
+struct ImGui_ImplVulkanH_FrameSemaphores
+{
+    VkSemaphore         ImageAcquiredSemaphore;
+    VkSemaphore         RenderCompleteSemaphore;
+};
+
+// Helper structure to hold the data needed by one rendering context into one OS window
+// (Used by example's main.cpp. Used by multi-viewport features. Probably NOT used by your own engine/app.)
+struct ImGui_ImplVulkanH_Window
+{
+    int                 Width;
+    int                 Height;
+    VkSwapchainKHR      Swapchain;
+    VkSurfaceKHR        Surface;
+    VkSurfaceFormatKHR  SurfaceFormat;
+    VkPresentModeKHR    PresentMode;
+    VkRenderPass        RenderPass;
+    bool                ClearEnable;
+    VkClearValue        ClearValue;
+    uint32_t            FrameIndex;             // Current frame being rendered to (0 <= FrameIndex < FrameInFlightCount)
+    uint32_t            ImageCount;             // Number of simultaneous in-flight frames (returned by vkGetSwapchainImagesKHR, usually derived from min_image_count)
+    uint32_t            SemaphoreIndex;         // Current set of swapchain wait semaphores we're using (needs to be distinct from per frame data)
+    ImGui_ImplVulkanH_Frame*            Frames;
+    ImGui_ImplVulkanH_FrameSemaphores*  FrameSemaphores;
+
+    ImGui_ImplVulkanH_Window()
+    {
+        memset(this, 0, sizeof(*this));
+        PresentMode = VK_PRESENT_MODE_MAX_ENUM_KHR;
+        ClearEnable = true;
+    }
+};
+

lib/imgui/imstb_rectpack.h

@@ -0,0 +1,639 @@
+// [DEAR IMGUI]
+// This is a slightly modified version of stb_rect_pack.h 1.00.
+// Those changes would need to be pushed into nothings/stb:
+// - Added STBRP__CDECL
+// Grep for [DEAR IMGUI] to find the changes.
+
+// stb_rect_pack.h - v1.00 - public domain - rectangle packing
+// Sean Barrett 2014
+//
+// Useful for e.g. packing rectangular textures into an atlas.
+// Does not do rotation.
+//
+// Not necessarily the awesomest packing method, but better than
+// the totally naive one in stb_truetype (which is primarily what
+// this is meant to replace).
+//
+// Has only had a few tests run, may have issues.
+//
+// More docs to come.
+//
+// No memory allocations; uses qsort() and assert() from stdlib.
+// Can override those by defining STBRP_SORT and STBRP_ASSERT.
+//
+// This library currently uses the Skyline Bottom-Left algorithm.
+//
+// Please note: better rectangle packers are welcome! Please
+// implement them to the same API, but with a different init
+// function.
+//
+// Credits
+//
+//  Library
+//    Sean Barrett
+//  Minor features
+//    Martins Mozeiko
+//    github:IntellectualKitty
+//    
+//  Bugfixes / warning fixes
+//    Jeremy Jaussaud
+//    Fabian Giesen
+//
+// Version history:
+//
+//     1.00  (2019-02-25)  avoid small space waste; gracefully fail too-wide rectangles
+//     0.99  (2019-02-07)  warning fixes
+//     0.11  (2017-03-03)  return packing success/fail result
+//     0.10  (2016-10-25)  remove cast-away-const to avoid warnings
+//     0.09  (2016-08-27)  fix compiler warnings
+//     0.08  (2015-09-13)  really fix bug with empty rects (w=0 or h=0)
+//     0.07  (2015-09-13)  fix bug with empty rects (w=0 or h=0)
+//     0.06  (2015-04-15)  added STBRP_SORT to allow replacing qsort
+//     0.05:  added STBRP_ASSERT to allow replacing assert
+//     0.04:  fixed minor bug in STBRP_LARGE_RECTS support
+//     0.01:  initial release
+//
+// LICENSE
+//
+//   See end of file for license information.
+
+//////////////////////////////////////////////////////////////////////////////
+//
+//       INCLUDE SECTION
+//
+
+#ifndef STB_INCLUDE_STB_RECT_PACK_H
+#define STB_INCLUDE_STB_RECT_PACK_H
+
+#define STB_RECT_PACK_VERSION  1
+
+#ifdef STBRP_STATIC
+#define STBRP_DEF static
+#else
+#define STBRP_DEF extern
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct stbrp_context stbrp_context;
+typedef struct stbrp_node    stbrp_node;
+typedef struct stbrp_rect    stbrp_rect;
+
+#ifdef STBRP_LARGE_RECTS
+typedef int            stbrp_coord;
+#else
+typedef unsigned short stbrp_coord;
+#endif
+
+STBRP_DEF int stbrp_pack_rects (stbrp_context *context, stbrp_rect *rects, int num_rects);
+// Assign packed locations to rectangles. The rectangles are of type
+// 'stbrp_rect' defined below, stored in the array 'rects', and there
+// are 'num_rects' many of them.
+//
+// Rectangles which are successfully packed have the 'was_packed' flag
+// set to a non-zero value and 'x' and 'y' store the minimum location
+// on each axis (i.e. bottom-left in cartesian coordinates, top-left
+// if you imagine y increasing downwards). Rectangles which do not fit
+// have the 'was_packed' flag set to 0.
+//
+// You should not try to access the 'rects' array from another thread
+// while this function is running, as the function temporarily reorders
+// the array while it executes.
+//
+// To pack into another rectangle, you need to call stbrp_init_target
+// again. To continue packing into the same rectangle, you can call
+// this function again. Calling this multiple times with multiple rect
+// arrays will probably produce worse packing results than calling it
+// a single time with the full rectangle array, but the option is
+// available.
+//
+// The function returns 1 if all of the rectangles were successfully
+// packed and 0 otherwise.
+
+struct stbrp_rect
+{
+   // reserved for your use:
+   int            id;
+
+   // input:
+   stbrp_coord    w, h;
+
+   // output:
+   stbrp_coord    x, y;
+   int            was_packed;  // non-zero if valid packing
+
+}; // 16 bytes, nominally
+
+
+STBRP_DEF void stbrp_init_target (stbrp_context *context, int width, int height, stbrp_node *nodes, int num_nodes);
+// Initialize a rectangle packer to:
+//    pack a rectangle that is 'width' by 'height' in dimensions
+//    using temporary storage provided by the array 'nodes', which is 'num_nodes' long
+//
+// You must call this function every time you start packing into a new target.
+//
+// There is no "shutdown" function. The 'nodes' memory must stay valid for
+// the following stbrp_pack_rects() call (or calls), but can be freed after
+// the call (or calls) finish.
+//
+// Note: to guarantee best results, either:
+//       1. make sure 'num_nodes' >= 'width'
+//   or  2. call stbrp_allow_out_of_mem() defined below with 'allow_out_of_mem = 1'
+//
+// If you don't do either of the above things, widths will be quantized to multiples
+// of small integers to guarantee the algorithm doesn't run out of temporary storage.
+//
+// If you do #2, then the non-quantized algorithm will be used, but the algorithm
+// may run out of temporary storage and be unable to pack some rectangles.
+
+STBRP_DEF void stbrp_setup_allow_out_of_mem (stbrp_context *context, int allow_out_of_mem);
+// Optionally call this function after init but before doing any packing to
+// change the handling of the out-of-temp-memory scenario, described above.
+// If you call init again, this will be reset to the default (false).
+
+
+STBRP_DEF void stbrp_setup_heuristic (stbrp_context *context, int heuristic);
+// Optionally select which packing heuristic the library should use. Different
+// heuristics will produce better/worse results for different data sets.
+// If you call init again, this will be reset to the default.
+
+enum
+{
+   STBRP_HEURISTIC_Skyline_default=0,
+   STBRP_HEURISTIC_Skyline_BL_sortHeight = STBRP_HEURISTIC_Skyline_default,
+   STBRP_HEURISTIC_Skyline_BF_sortHeight
+};
+
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// the details of the following structures don't matter to you, but they must
+// be visible so you can handle the memory allocations for them
+
+struct stbrp_node
+{
+   stbrp_coord  x,y;
+   stbrp_node  *next;
+};
+
+struct stbrp_context
+{
+   int width;
+   int height;
+   int align;
+   int init_mode;
+   int heuristic;
+   int num_nodes;
+   stbrp_node *active_head;
+   stbrp_node *free_head;
+   stbrp_node extra[2]; // we allocate two extra nodes so optimal user-node-count is 'width' not 'width+2'
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+
+//////////////////////////////////////////////////////////////////////////////
+//
+//     IMPLEMENTATION SECTION
+//
+
+#ifdef STB_RECT_PACK_IMPLEMENTATION
+#ifndef STBRP_SORT
+#include <stdlib.h>
+#define STBRP_SORT qsort
+#endif
+
+#ifndef STBRP_ASSERT
+#include <assert.h>
+#define STBRP_ASSERT assert
+#endif
+
+// [DEAR IMGUI] Added STBRP__CDECL
+#ifdef _MSC_VER
+#define STBRP__NOTUSED(v)  (void)(v)
+#define STBRP__CDECL __cdecl
+#else
+#define STBRP__NOTUSED(v)  (void)sizeof(v)
+#define STBRP__CDECL
+#endif
+
+enum
+{
+   STBRP__INIT_skyline = 1
+};
+
+STBRP_DEF void stbrp_setup_heuristic(stbrp_context *context, int heuristic)
+{
+   switch (context->init_mode) {
+      case STBRP__INIT_skyline:
+         STBRP_ASSERT(heuristic == STBRP_HEURISTIC_Skyline_BL_sortHeight || heuristic == STBRP_HEURISTIC_Skyline_BF_sortHeight);
+         context->heuristic = heuristic;
+         break;
+      default:
+         STBRP_ASSERT(0);
+   }
+}
+
+STBRP_DEF void stbrp_setup_allow_out_of_mem(stbrp_context *context, int allow_out_of_mem)
+{
+   if (allow_out_of_mem)
+      // if it's ok to run out of memory, then don't bother aligning them;
+      // this gives better packing, but may fail due to OOM (even though
+      // the rectangles easily fit). @TODO a smarter approach would be to only
+      // quantize once we've hit OOM, then we could get rid of this parameter.
+      context->align = 1;
+   else {
+      // if it's not ok to run out of memory, then quantize the widths
+      // so that num_nodes is always enough nodes.
+      //
+      // I.e. num_nodes * align >= width
+      //                  align >= width / num_nodes
+      //                  align = ceil(width/num_nodes)
+
+      context->align = (context->width + context->num_nodes-1) / context->num_nodes;
+   }
+}
+
+STBRP_DEF void stbrp_init_target(stbrp_context *context, int width, int height, stbrp_node *nodes, int num_nodes)
+{
+   int i;
+#ifndef STBRP_LARGE_RECTS
+   STBRP_ASSERT(width <= 0xffff && height <= 0xffff);
+#endif
+
+   for (i=0; i < num_nodes-1; ++i)
+      nodes[i].next = &nodes[i+1];
+   nodes[i].next = NULL;
+   context->init_mode = STBRP__INIT_skyline;
+   context->heuristic = STBRP_HEURISTIC_Skyline_default;
+   context->free_head = &nodes[0];
+   context->active_head = &context->extra[0];
+   context->width = width;
+   context->height = height;
+   context->num_nodes = num_nodes;
+   stbrp_setup_allow_out_of_mem(context, 0);
+
+   // node 0 is the full width, node 1 is the sentinel (lets us not store width explicitly)
+   context->extra[0].x = 0;
+   context->extra[0].y = 0;
+   context->extra[0].next = &context->extra[1];
+   context->extra[1].x = (stbrp_coord) width;
+#ifdef STBRP_LARGE_RECTS
+   context->extra[1].y = (1<<30);
+#else
+   context->extra[1].y = 65535;
+#endif
+   context->extra[1].next = NULL;
+}
+
+// find minimum y position if it starts at x1
+static int stbrp__skyline_find_min_y(stbrp_context *c, stbrp_node *first, int x0, int width, int *pwaste)
+{
+   stbrp_node *node = first;
+   int x1 = x0 + width;
+   int min_y, visited_width, waste_area;
+
+   STBRP__NOTUSED(c);
+
+   STBRP_ASSERT(first->x <= x0);
+
+   #if 0
+   // skip in case we're past the node
+   while (node->next->x <= x0)
+      ++node;
+   #else
+   STBRP_ASSERT(node->next->x > x0); // we ended up handling this in the caller for efficiency
+   #endif
+
+   STBRP_ASSERT(node->x <= x0);
+
+   min_y = 0;
+   waste_area = 0;
+   visited_width = 0;
+   while (node->x < x1) {
+      if (node->y > min_y) {
+         // raise min_y higher.
+         // we've accounted for all waste up to min_y,
+         // but we'll now add more waste for everything we've visted
+         waste_area += visited_width * (node->y - min_y);
+         min_y = node->y;
+         // the first time through, visited_width might be reduced
+         if (node->x < x0)
+            visited_width += node->next->x - x0;
+         else
+            visited_width += node->next->x - node->x;
+      } else {
+         // add waste area
+         int under_width = node->next->x - node->x;
+         if (under_width + visited_width > width)
+            under_width = width - visited_width;
+         waste_area += under_width * (min_y - node->y);
+         visited_width += under_width;
+      }
+      node = node->next;
+   }
+
+   *pwaste = waste_area;
+   return min_y;
+}
+
+typedef struct
+{
+   int x,y;
+   stbrp_node **prev_link;
+} stbrp__findresult;
+
+static stbrp__findresult stbrp__skyline_find_best_pos(stbrp_context *c, int width, int height)
+{
+   int best_waste = (1<<30), best_x, best_y = (1 << 30);
+   stbrp__findresult fr;
+   stbrp_node **prev, *node, *tail, **best = NULL;
+
+   // align to multiple of c->align
+   width = (width + c->align - 1);
+   width -= width % c->align;
+   STBRP_ASSERT(width % c->align == 0);
+
+   // if it can't possibly fit, bail immediately
+   if (width > c->width || height > c->height) {
+      fr.prev_link = NULL;
+      fr.x = fr.y = 0;
+      return fr;
+   }
+
+   node = c->active_head;
+   prev = &c->active_head;
+   while (node->x + width <= c->width) {
+      int y,waste;
+      y = stbrp__skyline_find_min_y(c, node, node->x, width, &waste);
+      if (c->heuristic == STBRP_HEURISTIC_Skyline_BL_sortHeight) { // actually just want to test BL
+         // bottom left
+         if (y < best_y) {
+            best_y = y;
+            best = prev;
+         }
+      } else {
+         // best-fit
+         if (y + height <= c->height) {
+            // can only use it if it first vertically
+            if (y < best_y || (y == best_y && waste < best_waste)) {
+               best_y = y;
+               best_waste = waste;
+               best = prev;
+            }
+         }
+      }
+      prev = &node->next;
+      node = node->next;
+   }
+
+   best_x = (best == NULL) ? 0 : (*best)->x;
+
+   // if doing best-fit (BF), we also have to try aligning right edge to each node position
+   //
+   // e.g, if fitting
+   //
+   //     ____________________
+   //    |____________________|
+   //
+   //            into
+   //
+   //   |                         |
+   //   |             ____________|
+   //   |____________|
+   //
+   // then right-aligned reduces waste, but bottom-left BL is always chooses left-aligned
+   //
+   // This makes BF take about 2x the time
+
+   if (c->heuristic == STBRP_HEURISTIC_Skyline_BF_sortHeight) {
+      tail = c->active_head;
+      node = c->active_head;
+      prev = &c->active_head;
+      // find first node that's admissible
+      while (tail->x < width)
+         tail = tail->next;
+      while (tail) {
+         int xpos = tail->x - width;
+         int y,waste;
+         STBRP_ASSERT(xpos >= 0);
+         // find the left position that matches this
+         while (node->next->x <= xpos) {
+            prev = &node->next;
+            node = node->next;
+         }
+         STBRP_ASSERT(node->next->x > xpos && node->x <= xpos);
+         y = stbrp__skyline_find_min_y(c, node, xpos, width, &waste);
+         if (y + height <= c->height) {
+            if (y <= best_y) {
+               if (y < best_y || waste < best_waste || (waste==best_waste && xpos < best_x)) {
+                  best_x = xpos;
+                  STBRP_ASSERT(y <= best_y);
+                  best_y = y;
+                  best_waste = waste;
+                  best = prev;
+               }
+            }
+         }
+         tail = tail->next;
+      }         
+   }
+
+   fr.prev_link = best;
+   fr.x = best_x;
+   fr.y = best_y;
+   return fr;
+}
+
+static stbrp__findresult stbrp__skyline_pack_rectangle(stbrp_context *context, int width, int height)
+{
+   // find best position according to heuristic
+   stbrp__findresult res = stbrp__skyline_find_best_pos(context, width, height);
+   stbrp_node *node, *cur;
+
+   // bail if:
+   //    1. it failed
+   //    2. the best node doesn't fit (we don't always check this)
+   //    3. we're out of memory
+   if (res.prev_link == NULL || res.y + height > context->height || context->free_head == NULL) {
+      res.prev_link = NULL;
+      return res;
+   }
+
+   // on success, create new node
+   node = context->free_head;
+   node->x = (stbrp_coord) res.x;
+   node->y = (stbrp_coord) (res.y + height);
+
+   context->free_head = node->next;
+
+   // insert the new node into the right starting point, and
+   // let 'cur' point to the remaining nodes needing to be
+   // stiched back in
+
+   cur = *res.prev_link;
+   if (cur->x < res.x) {
+      // preserve the existing one, so start testing with the next one
+      stbrp_node *next = cur->next;
+      cur->next = node;
+      cur = next;
+   } else {
+      *res.prev_link = node;
+   }
+
+   // from here, traverse cur and free the nodes, until we get to one
+   // that shouldn't be freed
+   while (cur->next && cur->next->x <= res.x + width) {
+      stbrp_node *next = cur->next;
+      // move the current node to the free list
+      cur->next = context->free_head;
+      context->free_head = cur;
+      cur = next;
+   }
+
+   // stitch the list back in
+   node->next = cur;
+
+   if (cur->x < res.x + width)
+      cur->x = (stbrp_coord) (res.x + width);
+
+#ifdef _DEBUG
+   cur = context->active_head;
+   while (cur->x < context->width) {
+      STBRP_ASSERT(cur->x < cur->next->x);
+      cur = cur->next;
+   }
+   STBRP_ASSERT(cur->next == NULL);
+
+   {
+      int count=0;
+      cur = context->active_head;
+      while (cur) {
+         cur = cur->next;
+         ++count;
+      }
+      cur = context->free_head;
+      while (cur) {
+         cur = cur->next;
+         ++count;
+      }
+      STBRP_ASSERT(count == context->num_nodes+2);
+   }
+#endif
+
+   return res;
+}
+
+// [DEAR IMGUI] Added STBRP__CDECL
+static int STBRP__CDECL rect_height_compare(const void *a, const void *b)
+{
+   const stbrp_rect *p = (const stbrp_rect *) a;
+   const stbrp_rect *q = (const stbrp_rect *) b;
+   if (p->h > q->h)
+      return -1;
+   if (p->h < q->h)
+      return  1;
+   return (p->w > q->w) ? -1 : (p->w < q->w);
+}
+
+// [DEAR IMGUI] Added STBRP__CDECL
+static int STBRP__CDECL rect_original_order(const void *a, const void *b)
+{
+   const stbrp_rect *p = (const stbrp_rect *) a;
+   const stbrp_rect *q = (const stbrp_rect *) b;
+   return (p->was_packed < q->was_packed) ? -1 : (p->was_packed > q->was_packed);
+}
+
+#ifdef STBRP_LARGE_RECTS
+#define STBRP__MAXVAL  0xffffffff
+#else
+#define STBRP__MAXVAL  0xffff
+#endif
+
+STBRP_DEF int stbrp_pack_rects(stbrp_context *context, stbrp_rect *rects, int num_rects)
+{
+   int i, all_rects_packed = 1;
+
+   // we use the 'was_packed' field internally to allow sorting/unsorting
+   for (i=0; i < num_rects; ++i) {
+      rects[i].was_packed = i;
+   }
+
+   // sort according to heuristic
+   STBRP_SORT(rects, num_rects, sizeof(rects[0]), rect_height_compare);
+
+   for (i=0; i < num_rects; ++i) {
+      if (rects[i].w == 0 || rects[i].h == 0) {
+         rects[i].x = rects[i].y = 0;  // empty rect needs no space
+      } else {
+         stbrp__findresult fr = stbrp__skyline_pack_rectangle(context, rects[i].w, rects[i].h);
+         if (fr.prev_link) {
+            rects[i].x = (stbrp_coord) fr.x;
+            rects[i].y = (stbrp_coord) fr.y;
+         } else {
+            rects[i].x = rects[i].y = STBRP__MAXVAL;
+         }
+      }
+   }
+
+   // unsort
+   STBRP_SORT(rects, num_rects, sizeof(rects[0]), rect_original_order);
+
+   // set was_packed flags and all_rects_packed status
+   for (i=0; i < num_rects; ++i) {
+      rects[i].was_packed = !(rects[i].x == STBRP__MAXVAL && rects[i].y == STBRP__MAXVAL);
+      if (!rects[i].was_packed)
+         all_rects_packed = 0;
+   }
+
+   // return the all_rects_packed status
+   return all_rects_packed;
+}
+#endif
+
+/*
+------------------------------------------------------------------------------
+This software is available under 2 licenses -- choose whichever you prefer.
+------------------------------------------------------------------------------
+ALTERNATIVE A - MIT License
+Copyright (c) 2017 Sean Barrett
+Permission is hereby granted, free of charge, to any person obtaining a copy of 
+this software and associated documentation files (the "Software"), to deal in 
+the Software without restriction, including without limitation the rights to 
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies 
+of the Software, and to permit persons to whom the Software is furnished to do 
+so, subject to the following conditions:
+The above copyright notice and this permission notice shall be included in all 
+copies or substantial portions of the Software.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 
+SOFTWARE.
+------------------------------------------------------------------------------
+ALTERNATIVE B - Public Domain (www.unlicense.org)
+This is free and unencumbered software released into the public domain.
+Anyone is free to copy, modify, publish, use, compile, sell, or distribute this 
+software, either in source code form or as a compiled binary, for any purpose, 
+commercial or non-commercial, and by any means.
+In jurisdictions that recognize copyright laws, the author or authors of this 
+software dedicate any and all copyright interest in the software to the public 
+domain. We make this dedication for the benefit of the public at large and to 
+the detriment of our heirs and successors. We intend this dedication to be an 
+overt act of relinquishment in perpetuity of all present and future rights to 
+this software under copyright law.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
+AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 
+ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+------------------------------------------------------------------------------
+*/