ImGui

.gitignore

@@ -1,3 +1,4 @@
 build/
+out/
 .vs/
 .vscode/

CMakeLists.txt

@@ -64,6 +64,7 @@ file(GLOB SourceFiles
     ${SrcDIR}/definitions/*
     ${SrcDIR}/definitions/primatives/*
 	${SrcDIR}/util/*
+	${SrcDIR}/util/imgui/*
     ${TestDIR}/${CurrentTest}
 )
 
@@ -80,7 +81,7 @@ if (UNIX)
 		#SDL2_image
 		#PNG::PNG
 		#JPEG::JPEG
-		OpenGL::GL
+		OpenGL::OpenGL
 		Threads::Threads
 	)
 endif (UNIX)

include/KHR/khrplatform.h

@@ -0,0 +1,282 @@
+#ifndef __khrplatform_h_
+#define __khrplatform_h_
+
+/*
+** Copyright (c) 2008-2018 The Khronos Group Inc.
+**
+** Permission is hereby granted, free of charge, to any person obtaining a
+** copy of this software and/or associated documentation files (the
+** "Materials"), to deal in the Materials without restriction, including
+** without limitation the rights to use, copy, modify, merge, publish,
+** distribute, sublicense, and/or sell copies of the Materials, and to
+** permit persons to whom the Materials are 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 Materials.
+**
+** THE MATERIALS ARE 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
+** MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.
+*/
+
+/* Khronos platform-specific types and definitions.
+ *
+ * The master copy of khrplatform.h is maintained in the Khronos EGL
+ * Registry repository at https://github.com/KhronosGroup/EGL-Registry
+ * The last semantic modification to khrplatform.h was at commit ID:
+ *      67a3e0864c2d75ea5287b9f3d2eb74a745936692
+ *
+ * Adopters may modify this file to suit their platform. Adopters are
+ * encouraged to submit platform specific modifications to the Khronos
+ * group so that they can be included in future versions of this file.
+ * Please submit changes by filing pull requests or issues on
+ * the EGL Registry repository linked above.
+ *
+ *
+ * See the Implementer's Guidelines for information about where this file
+ * should be located on your system and for more details of its use:
+ *    http://www.khronos.org/registry/implementers_guide.pdf
+ *
+ * This file should be included as
+ *        #include <KHR/khrplatform.h>
+ * by Khronos client API header files that use its types and defines.
+ *
+ * The types in khrplatform.h should only be used to define API-specific types.
+ *
+ * Types defined in khrplatform.h:
+ *    khronos_int8_t              signed   8  bit
+ *    khronos_uint8_t             unsigned 8  bit
+ *    khronos_int16_t             signed   16 bit
+ *    khronos_uint16_t            unsigned 16 bit
+ *    khronos_int32_t             signed   32 bit
+ *    khronos_uint32_t            unsigned 32 bit
+ *    khronos_int64_t             signed   64 bit
+ *    khronos_uint64_t            unsigned 64 bit
+ *    khronos_intptr_t            signed   same number of bits as a pointer
+ *    khronos_uintptr_t           unsigned same number of bits as a pointer
+ *    khronos_ssize_t             signed   size
+ *    khronos_usize_t             unsigned size
+ *    khronos_float_t             signed   32 bit floating point
+ *    khronos_time_ns_t           unsigned 64 bit time in nanoseconds
+ *    khronos_utime_nanoseconds_t unsigned time interval or absolute time in
+ *                                         nanoseconds
+ *    khronos_stime_nanoseconds_t signed time interval in nanoseconds
+ *    khronos_boolean_enum_t      enumerated boolean type. This should
+ *      only be used as a base type when a client API's boolean type is
+ *      an enum. Client APIs which use an integer or other type for
+ *      booleans cannot use this as the base type for their boolean.
+ *
+ * Tokens defined in khrplatform.h:
+ *
+ *    KHRONOS_FALSE, KHRONOS_TRUE Enumerated boolean false/true values.
+ *
+ *    KHRONOS_SUPPORT_INT64 is 1 if 64 bit integers are supported; otherwise 0.
+ *    KHRONOS_SUPPORT_FLOAT is 1 if floats are supported; otherwise 0.
+ *
+ * Calling convention macros defined in this file:
+ *    KHRONOS_APICALL
+ *    KHRONOS_APIENTRY
+ *    KHRONOS_APIATTRIBUTES
+ *
+ * These may be used in function prototypes as:
+ *
+ *      KHRONOS_APICALL void KHRONOS_APIENTRY funcname(
+ *                                  int arg1,
+ *                                  int arg2) KHRONOS_APIATTRIBUTES;
+ */
+
+/*-------------------------------------------------------------------------
+ * Definition of KHRONOS_APICALL
+ *-------------------------------------------------------------------------
+ * This precedes the return type of the function in the function prototype.
+ */
+#if defined(_WIN32) && !defined(__SCITECH_SNAP__)
+#   define KHRONOS_APICALL __declspec(dllimport)
+#elif defined (__SYMBIAN32__)
+#   define KHRONOS_APICALL IMPORT_C
+#elif defined(__ANDROID__)
+#   define KHRONOS_APICALL __attribute__((visibility("default")))
+#else
+#   define KHRONOS_APICALL
+#endif
+
+/*-------------------------------------------------------------------------
+ * Definition of KHRONOS_APIENTRY
+ *-------------------------------------------------------------------------
+ * This follows the return type of the function  and precedes the function
+ * name in the function prototype.
+ */
+#if defined(_WIN32) && !defined(_WIN32_WCE) && !defined(__SCITECH_SNAP__)
+    /* Win32 but not WinCE */
+#   define KHRONOS_APIENTRY __stdcall
+#else
+#   define KHRONOS_APIENTRY
+#endif
+
+/*-------------------------------------------------------------------------
+ * Definition of KHRONOS_APIATTRIBUTES
+ *-------------------------------------------------------------------------
+ * This follows the closing parenthesis of the function prototype arguments.
+ */
+#if defined (__ARMCC_2__)
+#define KHRONOS_APIATTRIBUTES __softfp
+#else
+#define KHRONOS_APIATTRIBUTES
+#endif
+
+/*-------------------------------------------------------------------------
+ * basic type definitions
+ *-----------------------------------------------------------------------*/
+#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) || defined(__GNUC__) || defined(__SCO__) || defined(__USLC__)
+
+
+/*
+ * Using <stdint.h>
+ */
+#include <stdint.h>
+typedef int32_t                 khronos_int32_t;
+typedef uint32_t                khronos_uint32_t;
+typedef int64_t                 khronos_int64_t;
+typedef uint64_t                khronos_uint64_t;
+#define KHRONOS_SUPPORT_INT64   1
+#define KHRONOS_SUPPORT_FLOAT   1
+
+#elif defined(__VMS ) || defined(__sgi)
+
+/*
+ * Using <inttypes.h>
+ */
+#include <inttypes.h>
+typedef int32_t                 khronos_int32_t;
+typedef uint32_t                khronos_uint32_t;
+typedef int64_t                 khronos_int64_t;
+typedef uint64_t                khronos_uint64_t;
+#define KHRONOS_SUPPORT_INT64   1
+#define KHRONOS_SUPPORT_FLOAT   1
+
+#elif defined(_WIN32) && !defined(__SCITECH_SNAP__)
+
+/*
+ * Win32
+ */
+typedef __int32                 khronos_int32_t;
+typedef unsigned __int32        khronos_uint32_t;
+typedef __int64                 khronos_int64_t;
+typedef unsigned __int64        khronos_uint64_t;
+#define KHRONOS_SUPPORT_INT64   1
+#define KHRONOS_SUPPORT_FLOAT   1
+
+#elif defined(__sun__) || defined(__digital__)
+
+/*
+ * Sun or Digital
+ */
+typedef int                     khronos_int32_t;
+typedef unsigned int            khronos_uint32_t;
+#if defined(__arch64__) || defined(_LP64)
+typedef long int                khronos_int64_t;
+typedef unsigned long int       khronos_uint64_t;
+#else
+typedef long long int           khronos_int64_t;
+typedef unsigned long long int  khronos_uint64_t;
+#endif /* __arch64__ */
+#define KHRONOS_SUPPORT_INT64   1
+#define KHRONOS_SUPPORT_FLOAT   1
+
+#elif 0
+
+/*
+ * Hypothetical platform with no float or int64 support
+ */
+typedef int                     khronos_int32_t;
+typedef unsigned int            khronos_uint32_t;
+#define KHRONOS_SUPPORT_INT64   0
+#define KHRONOS_SUPPORT_FLOAT   0
+
+#else
+
+/*
+ * Generic fallback
+ */
+#include <stdint.h>
+typedef int32_t                 khronos_int32_t;
+typedef uint32_t                khronos_uint32_t;
+typedef int64_t                 khronos_int64_t;
+typedef uint64_t                khronos_uint64_t;
+#define KHRONOS_SUPPORT_INT64   1
+#define KHRONOS_SUPPORT_FLOAT   1
+
+#endif
+
+
+/*
+ * Types that are (so far) the same on all platforms
+ */
+typedef signed   char          khronos_int8_t;
+typedef unsigned char          khronos_uint8_t;
+typedef signed   short int     khronos_int16_t;
+typedef unsigned short int     khronos_uint16_t;
+
+/*
+ * Types that differ between LLP64 and LP64 architectures - in LLP64,
+ * pointers are 64 bits, but 'long' is still 32 bits. Win64 appears
+ * to be the only LLP64 architecture in current use.
+ */
+#ifdef _WIN64
+typedef signed   long long int khronos_intptr_t;
+typedef unsigned long long int khronos_uintptr_t;
+typedef signed   long long int khronos_ssize_t;
+typedef unsigned long long int khronos_usize_t;
+#else
+typedef signed   long  int     khronos_intptr_t;
+typedef unsigned long  int     khronos_uintptr_t;
+typedef signed   long  int     khronos_ssize_t;
+typedef unsigned long  int     khronos_usize_t;
+#endif
+
+#if KHRONOS_SUPPORT_FLOAT
+/*
+ * Float type
+ */
+typedef          float         khronos_float_t;
+#endif
+
+#if KHRONOS_SUPPORT_INT64
+/* Time types
+ *
+ * These types can be used to represent a time interval in nanoseconds or
+ * an absolute Unadjusted System Time.  Unadjusted System Time is the number
+ * of nanoseconds since some arbitrary system event (e.g. since the last
+ * time the system booted).  The Unadjusted System Time is an unsigned
+ * 64 bit value that wraps back to 0 every 584 years.  Time intervals
+ * may be either signed or unsigned.
+ */
+typedef khronos_uint64_t       khronos_utime_nanoseconds_t;
+typedef khronos_int64_t        khronos_stime_nanoseconds_t;
+#endif
+
+/*
+ * Dummy value used to pad enum types to 32 bits.
+ */
+#ifndef KHRONOS_MAX_ENUM
+#define KHRONOS_MAX_ENUM 0x7FFFFFFF
+#endif
+
+/*
+ * Enumerated boolean type
+ *
+ * Values other than zero should be considered to be true.  Therefore
+ * comparisons should not be made against KHRONOS_TRUE.
+ */
+typedef enum {
+    KHRONOS_FALSE = 0,
+    KHRONOS_TRUE  = 1,
+    KHRONOS_BOOLEAN_ENUM_FORCE_SIZE = KHRONOS_MAX_ENUM
+} khronos_boolean_enum_t;
+
+#endif /* __khrplatform_h_ */

include/imgui/imconfig.h

@@ -0,0 +1,84 @@
+//-----------------------------------------------------------------------------
+// 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().
+//#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 names. Consider enabling from time to time after updating to avoid using soon-to-be obsolete function/names.
+//#define IMGUI_DISABLE_OBSOLETE_FUNCTIONS
+
+//---- Don't implement demo windows functionality (ShowDemoWindow()/ShowStyleEditor()/ShowUserGuide() methods will be empty)
+// It is very strongly recommended to NOT disable the demo windows during development. Please read the comments in imgui_demo.cpp.
+//#define IMGUI_DISABLE_DEMO_WINDOWS
+
+//---- 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_DISABLE_OSX_FUNCTIONS                       // [OSX] Won't use and link with any OSX function (clipboard).
+//#define IMGUI_DISABLE_FORMAT_STRING_FUNCTIONS             // Don't implement ImFormatString/ImFormatStringV so you can implement them yourself if you don't want to link with vsnprintf.
+//#define IMGUI_DISABLE_MATH_FUNCTIONS                      // Don't implement ImFabs/ImSqrt/ImPow/ImFmod/ImCos/ImSin/ImAcos/ImAtan2 wrapper so you can implement them yourself. Declare your prototypes in imconfig.h.
+//#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
+
+//---- 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
+
+//---- 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); }
+*/
+
+//---- Using 32-bits vertex indices (default is 16-bits) 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-bits indices).
+// Another way to allow large meshes while keeping 16-bits 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
+
+//---- 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);
+}
+*/

include/imgui/imgui_impl_opengl3.h

@@ -0,0 +1,47 @@
+// dear imgui: Renderer for modern OpenGL with shaders / programmatic pipeline
+// - Desktop GL: 3.x 4.x
+// - Embedded GL: ES 2.0 (WebGL 1.0), ES 3.0 (WebGL 2.0)
+// This needs to be used along with a Platform Binding (e.g. GLFW, SDL, Win32, custom..)
+
+// Implemented features:
+//  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
+//  [x] Renderer: Desktop GL only: Support for large meshes (64k+ vertices) with 16-bits indices.
+
+// 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
+
+// About Desktop OpenGL function loaders:
+//  Modern desktop OpenGL doesn't have a standard portable header file to load OpenGL function pointers.
+//  Helper libraries are often used for this purpose! Here we are supporting a few common ones (gl3w, glew, glad).
+//  You may use another loader/header of your choice (glext, glLoadGen, etc.), or chose to manually implement your own.
+
+// About GLSL version:
+//  The 'glsl_version' initialization parameter should be NULL (default) or a "#version XXX" string.
+//  On computer platform the GLSL version default to "#version 130". On OpenGL ES 3 platform it defaults to "#version 300 es"
+//  Only override if your GL version doesn't handle this GLSL version. See GLSL version table at the top of imgui_impl_opengl3.cpp.
+
+#pragma once
+
+// Specific OpenGL versions
+//#define IMGUI_IMPL_OPENGL_ES2     // Auto-detected on Emscripten
+//#define IMGUI_IMPL_OPENGL_ES3     // Auto-detected on iOS/Android
+
+// Set default OpenGL3 loader to be gl3w
+#if !defined(IMGUI_IMPL_OPENGL_LOADER_GL3W)     \
+ && !defined(IMGUI_IMPL_OPENGL_LOADER_GLEW)     \
+ && !defined(IMGUI_IMPL_OPENGL_LOADER_GLAD)     \
+ && !defined(IMGUI_IMPL_OPENGL_LOADER_CUSTOM)
+#define IMGUI_IMPL_OPENGL_LOADER_GL3W
+#endif
+
+IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_Init(const char* glsl_version = NULL);
+IMGUI_IMPL_API void     ImGui_ImplOpenGL3_Shutdown();
+IMGUI_IMPL_API void     ImGui_ImplOpenGL3_NewFrame();
+IMGUI_IMPL_API void     ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data);
+
+// Called by Init/NewFrame/Shutdown
+IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_CreateFontsTexture();
+IMGUI_IMPL_API void     ImGui_ImplOpenGL3_DestroyFontsTexture();
+IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_CreateDeviceObjects();
+IMGUI_IMPL_API void     ImGui_ImplOpenGL3_DestroyDeviceObjects();

include/imgui/imgui_impl_sdl.h

@@ -0,0 +1,27 @@
+// 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
+
+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 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);

include/imgui/imgui_sdl.h

@@ -0,0 +1,17 @@
+#pragma once
+
+struct ImDrawData;
+struct SDL_Renderer;
+
+namespace ImGuiSDL
+{
+	// Call this to initialize the SDL renderer device that is internally used by the renderer.
+	void Initialize(SDL_Renderer* renderer, int windowWidth, int windowHeight);
+	// Call this before destroying your SDL renderer or ImGui to ensure that proper cleanup is done. This doesn't do anything critically important though,
+	// so if you're fine with small memory leaks at the end of your application, you can even omit this.
+	void Deinitialize();
+
+	// Call this every frame after ImGui::Render with ImGui::GetDrawData(). This will use the SDL_Renderer provided to the interfrace with Initialize
+	// to draw the contents of the draw data to the screen.
+	void Render(ImDrawData* drawData);
+};

include/imgui/imstb_rectpack.h

@@ -0,0 +1,630 @@
+// [DEAR IMGUI] 
+// This is a slightly modified version of stb_rect_pack.h 0.99. 
+// 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 - v0.99 - 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
+//
+// Version history:
+//
+//     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);
+
+   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.
+------------------------------------------------------------------------------
+*/

src/common.hpp

@@ -7,6 +7,9 @@
 #include <SDL2/SDL.h>
 #endif
 
+#include <imgui/imgui.h>
+#include <imgui/imgui_sdl.h>
+
 #include <iostream>
 #include <string>
 

src/display/display.cpp

@@ -15,6 +15,7 @@ bool Display::Init() {
 
 bool Display::InitVideoDisplay(std::string title, int x, int y) {
     this->XRes = x; this->YRes = y;
+	Title = title;
 
     m_window = SDL_CreateWindow(
         title.c_str(), SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
@@ -62,6 +63,16 @@ bool Display::InitVideoDisplay(std::string title, int x, int y) {
     return true;
 }
 
+bool Display::InitImGui() {
+	ImGui::CreateContext();
+	ImGuiSDL::Initialize(m_renderer, XRes, YRes);
+
+	m_imguiTexture = SDL_CreateTexture(m_renderer, SDL_PIXELFORMAT_RGBA32, SDL_TEXTUREACCESS_TARGET, 100, 100);
+
+	if (!m_imguiTexture) return false;
+	m_imGui = true;
+	return true;
+}
 
 void Display::SetPixel(int x, int y, Pixel p) {
     Framebuffer[y * this->XRes + x] = p.rgb();
@@ -89,15 +100,42 @@ void Display::SetFramebuffer(uint32_t* fb) {
 }
 
 void Display::Update() {
+	ImGuiIO& io = ImGui::GetIO();
+	int mouseX, mouseY, wheel = 0;
+	const int buttons = SDL_GetMouseState(&mouseX, &mouseY);
+	io.DeltaTime = 1.0f / 60.0f;
+	io.MousePos = ImVec2(static_cast<float>(mouseX), static_cast<float>(mouseY));
+	io.MouseDown[0] = buttons & SDL_BUTTON(SDL_BUTTON_LEFT);
+	io.MouseDown[1] = buttons & SDL_BUTTON(SDL_BUTTON_RIGHT);
+	io.MouseWheel = static_cast<float>(wheel);
+
+    SDL_UpdateTexture(m_texture, NULL, Framebuffer, this->XRes * sizeof(uint32_t));
+    SDL_RenderCopy(m_renderer, m_texture, NULL, NULL);
+
+	ImGui::Render();
+	ImGuiSDL::Render(ImGui::GetDrawData());
+    SDL_RenderPresent(m_renderer);
+}
+
+void Display::UpdatePartial() {
 	SDL_UpdateTexture(m_texture, NULL, Framebuffer, this->XRes * sizeof(uint32_t));
 	SDL_RenderCopy(m_renderer, m_texture, NULL, NULL);
 	SDL_RenderPresent(m_renderer);
-    memset((void*)Framebuffer, 0, this->XRes * this->YRes * sizeof(uint32_t));
+}
+
+void Display::UpdateTitle(std::string title) {
+	Title = title;
+	UpdateTitle();
+}
+
+void Display::UpdateTitle() {
+	SDL_SetWindowTitle(m_window, Title.c_str());
 }
 
 void Display::Close() {
     free(Framebuffer);
 	SDL_DestroyTexture(m_texture);
+	SDL_DestroyTexture(m_imguiTexture);
     SDL_DestroyRenderer(m_renderer);
     SDL_DestroyWindow(m_window);
     SDL_Quit();

src/display/display.hpp

@@ -12,6 +12,7 @@ public:
 
     bool Init() override;
     bool InitVideoDisplay(std::string title, int x, int y);
+	bool InitImGui();
 
     void SetPixel(int x, int y, Pixel p) override;
     void SetPixel(int x, int y, uint32_t p) override;
@@ -21,6 +22,9 @@ public:
     void SetFramebuffer(uint32_t* fb);
 
     void Update() override;
+	void UpdatePartial() override;
+	void UpdateTitle(std::string title);
+	void UpdateTitle();
 
     void Close() override;
 
@@ -30,6 +34,8 @@ private:
     SDL_Window* m_window;
     SDL_Renderer* m_renderer;
     SDL_Texture* m_texture;
+	SDL_Texture* m_imguiTexture;
+	bool m_imGui = false;
 };
 
 #endif

src/display/displayinterface.hpp

@@ -16,13 +16,16 @@ public:
     
     uint32_t* Framebuffer;
 
+    virtual bool Init() = 0;
+
     virtual void SetPixel(int x, int y, Pixel p) = 0;
     virtual void SetPixel(int x, int y, uint32_t p) = 0;
     virtual void SetPixelSafe(int x, int y, Pixel p) = 0;
     virtual void SetPixelSafe(int x, int y, uint32_t p) = 0;
 
-    virtual bool Init() = 0;
     virtual void Update() = 0;
+	virtual void UpdatePartial() = 0;
+
     virtual void Close() = 0;
 };
 

src/engine/progressiverenderer.cpp

@@ -31,9 +31,17 @@ void ProgressiveRenderer::Render() {
     while (m_interface->Active) {
         auto frameStartTime = std::chrono::high_resolution_clock::now();
 
+		ImGui::NewFrame();
+		ImGui::Begin("Thing");
+		ImGui::Text("Hello, world %d", 123);
+		if (ImGui::Button("Save")) {}
+		char* buf = ""; float f;
+		ImGui::InputText("string", buf, IM_ARRAYSIZE(buf));
+		ImGui::SliderFloat("float", &f, 0.0f, 1.0f);
+		ImGui::End();
 
-        for (int x = 0; x < m_scene->w; x++)
 		#pragma omp parallel for schedule(dynamic)
+        for (int x = 0; x < m_scene->w; x++)
         for (int y = 0; y < m_scene->h; y++) {
 
             SDL_Event e;

src/inferno.cpp

@@ -31,6 +31,10 @@ bool InfernoEngine::InitWindow(int xRes, int yRes) {
     if (!status) {
         return false;
     }
+	status = m_display->InitImGui();
+	if (!status) {
+		return false;
+	}
 
     m_renderer = new Renderer(m_mode);
     if (!m_renderer) {

src/util/imgui/imgui_impl_opengl3.cpp

@@ -0,0 +1,634 @@
+// dear imgui: Renderer for modern OpenGL with shaders / programmatic pipeline
+// - Desktop GL: 3.x 4.x
+// - Embedded GL: ES 2.0 (WebGL 1.0), ES 3.0 (WebGL 2.0)
+// This needs to be used along with a Platform Binding (e.g. GLFW, SDL, Win32, custom..)
+
+// Implemented features:
+//  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
+//  [x] Renderer: Desktop GL only: Support for large meshes (64k+ vertices) with 16-bits indices.
+
+// 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)
+//  2019-05-29: OpenGL: Desktop GL only: Added support for large mesh (64K+ vertices), enable ImGuiBackendFlags_RendererHasVtxOffset flag.
+//  2019-04-30: OpenGL: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
+//  2019-03-29: OpenGL: Not calling glBindBuffer more than necessary in the render loop.
+//  2019-03-15: OpenGL: Added a dummy GL call + comments in ImGui_ImplOpenGL3_Init() to detect uninitialized GL function loaders early.
+//  2019-03-03: OpenGL: Fix support for ES 2.0 (WebGL 1.0).
+//  2019-02-20: OpenGL: Fix for OSX not supporting OpenGL 4.5, we don't try to read GL_CLIP_ORIGIN even if defined by the headers/loader.
+//  2019-02-11: OpenGL: Projecting clipping rectangles correctly using draw_data->FramebufferScale to allow multi-viewports for retina display.
+//  2019-02-01: OpenGL: Using GLSL 410 shaders for any version over 410 (e.g. 430, 450).
+//  2018-11-30: Misc: Setting up io.BackendRendererName so it can be displayed in the About Window.
+//  2018-11-13: OpenGL: Support for GL 4.5's glClipControl(GL_UPPER_LEFT) / GL_CLIP_ORIGIN.
+//  2018-08-29: OpenGL: Added support for more OpenGL loaders: glew and glad, with comments indicative that any loader can be used.
+//  2018-08-09: OpenGL: Default to OpenGL ES 3 on iOS and Android. GLSL version default to "#version 300 ES".
+//  2018-07-30: OpenGL: Support for GLSL 300 ES and 410 core. Fixes for Emscripten compilation.
+//  2018-07-10: OpenGL: Support for more GLSL versions (based on the GLSL version string). Added error output when shaders fail to compile/link.
+//  2018-06-08: Misc: Extracted imgui_impl_opengl3.cpp/.h away from the old combined GLFW/SDL+OpenGL3 examples.
+//  2018-06-08: OpenGL: Use draw_data->DisplayPos and draw_data->DisplaySize to setup projection matrix and clipping rectangle.
+//  2018-05-25: OpenGL: Removed unnecessary backup/restore of GL_ELEMENT_ARRAY_BUFFER_BINDING since this is part of the VAO state.
+//  2018-05-14: OpenGL: Making the call to glBindSampler() optional so 3.2 context won't fail if the function is a NULL pointer.
+//  2018-03-06: OpenGL: Added const char* glsl_version parameter to ImGui_ImplOpenGL3_Init() so user can override the GLSL version e.g. "#version 150".
+//  2018-02-23: OpenGL: Create the VAO in the render function so the setup can more easily be used with multiple shared GL context.
+//  2018-02-16: Misc: Obsoleted the io.RenderDrawListsFn callback and exposed ImGui_ImplSdlGL3_RenderDrawData() in the .h file so you can call it yourself.
+//  2018-01-07: OpenGL: Changed GLSL shader version from 330 to 150.
+//  2017-09-01: OpenGL: Save and restore current bound sampler. Save and restore current polygon mode.
+//  2017-05-01: OpenGL: Fixed save and restore of current blend func state.
+//  2017-05-01: OpenGL: Fixed save and restore of current GL_ACTIVE_TEXTURE.
+//  2016-09-05: OpenGL: Fixed save and restore of current scissor rectangle.
+//  2016-07-29: OpenGL: Explicitly setting GL_UNPACK_ROW_LENGTH to reduce issues because SDL changes it. (#752)
+
+//----------------------------------------
+// OpenGL    GLSL      GLSL
+// version   version   string
+//----------------------------------------
+//  2.0       110       "#version 110"
+//  2.1       120       "#version 120"
+//  3.0       130       "#version 130"
+//  3.1       140       "#version 140"
+//  3.2       150       "#version 150"
+//  3.3       330       "#version 330 core"
+//  4.0       400       "#version 400 core"
+//  4.1       410       "#version 410 core"
+//  4.2       420       "#version 410 core"
+//  4.3       430       "#version 430 core"
+//  ES 2.0    100       "#version 100"      = WebGL 1.0
+//  ES 3.0    300       "#version 300 es"   = WebGL 2.0
+//----------------------------------------
+
+#if defined(_MSC_VER) && !defined(_CRT_SECURE_NO_WARNINGS)
+#define _CRT_SECURE_NO_WARNINGS
+#endif
+
+#include <imgui/imgui.h>
+#include <imgui/imgui_impl_opengl3.h>
+#include <stdio.h>
+#if defined(_MSC_VER) && _MSC_VER <= 1500 // MSVC 2008 or earlier
+#include <stddef.h>     // intptr_t
+#else
+#include <stdint.h>     // intptr_t
+#endif
+#if defined(__APPLE__)
+#include "TargetConditionals.h"
+#endif
+
+// Auto-detect GL version
+#if !defined(IMGUI_IMPL_OPENGL_ES2) && !defined(IMGUI_IMPL_OPENGL_ES3)
+#if (defined(__APPLE__) && (TARGET_OS_IOS || TARGET_OS_TV)) || (defined(__ANDROID__))
+#define IMGUI_IMPL_OPENGL_ES3       // iOS, Android  -> GL ES 3, "#version 300 es"
+#elif defined(__EMSCRIPTEN__)
+#define IMGUI_IMPL_OPENGL_ES2       // Emscripten    -> GL ES 2, "#version 100"
+#endif
+#endif
+
+#if defined(IMGUI_IMPL_OPENGL_ES2)
+#include <GLES2/gl2.h>
+#elif defined(IMGUI_IMPL_OPENGL_ES3)
+#if (defined(__APPLE__) && (TARGET_OS_IOS || TARGET_OS_TV))
+#include <OpenGLES/ES3/gl.h>  // Use GL ES 3
+#else
+#include <GLES3/gl3.h>  // Use GL ES 3
+#endif
+#else
+// About Desktop OpenGL function loaders:
+//  Modern desktop OpenGL doesn't have a standard portable header file to load OpenGL function pointers.
+//  Helper libraries are often used for this purpose! Here we are supporting a few common ones (gl3w, glew, glad).
+//  You may use another loader/header of your choice (glext, glLoadGen, etc.), or chose to manually implement your own.
+#undef IMGUI_IMPL_OPENGL_LOADER_GL3W
+#define IMGUI_IMPL_OPENGL_LOADER_GLAD
+#if defined(IMGUI_IMPL_OPENGL_LOADER_GL3W)
+#include <GL/gl3w.h>    // Needs to be initialized with gl3wInit() in user's code
+#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLEW)
+#include <GL/glew.h>    // Needs to be initialized with glewInit() in user's code
+#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD)
+#include <glad/glad.h>  // Needs to be initialized with gladLoadGL() in user's code
+#else
+#include IMGUI_IMPL_OPENGL_LOADER_CUSTOM
+#endif
+#endif
+
+// Desktop GL has glDrawElementsBaseVertex() which GL ES and WebGL don't have.
+#if defined(IMGUI_IMPL_OPENGL_ES2) || defined(IMGUI_IMPL_OPENGL_ES3)
+#define IMGUI_IMPL_OPENGL_HAS_DRAW_WITH_BASE_VERTEX     0
+#else
+#define IMGUI_IMPL_OPENGL_HAS_DRAW_WITH_BASE_VERTEX     1
+#endif
+
+// OpenGL Data
+static char         g_GlslVersionString[32] = "";
+static GLuint       g_FontTexture = 0;
+static GLuint       g_ShaderHandle = 0, g_VertHandle = 0, g_FragHandle = 0;
+static int          g_AttribLocationTex = 0, g_AttribLocationProjMtx = 0;                                // Uniforms location
+static int          g_AttribLocationVtxPos = 0, g_AttribLocationVtxUV = 0, g_AttribLocationVtxColor = 0; // Vertex attributes location
+static unsigned int g_VboHandle = 0, g_ElementsHandle = 0;
+
+// Functions
+bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
+{
+    // Setup back-end capabilities flags
+    ImGuiIO& io = ImGui::GetIO();
+    io.BackendRendererName = "imgui_impl_opengl3";
+#if IMGUI_IMPL_OPENGL_HAS_DRAW_WITH_BASE_VERTEX
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+#endif
+
+    // Store GLSL version string so we can refer to it later in case we recreate shaders. Note: GLSL version is NOT the same as GL version. Leave this to NULL if unsure.
+#if defined(IMGUI_IMPL_OPENGL_ES2)
+    if (glsl_version == NULL)
+        glsl_version = "#version 100";
+#elif defined(IMGUI_IMPL_OPENGL_ES3)
+    if (glsl_version == NULL)
+        glsl_version = "#version 300 es";
+#else
+    if (glsl_version == NULL)
+        glsl_version = "#version 130";
+#endif
+    IM_ASSERT((int)strlen(glsl_version) + 2 < IM_ARRAYSIZE(g_GlslVersionString));
+    strcpy(g_GlslVersionString, glsl_version);
+    strcat(g_GlslVersionString, "\n");
+
+    // Make a dummy GL call (we don't actually need the result)
+    // IF YOU GET A CRASH HERE: it probably means that you haven't initialized the OpenGL function loader used by this code.
+    // Desktop OpenGL 3/4 need a function loader. See the IMGUI_IMPL_OPENGL_LOADER_xxx explanation above.
+    GLint current_texture;
+    glGetIntegerv(GL_TEXTURE_BINDING_2D, &current_texture);
+
+    return true;
+}
+
+void    ImGui_ImplOpenGL3_Shutdown()
+{
+    ImGui_ImplOpenGL3_DestroyDeviceObjects();
+}
+
+void    ImGui_ImplOpenGL3_NewFrame()
+{
+    if (!g_FontTexture)
+        ImGui_ImplOpenGL3_CreateDeviceObjects();
+}
+
+static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, int fb_width, int fb_height, GLuint vertex_array_object)
+{
+    // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, polygon fill
+    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);
+#ifdef GL_POLYGON_MODE
+    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
+#endif
+
+    // Setup viewport, orthographic projection matrix
+    // Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayPos is (0,0) for single viewport apps.
+    glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
+    float L = draw_data->DisplayPos.x;
+    float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x;
+    float T = draw_data->DisplayPos.y;
+    float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y;
+    const float ortho_projection[4][4] =
+    {
+        { 2.0f/(R-L),   0.0f,         0.0f,   0.0f },
+        { 0.0f,         2.0f/(T-B),   0.0f,   0.0f },
+        { 0.0f,         0.0f,        -1.0f,   0.0f },
+        { (R+L)/(L-R),  (T+B)/(B-T),  0.0f,   1.0f },
+    };
+    glUseProgram(g_ShaderHandle);
+    glUniform1i(g_AttribLocationTex, 0);
+    glUniformMatrix4fv(g_AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);
+#ifdef GL_SAMPLER_BINDING
+    glBindSampler(0, 0); // We use combined texture/sampler state. Applications using GL 3.3 may set that otherwise.
+#endif
+
+    (void)vertex_array_object;
+#ifndef IMGUI_IMPL_OPENGL_ES2
+    glBindVertexArray(vertex_array_object);
+#endif
+
+    // Bind vertex/index buffers and setup attributes for ImDrawVert
+    glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, g_ElementsHandle);
+    glEnableVertexAttribArray(g_AttribLocationVtxPos);
+    glEnableVertexAttribArray(g_AttribLocationVtxUV);
+    glEnableVertexAttribArray(g_AttribLocationVtxColor);
+    glVertexAttribPointer(g_AttribLocationVtxPos,   2, GL_FLOAT,         GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, pos));
+    glVertexAttribPointer(g_AttribLocationVtxUV,    2, GL_FLOAT,         GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, uv));
+    glVertexAttribPointer(g_AttribLocationVtxColor, 4, GL_UNSIGNED_BYTE, GL_TRUE,  sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, col));
+}
+
+// OpenGL3 Render function.
+// (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
+// Note that this implementation is little overcomplicated because we are saving/setting up/restoring every OpenGL state explicitly, in order to be able to run within any OpenGL engine that doesn't do so.
+void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
+{
+    // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
+    int fb_width = (int)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x);
+    int fb_height = (int)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y);
+    if (fb_width <= 0 || fb_height <= 0)
+        return;
+
+    // Backup GL state
+    GLenum last_active_texture; glGetIntegerv(GL_ACTIVE_TEXTURE, (GLint*)&last_active_texture);
+    glActiveTexture(GL_TEXTURE0);
+    GLint last_program; glGetIntegerv(GL_CURRENT_PROGRAM, &last_program);
+    GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
+#ifdef GL_SAMPLER_BINDING
+    GLint last_sampler; glGetIntegerv(GL_SAMPLER_BINDING, &last_sampler);
+#endif
+    GLint last_array_buffer; glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
+#ifndef IMGUI_IMPL_OPENGL_ES2
+    GLint last_vertex_array_object; glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array_object);
+#endif
+#ifdef GL_POLYGON_MODE
+    GLint last_polygon_mode[2]; glGetIntegerv(GL_POLYGON_MODE, last_polygon_mode);
+#endif
+    GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport);
+    GLint last_scissor_box[4]; glGetIntegerv(GL_SCISSOR_BOX, last_scissor_box);
+    GLenum last_blend_src_rgb; glGetIntegerv(GL_BLEND_SRC_RGB, (GLint*)&last_blend_src_rgb);
+    GLenum last_blend_dst_rgb; glGetIntegerv(GL_BLEND_DST_RGB, (GLint*)&last_blend_dst_rgb);
+    GLenum last_blend_src_alpha; glGetIntegerv(GL_BLEND_SRC_ALPHA, (GLint*)&last_blend_src_alpha);
+    GLenum last_blend_dst_alpha; glGetIntegerv(GL_BLEND_DST_ALPHA, (GLint*)&last_blend_dst_alpha);
+    GLenum last_blend_equation_rgb; glGetIntegerv(GL_BLEND_EQUATION_RGB, (GLint*)&last_blend_equation_rgb);
+    GLenum last_blend_equation_alpha; glGetIntegerv(GL_BLEND_EQUATION_ALPHA, (GLint*)&last_blend_equation_alpha);
+    GLboolean last_enable_blend = glIsEnabled(GL_BLEND);
+    GLboolean last_enable_cull_face = glIsEnabled(GL_CULL_FACE);
+    GLboolean last_enable_depth_test = glIsEnabled(GL_DEPTH_TEST);
+    GLboolean last_enable_scissor_test = glIsEnabled(GL_SCISSOR_TEST);
+    bool clip_origin_lower_left = true;
+#if defined(GL_CLIP_ORIGIN) && !defined(__APPLE__)
+    GLenum last_clip_origin = 0; glGetIntegerv(GL_CLIP_ORIGIN, (GLint*)&last_clip_origin); // Support for GL 4.5's glClipControl(GL_UPPER_LEFT)
+    if (last_clip_origin == GL_UPPER_LEFT)
+        clip_origin_lower_left = false;
+#endif
+
+    // Setup desired GL state
+    // Recreate the VAO every time (this is to easily allow multiple GL contexts to be rendered to. VAO are not shared among GL contexts)
+    // The renderer would actually work without any VAO bound, but then our VertexAttrib calls would overwrite the default one currently bound.
+    GLuint vertex_array_object = 0;
+#ifndef IMGUI_IMPL_OPENGL_ES2
+    glGenVertexArrays(1, &vertex_array_object);
+#endif
+    ImGui_ImplOpenGL3_SetupRenderState(draw_data, fb_width, fb_height, vertex_array_object);
+
+    // Will project scissor/clipping rectangles into framebuffer space
+    ImVec2 clip_off = draw_data->DisplayPos;         // (0,0) unless using multi-viewports
+    ImVec2 clip_scale = draw_data->FramebufferScale; // (1,1) unless using retina display which are often (2,2)
+
+    // Render command lists
+    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    {
+        const ImDrawList* cmd_list = draw_data->CmdLists[n];
+
+        // Upload vertex/index buffers
+        glBufferData(GL_ARRAY_BUFFER, (GLsizeiptr)cmd_list->VtxBuffer.Size * sizeof(ImDrawVert), (const GLvoid*)cmd_list->VtxBuffer.Data, GL_STREAM_DRAW);
+        glBufferData(GL_ELEMENT_ARRAY_BUFFER, (GLsizeiptr)cmd_list->IdxBuffer.Size * sizeof(ImDrawIdx), (const GLvoid*)cmd_list->IdxBuffer.Data, GL_STREAM_DRAW);
+
+        for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
+        {
+            const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
+            if (pcmd->UserCallback != NULL)
+            {
+                // User callback, registered via ImDrawList::AddCallback()
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
+                    ImGui_ImplOpenGL3_SetupRenderState(draw_data, fb_width, fb_height, vertex_array_object);
+                else
+                    pcmd->UserCallback(cmd_list, pcmd);
+            }
+            else
+            {
+                // Project scissor/clipping rectangles into framebuffer space
+                ImVec4 clip_rect;
+                clip_rect.x = (pcmd->ClipRect.x - clip_off.x) * clip_scale.x;
+                clip_rect.y = (pcmd->ClipRect.y - clip_off.y) * clip_scale.y;
+                clip_rect.z = (pcmd->ClipRect.z - clip_off.x) * clip_scale.x;
+                clip_rect.w = (pcmd->ClipRect.w - clip_off.y) * clip_scale.y;
+
+                if (clip_rect.x < fb_width && clip_rect.y < fb_height && clip_rect.z >= 0.0f && clip_rect.w >= 0.0f)
+                {
+                    // Apply scissor/clipping rectangle
+                    if (clip_origin_lower_left)
+                        glScissor((int)clip_rect.x, (int)(fb_height - clip_rect.w), (int)(clip_rect.z - clip_rect.x), (int)(clip_rect.w - clip_rect.y));
+                    else
+                        glScissor((int)clip_rect.x, (int)clip_rect.y, (int)clip_rect.z, (int)clip_rect.w); // Support for GL 4.5 rarely used glClipControl(GL_UPPER_LEFT)
+
+                    // Bind texture, Draw
+                    glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->TextureId);
+#if IMGUI_IMPL_OPENGL_HAS_DRAW_WITH_BASE_VERTEX
+                    glDrawElementsBaseVertex(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, (void*)(intptr_t)(pcmd->IdxOffset * sizeof(ImDrawIdx)), (GLint)pcmd->VtxOffset);
+#else
+                    glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, (void*)(intptr_t)(pcmd->IdxOffset * sizeof(ImDrawIdx)));
+#endif
+                }
+            }
+        }
+    }
+
+    // Destroy the temporary VAO
+#ifndef IMGUI_IMPL_OPENGL_ES2
+    glDeleteVertexArrays(1, &vertex_array_object);
+#endif
+
+    // Restore modified GL state
+    glUseProgram(last_program);
+    glBindTexture(GL_TEXTURE_2D, last_texture);
+#ifdef GL_SAMPLER_BINDING
+    glBindSampler(0, last_sampler);
+#endif
+    glActiveTexture(last_active_texture);
+#ifndef IMGUI_IMPL_OPENGL_ES2
+    glBindVertexArray(last_vertex_array_object);
+#endif
+    glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
+    glBlendEquationSeparate(last_blend_equation_rgb, last_blend_equation_alpha);
+    glBlendFuncSeparate(last_blend_src_rgb, last_blend_dst_rgb, last_blend_src_alpha, last_blend_dst_alpha);
+    if (last_enable_blend) glEnable(GL_BLEND); else glDisable(GL_BLEND);
+    if (last_enable_cull_face) glEnable(GL_CULL_FACE); else glDisable(GL_CULL_FACE);
+    if (last_enable_depth_test) glEnable(GL_DEPTH_TEST); else glDisable(GL_DEPTH_TEST);
+    if (last_enable_scissor_test) glEnable(GL_SCISSOR_TEST); else glDisable(GL_SCISSOR_TEST);
+#ifdef GL_POLYGON_MODE
+    glPolygonMode(GL_FRONT_AND_BACK, (GLenum)last_polygon_mode[0]);
+#endif
+    glViewport(last_viewport[0], last_viewport[1], (GLsizei)last_viewport[2], (GLsizei)last_viewport[3]);
+    glScissor(last_scissor_box[0], last_scissor_box[1], (GLsizei)last_scissor_box[2], (GLsizei)last_scissor_box[3]);
+}
+
+bool ImGui_ImplOpenGL3_CreateFontsTexture()
+{
+    // Build texture atlas
+    ImGuiIO& io = ImGui::GetIO();
+    unsigned char* pixels;
+    int width, height;
+    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);   // Load as RGBA 32-bits (75% of the memory is wasted, but default font is so small) because it is more likely to be compatible with user's existing shaders. If your ImTextureId represent a higher-level concept than just a GL texture id, consider calling GetTexDataAsAlpha8() instead to save on GPU memory.
+
+    // Upload texture to graphics system
+    GLint last_texture;
+    glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
+    glGenTextures(1, &g_FontTexture);
+    glBindTexture(GL_TEXTURE_2D, g_FontTexture);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+#ifdef GL_UNPACK_ROW_LENGTH
+    glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
+#endif
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
+
+    // Store our identifier
+    io.Fonts->TexID = (ImTextureID)(intptr_t)g_FontTexture;
+
+    // Restore state
+    glBindTexture(GL_TEXTURE_2D, last_texture);
+
+    return true;
+}
+
+void ImGui_ImplOpenGL3_DestroyFontsTexture()
+{
+    if (g_FontTexture)
+    {
+        ImGuiIO& io = ImGui::GetIO();
+        glDeleteTextures(1, &g_FontTexture);
+        io.Fonts->TexID = 0;
+        g_FontTexture = 0;
+    }
+}
+
+// If you get an error please report on github. You may try different GL context version or GLSL version. See GL<>GLSL version table at the top of this file.
+static bool CheckShader(GLuint handle, const char* desc)
+{
+    GLint status = 0, log_length = 0;
+    glGetShaderiv(handle, GL_COMPILE_STATUS, &status);
+    glGetShaderiv(handle, GL_INFO_LOG_LENGTH, &log_length);
+    if ((GLboolean)status == GL_FALSE)
+        fprintf(stderr, "ERROR: ImGui_ImplOpenGL3_CreateDeviceObjects: failed to compile %s!\n", desc);
+    if (log_length > 1)
+    {
+        ImVector<char> buf;
+        buf.resize((int)(log_length + 1));
+        glGetShaderInfoLog(handle, log_length, NULL, (GLchar*)buf.begin());
+        fprintf(stderr, "%s\n", buf.begin());
+    }
+    return (GLboolean)status == GL_TRUE;
+}
+
+// If you get an error please report on GitHub. You may try different GL context version or GLSL version.
+static bool CheckProgram(GLuint handle, const char* desc)
+{
+    GLint status = 0, log_length = 0;
+    glGetProgramiv(handle, GL_LINK_STATUS, &status);
+    glGetProgramiv(handle, GL_INFO_LOG_LENGTH, &log_length);
+    if ((GLboolean)status == GL_FALSE)
+        fprintf(stderr, "ERROR: ImGui_ImplOpenGL3_CreateDeviceObjects: failed to link %s! (with GLSL '%s')\n", desc, g_GlslVersionString);
+    if (log_length > 1)
+    {
+        ImVector<char> buf;
+        buf.resize((int)(log_length + 1));
+        glGetProgramInfoLog(handle, log_length, NULL, (GLchar*)buf.begin());
+        fprintf(stderr, "%s\n", buf.begin());
+    }
+    return (GLboolean)status == GL_TRUE;
+}
+
+bool    ImGui_ImplOpenGL3_CreateDeviceObjects()
+{
+    // Backup GL state
+    GLint last_texture, last_array_buffer;
+    glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
+    glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
+#ifndef IMGUI_IMPL_OPENGL_ES2
+    GLint last_vertex_array;
+    glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array);
+#endif
+
+    // Parse GLSL version string
+    int glsl_version = 130;
+    sscanf(g_GlslVersionString, "#version %d", &glsl_version);
+
+    const GLchar* vertex_shader_glsl_120 =
+        "uniform mat4 ProjMtx;\n"
+        "attribute vec2 Position;\n"
+        "attribute vec2 UV;\n"
+        "attribute vec4 Color;\n"
+        "varying vec2 Frag_UV;\n"
+        "varying vec4 Frag_Color;\n"
+        "void main()\n"
+        "{\n"
+        "    Frag_UV = UV;\n"
+        "    Frag_Color = Color;\n"
+        "    gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
+        "}\n";
+
+    const GLchar* vertex_shader_glsl_130 =
+        "uniform mat4 ProjMtx;\n"
+        "in vec2 Position;\n"
+        "in vec2 UV;\n"
+        "in vec4 Color;\n"
+        "out vec2 Frag_UV;\n"
+        "out vec4 Frag_Color;\n"
+        "void main()\n"
+        "{\n"
+        "    Frag_UV = UV;\n"
+        "    Frag_Color = Color;\n"
+        "    gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
+        "}\n";
+
+    const GLchar* vertex_shader_glsl_300_es =
+        "precision mediump float;\n"
+        "layout (location = 0) in vec2 Position;\n"
+        "layout (location = 1) in vec2 UV;\n"
+        "layout (location = 2) in vec4 Color;\n"
+        "uniform mat4 ProjMtx;\n"
+        "out vec2 Frag_UV;\n"
+        "out vec4 Frag_Color;\n"
+        "void main()\n"
+        "{\n"
+        "    Frag_UV = UV;\n"
+        "    Frag_Color = Color;\n"
+        "    gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
+        "}\n";
+
+    const GLchar* vertex_shader_glsl_410_core =
+        "layout (location = 0) in vec2 Position;\n"
+        "layout (location = 1) in vec2 UV;\n"
+        "layout (location = 2) in vec4 Color;\n"
+        "uniform mat4 ProjMtx;\n"
+        "out vec2 Frag_UV;\n"
+        "out vec4 Frag_Color;\n"
+        "void main()\n"
+        "{\n"
+        "    Frag_UV = UV;\n"
+        "    Frag_Color = Color;\n"
+        "    gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
+        "}\n";
+
+    const GLchar* fragment_shader_glsl_120 =
+        "#ifdef GL_ES\n"
+        "    precision mediump float;\n"
+        "#endif\n"
+        "uniform sampler2D Texture;\n"
+        "varying vec2 Frag_UV;\n"
+        "varying vec4 Frag_Color;\n"
+        "void main()\n"
+        "{\n"
+        "    gl_FragColor = Frag_Color * texture2D(Texture, Frag_UV.st);\n"
+        "}\n";
+
+    const GLchar* fragment_shader_glsl_130 =
+        "uniform sampler2D Texture;\n"
+        "in vec2 Frag_UV;\n"
+        "in vec4 Frag_Color;\n"
+        "out vec4 Out_Color;\n"
+        "void main()\n"
+        "{\n"
+        "    Out_Color = Frag_Color * texture(Texture, Frag_UV.st);\n"
+        "}\n";
+
+    const GLchar* fragment_shader_glsl_300_es =
+        "precision mediump float;\n"
+        "uniform sampler2D Texture;\n"
+        "in vec2 Frag_UV;\n"
+        "in vec4 Frag_Color;\n"
+        "layout (location = 0) out vec4 Out_Color;\n"
+        "void main()\n"
+        "{\n"
+        "    Out_Color = Frag_Color * texture(Texture, Frag_UV.st);\n"
+        "}\n";
+
+    const GLchar* fragment_shader_glsl_410_core =
+        "in vec2 Frag_UV;\n"
+        "in vec4 Frag_Color;\n"
+        "uniform sampler2D Texture;\n"
+        "layout (location = 0) out vec4 Out_Color;\n"
+        "void main()\n"
+        "{\n"
+        "    Out_Color = Frag_Color * texture(Texture, Frag_UV.st);\n"
+        "}\n";
+
+    // Select shaders matching our GLSL versions
+    const GLchar* vertex_shader = NULL;
+    const GLchar* fragment_shader = NULL;
+    if (glsl_version < 130)
+    {
+        vertex_shader = vertex_shader_glsl_120;
+        fragment_shader = fragment_shader_glsl_120;
+    }
+    else if (glsl_version >= 410)
+    {
+        vertex_shader = vertex_shader_glsl_410_core;
+        fragment_shader = fragment_shader_glsl_410_core;
+    }
+    else if (glsl_version == 300)
+    {
+        vertex_shader = vertex_shader_glsl_300_es;
+        fragment_shader = fragment_shader_glsl_300_es;
+    }
+    else
+    {
+        vertex_shader = vertex_shader_glsl_130;
+        fragment_shader = fragment_shader_glsl_130;
+    }
+
+    // Create shaders
+    const GLchar* vertex_shader_with_version[2] = { g_GlslVersionString, vertex_shader };
+    g_VertHandle = glCreateShader(GL_VERTEX_SHADER);
+    glShaderSource(g_VertHandle, 2, vertex_shader_with_version, NULL);
+    glCompileShader(g_VertHandle);
+    CheckShader(g_VertHandle, "vertex shader");
+
+    const GLchar* fragment_shader_with_version[2] = { g_GlslVersionString, fragment_shader };
+    g_FragHandle = glCreateShader(GL_FRAGMENT_SHADER);
+    glShaderSource(g_FragHandle, 2, fragment_shader_with_version, NULL);
+    glCompileShader(g_FragHandle);
+    CheckShader(g_FragHandle, "fragment shader");
+
+    g_ShaderHandle = glCreateProgram();
+    glAttachShader(g_ShaderHandle, g_VertHandle);
+    glAttachShader(g_ShaderHandle, g_FragHandle);
+    glLinkProgram(g_ShaderHandle);
+    CheckProgram(g_ShaderHandle, "shader program");
+
+    g_AttribLocationTex = glGetUniformLocation(g_ShaderHandle, "Texture");
+    g_AttribLocationProjMtx = glGetUniformLocation(g_ShaderHandle, "ProjMtx");
+    g_AttribLocationVtxPos = glGetAttribLocation(g_ShaderHandle, "Position");
+    g_AttribLocationVtxUV = glGetAttribLocation(g_ShaderHandle, "UV");
+    g_AttribLocationVtxColor = glGetAttribLocation(g_ShaderHandle, "Color");
+
+    // Create buffers
+    glGenBuffers(1, &g_VboHandle);
+    glGenBuffers(1, &g_ElementsHandle);
+
+    ImGui_ImplOpenGL3_CreateFontsTexture();
+
+    // Restore modified GL state
+    glBindTexture(GL_TEXTURE_2D, last_texture);
+    glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
+#ifndef IMGUI_IMPL_OPENGL_ES2
+    glBindVertexArray(last_vertex_array);
+#endif
+
+    return true;
+}
+
+void    ImGui_ImplOpenGL3_DestroyDeviceObjects()
+{
+    if (g_VboHandle) glDeleteBuffers(1, &g_VboHandle);
+    if (g_ElementsHandle) glDeleteBuffers(1, &g_ElementsHandle);
+    g_VboHandle = g_ElementsHandle = 0;
+
+    if (g_ShaderHandle && g_VertHandle) glDetachShader(g_ShaderHandle, g_VertHandle);
+    if (g_VertHandle) glDeleteShader(g_VertHandle);
+    g_VertHandle = 0;
+
+    if (g_ShaderHandle && g_FragHandle) glDetachShader(g_ShaderHandle, g_FragHandle);
+    if (g_FragHandle) glDeleteShader(g_FragHandle);
+    g_FragHandle = 0;
+
+    if (g_ShaderHandle) glDeleteProgram(g_ShaderHandle);
+    g_ShaderHandle = 0;
+
+    ImGui_ImplOpenGL3_DestroyFontsTexture();
+}

src/util/imgui/imgui_impl_sdl.cpp

@@ -0,0 +1,343 @@
+// 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)
+//  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/imgui.h>
+#include <imgui/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] = { 0 };
+static char*        g_ClipboardTextData = NULL;
+
+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);
+            io.KeySuper = ((SDL_GetModState() & KMOD_GUI) != 0);
+            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_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;
+
+    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);
+
+#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);
+}
+
+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)
+    {
+        // 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.
+        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();
+}

src/util/imgui/imgui_sdl.cpp

@@ -0,0 +1,664 @@
+#include <imgui/imgui_sdl.h>
+
+#if _WIN32
+#include <SDL.h>
+#else
+#include <SDL2/SDL.h>
+#endif
+
+#include <imgui/imgui.h>
+
+#include <map>
+#include <list>
+#include <cmath>
+#include <array>
+#include <vector>
+#include <memory>
+#include <iostream>
+#include <algorithm>
+#include <functional>
+#include <unordered_map>
+
+namespace
+{
+	struct Device* CurrentDevice = nullptr;
+
+	namespace TupleHash
+	{
+		template <typename T> struct Hash
+		{
+			std::size_t operator()(const T& value) const
+			{
+				return std::hash<T>()(value);
+			}
+		};
+
+		template <typename T> void CombineHash(std::size_t& seed, const T& value)
+		{
+			seed ^= TupleHash::Hash<T>()(value) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
+		}
+
+		template <typename Tuple, std::size_t Index = std::tuple_size<Tuple>::value - 1> struct Hasher
+		{
+			static void Hash(std::size_t& seed, const Tuple& tuple)
+			{
+				Hasher<Tuple, Index - 1>::Hash(seed, tuple);
+				CombineHash(seed, std::get<Index>(tuple));
+			}
+		};
+
+		template <typename Tuple> struct Hasher<Tuple, 0>
+		{
+			static void Hash(std::size_t& seed, const Tuple& tuple)
+			{
+				CombineHash(seed, std::get<0>(tuple));
+			}
+		};
+
+		template <typename... T> struct Hash<std::tuple<T...>>
+		{
+			std::size_t operator()(const std::tuple<T...>& value) const
+			{
+				std::size_t seed = 0;
+				Hasher<std::tuple<T...>>::Hash(seed, value);
+				return seed;
+			}
+		};
+	}
+
+	template <typename Key, typename Value, std::size_t Size> class LRUCache
+	{
+	public:
+		bool Contains(const Key& key) const
+		{
+			return Container.find(key) != Container.end();
+		}
+
+		const Value& At(const Key& key)
+		{
+			assert(Contains(key));
+
+			const auto location = Container.find(key);
+			Order.splice(Order.begin(), Order, location->second);
+			return location->second->second;
+		}
+
+		void Insert(const Key& key, Value value)
+		{
+			const auto existingLocation = Container.find(key);
+			if (existingLocation != Container.end())
+			{
+				Order.erase(existingLocation->second);
+				Container.erase(existingLocation);
+			}
+
+			Order.push_front(std::make_pair(key, std::move(value)));
+			Container.insert(std::make_pair(key, Order.begin()));
+
+			Clean();
+		}
+	private:
+		void Clean()
+		{
+			while (Container.size() > Size)
+			{
+				auto last = Order.end();
+				last--;
+				Container.erase(last->first);
+				Order.pop_back();
+			}
+		}
+
+		std::list<std::pair<Key, Value>> Order;
+		std::unordered_map<Key, decltype(Order.begin()), TupleHash::Hash<Key>> Container;
+	};
+
+	struct Color
+	{
+		const float R, G, B, A;
+
+		explicit Color(uint32_t color)
+			: R(((color >> 0) & 0xff) / 255.0f), G(((color >> 8) & 0xff) / 255.0f), B(((color >> 16) & 0xff) / 255.0f), A(((color >> 24) & 0xff) / 255.0f) { }
+		Color(float r, float g, float b, float a) : R(r), G(g), B(b), A(a) { }
+
+		Color operator*(const Color& c) const { return Color(R * c.R, G * c.G, B * c.B, A * c.A); }
+		Color operator*(float v) const { return Color(R * v, G * v, B * v, A * v); }
+		Color operator+(const Color& c) const { return Color(R + c.R, G + c.G, B + c.B, A + c.A); }
+
+		uint32_t ToInt() const
+		{
+			return	((static_cast<int>(R * 255) & 0xff) << 0)
+				  | ((static_cast<int>(G * 255) & 0xff) << 8)
+				  | ((static_cast<int>(B * 255) & 0xff) << 16)
+				  | ((static_cast<int>(A * 255) & 0xff) << 24);
+		}
+
+		void UseAsDrawColor(SDL_Renderer* renderer) const
+		{
+			SDL_SetRenderDrawColor(renderer,
+				static_cast<uint8_t>(R * 255),
+				static_cast<uint8_t>(G * 255),
+				static_cast<uint8_t>(B * 255),
+				static_cast<uint8_t>(A * 255));
+		}
+	};
+
+	struct Device
+	{
+		SDL_Renderer* Renderer;
+
+		struct ClipRect
+		{
+			int X, Y, Width, Height;
+		} Clip;
+
+		struct TriangleCacheItem
+		{
+			SDL_Texture* Texture = nullptr;
+			int Width = 0, Height = 0;
+
+			~TriangleCacheItem() { if (Texture) SDL_DestroyTexture(Texture); }
+		};
+
+		// You can tweak these to values that you find that work the best.
+		static constexpr std::size_t UniformColorTriangleCacheSize = 512;
+		static constexpr std::size_t GenericTriangleCacheSize = 64;
+
+		// Uniform color is identified by its color and the coordinates of the edges.
+		using UniformColorTriangleKey = std::tuple<uint32_t, int, int, int, int, int, int>;
+		// The generic triangle cache unfortunately has to be basically a full representation of the triangle. 
+		// This includes the (offset) vertex positions, texture coordinates and vertex colors.
+		using GenericTriangleVertexKey = std::tuple<int, int, double, double, uint32_t>;
+		using GenericTriangleKey = std::tuple<GenericTriangleVertexKey, GenericTriangleVertexKey, GenericTriangleVertexKey>;
+
+		LRUCache<UniformColorTriangleKey, std::unique_ptr<TriangleCacheItem>, UniformColorTriangleCacheSize> UniformColorTriangleCache;
+		LRUCache<GenericTriangleKey, std::unique_ptr<TriangleCacheItem>, GenericTriangleCacheSize> GenericTriangleCache;
+
+		Device(SDL_Renderer* renderer) : Renderer(renderer) { }
+
+		void SetClipRect(const ClipRect& rect)
+		{
+			Clip = rect;
+			const SDL_Rect clip = { rect.X, rect.Y, rect.Width, rect.Height };
+			SDL_RenderSetClipRect(Renderer, &clip);
+		}
+
+		void EnableClip() { SetClipRect(Clip); }
+		void DisableClip() { SDL_RenderSetClipRect(Renderer, nullptr); }
+
+		void SetAt(int x, int y, const Color& color)
+		{
+			color.UseAsDrawColor(Renderer);
+			SDL_RenderDrawPoint(Renderer, x, y);
+		}
+
+		SDL_Texture* MakeTexture(int width, int height)
+		{
+			SDL_Texture* texture = SDL_CreateTexture(Renderer, SDL_PIXELFORMAT_RGBA32, SDL_TEXTUREACCESS_TARGET, width, height);
+			SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_BLEND);
+			return texture;
+		}
+
+		void UseAsRenderTarget(SDL_Texture* texture)
+		{
+			SDL_SetRenderTarget(Renderer, texture);
+			if (texture)
+			{
+				SDL_SetRenderDrawColor(Renderer, 0, 0, 0, 0);
+				SDL_RenderClear(Renderer);
+			}
+		}
+	};
+
+	struct Texture
+	{
+		SDL_Surface* Surface;
+		SDL_Texture* Source;
+
+		~Texture()
+		{
+			SDL_FreeSurface(Surface);
+			SDL_DestroyTexture(Source);
+		}
+
+		Color Sample(float u, float v) const
+		{
+			const int x = static_cast<int>(std::round(u * (Surface->w - 1) + 0.5f));
+			const int y = static_cast<int>(std::round(v * (Surface->h - 1) + 0.5f));
+
+			const int location = y * Surface->w + x;
+			assert(location < Surface->w * Surface->h);
+
+			return Color(static_cast<uint32_t*>(Surface->pixels)[location]);
+		}
+	};
+
+	template <typename T> class InterpolatedFactorEquation
+	{
+	public:
+		InterpolatedFactorEquation(const T& value0, const T& value1, const T& value2, const ImVec2& v0, const ImVec2& v1, const ImVec2& v2)
+			: Value0(value0), Value1(value1), Value2(value2), V0(v0), V1(v1), V2(v2),
+			Divisor((V1.y - V2.y) * (V0.x - V2.x) + (V2.x - V1.x) * (V0.y - V2.y)) { }
+
+		T Evaluate(float x, float y) const
+		{
+			const float w1 = ((V1.y - V2.y) * (x - V2.x) + (V2.x - V1.x) * (y - V2.y)) / Divisor;
+			const float w2 = ((V2.y - V0.y) * (x - V2.x) + (V0.x - V2.x) * (y - V2.y)) / Divisor;
+			const float w3 = 1.0f - w1 - w2;
+
+			return static_cast<T>((Value0 * w1) + (Value1 * w2) + (Value2 * w3));
+		}
+	private:
+		const T Value0;
+		const T Value1;
+		const T Value2;
+
+		const ImVec2& V0;
+		const ImVec2& V1;
+		const ImVec2& V2;
+
+		const float Divisor;
+	};
+
+	struct Rect
+	{
+		float MinX, MinY, MaxX, MaxY;
+		float MinU, MinV, MaxU, MaxV;
+
+		bool IsOnExtreme(const ImVec2& point) const
+		{
+			return (point.x == MinX || point.x == MaxX) && (point.y == MinY || point.y == MaxY);
+		}
+
+		bool UsesOnlyColor() const
+		{
+			const ImVec2& whitePixel = ImGui::GetIO().Fonts->TexUvWhitePixel;
+
+			return MinU == MaxU && MinU == whitePixel.x && MinV == MaxV && MaxV == whitePixel.y;
+		}
+
+		static Rect CalculateBoundingBox(const ImDrawVert& v0, const ImDrawVert& v1, const ImDrawVert& v2)
+		{
+			return Rect{
+				std::min({ v0.pos.x, v1.pos.x, v2.pos.x }),
+				std::min({ v0.pos.y, v1.pos.y, v2.pos.y }),
+				std::max({ v0.pos.x, v1.pos.x, v2.pos.x }),
+				std::max({ v0.pos.y, v1.pos.y, v2.pos.y }),
+				std::min({ v0.uv.x, v1.uv.x, v2.uv.x }),
+				std::min({ v0.uv.y, v1.uv.y, v2.uv.y }),
+				std::max({ v0.uv.x, v1.uv.x, v2.uv.x }),
+				std::max({ v0.uv.y, v1.uv.y, v2.uv.y })
+			};
+		}
+	};
+
+	struct FixedPointTriangleRenderInfo
+	{
+		int X1, X2, X3, Y1, Y2, Y3;
+		int MinX, MaxX, MinY, MaxY;
+
+		static FixedPointTriangleRenderInfo CalculateFixedPointTriangleInfo(const ImVec2& v1, const ImVec2& v2, const ImVec2& v3)
+		{
+			static constexpr float scale = 16.0f;
+
+			const int x1 = static_cast<int>(std::round(v1.x * scale));
+			const int x2 = static_cast<int>(std::round(v2.x * scale));
+			const int x3 = static_cast<int>(std::round(v3.x * scale));
+
+			const int y1 = static_cast<int>(std::round(v1.y * scale));
+			const int y2 = static_cast<int>(std::round(v2.y * scale));
+			const int y3 = static_cast<int>(std::round(v3.y * scale));
+
+			int minX = (std::min({ x1, x2, x3 }) + 0xF) >> 4;
+			int maxX = (std::max({ x1, x2, x3 }) + 0xF) >> 4;
+			int minY = (std::min({ y1, y2, y3 }) + 0xF) >> 4;
+			int maxY = (std::max({ y1, y2, y3 }) + 0xF) >> 4;
+
+			return FixedPointTriangleRenderInfo{ x1, x2, x3, y1, y2, y3, minX, maxX, minY, maxY };
+		}
+	};
+
+	void DrawTriangleWithColorFunction(const FixedPointTriangleRenderInfo& renderInfo, const std::function<Color(float x, float y)>& colorFunction, Device::TriangleCacheItem* cacheItem)
+	{
+		// Implementation source: https://web.archive.org/web/20171128164608/http://forum.devmaster.net/t/advanced-rasterization/6145.
+		// This is a fixed point implementation that rounds to top-left.
+
+		const int deltaX12 = renderInfo.X1 - renderInfo.X2;
+		const int deltaX23 = renderInfo.X2 - renderInfo.X3;
+		const int deltaX31 = renderInfo.X3 - renderInfo.X1;
+
+		const int deltaY12 = renderInfo.Y1 - renderInfo.Y2;
+		const int deltaY23 = renderInfo.Y2 - renderInfo.Y3;
+		const int deltaY31 = renderInfo.Y3 - renderInfo.Y1;
+
+		const int fixedDeltaX12 = deltaX12 << 4;
+		const int fixedDeltaX23 = deltaX23 << 4;
+		const int fixedDeltaX31 = deltaX31 << 4;
+
+		const int fixedDeltaY12 = deltaY12 << 4;
+		const int fixedDeltaY23 = deltaY23 << 4;
+		const int fixedDeltaY31 = deltaY31 << 4;
+
+		const int width = renderInfo.MaxX - renderInfo.MinX;
+		const int height = renderInfo.MaxY - renderInfo.MinY;
+		if (width == 0 || height == 0) return;
+
+		int c1 = deltaY12 * renderInfo.X1 - deltaX12 * renderInfo.Y1;
+		int c2 = deltaY23 * renderInfo.X2 - deltaX23 * renderInfo.Y2;
+		int c3 = deltaY31 * renderInfo.X3 - deltaX31 * renderInfo.Y3;
+
+		if (deltaY12 < 0 || (deltaY12 == 0 && deltaX12 > 0)) c1++;
+		if (deltaY23 < 0 || (deltaY23 == 0 && deltaX23 > 0)) c2++;
+		if (deltaY31 < 0 || (deltaY31 == 0 && deltaX31 > 0)) c3++;
+
+		int edgeStart1 = c1 + deltaX12 * (renderInfo.MinY << 4) - deltaY12 * (renderInfo.MinX << 4);
+		int edgeStart2 = c2 + deltaX23 * (renderInfo.MinY << 4) - deltaY23 * (renderInfo.MinX << 4);
+		int edgeStart3 = c3 + deltaX31 * (renderInfo.MinY << 4) - deltaY31 * (renderInfo.MinX << 4);
+
+		SDL_Texture* cache = CurrentDevice->MakeTexture(width, height);
+		CurrentDevice->DisableClip();
+		CurrentDevice->UseAsRenderTarget(cache);
+
+		for (int y = renderInfo.MinY; y < renderInfo.MaxY; y++)
+		{
+			int edge1 = edgeStart1;
+			int edge2 = edgeStart2;
+			int edge3 = edgeStart3;
+
+			for (int x = renderInfo.MinX; x < renderInfo.MaxX; x++)
+			{
+				if (edge1 > 0 && edge2 > 0 && edge3 > 0)
+				{
+					CurrentDevice->SetAt(x - renderInfo.MinX, y - renderInfo.MinY, colorFunction(x + 0.5f, y + 0.5f));
+				}
+
+				edge1 -= fixedDeltaY12;
+				edge2 -= fixedDeltaY23;
+				edge3 -= fixedDeltaY31;
+			}
+
+			edgeStart1 += fixedDeltaX12;
+			edgeStart2 += fixedDeltaX23;
+			edgeStart3 += fixedDeltaX31;
+		}
+
+		CurrentDevice->UseAsRenderTarget(nullptr);
+		CurrentDevice->EnableClip();
+
+		cacheItem->Texture = cache;
+		cacheItem->Width = width;
+		cacheItem->Height = height;
+	}
+
+	void DrawCachedTriangle(const Device::TriangleCacheItem& triangle, const FixedPointTriangleRenderInfo& renderInfo)
+	{
+		const SDL_Rect destination = { renderInfo.MinX, renderInfo.MinY, triangle.Width, triangle.Height };
+		SDL_RenderCopy(CurrentDevice->Renderer, triangle.Texture, nullptr, &destination);
+	}
+
+	void DrawTriangle(const ImDrawVert& v1, const ImDrawVert& v2, const ImDrawVert& v3, const Texture* texture)
+	{
+		// The naming inconsistency in the parameters is intentional. The fixed point algorithm wants the vertices in a counter clockwise order.
+		const auto& renderInfo = FixedPointTriangleRenderInfo::CalculateFixedPointTriangleInfo(v3.pos, v2.pos, v1.pos);
+
+		// First we check if there is a cached version of this triangle already waiting for us. If so, we can just do a super fast texture copy.
+
+		const auto key = std::make_tuple(
+			std::make_tuple(static_cast<int>(std::round(v1.pos.x)) - renderInfo.MinX, static_cast<int>(std::round(v1.pos.y)) - renderInfo.MinY, v1.uv.x, v1.uv.y, v1.col),
+			std::make_tuple(static_cast<int>(std::round(v2.pos.x)) - renderInfo.MinX, static_cast<int>(std::round(v2.pos.y)) - renderInfo.MinY, v2.uv.x, v2.uv.y, v2.col),
+			std::make_tuple(static_cast<int>(std::round(v3.pos.x)) - renderInfo.MinX, static_cast<int>(std::round(v3.pos.y)) - renderInfo.MinY, v3.uv.x, v3.uv.y, v3.col));
+
+		if (CurrentDevice->GenericTriangleCache.Contains(key))
+		{
+			const auto& cached = CurrentDevice->GenericTriangleCache.At(key);
+			DrawCachedTriangle(*cached, renderInfo);
+
+			return;
+		}
+
+		const InterpolatedFactorEquation<float> textureU(v1.uv.x, v2.uv.x, v3.uv.x, v1.pos, v2.pos, v3.pos);
+		const InterpolatedFactorEquation<float> textureV(v1.uv.y, v2.uv.y, v3.uv.y, v1.pos, v2.pos, v3.pos);
+
+		const InterpolatedFactorEquation<Color> shadeColor(Color(v1.col), Color(v2.col), Color(v3.col), v1.pos, v2.pos, v3.pos);
+
+		auto cached = std::make_unique<Device::TriangleCacheItem>();
+		DrawTriangleWithColorFunction(renderInfo, [&](float x, float y) {
+			const float u = textureU.Evaluate(x, y);
+			const float v = textureV.Evaluate(x, y);
+			const Color sampled = texture->Sample(u, v);
+			const Color shade = shadeColor.Evaluate(x, y);
+
+			return sampled * shade;
+		}, cached.get());
+
+		if (!cached->Texture) return;
+
+		const SDL_Rect destination = { renderInfo.MinX, renderInfo.MinY, cached->Width, cached->Height };
+		SDL_RenderCopy(CurrentDevice->Renderer, cached->Texture, nullptr, &destination);
+
+		CurrentDevice->GenericTriangleCache.Insert(key, std::move(cached));
+	}
+
+	void DrawUniformColorTriangle(const ImDrawVert& v1, const ImDrawVert& v2, const ImDrawVert& v3)
+	{
+		const Color color(v1.col);
+
+		// The naming inconsistency in the parameters is intentional. The fixed point algorithm wants the vertices in a counter clockwise order.
+		const auto& renderInfo = FixedPointTriangleRenderInfo::CalculateFixedPointTriangleInfo(v3.pos, v2.pos, v1.pos);
+
+		const auto key =std::make_tuple(v1.col,
+			static_cast<int>(std::round(v1.pos.x)) - renderInfo.MinX, static_cast<int>(std::round(v1.pos.y)) - renderInfo.MinY,
+			static_cast<int>(std::round(v2.pos.x)) - renderInfo.MinX, static_cast<int>(std::round(v2.pos.y)) - renderInfo.MinY,
+			static_cast<int>(std::round(v3.pos.x)) - renderInfo.MinX, static_cast<int>(std::round(v3.pos.y)) - renderInfo.MinY);
+		if (CurrentDevice->UniformColorTriangleCache.Contains(key))
+		{
+			const auto& cached = CurrentDevice->UniformColorTriangleCache.At(key);
+			DrawCachedTriangle(*cached, renderInfo);
+
+			return;
+		}
+
+		auto cached = std::make_unique<Device::TriangleCacheItem>();
+		DrawTriangleWithColorFunction(renderInfo, [&color](float, float) { return color; }, cached.get());
+
+		if (!cached->Texture) return;
+
+		const SDL_Rect destination = { renderInfo.MinX, renderInfo.MinY, cached->Width, cached->Height };
+		SDL_RenderCopy(CurrentDevice->Renderer, cached->Texture, nullptr, &destination);
+
+		CurrentDevice->UniformColorTriangleCache.Insert(key, std::move(cached));
+	}
+
+	void DrawRectangle(const Rect& bounding, SDL_Texture* texture, int textureWidth, int textureHeight, const Color& color, bool doHorizontalFlip, bool doVerticalFlip)
+	{
+		// We are safe to assume uniform color here, because the caller checks it and and uses the triangle renderer to render those.
+
+		const SDL_Rect destination = {
+			static_cast<int>(bounding.MinX),
+			static_cast<int>(bounding.MinY),
+			static_cast<int>(bounding.MaxX - bounding.MinX),
+			static_cast<int>(bounding.MaxY - bounding.MinY)
+		};
+
+		// If the area isn't textured, we can just draw a rectangle with the correct color.
+		if (bounding.UsesOnlyColor())
+		{
+			color.UseAsDrawColor(CurrentDevice->Renderer);
+			SDL_RenderFillRect(CurrentDevice->Renderer, &destination);
+		}
+		else
+		{
+			// We can now just calculate the correct source rectangle and draw it.
+
+			const SDL_Rect source = {
+				static_cast<int>(bounding.MinU * textureWidth),
+				static_cast<int>(bounding.MinV * textureHeight),
+				static_cast<int>((bounding.MaxU - bounding.MinU) * textureWidth),
+				static_cast<int>((bounding.MaxV - bounding.MinV) * textureHeight)
+			};
+
+			const SDL_RendererFlip flip = static_cast<SDL_RendererFlip>((doHorizontalFlip ? SDL_FLIP_HORIZONTAL : 0) | (doVerticalFlip ? SDL_FLIP_VERTICAL : 0));
+
+			SDL_SetTextureColorMod(texture, static_cast<uint8_t>(color.R * 255), static_cast<uint8_t>(color.G * 255), static_cast<uint8_t>(color.B * 255));
+			SDL_RenderCopyEx(CurrentDevice->Renderer, texture, &source, &destination, 0.0, nullptr, flip);
+		}
+	}
+
+	void DrawRectangle(const Rect& bounding, const Texture* texture, const Color& color, bool doHorizontalFlip, bool doVerticalFlip)
+	{
+		DrawRectangle(bounding, texture->Source, texture->Surface->w, texture->Surface->h, color, doHorizontalFlip, doVerticalFlip);
+	}
+
+	void DrawRectangle(const Rect& bounding, SDL_Texture* texture, const Color& color, bool doHorizontalFlip, bool doVerticalFlip)
+	{
+		int width, height;
+		SDL_QueryTexture(texture, nullptr, nullptr, &width, &height);
+		DrawRectangle(bounding, texture, width, height, color, doHorizontalFlip, doVerticalFlip);
+	}
+}
+
+namespace ImGuiSDL
+{
+	void Initialize(SDL_Renderer* renderer, int windowWidth, int windowHeight)
+	{
+		ImGuiIO& io = ImGui::GetIO();
+		io.DisplaySize.x = static_cast<float>(windowWidth);
+		io.DisplaySize.y = static_cast<float>(windowHeight);
+
+		ImGui::GetStyle().WindowRounding = 0.0f;
+		ImGui::GetStyle().AntiAliasedFill = false;
+		ImGui::GetStyle().AntiAliasedLines = false;
+
+		// Loads the font texture.
+		unsigned char* pixels;
+		int width, height;
+		io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);
+		static constexpr uint32_t rmask = 0x000000ff, gmask = 0x0000ff00, bmask = 0x00ff0000, amask = 0xff000000;
+		SDL_Surface* surface = SDL_CreateRGBSurfaceFrom(pixels, width, height, 32, 4 * width, rmask, gmask, bmask, amask);
+
+		Texture* texture = new Texture();
+		texture->Surface = surface;
+		texture->Source = SDL_CreateTextureFromSurface(renderer, surface);
+		io.Fonts->TexID = (void*)texture;
+
+		CurrentDevice = new Device(renderer);
+	}
+
+	void Deinitialize()
+	{
+		// Frees up the memory of the font texture.
+		ImGuiIO& io = ImGui::GetIO();
+		Texture* texture = static_cast<Texture*>(io.Fonts->TexID);
+		delete texture;
+
+		delete CurrentDevice;
+	}
+
+	void Render(ImDrawData* drawData)
+	{
+		SDL_BlendMode blendMode;
+		SDL_GetRenderDrawBlendMode(CurrentDevice->Renderer, &blendMode);
+		SDL_SetRenderDrawBlendMode(CurrentDevice->Renderer, SDL_BLENDMODE_BLEND);
+
+		ImGuiIO& io = ImGui::GetIO();
+
+		for (int n = 0; n < drawData->CmdListsCount; n++)
+		{
+			auto commandList = drawData->CmdLists[n];
+			auto vertexBuffer = commandList->VtxBuffer;
+			auto indexBuffer = commandList->IdxBuffer.Data;
+
+			for (int cmd_i = 0; cmd_i < commandList->CmdBuffer.Size; cmd_i++)
+			{
+				const ImDrawCmd* drawCommand = &commandList->CmdBuffer[cmd_i];
+
+				const Device::ClipRect clipRect = {
+					static_cast<int>(drawCommand->ClipRect.x),
+					static_cast<int>(drawCommand->ClipRect.y),
+					static_cast<int>(drawCommand->ClipRect.z - drawCommand->ClipRect.x),
+					static_cast<int>(drawCommand->ClipRect.w - drawCommand->ClipRect.y)
+				};
+				CurrentDevice->SetClipRect(clipRect);
+
+				if (drawCommand->UserCallback)
+				{
+					drawCommand->UserCallback(commandList, drawCommand);
+				}
+				else
+				{
+					const bool isWrappedTexture = drawCommand->TextureId == io.Fonts->TexID;
+
+					// Loops over triangles.
+					for (unsigned int i = 0; i + 3 <= drawCommand->ElemCount; i += 3)
+					{
+						const ImDrawVert& v0 = vertexBuffer[indexBuffer[i + 0]];
+						const ImDrawVert& v1 = vertexBuffer[indexBuffer[i + 1]];
+						const ImDrawVert& v2 = vertexBuffer[indexBuffer[i + 2]];
+
+						const Rect& bounding = Rect::CalculateBoundingBox(v0, v1, v2);
+
+						const bool isTriangleUniformColor = v0.col == v1.col && v1.col == v2.col;
+						const bool doesTriangleUseOnlyColor = bounding.UsesOnlyColor();
+
+						// Actually, since we render a whole bunch of rectangles, we try to first detect those, and render them more efficiently.
+						// How are rectangles detected? It's actually pretty simple: If all 6 vertices lie on the extremes of the bounding box, 
+						// it's a rectangle.
+						if (i + 6 <= drawCommand->ElemCount)
+						{
+							const ImDrawVert& v3 = vertexBuffer[indexBuffer[i + 3]];
+							const ImDrawVert& v4 = vertexBuffer[indexBuffer[i + 4]];
+							const ImDrawVert& v5 = vertexBuffer[indexBuffer[i + 5]];
+
+							const bool isUniformColor = isTriangleUniformColor && v2.col == v3.col && v3.col == v4.col && v4.col == v5.col;
+
+							if (isUniformColor
+							&& bounding.IsOnExtreme(v0.pos)
+							&& bounding.IsOnExtreme(v1.pos)
+							&& bounding.IsOnExtreme(v2.pos)
+							&& bounding.IsOnExtreme(v3.pos)
+							&& bounding.IsOnExtreme(v4.pos)
+							&& bounding.IsOnExtreme(v5.pos))
+							{
+								// ImGui gives the triangles in a nice order: the first vertex happens to be the topleft corner of our rectangle.
+								// We need to check for the orientation of the texture, as I believe in theory ImGui could feed us a flipped texture,
+								// so that the larger texture coordinates are at topleft instead of bottomright.
+								// We don't consider equal texture coordinates to require a flip, as then the rectangle is mostlikely simply a colored rectangle.
+								const bool doHorizontalFlip = v2.uv.x < v0.uv.x;
+								const bool doVerticalFlip = v2.uv.x < v0.uv.x;
+
+								if (isWrappedTexture)
+								{
+									DrawRectangle(bounding, static_cast<const Texture*>(drawCommand->TextureId), Color(v0.col), doHorizontalFlip, doVerticalFlip);
+								}
+								else
+								{
+									DrawRectangle(bounding, static_cast<SDL_Texture*>(drawCommand->TextureId), Color(v0.col), doHorizontalFlip, doVerticalFlip);
+								}
+
+								i += 3;  // Additional increment to account for the extra 3 vertices we consumed.
+								continue;
+							}
+						}
+
+						if (isTriangleUniformColor && doesTriangleUseOnlyColor)
+						{
+							DrawUniformColorTriangle(v0, v1, v2);
+						}
+						else
+						{
+							// Currently we assume that any non rectangular texture samples the font texture. Dunno if that's what actually happens, but it seems to work.
+							assert(isWrappedTexture);
+							DrawTriangle(v0, v1, v2, static_cast<const Texture*>(drawCommand->TextureId));
+						}
+					}
+				}
+
+				indexBuffer += drawCommand->ElemCount;
+			}
+		}
+
+		CurrentDevice->DisableClip();
+
+		SDL_SetRenderDrawBlendMode(CurrentDevice->Renderer, blendMode);
+	}
+};

test/main.cpp

@@ -24,14 +24,14 @@ int main(int argc, char** argv) {
   	//     object->Translate({ 0.0f, -5.0f, -20.0f });
 
 	// std::vector<Triangle*> tris = LoadTrianglesBasic("/home/ben/programming/inferno/resources/lucy-normals.obj");
-	std::vector<Triangle*> tris = LoadTrianglesBasic("E:/Projects/Inferno/resources/lucy-normals.obj");
-    for (const auto& object : tris)
-	    object->Translate({ 0.0f, -3.9f, -10.6f });
+	// std::vector<Triangle*> tris = LoadTrianglesBasic("E:/Projects/Inferno/resources/lucy-normals.obj");
+    // for (const auto& object : tris)
+	//     object->Translate({ 0.0f, -3.9f, -10.6f });
 
 	// std::vector<Triangle*> tris = LoadTrianglesBasic("/home/ben/programming/inferno/resources/cornell.obj");
-	// std::vector<Triangle*> tris = LoadTrianglesBasic("E:/Projects/Inferno/resources/cornell.obj");
-    // for (const auto& object : tris)
-	//     object->Translate({ 0.0f, -0.9f, -3.0f });
+	std::vector<Triangle*> tris = LoadTrianglesBasic("E:/Projects/Inferno/resources/cornell.obj");
+    for (const auto& object : tris)
+	    object->Translate({ 0.0f, -0.9f, -3.0f });
 
     Mesh* mesh = new Mesh(tris);
     mesh->Optimise();