VS Code IntelliSense slowdown

c_cpp_properties.json

{
    "env": {
        "includePath": [
            "${workspaceFolder}",
            "${workspaceFolder}/glfw/include",
            "${workspaceFolder}/imgui"
        ],
        "includePathWin32": [
            "C:/Program Files (x86)/Microsoft Visual Studio/2017/Community/VC/Tools/MSVC/14.16.27023/include/*",
            "C:/Program Files (x86)/Microsoft Visual Studio/2017/Community/VC/Tools/MSVC/14.16.27023/atlmfc/include/*",
            "C:/Program Files (x86)/Windows Kits/10/Include/10.0.17763.0/um",
            "C:/Program Files (x86)/Windows Kits/10/Include/10.0.17763.0/ucrt",
            "C:/Program Files (x86)/Windows Kits/10/Include/10.0.17763.0/shared",
            "C:/Program Files (x86)/Windows Kits/10/Include/10.0.17763.0/winrt",
            "C:/Program Files (x86)/Windows Kits/10/Include/10.0.17763.0/cppwinrt",
            "C:/VulkanSDK/1.1.101.0/Include"
        ],
        "includePathMac": [
            "/usr/include",
            "/usr/local/include"
        ],
        "includePathLinux": [
            "/usr/include",
            "/usr/local/include"
        ]
    },
    "configurations": [
        {
            "name": "Mac",
            "includePath": [
                "${includePathMac}",
                "${includePath}"
            ],
            "defines": [
                "_EDITOR"
            ],
            "browse": {
                "path": [
                    "${includePathMac}",
                    "${includePath}"
                ],
                "limitSymbolsToIncludedHeaders": false,
                "databaseFilename": ""
            },
            "intelliSenseMode": "clang-x64",
            "macFrameworkPath": [
                "/System/Library/Frameworks",
                "/Library/Frameworks"
            ]
        },
        {
            "name": "Linux",
            "includePath": [
                "${includePathLinux}",
                "${includePath}"
            ],
            "defines": [
                "_EDITOR"
            ],
            "browse": {
                "path": [
                    "${includePathLinux}",
                    "${includePath}"
                ],
                "limitSymbolsToIncludedHeaders": false,
                "databaseFilename": ""
            },
            "intelliSenseMode": "clang-x64"
        },
        {
            "name": "Win32",
            "includePath": [
                "${includePathWin32}",
                "${includePath}"
            ],
            "defines": [
                "_DEBUG",
                "UNICODE",
                "_UNICODE",
                "_EDITOR"
            ],
            "browse": {
                "path": [
                    "${includePathWin32}",
                    "${includePath}"
                ],
                "limitSymbolsToIncludedHeaders": false,
                "databaseFilename": ""
            },
            "intelliSenseMode": "msvc-x64",
            "cStandard": "c11",
            "cppStandard": "c++14"
        }
    ],
    "version": 4
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.12)
project(Demo)

# GLFW:
set(GLFW_BUILD_DOCS     OFF CACHE BOOL "" FORCE)
set(GLFW_BUILD_TESTS    OFF CACHE BOOL "" FORCE)
set(GLFW_BUILD_EXAMPLES OFF CACHE BOOL "" FORCE)
add_subdirectory(glfw)

# dear imgui:
add_library(imgui
    "imgui/imgui.cpp"
    "imgui/imgui_demo.cpp"
    "imgui/imgui_draw.cpp"
    "imgui/imgui_widgets.cpp"
    "imgui/examples/imgui_impl_opengl3.cpp"
    "imgui/examples/imgui_impl_glfw.cpp"
)
target_include_directories(imgui PUBLIC "./")
target_include_directories(imgui PUBLIC "imgui")
target_compile_definitions(imgui PUBLIC "IMGUI_IMPL_OPENGL_LOADER_GLAD")
target_link_libraries(imgui PUBLIC glfw)

# Main target:
add_executable(Demo
    "glad/glad.c"
    "Main.cpp"
)

# Headers:
target_include_directories(Demo PUBLIC "./")

# Libraries:
target_link_libraries(Demo PUBLIC glfw)
target_link_libraries(Demo PUBLIC imgui)

# Use C++14:
target_compile_features(Demo PUBLIC cxx_std_14)

# Compiler options for MSVC:
if (MSVC)
    target_compile_definitions(Demo PUBLIC _CRT_SECURE_NO_WARNINGS)
endif()

# Set the working directory for debugging:
set_target_properties(Demo PROPERTIES VS_DEBUGGER_WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}")

Main.cpp

#include <assert.h>
#include <stdlib.h>
#include <stdint.h>
#include <stddef.h>
#include <stdio.h>

#if defined(_WIN32) && !defined(APIENTRY)
    #define APIENTRY __stdcall
#endif
#include <glad/glad.h>
#include <glfw/glfw3.h>
#include <imgui/imgui.h>
#include <imgui/examples/imgui_impl_opengl3.h>
#include <imgui/examples/imgui_impl_glfw.h>

int main() {
    glfwInit();

    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, true);
    GLFWwindow* window = glfwCreateWindow(1280, 1024, "Codex", nullptr, nullptr);
    glfwMakeContextCurrent(window);
    gladLoadGL();
    glfwSwapInterval(0);

    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    ImGuiIO& io = ImGui::GetIO();
    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
    ImGui_ImplOpenGL3_Init("#version 140");
    ImGui_ImplGlfw_InitForOpenGL(window, true);

    while (!glfwWindowShouldClose(window)) {
        int w, h;
        glfwGetFramebufferSize(window, &w, &h);
        glViewport(0, 0, w, h);
        glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
        glClear(GL_COLOR_BUFFER_BIT);
        ImGui_ImplOpenGL3_NewFrame();
        ImGui_ImplGlfw_NewFrame();
        ImGui::NewFrame();

        ImGui::ShowDemoWindow();

        ImGui::Begin("Test"); {
            static float a = 0.0f;
            ImGui::SliderAngle("Angle", &a);
        } ImGui::End();

        ImGui::Render();
        ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
        glfwSwapBuffers(window);
        glfwWaitEvents();
    }
}