newpolaris · May 20, 2021 17:35 · May 20, 2021
diff --git a/gistfile1.txt b/gistfile1.txt
@@ -0,0 +1,555 @@
+// Dear ImGui: standalone example application for GLFW + OpenGL 3, using programmable pipeline
+// (GLFW is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan/Metal graphics context creation, etc.)
+// If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
+// Read online: https://github.com/ocornut/imgui/tree/master/docs
+
+#define _CRT_SECURE_NO_WARNINGS
+
+#include "imgui.h"
+#include "imgui_impl_glfw.h"
+#include "imgui_impl_opengl3.h"
+#include <stdio.h>
+#include <glm/glm.hpp>
+#include <vector>
+#include <cstdio>
+#include <cstdarg>
+#include <vector>
+#include <cassert>
+#include <string>
+
+#include "stb_image.h"
+
+// 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.
+#if defined(IMGUI_IMPL_OPENGL_LOADER_GL3W)
+#include <GL/gl3w.h>            // Initialize with gl3wInit()
+#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLEW)
+#include <GL/glew.h>            // Initialize with glewInit()
+#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD)
+#include <glad/glad.h>          // Initialize with gladLoadGL()
+#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD2)
+#include <glad/gl.h>            // Initialize with gladLoadGL(...) or gladLoaderLoadGL()
+#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLBINDING2)
+#define GLFW_INCLUDE_NONE       // GLFW including OpenGL headers causes ambiguity or multiple definition errors.
+#include <glbinding/Binding.h>  // Initialize with glbinding::Binding::initialize()
+#include <glbinding/gl/gl.h>
+using namespace gl;
+#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLBINDING3)
+#define GLFW_INCLUDE_NONE       // GLFW including OpenGL headers causes ambiguity or multiple definition errors.
+#include <glbinding/glbinding.h>// Initialize with glbinding::initialize()
+#include <glbinding/gl/gl.h>
+using namespace gl;
+#else
+#include IMGUI_IMPL_OPENGL_LOADER_CUSTOM
+#endif
+
+// Include glfw3.h after our OpenGL definitions
+#include <GLFW/glfw3.h>
+
+// [Win32] Our example includes a copy of glfw3.lib pre-compiled with VS2010 to maximize ease of testing and compatibility with old VS compilers.
+// To link with VS2010-era libraries, VS2015+ requires linking with legacy_stdio_definitions.lib, which we do using this pragma.
+// Your own project should not be affected, as you are likely to link with a newer binary of GLFW that is adequate for your version of Visual Studio.
+#if defined(_MSC_VER) && (_MSC_VER >= 1900) && !defined(IMGUI_DISABLE_WIN32_FUNCTIONS)
+#pragma comment(lib, "legacy_stdio_definitions")
+#endif
+
+static void glfw_error_callback(int error, const char* description)
+{
+    fprintf(stderr, "Glfw Error %d: %s\n", error, description);
+}
+#if _WIN32
+extern "C" __declspec(dllimport) void __stdcall OutputDebugStringA(const char* _str);
+#else
+#   if defined(__OBJC__)
+#       import <Foundation/NSObjCRuntime.h>
+#   else
+#       include <CoreFoundation/CFString.h>
+extern "C" void NSLog(CFStringRef _format, ...);
+#   endif
+#endif
+
+void debug_output(const char* message)
+{
+#if _WIN32
+    fprintf(stderr, message);
+    OutputDebugStringA(message);
+#else
+#   if defined(__OBJC__)
+    NSLog(@"%s", message);
+#   else
+    NSLog(CFSTR("%s"), message);
+#   endif
+#endif
+}
+
+void trace(const char* format...)
+{
+    const int kLength = 1024;
+    char buffer[kLength + 1] = { 0, };
+
+    va_list argList;
+    va_start(argList, format);
+    int len = vsnprintf(buffer, kLength, format, argList);
+    va_end(argList);
+    if (len > kLength)
+        len = kLength;
+    buffer[len] = '\0';
+
+    debug_output(buffer);
+}
+
+GLuint createTexture(int32_t width, int32_t height, float* data)
+{
+    GLenum format = GL_RGBA;
+    GLenum internalFormat = GL_RGBA;
+
+    GLuint instance = 0;
+    glGenTextures(1, &instance);
+    glActiveTexture(GL_TEXTURE0 + 16 - 1);
+    glBindTexture(GL_TEXTURE_2D, instance);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+    glTexImage2D(GL_TEXTURE_2D, 0, internalFormat, width, height, 0, format, GL_FLOAT, data);
+    glBindTexture(GL_TEXTURE_2D, 0);
+
+    return instance;
+}
+
+GLuint createTexture(std::string path)
+{
+    stbi_set_flip_vertically_on_load(true);
+
+    FILE* fp = fopen(path.c_str(), "rb");
+    if (fp == NULL)
+        return 0;
+
+    fseek(fp, 0, SEEK_END);
+    long length = ftell(fp);
+    fseek(fp, 0, SEEK_SET);
+    std::vector<char> storage(length);;
+    length = (long)fread(storage.data(), 1, length, fp);
+    fclose(fp);
+
+    GLenum target = GL_TEXTURE_2D;
+    GLenum type = GL_UNSIGNED_BYTE;
+    int width = 0, height = 0, nrComponents = 0;
+    stbi_uc* imagedata = stbi_load_from_memory(
+        (stbi_uc*)storage.data(),
+        (int)length, &width, &height, &nrComponents, 0);
+
+    if (!imagedata)
+        return 0;
+
+    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+
+    GLuint instance = 0;
+    glGenTextures(1, &instance);
+    glActiveTexture(GL_TEXTURE0 + 16 - 1);
+    glBindTexture(target, instance);
+    glTexImage2D(target, 0, GL_RGB, width, height, 0, GL_RGB, type, imagedata);
+    glTexParameteri(target, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
+    glTexParameteri(target, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    glTexParameteri(target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+    glTexParameteri(target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+    glTexParameterf(target, GL_TEXTURE_MAX_ANISOTROPY, 16);
+    glGenerateMipmap(target);
+    glBindTexture(GL_TEXTURE_2D, 0);
+
+    stbi_image_free(imagedata);
+
+    glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
+
+    return instance;
+}
+
+void bindTexture(GLuint texID, uint8_t slot)
+{
+    assert(texID != 0);
+    glActiveTexture(GL_TEXTURE0 + slot);
+    glBindTexture(GL_TEXTURE_2D, texID);
+};
+
+GLuint createShader(GLenum type, const char* shaderCode)
+{
+    GLuint id = glCreateShader(type);
+    if (id == 0)
+        return 0;
+
+    glShaderSource(id, 1, &shaderCode, 0);
+    glCompileShader(id);
+
+    GLint compiled = 0;
+    glGetShaderiv(id, GL_COMPILE_STATUS, &compiled);
+    if (compiled == GL_FALSE)
+    {
+        GLint length = 0;
+        glGetShaderiv(id, GL_INFO_LOG_LENGTH, &length);
+        std::vector<GLchar> buffer(length + 1);
+        glGetShaderInfoLog(id, length, 0, buffer.data());
+        trace("%s (%d) %s\n", __FILE__, __LINE__, buffer.data());
+        glDeleteShader(id);
+        return 0;
+    }
+    return id;
+}
+
+GLuint createProgram(GLuint vertex, GLuint fragment)
+{
+    GLuint id = glCreateProgram();
+
+    GLint status = 0;
+    if (vertex != 0)
+    {
+        glAttachShader(id, vertex);
+        if (fragment != 0)
+            glAttachShader(id, fragment);
+        glLinkProgram(id);
+        glGetProgramiv(id, GL_LINK_STATUS, &status);
+
+        if (status == GL_FALSE)
+        {
+            const uint32_t kBufferSize = 512u;
+            char log[kBufferSize];
+            glGetProgramInfoLog(id, sizeof(log), nullptr, log);
+            trace("%s:%d %d: %s", __FILE__, __LINE__, status, log);
+            return 0;
+        }
+    }
+
+    if (status == GL_FALSE)
+    {
+        glDeleteProgram(id);
+        id = 0;
+        return id;
+    }
+
+    return id;
+}
+
+struct ProgramDesc
+{
+    const char* vertexShader = nullptr;
+    const char* fragmentShader = nullptr;
+};
+
+struct Program
+{
+    GLuint vertex = 0;
+    GLuint framgment = 0;
+    GLuint id = 0;
+};
+
+GLuint createShader(GLenum type, const char* shaderCode);
+GLuint createProgram(GLuint vertex, GLuint fragment);
+
+Program createProgram(const ProgramDesc& desc);
+void destroyProgram(Program& program);
+
+Program createProgram(const ProgramDesc& desc)
+{
+    GLuint vs = createShader(GL_VERTEX_SHADER, desc.vertexShader);
+    GLuint fs = createShader(GL_FRAGMENT_SHADER, desc.fragmentShader);
+
+    assert(vs != 0);
+    assert(fs != 0);
+
+    GLuint id = createProgram(vs, fs);
+
+    Program program;
+    program.vertex = vs;
+    program.framgment = fs;
+    program.id = id;
+
+    return program;
+}
+
+void destroyProgram(Program& program)
+{
+    glDeleteProgram(program.id);
+    glDeleteShader(program.vertex);
+    glDeleteShader(program.framgment);
+
+    program.vertex = 0;
+    program.framgment = 0;
+    program.id = 0;
+}
+
+
+struct vertex_t {
+    glm::vec3 position;
+    glm::vec2 texcoord;
+};
+
+struct VertexArray
+{
+    GLuint vao = 0;
+    GLuint vbo = 0;
+    GLuint ibo = 0;
+    size_t vertexCount = 0;
+    size_t indexCount = 0;
+};
+
+VertexArray* createVertexArray(float* vertices, size_t vertexCount, uint32_t* indices, size_t indexCount) {
+    GLuint ibo = 0;
+    GLuint vbo = 0;
+    glGenBuffers(1, &vbo);
+    glGenBuffers(1, &ibo);
+
+    const size_t vertexBytes = sizeof(vertex_t)*vertexCount;
+
+    GLuint vao = 0;
+    glCreateVertexArrays(1, &vao);
+    glBindVertexArray(vao);
+    glBindBuffer(GL_ARRAY_BUFFER, vbo);
+    glBufferData(GL_ARRAY_BUFFER, vertexBytes, vertices, GL_DYNAMIC_DRAW);
+
+    const size_t indexBytes = sizeof(uint32_t) * indexCount;
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, indexBytes, indices, GL_DYNAMIC_DRAW);
+
+    glEnableVertexAttribArray(0);
+    glEnableVertexAttribArray(1);
+
+    GLsizei stride = sizeof(vertex_t);
+    auto positionOffset = (const void*)offsetof(vertex_t, position);
+    auto texcoordOffset = (const void*)offsetof(vertex_t, texcoord);
+
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, stride, positionOffset);
+    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, stride, texcoordOffset);
+
+    glBindVertexArray(0);
+
+    auto vtxArr = new VertexArray();
+    if (vtxArr) {
+        vtxArr->vao = vao;
+        vtxArr->vbo = vbo;
+        vtxArr->ibo = ibo;
+        vtxArr->vertexCount = vertexCount;
+        vtxArr->indexCount = indexCount;
+    }
+    return vtxArr;
+}
+
+int main(int, char**)
+{
+    // Setup window
+    glfwSetErrorCallback(glfw_error_callback);
+    if (!glfwInit())
+        return 1;
+
+    // Decide GL+GLSL versions
+#ifdef __APPLE__
+    // GL 3.2 + GLSL 150
+    const char* glsl_version = "#version 150";
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
+    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);  // 3.2+ only
+    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);            // Required on Mac
+#else
+    // GL 3.0 + GLSL 130
+    const char* glsl_version = "#version 130";
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
+    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);  // 3.2+ only
+    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);            // 3.0+ only
+#endif
+
+    // Create window with graphics context
+    GLFWwindow* window = glfwCreateWindow(1280, 720, "Dear ImGui GLFW+OpenGL3 example", NULL, NULL);
+    if (window == NULL)
+        return 1;
+    glfwMakeContextCurrent(window);
+    glfwSwapInterval(1); // Enable vsync
+
+    // Initialize OpenGL loader
+#if defined(IMGUI_IMPL_OPENGL_LOADER_GL3W)
+    bool err = gl3wInit() != 0;
+#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLEW)
+    bool err = glewInit() != GLEW_OK;
+#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD)
+    bool err = gladLoadGL() == 0;
+#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD2)
+    bool err = gladLoadGL(glfwGetProcAddress) == 0; // glad2 recommend using the windowing library loader instead of the (optionally) bundled one.
+#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLBINDING2)
+    bool err = false;
+    glbinding::Binding::initialize();
+#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLBINDING3)
+    bool err = false;
+    glbinding::initialize([](const char* name) { return (glbinding::ProcAddress)glfwGetProcAddress(name); });
+#else
+    bool err = false; // If you use IMGUI_IMPL_OPENGL_LOADER_CUSTOM, your loader is likely to requires some form of initialization.
+#endif
+    if (err)
+    {
+        fprintf(stderr, "Failed to initialize OpenGL loader!\n");
+        return 1;
+    }
+
+    // Setup Dear ImGui context
+    IMGUI_CHECKVERSION();
+    ImGui::CreateContext();
+    ImGuiIO& io = ImGui::GetIO(); (void)io;
+    //io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
+    //io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+
+    // Setup Dear ImGui style
+    ImGui::StyleColorsDark();
+    //ImGui::StyleColorsClassic();
+
+    // Setup Platform/Renderer backends
+    ImGui_ImplGlfw_InitForOpenGL(window, true);
+    ImGui_ImplOpenGL3_Init(glsl_version);
+
+    // Load Fonts
+    // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
+    // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
+    // - If the file cannot be loaded, the function will return NULL. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
+    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
+    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //io.Fonts->AddFontDefault();
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/ProggyTiny.ttf", 10.0f);
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, NULL, io.Fonts->GetGlyphRangesJapanese());
+    //IM_ASSERT(font != NULL);
+
+    // Our state
+    bool show_demo_window = true;
+    bool show_another_window = false;
+    ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
+
+    std::vector<float> vertices = {
+        -1.0, -1.0, 0.0, 0.0, 0.0,
+        +3.0, -1.0, 0.0, 2.0, 0.0,
+        -1.0, +3.0, 0.0, 0.0, 2.0,
+    };
+    std::vector<uint32_t> indices = {
+        0, 1, 2
+    };
+
+    auto vertexArray = createVertexArray(
+        vertices.data(),
+        vertices.size(),
+        indices.data(),
+        indices.size());
+
+    const char* vertexShader = R"__(
+attribute vec3 a_position;
+attribute vec2 a_texcoord;
+varying vec2 v_texcoord;
+
+void main() {
+    gl_Position = vec4(a_position, 1.0);
+    v_texcoord = a_texcoord;
+}
+)__";
+    const char* fragmentShader = R"__(
+#ifdef GL_ES
+    precision mediump float;
+#endif
+varying vec2 v_texcoord;
+uniform sampler2D u_texture;
+
+void main() {
+    gl_FragColor = texture2D(u_texture, v_texcoord);
+}
+)__";
+    auto program = createProgram({vertexShader, fragmentShader});
+    glUseProgram(program.id);
+
+    GLuint tmu = 0;
+    GLint sampler = glGetUniformLocation(program.id, "u_texture");
+    assert(sampler >= 0);
+    glUniform1i(sampler, tmu++);
+
+    glUseProgram(0);
+
+    GLuint texture = createTexture("checker.jpg");
+
+    // Main loop
+    while (!glfwWindowShouldClose(window))
+    {
+        // Poll and handle events (inputs, window resize, etc.)
+        // 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.
+        glfwPollEvents();
+
+        // Start the Dear ImGui frame
+        ImGui_ImplOpenGL3_NewFrame();
+        ImGui_ImplGlfw_NewFrame();
+        ImGui::NewFrame();
+
+        // 1. Show the big demo window (Most of the sample code is in ImGui::ShowDemoWindow()! You can browse its code to learn more about Dear ImGui!).
+        if (show_demo_window)
+            ImGui::ShowDemoWindow(&show_demo_window);
+
+        // 2. Show a simple window that we create ourselves. We use a Begin/End pair to created a named window.
+        {
+            static float f = 0.0f;
+            static int counter = 0;
+
+            ImGui::Begin("Hello, world!");                          // Create a window called "Hello, world!" and append into it.
+
+            ImGui::Text("This is some useful text.");               // Display some text (you can use a format strings too)
+            ImGui::Checkbox("Demo Window", &show_demo_window);      // Edit bools storing our window open/close state
+            ImGui::Checkbox("Another Window", &show_another_window);
+
+            ImGui::SliderFloat("float", &f, 0.0f, 1.0f);            // Edit 1 float using a slider from 0.0f to 1.0f
+            ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color
+
+            if (ImGui::Button("Button"))                            // Buttons return true when clicked (most widgets return true when edited/activated)
+                counter++;
+            ImGui::SameLine();
+            ImGui::Text("counter = %d", counter);
+
+            ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / ImGui::GetIO().Framerate, ImGui::GetIO().Framerate);
+            ImGui::End();
+        }
+
+        // 3. Show another simple window.
+        if (show_another_window)
+        {
+            ImGui::Begin("Another Window", &show_another_window);   // Pass a pointer to our bool variable (the window will have a closing button that will clear the bool when clicked)
+            ImGui::Text("Hello from another window!");
+            if (ImGui::Button("Close Me"))
+                show_another_window = false;
+            ImGui::End();
+        }
+
+        // Rendering
+        ImGui::Render();
+        int display_w, display_h;
+        glfwGetFramebufferSize(window, &display_w, &display_h);
+        glViewport(0, 0, display_w, display_h);
+        glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w);
+        glClear(GL_COLOR_BUFFER_BIT);
+
+        glUseProgram(program.id);
+        bindTexture(texture, 0);
+        glBindVertexArray(vertexArray->vao);
+        glDrawArrays(GL_TRIANGLES, 0, 3);
+        glUseProgram(0);
+
+        ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
+
+        glfwSwapBuffers(window);
+    }
+
+    // Cleanup
+    ImGui_ImplOpenGL3_Shutdown();
+    ImGui_ImplGlfw_Shutdown();
+    ImGui::DestroyContext();
+
+    glfwDestroyWindow(window);
+    glfwTerminate();
+
+    return 0;
+}
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