examples/opengl_example/main.cpp - external/github.com/ocornut/imgui - Git at Google

 #ifdef _MSC_VER
 #pragma warning (disable: 4996)         // 'This function or variable may be unsafe': strcpy, strdup, sprintf, vsnprintf, sscanf, fopen
 #include <Windows.h>
 #include <Imm.h>
 #endif
 #define STB_IMAGE_IMPLEMENTATION
 #include "stb_image.h"                  // for .png loading
 #include "../../imgui.h"

 // glew & glfw
 #define GLEW_STATIC
 #include <GL/glew.h>
 #include <GLFW/glfw3.h>
 #ifdef _MSC_VER
 #define GLFW_EXPOSE_NATIVE_WIN32
 #define GLFW_EXPOSE_NATIVE_WGL
 #include <GLFW/glfw3native.h>
 #endif

 static GLFWwindow* window;
 static GLuint fontTex;
 static bool mousePressed[2] = { false, false };
 static ImVec2 mousePosScale(1.0f, 1.0f);

 // This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
 // If text or lines are blurry when integrating ImGui in your engine:
 // - in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
 // - try adjusting ImGui::GetIO().PixelCenterOffset to 0.5f or 0.375f
 static void ImImpl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count)
 {
     if (cmd_lists_count == 0)
         return;

     // We are using the OpenGL fixed pipeline to make the example code simpler to read!
     // A probable faster way to render would be to collate all vertices from all cmd_lists into a single vertex buffer.
     // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, vertex/texcoord/color pointers.
     glEnable(GL_BLEND);
     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
     glDisable(GL_CULL_FACE);
     glDisable(GL_DEPTH_TEST);
     glEnable(GL_SCISSOR_TEST);
     glEnableClientState(GL_VERTEX_ARRAY);
     glEnableClientState(GL_TEXTURE_COORD_ARRAY);
     glEnableClientState(GL_COLOR_ARRAY);

     // Setup texture
     glBindTexture(GL_TEXTURE_2D, fontTex);
     glEnable(GL_TEXTURE_2D);

     // Setup orthographic projection matrix
     const float width = ImGui::GetIO().DisplaySize.x;
     const float height = ImGui::GetIO().DisplaySize.y;
     glMatrixMode(GL_PROJECTION);
     glLoadIdentity();
     glOrtho(0.0f, width, height, 0.0f, -1.0f, +1.0f);
     glMatrixMode(GL_MODELVIEW);
     glLoadIdentity();

     // Render command lists
     for (int n = 0; n < cmd_lists_count; n++)
     {
         const ImDrawList* cmd_list = cmd_lists[n];
         const unsigned char* vtx_buffer = (const unsigned char*)cmd_list->vtx_buffer.begin();
         glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer));
         glTexCoordPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer+8));
         glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(ImDrawVert), (void*)(vtx_buffer+16));

         int vtx_offset = 0;
         const ImDrawCmd* pcmd_end = cmd_list->commands.end();
         for (const ImDrawCmd* pcmd = cmd_list->commands.begin(); pcmd != pcmd_end; pcmd++)
         {
             glScissor((int)pcmd->clip_rect.x, (int)(height - pcmd->clip_rect.w), (int)(pcmd->clip_rect.z - pcmd->clip_rect.x), (int)(pcmd->clip_rect.w - pcmd->clip_rect.y));
             glDrawArrays(GL_TRIANGLES, vtx_offset, pcmd->vtx_count);
             vtx_offset += pcmd->vtx_count;
         }
     }
     glDisable(GL_SCISSOR_TEST);
     glDisableClientState(GL_COLOR_ARRAY);
     glDisableClientState(GL_TEXTURE_COORD_ARRAY);
     glDisableClientState(GL_VERTEX_ARRAY);
 }

 // NB: ImGui already provide OS clipboard support for Windows so this isn't needed if you are using Windows only.
 static const char* ImImpl_GetClipboardTextFn()
 {
     return glfwGetClipboardString(window);
 }

 static void ImImpl_SetClipboardTextFn(const char* text)
 {
     glfwSetClipboardString(window, text);
 }

 #ifdef _MSC_VER
 // Notify OS Input Method Editor of text input position (e.g. when using Japanese/Chinese inputs, otherwise this isn't needed)
 static void ImImpl_ImeSetInputScreenPosFn(int x, int y)
 {
     HWND hwnd = glfwGetWin32Window(window);
     if (HIMC himc = ImmGetContext(hwnd))
     {
         COMPOSITIONFORM cf;
         cf.ptCurrentPos.x = x;
         cf.ptCurrentPos.y = y;
         cf.dwStyle = CFS_FORCE_POSITION;
         ImmSetCompositionWindow(himc, &cf);
     }
 }
 #endif

 // GLFW callbacks to get events
 static void glfw_error_callback(int error, const char* description)
 {
     fputs(description, stderr);
 }

 static void glfw_mouse_button_callback(GLFWwindow* window, int button, int action, int mods)
 {
     if (action == GLFW_PRESS && button >= 0 && button < 2)
         mousePressed[button] = true;
 }

 static void glfw_scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
 {
     ImGuiIO& io = ImGui::GetIO();
     io.MouseWheel = (yoffset != 0.0f) ? yoffset > 0.0f ? 1 : - 1 : 0;           // Mouse wheel: -1,0,+1
 }

 static void glfw_key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
 {
     ImGuiIO& io = ImGui::GetIO();
     if (action == GLFW_PRESS)
         io.KeysDown[key] = true;
     if (action == GLFW_RELEASE)
         io.KeysDown[key] = false;
     io.KeyCtrl = (mods & GLFW_MOD_CONTROL) != 0;
     io.KeyShift = (mods & GLFW_MOD_SHIFT) != 0;
 }

 static void glfw_char_callback(GLFWwindow* window, unsigned int c)
 {
     if (c > 0 && c < 0x10000)
         ImGui::GetIO().AddInputCharacter((unsigned short)c);
 }

 // OpenGL code based on http://open.gl tutorials
 void InitGL()
 {
     glfwSetErrorCallback(glfw_error_callback);

     if (!glfwInit())
         exit(1);

     glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
     window = glfwCreateWindow(1280, 720, "ImGui OpenGL example", NULL, NULL);
     glfwMakeContextCurrent(window);
     glfwSetKeyCallback(window, glfw_key_callback);
     glfwSetMouseButtonCallback(window, glfw_mouse_button_callback);
     glfwSetScrollCallback(window, glfw_scroll_callback);
     glfwSetCharCallback(window, glfw_char_callback);

     glewInit();
 }

 void InitImGui()
 {
     int w, h;
     int fb_w, fb_h;
     glfwGetWindowSize(window, &w, &h);
     glfwGetFramebufferSize(window, &fb_w, &fb_h);
     mousePosScale.x = (float)fb_w / w;                  // Some screens e.g. Retina display have framebuffer size != from window size, and mouse inputs are given in window/screen coordinates.
     mousePosScale.y = (float)fb_h / h;

     ImGuiIO& io = ImGui::GetIO();
     io.DisplaySize = ImVec2((float)fb_w, (float)fb_h);  // Display size, in pixels. For clamping windows positions.
     io.DeltaTime = 1.0f/60.0f;                          // Time elapsed since last frame, in seconds (in this sample app we'll override this every frame because our timestep is variable)
     io.PixelCenterOffset = 0.0f;                        // Align OpenGL texels
     io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB;             // Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array.
     io.KeyMap[ImGuiKey_LeftArrow] = GLFW_KEY_LEFT;
     io.KeyMap[ImGuiKey_RightArrow] = GLFW_KEY_RIGHT;
     io.KeyMap[ImGuiKey_UpArrow] = GLFW_KEY_UP;
     io.KeyMap[ImGuiKey_DownArrow] = GLFW_KEY_DOWN;
     io.KeyMap[ImGuiKey_Home] = GLFW_KEY_HOME;
     io.KeyMap[ImGuiKey_End] = GLFW_KEY_END;
     io.KeyMap[ImGuiKey_Delete] = GLFW_KEY_DELETE;
     io.KeyMap[ImGuiKey_Backspace] = GLFW_KEY_BACKSPACE;
     io.KeyMap[ImGuiKey_Enter] = GLFW_KEY_ENTER;
     io.KeyMap[ImGuiKey_Escape] = GLFW_KEY_ESCAPE;
     io.KeyMap[ImGuiKey_A] = GLFW_KEY_A;
     io.KeyMap[ImGuiKey_C] = GLFW_KEY_C;
     io.KeyMap[ImGuiKey_V] = GLFW_KEY_V;
     io.KeyMap[ImGuiKey_X] = GLFW_KEY_X;
     io.KeyMap[ImGuiKey_Y] = GLFW_KEY_Y;
     io.KeyMap[ImGuiKey_Z] = GLFW_KEY_Z;

     io.RenderDrawListsFn = ImImpl_RenderDrawLists;
     io.SetClipboardTextFn = ImImpl_SetClipboardTextFn;
     io.GetClipboardTextFn = ImImpl_GetClipboardTextFn;
 #ifdef _MSC_VER
     io.ImeSetInputScreenPosFn = ImImpl_ImeSetInputScreenPosFn;
 #endif

     // Load font texture
     glGenTextures(1, &fontTex);
     glBindTexture(GL_TEXTURE_2D, fontTex);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

 #if 1
     // Default font (embedded in code)
     const void* png_data;
     unsigned int png_size;
     ImGui::GetDefaultFontData(NULL, NULL, &png_data, &png_size);
     int tex_x, tex_y, tex_comp;
     void* tex_data = stbi_load_from_memory((const unsigned char*)png_data, (int)png_size, &tex_x, &tex_y, &tex_comp, 0);
     IM_ASSERT(tex_data != NULL);
 #else
     // Custom font from filesystem
     io.Font = new ImBitmapFont();
     io.Font->LoadFromFile("../../extra_fonts/mplus-2m-medium_18.fnt");
     IM_ASSERT(io.Font->IsLoaded());

     int tex_x, tex_y, tex_comp;
     void* tex_data = stbi_load("../../extra_fonts/mplus-2m-medium_18.png", &tex_x, &tex_y, &tex_comp, 0);
     IM_ASSERT(tex_data != NULL);

     // Automatically find white pixel from the texture we just loaded
     // (io.FontTexUvForWhite needs to contains UV coordinates pointing to a white pixel in order to render solid objects)
     for (int tex_data_off = 0; tex_data_off < tex_x*tex_y; tex_data_off++)
         if (((unsigned int*)tex_data)[tex_data_off] == 0xffffffff)
         {
             io.FontTexUvForWhite = ImVec2((float)(tex_data_off % tex_x)/(tex_x), (float)(tex_data_off / tex_x)/(tex_y));
             break;
         }
 #endif

     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, tex_x, tex_y, 0, GL_RGBA, GL_UNSIGNED_BYTE, tex_data);
     stbi_image_free(tex_data);
 }

 void UpdateImGui()
 {
     ImGuiIO& io = ImGui::GetIO();

     // Setup timestep
     static double time = 0.0f;
     const double current_time =  glfwGetTime();
     io.DeltaTime = (float)(current_time - time);
     time = current_time;

     // Setup inputs
     // (we already got mouse wheel, keyboard keys & characters from glfw callbacks polled in glfwPollEvents())
     double mouse_x, mouse_y;
     glfwGetCursorPos(window, &mouse_x, &mouse_y);
     io.MousePos = ImVec2((float)mouse_x * mousePosScale.x, (float)mouse_y * mousePosScale.y);      // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.)
     io.MouseDown[0] = mousePressed[0] || glfwGetMouseButton(window, GLFW_MOUSE_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] = mousePressed[1] || glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_RIGHT) != 0;

     // Start the frame
     ImGui::NewFrame();
 }

 // Application code
 int main(int argc, char** argv)
 {
     InitGL();
     InitImGui();

     while (!glfwWindowShouldClose(window))
     {
         ImGuiIO& io = ImGui::GetIO();
         mousePressed[0] = mousePressed[1] = false;
         io.MouseWheel = 0;
         glfwPollEvents();
         UpdateImGui();

         static bool show_test_window = true;
         static bool show_another_window = false;

         // 1. Show a simple window
         // Tip: if we don't call ImGui::Begin()/ImGui::End() the widgets appears in a window automatically called "Debug"
         {
             static float f;
             ImGui::Text("Hello, world!");
             ImGui::SliderFloat("float", &f, 0.0f, 1.0f);
             show_test_window ^= ImGui::Button("Test Window");
             show_another_window ^= ImGui::Button("Another Window");

             // Calculate and show framerate
             static float ms_per_frame[120] = { 0 };
             static int ms_per_frame_idx = 0;
             static float ms_per_frame_accum = 0.0f;
             ms_per_frame_accum -= ms_per_frame[ms_per_frame_idx];
             ms_per_frame[ms_per_frame_idx] = ImGui::GetIO().DeltaTime * 1000.0f;
             ms_per_frame_accum += ms_per_frame[ms_per_frame_idx];
             ms_per_frame_idx = (ms_per_frame_idx + 1) % 120;
             const float ms_per_frame_avg = ms_per_frame_accum / 120;
             ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", ms_per_frame_avg, 1000.0f / ms_per_frame_avg);
         }

         // 2. Show another simple window, this time using an explicit Begin/End pair
         if (show_another_window)
         {
             ImGui::Begin("Another Window", &show_another_window, ImVec2(200,100));
             ImGui::Text("Hello");
             ImGui::End();
         }

         // 3. Show the ImGui test window. Most of the sample code is in ImGui::ShowTestWindow()
         if (show_test_window)
         {
             ImGui::SetNewWindowDefaultPos(ImVec2(650, 20));        // Normally user code doesn't need/want to call this, because positions are saved in .ini file. Here we just want to make the demo initial state a bit more friendly!
             ImGui::ShowTestWindow(&show_test_window);
         }

         // Rendering
         glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
         glClearColor(0.8f, 0.6f, 0.6f, 1.0f);
         glClear(GL_COLOR_BUFFER_BIT);
         ImGui::Render();
         glfwSwapBuffers(window);
     }

     ImGui::Shutdown();
     glfwTerminate();
     return 0;
 }
	#ifdef _MSC_VER
	#pragma warning (disable: 4996) // 'This function or variable may be unsafe': strcpy, strdup, sprintf, vsnprintf, sscanf, fopen
	#include <Windows.h>
	#include <Imm.h>
	#endif
	#define STB_IMAGE_IMPLEMENTATION
	#include "stb_image.h" // for .png loading
	#include "../../imgui.h"

	// glew & glfw
	#define GLEW_STATIC
	#include <GL/glew.h>
	#include <GLFW/glfw3.h>
	#ifdef _MSC_VER
	#define GLFW_EXPOSE_NATIVE_WIN32
	#define GLFW_EXPOSE_NATIVE_WGL
	#include <GLFW/glfw3native.h>
	#endif

	static GLFWwindow* window;
	static GLuint fontTex;
	static bool mousePressed[2] = { false, false };
	static ImVec2 mousePosScale(1.0f, 1.0f);

	// This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
	// If text or lines are blurry when integrating ImGui in your engine:
	// - in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
	// - try adjusting ImGui::GetIO().PixelCenterOffset to 0.5f or 0.375f
	static void ImImpl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count)
	{
	if (cmd_lists_count == 0)
	return;

	// We are using the OpenGL fixed pipeline to make the example code simpler to read!
	// A probable faster way to render would be to collate all vertices from all cmd_lists into a single vertex buffer.
	// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, vertex/texcoord/color pointers.
	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	glDisable(GL_CULL_FACE);
	glDisable(GL_DEPTH_TEST);
	glEnable(GL_SCISSOR_TEST);
	glEnableClientState(GL_VERTEX_ARRAY);
	glEnableClientState(GL_TEXTURE_COORD_ARRAY);
	glEnableClientState(GL_COLOR_ARRAY);

	// Setup texture
	glBindTexture(GL_TEXTURE_2D, fontTex);
	glEnable(GL_TEXTURE_2D);

	// Setup orthographic projection matrix
	const float width = ImGui::GetIO().DisplaySize.x;
	const float height = ImGui::GetIO().DisplaySize.y;
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glOrtho(0.0f, width, height, 0.0f, -1.0f, +1.0f);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();

	// Render command lists
	for (int n = 0; n < cmd_lists_count; n++)
	{
	const ImDrawList* cmd_list = cmd_lists[n];
	const unsigned char* vtx_buffer = (const unsigned char*)cmd_list->vtx_buffer.begin();
	glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer));
	glTexCoordPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer+8));
	glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(ImDrawVert), (void*)(vtx_buffer+16));

	int vtx_offset = 0;
	const ImDrawCmd* pcmd_end = cmd_list->commands.end();
	for (const ImDrawCmd* pcmd = cmd_list->commands.begin(); pcmd != pcmd_end; pcmd++)
	{
	glScissor((int)pcmd->clip_rect.x, (int)(height - pcmd->clip_rect.w), (int)(pcmd->clip_rect.z - pcmd->clip_rect.x), (int)(pcmd->clip_rect.w - pcmd->clip_rect.y));
	glDrawArrays(GL_TRIANGLES, vtx_offset, pcmd->vtx_count);
	vtx_offset += pcmd->vtx_count;
	}
	}
	glDisable(GL_SCISSOR_TEST);
	glDisableClientState(GL_COLOR_ARRAY);
	glDisableClientState(GL_TEXTURE_COORD_ARRAY);
	glDisableClientState(GL_VERTEX_ARRAY);
	}

	// NB: ImGui already provide OS clipboard support for Windows so this isn't needed if you are using Windows only.
	static const char* ImImpl_GetClipboardTextFn()
	{
	return glfwGetClipboardString(window);
	}

	static void ImImpl_SetClipboardTextFn(const char* text)
	{
	glfwSetClipboardString(window, text);
	}

	#ifdef _MSC_VER
	// Notify OS Input Method Editor of text input position (e.g. when using Japanese/Chinese inputs, otherwise this isn't needed)
	static void ImImpl_ImeSetInputScreenPosFn(int x, int y)
	{
	HWND hwnd = glfwGetWin32Window(window);
	if (HIMC himc = ImmGetContext(hwnd))
	{
	COMPOSITIONFORM cf;
	cf.ptCurrentPos.x = x;
	cf.ptCurrentPos.y = y;
	cf.dwStyle = CFS_FORCE_POSITION;
	ImmSetCompositionWindow(himc, &cf);
	}
	}
	#endif

	// GLFW callbacks to get events
	static void glfw_error_callback(int error, const char* description)
	{
	fputs(description, stderr);
	}

	static void glfw_mouse_button_callback(GLFWwindow* window, int button, int action, int mods)
	{
	if (action == GLFW_PRESS && button >= 0 && button < 2)
	mousePressed[button] = true;
	}

	static void glfw_scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
	{
	ImGuiIO& io = ImGui::GetIO();
	io.MouseWheel = (yoffset != 0.0f) ? yoffset > 0.0f ? 1 : - 1 : 0; // Mouse wheel: -1,0,+1
	}

	static void glfw_key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
	{
	ImGuiIO& io = ImGui::GetIO();
	if (action == GLFW_PRESS)
	io.KeysDown[key] = true;
	if (action == GLFW_RELEASE)
	io.KeysDown[key] = false;
	io.KeyCtrl = (mods & GLFW_MOD_CONTROL) != 0;
	io.KeyShift = (mods & GLFW_MOD_SHIFT) != 0;
	}

	static void glfw_char_callback(GLFWwindow* window, unsigned int c)
	{
	if (c > 0 && c < 0x10000)
	ImGui::GetIO().AddInputCharacter((unsigned short)c);
	}

	// OpenGL code based on http://open.gl tutorials
	void InitGL()
	{
	glfwSetErrorCallback(glfw_error_callback);

	if (!glfwInit())
	exit(1);

	glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
	window = glfwCreateWindow(1280, 720, "ImGui OpenGL example", NULL, NULL);
	glfwMakeContextCurrent(window);
	glfwSetKeyCallback(window, glfw_key_callback);
	glfwSetMouseButtonCallback(window, glfw_mouse_button_callback);
	glfwSetScrollCallback(window, glfw_scroll_callback);
	glfwSetCharCallback(window, glfw_char_callback);

	glewInit();
	}

	void InitImGui()
	{
	int w, h;
	int fb_w, fb_h;
	glfwGetWindowSize(window, &w, &h);
	glfwGetFramebufferSize(window, &fb_w, &fb_h);
	mousePosScale.x = (float)fb_w / w; // Some screens e.g. Retina display have framebuffer size != from window size, and mouse inputs are given in window/screen coordinates.
	mousePosScale.y = (float)fb_h / h;

	ImGuiIO& io = ImGui::GetIO();
	io.DisplaySize = ImVec2((float)fb_w, (float)fb_h); // Display size, in pixels. For clamping windows positions.
	io.DeltaTime = 1.0f/60.0f; // Time elapsed since last frame, in seconds (in this sample app we'll override this every frame because our timestep is variable)
	io.PixelCenterOffset = 0.0f; // Align OpenGL texels
	io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB; // Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array.
	io.KeyMap[ImGuiKey_LeftArrow] = GLFW_KEY_LEFT;
	io.KeyMap[ImGuiKey_RightArrow] = GLFW_KEY_RIGHT;
	io.KeyMap[ImGuiKey_UpArrow] = GLFW_KEY_UP;
	io.KeyMap[ImGuiKey_DownArrow] = GLFW_KEY_DOWN;
	io.KeyMap[ImGuiKey_Home] = GLFW_KEY_HOME;
	io.KeyMap[ImGuiKey_End] = GLFW_KEY_END;
	io.KeyMap[ImGuiKey_Delete] = GLFW_KEY_DELETE;
	io.KeyMap[ImGuiKey_Backspace] = GLFW_KEY_BACKSPACE;
	io.KeyMap[ImGuiKey_Enter] = GLFW_KEY_ENTER;
	io.KeyMap[ImGuiKey_Escape] = GLFW_KEY_ESCAPE;
	io.KeyMap[ImGuiKey_A] = GLFW_KEY_A;
	io.KeyMap[ImGuiKey_C] = GLFW_KEY_C;
	io.KeyMap[ImGuiKey_V] = GLFW_KEY_V;
	io.KeyMap[ImGuiKey_X] = GLFW_KEY_X;
	io.KeyMap[ImGuiKey_Y] = GLFW_KEY_Y;
	io.KeyMap[ImGuiKey_Z] = GLFW_KEY_Z;

	io.RenderDrawListsFn = ImImpl_RenderDrawLists;
	io.SetClipboardTextFn = ImImpl_SetClipboardTextFn;
	io.GetClipboardTextFn = ImImpl_GetClipboardTextFn;
	#ifdef _MSC_VER
	io.ImeSetInputScreenPosFn = ImImpl_ImeSetInputScreenPosFn;
	#endif

	// Load font texture
	glGenTextures(1, &fontTex);
	glBindTexture(GL_TEXTURE_2D, fontTex);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

	#if 1
	// Default font (embedded in code)
	const void* png_data;
	unsigned int png_size;
	ImGui::GetDefaultFontData(NULL, NULL, &png_data, &png_size);
	int tex_x, tex_y, tex_comp;
	void* tex_data = stbi_load_from_memory((const unsigned char*)png_data, (int)png_size, &tex_x, &tex_y, &tex_comp, 0);
	IM_ASSERT(tex_data != NULL);
	#else
	// Custom font from filesystem
	io.Font = new ImBitmapFont();
	io.Font->LoadFromFile("../../extra_fonts/mplus-2m-medium_18.fnt");
	IM_ASSERT(io.Font->IsLoaded());

	int tex_x, tex_y, tex_comp;
	void* tex_data = stbi_load("../../extra_fonts/mplus-2m-medium_18.png", &tex_x, &tex_y, &tex_comp, 0);
	IM_ASSERT(tex_data != NULL);

	// Automatically find white pixel from the texture we just loaded
	// (io.FontTexUvForWhite needs to contains UV coordinates pointing to a white pixel in order to render solid objects)
	for (int tex_data_off = 0; tex_data_off < tex_x*tex_y; tex_data_off++)
	if (((unsigned int*)tex_data)[tex_data_off] == 0xffffffff)
	{
	io.FontTexUvForWhite = ImVec2((float)(tex_data_off % tex_x)/(tex_x), (float)(tex_data_off / tex_x)/(tex_y));
	break;
	}
	#endif

	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, tex_x, tex_y, 0, GL_RGBA, GL_UNSIGNED_BYTE, tex_data);
	stbi_image_free(tex_data);
	}

	void UpdateImGui()
	{
	ImGuiIO& io = ImGui::GetIO();

	// Setup timestep
	static double time = 0.0f;
	const double current_time = glfwGetTime();
	io.DeltaTime = (float)(current_time - time);
	time = current_time;

	// Setup inputs
	// (we already got mouse wheel, keyboard keys & characters from glfw callbacks polled in glfwPollEvents())
	double mouse_x, mouse_y;
	glfwGetCursorPos(window, &mouse_x, &mouse_y);
	io.MousePos = ImVec2((float)mouse_x * mousePosScale.x, (float)mouse_y * mousePosScale.y); // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.)
	io.MouseDown[0] = mousePressed[0] \|\| glfwGetMouseButton(window, GLFW_MOUSE_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] = mousePressed[1] \|\| glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_RIGHT) != 0;

	// Start the frame
	ImGui::NewFrame();
	}

	// Application code
	int main(int argc, char** argv)
	{
	InitGL();
	InitImGui();

	while (!glfwWindowShouldClose(window))
	{
	ImGuiIO& io = ImGui::GetIO();
	mousePressed[0] = mousePressed[1] = false;
	io.MouseWheel = 0;
	glfwPollEvents();
	UpdateImGui();

	static bool show_test_window = true;
	static bool show_another_window = false;

	// 1. Show a simple window
	// Tip: if we don't call ImGui::Begin()/ImGui::End() the widgets appears in a window automatically called "Debug"
	{
	static float f;
	ImGui::Text("Hello, world!");
	ImGui::SliderFloat("float", &f, 0.0f, 1.0f);
	show_test_window ^= ImGui::Button("Test Window");
	show_another_window ^= ImGui::Button("Another Window");

	// Calculate and show framerate
	static float ms_per_frame[120] = { 0 };
	static int ms_per_frame_idx = 0;
	static float ms_per_frame_accum = 0.0f;
	ms_per_frame_accum -= ms_per_frame[ms_per_frame_idx];
	ms_per_frame[ms_per_frame_idx] = ImGui::GetIO().DeltaTime * 1000.0f;
	ms_per_frame_accum += ms_per_frame[ms_per_frame_idx];
	ms_per_frame_idx = (ms_per_frame_idx + 1) % 120;
	const float ms_per_frame_avg = ms_per_frame_accum / 120;
	ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", ms_per_frame_avg, 1000.0f / ms_per_frame_avg);
	}

	// 2. Show another simple window, this time using an explicit Begin/End pair
	if (show_another_window)
	{
	ImGui::Begin("Another Window", &show_another_window, ImVec2(200,100));
	ImGui::Text("Hello");
	ImGui::End();
	}

	// 3. Show the ImGui test window. Most of the sample code is in ImGui::ShowTestWindow()
	if (show_test_window)
	{
	ImGui::SetNewWindowDefaultPos(ImVec2(650, 20)); // Normally user code doesn't need/want to call this, because positions are saved in .ini file. Here we just want to make the demo initial state a bit more friendly!
	ImGui::ShowTestWindow(&show_test_window);
	}

	// Rendering
	glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
	glClearColor(0.8f, 0.6f, 0.6f, 1.0f);
	glClear(GL_COLOR_BUFFER_BIT);
	ImGui::Render();
	glfwSwapBuffers(window);
	}

	ImGui::Shutdown();
	glfwTerminate();
	return 0;
	}