Add useful ImGui windows

main.cpp

@@ -7,92 +7,117 @@
 
 #include "gldebug.hpp"
 
-void show_overlay() {
+void show_overlay(float* clear_color) {
-    ImGuiWindowFlags window_flags = ImGuiWindowFlags_None
+    static std::string gl_vendor = (const char *) glGetString(GL_VENDOR);
-        | ImGuiWindowFlags_NoDecoration
+    static std::string gl_renderer = (const char *) glGetString(GL_RENDERER);
-        | ImGuiWindowFlags_AlwaysAutoResize
+    static std::string gl_version = (const char *) glGetString(GL_VERSION);
-        | ImGuiWindowFlags_NoSavedSettings
+    static std::string glsl_version = (const char *) glGetString(GL_SHADING_LANGUAGE_VERSION);
-        | ImGuiWindowFlags_NoFocusOnAppearing
+
-        | ImGuiWindowFlags_NoNav
+    ImGuiWindowFlags window_flags =
-        | ImGuiWindowFlags_NoMove;
+        ImGuiWindowFlags_AlwaysAutoResize |
+            ImGuiWindowFlags_NoSavedSettings |
+            ImGuiWindowFlags_NoFocusOnAppearing |
+            ImGuiWindowFlags_NoNav |
+            ImGuiWindowFlags_NoBringToFrontOnFocus |
+            ImGuiWindowFlags_NoMove;
+
     ImGuiStyle &style = ImGui::GetStyle();
     const auto PAD = style.DisplaySafeAreaPadding;
-    const auto *viewport = ImGui::GetMainViewport();
+    auto window_pos = PAD;
-    const auto work_pos = viewport->WorkPos;
+
-    const auto work_size = viewport->WorkSize;
+    ImGui::SetNextWindowPos(window_pos, ImGuiCond_Always);
-    const auto window_pos = ImVec2(
-        work_pos.x + PAD.x,
-        work_pos.y + PAD.y
-    );
-    const auto window_pos_pivot = ImVec2(
-        0.0f,
-        0.0f
-    );
-    ImGui::SetNextWindowPos(
-        window_pos,
-        ImGuiCond_Always,
-        window_pos_pivot
-    );
     ImGui::SetNextWindowBgAlpha(0.35f * style.Alpha);
-    if (ImGui::Begin("Graphics Information", nullptr, window_flags)) {
+    ImGui::SetNextWindowCollapsed(true, ImGuiCond_Appearing);
-        ImGui::BeginTable("graphics", 2, ImGuiTableFlags_BordersInnerV);
+    ImGui::Begin("Graphics Information", nullptr, window_flags);
-        ImGui::TableNextRow();
+    ImGui::Text("GL Vendor    | %s", gl_vendor.c_str());
-        ImGui::TableNextColumn();
+    ImGui::Text("GL Renderer  | %s", gl_renderer.c_str());
-        ImGui::Text("GL Vendor");
+    ImGui::Text("GL Version   | %s", gl_version.c_str());
-        ImGui::TableNextColumn();
+    ImGui::Text("GLSL Version | %s", glsl_version.c_str());
-        ImGui::Text("%s", glGetString(GL_VENDOR));
+
-        ImGui::TableNextRow();
+    auto v2 = ImGui::GetWindowSize();
-        ImGui::TableNextColumn();
+    window_pos.y += v2.y + PAD.y;
-        ImGui::Text("GL Renderer");
+    ImGui::End();
-        ImGui::TableNextColumn();
+
-        ImGui::Text("%s", glGetString(GL_RENDERER));
+    ImGui::SetNextWindowPos(window_pos, ImGuiCond_Always);
-        ImGui::TableNextRow();
+    ImGui::SetNextWindowBgAlpha(0.35f * style.Alpha);
-        ImGui::TableNextColumn();
+    ImGui::Begin("Controls", nullptr, window_flags);
-        ImGui::Text("GL Version");
+
-        ImGui::TableNextColumn();
+    ImGuiIO &io = ImGui::GetIO();
-        ImGui::Text("%s", glGetString(GL_VERSION));
+    ImGui::Text("FPS          | %.2f", io.Framerate);
-        ImGui::TableNextRow();
+
-        ImGui::TableNextColumn();
+    ImGui::Separator();
-        ImGui::Text("GLSL Version");
+
-        ImGui::TableNextColumn();
+    ImGui::ColorEdit3("Background", state.bg, ImGuiColorEditFlags_Float);
-        ImGui::Text("%s", glGetString(GL_SHADING_LANGUAGE_VERSION));
+    ImGui::SliderFloat("Alpha", &state.fg[3], 0.0f, 1.0f, "%.2f");
-        ImGui::EndTable();
+
     ImGui::End();
 }
-}
-
-int main() {
-    if (!glfwInit()) {
-        std::cerr << "GLFW :: failed initialization" << std::endl;
-        exit(EXIT_FAILURE);
-    }
-
-    const char *glsl_version = "#version 130";
-    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
-    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
-    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
-    auto *window = glfwCreateWindow(1280, 720, "Hello OpenGL", nullptr, nullptr);
-    if (!window) {
-        std::cerr << "GLFW :: failed to create window" << std::endl;
-        exit(EXIT_FAILURE);
-    }
-
-    glfwMakeContextCurrent(window);
-    glfwSwapInterval(1);
-    gladLoadGLLoader((GLADloadproc) glfwGetProcAddress);
-
-    IMGUI_CHECKVERSION();
-    ImGui::CreateContext();
-    ImGuiIO &io = ImGui::GetIO();
 
+void set_style() {
     ImGui::StyleColorsDark();
 
-    ImGui_ImplGlfw_InitForOpenGL(window, true);
+    ImGuiStyle &style = ImGui::GetStyle();
-    ImGui_ImplOpenGL3_Init(glsl_version);
+    style.WindowRounding = 4;
+    style.FrameRounding = 2;
+    style.DisplaySafeAreaPadding.x = 10;
+    style.DisplaySafeAreaPadding.y = 10;
+}
 
-    io.Fonts->AddFontDefault();
+int run(GLFWwindow *window, ImGuiContext *context) {
+    State state;
 
-    ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
+    float points[]{
+        +0.5f, +0.5f, 0.0f, 1.0f,
+        +0.5f, -0.5f, 0.0f, 1.0f,
+        -0.5f, +0.5f, 0.0f, 1.0f,
+        -0.5f, -0.5f, 0.0f, 1.0f,
+    };
+
+    unsigned int inds[]{
+        0, 1, 2,
+        1, 2, 3,
+    };
+
+    GLuint vao;
+    glCreateVertexArrays(1, &vao);
+
+    GLuint vbo;
+    glCreateBuffers(1, &vbo);
+
+    glNamedBufferData(vbo, sizeof(points), (void *) points, GL_STATIC_DRAW);
+    glEnableVertexArrayAttrib(vao, 0);
+    glVertexArrayVertexBuffer(vao, 0, vbo, 0, sizeof(float) * 4);
+    glVertexArrayAttribFormat(vao, 0, 4, GL_FLOAT, GL_FALSE, 0);
+
+    GLuint ibo;
+    glCreateBuffers(1, &ibo);
+    glGetError();
+    glNamedBufferData(ibo, sizeof(inds), (void *) inds, GL_STATIC_DRAW);
+    glVertexArrayElementBuffer(vao, ibo);
+
+    const char *vs_src = "#version 440\n"
+                         "layout(location=0) in vec4 pos;"
+                         "void main() {"
+                         "  gl_Position = pos;"
+                         "}";
+    GLuint vs = glCreateShader(GL_VERTEX_SHADER);
+    glShaderSource(vs, 1, &vs_src, nullptr);
+    glCompileShader(vs);
+
+    const char *fs_src = "#version 440\n"
+                         "layout(location=0) uniform vec4 ucol;"
+                         "layout(location=0) out vec4 col;"
+                         "void main() {"
+                         "  col = ucol;"
+                         "}";
+    GLuint fs = glCreateShader(GL_FRAGMENT_SHADER);
+    glShaderSource(fs, 1, &fs_src, nullptr);
+    glCompileShader(fs);
+
+    GLuint pgm = glCreateProgram();
+    glAttachShader(pgm, vs);
+    glAttachShader(pgm, fs);
+    glLinkProgram(pgm);
 
     while (!glfwWindowShouldClose(window)) {
         glfwPollEvents();
@@ -100,20 +125,78 @@ int main() {
         ImGui_ImplOpenGL3_NewFrame();
         ImGui_ImplGlfw_NewFrame();
         ImGui::NewFrame();
-        show_overlay();
+        show_overlay(state);
         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.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w,
+        glClearColor(state.bg[0], state.bg[1], state.bg[2], state.bg[3]);
-            clear_color.w);
         glClear(GL_COLOR_BUFFER_BIT);
-        ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
 
+        glUseProgram(pgm);
+        glBindVertexArray(vao);
+        glUniform4fv(0, 1, state.fg);
+        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, nullptr);
+        glBindVertexArray(0);
+        glUseProgram(0);
+
+        ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
         glfwSwapBuffers(window);
     }
 
+    glDeleteBuffers(1, &vbo);
+    glDeleteBuffers(1, &ibo);
+    glDeleteVertexArrays(1, &vao);
+
+    return EXIT_SUCCESS;
+}
+
+int main() {
+    if (!glfwInit()) {
+        std::cerr << "GLFW:Failed initialization" << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 6);
+    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+    auto *window = glfwCreateWindow(1280, 720, "Cosets Visualization", nullptr, nullptr);
+    if (!window) {
+        std::cerr << "GLFW:Failed to create window" << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    glfwMakeContextCurrent(window);
+    glfwSwapInterval(1);
+    gladLoadGLLoader((GLADloadproc) glfwGetProcAddress);
+
+#ifndef NDEBUG
+    glEnable(GL_DEBUG_OUTPUT);
+    glDebugMessageCallback(log_gl_debug_callback, nullptr);
+    glDebugMessageControl(
+        GL_DONT_CARE, GL_DEBUG_TYPE_OTHER,
+        GL_DEBUG_SEVERITY_NOTIFICATION,
+        0, nullptr, GL_FALSE
+    );
+#endif
+
+    IMGUI_CHECKVERSION();
+    auto *context = ImGui::CreateContext();
+    ImGui_ImplGlfw_InitForOpenGL(window, true);
+    ImGui_ImplOpenGL3_Init("#version 130");
+
+    set_style();
+
+    int exit_code = EXIT_SUCCESS;
+
+    try {
+        exit_code = run(window, context);
+    } catch (const std::exception &e) {
+        std::cerr << e.what() << std::endl;
+        exit_code = EXIT_FAILURE;
+    }
+
     ImGui_ImplOpenGL3_Shutdown();
     ImGui_ImplGlfw_Shutdown();
     ImGui::DestroyContext();
@@ -121,5 +204,5 @@ int main() {
     glfwDestroyWindow(window);
     glfwTerminate();
 
-    exit(EXIT_SUCCESS);
+    return exit_code;
 }