我一直在尝试使用 vcpkg 和 cmake 为我的应用程序构建 imgui 和 glfw。我正在遵循 sdl2 和 imgui 提供的示例，当我按照给出的确切步骤this 时，出现链接错误。我已经尝试过链接 glfw 和 imgui 的现有解决方案，使用 vcpkg 减去 cmake 预设部分this。我修改了 glfw 和 imgui 的代码，因为这是我的要求。
之前我使用 vcpkg 进行全局安装，但我需要进行本地构建。
我收到以下链接错误：
main.obj : error LNK2019: unresolved external symbol __imp_glClear referenced in function main [C:\Users\gopik\OneDrive\Desktop\my-project\bin\MY_PROJECT.vcxproj]
main.obj : error LNK2019: unresolved external symbol __imp_glClearColor referenced in function main [C:\Users\gopik\OneDrive\Desktop\my-project\bin\MY_PROJECT.vcxproj]
main.obj : error LNK2019: unresolved external symbol __imp_glViewport referenced in function main [C:\Users\gopik\OneDrive\Desktop\my-project\bin\MY_PROJECT.vcxproj]
C:\Users\gopik\OneDrive\Desktop\my-project\bin\Debug\MY_PROJECT.exe : fatal error LNK1120: 3 unresolved externals [C:\Users\gopik\OneDrive\Desktop\my-project\bin\MY_PROJECT.vcxproj]
and this:
-- Running vcpkg install
Detecting compiler hash for triplet x64-windows...
All requested packages are currently installed.
Total install time: 200 ns
freetype is compatible with built-in CMake targets:
find_package(Freetype REQUIRED)
target_link_libraries(main PRIVATE Freetype::Freetype) # since CMake 3.10
glad provides CMake targets:
# this is heuristically generated, and may not be correct
find_package(glad CONFIG REQUIRED)
target_link_libraries(main PRIVATE glad::glad)
glfw3 provides CMake targets:
# this is heuristically generated, and may not be correct
find_package(glfw3 CONFIG REQUIRED)
target_link_libraries(main PRIVATE glfw)
glm provides CMake targets:
find_package(glm CONFIG REQUIRED)
target_link_libraries(main PRIVATE glm::glm)
imgui provides CMake targets:
# this is heuristically generated, and may not be correct
find_package(imgui CONFIG REQUIRED)
target_link_libraries(main PRIVATE imgui::imgui)
-- Running vcpkg install - done
CMake Warning (dev) at C:/Program Files/CMake/share/cmake-3.27/Modules/FindPackageHandleStandardArgs.cmake:438 (message):
The package name passed to `find_package_handle_standard_args` (Freetype)
does not match the name of the calling package (freetype). This can lead
to problems in calling code that expects `find_package` result variables
(e.g., `_FOUND`) to follow a certain pattern.
Call Stack (most recent call first):
C:/Program Files/CMake/share/cmake-3.27/Modules/FindFreetype.cmake:162 (find_package_handle_standard_args)
bin/vcpkg_installed/x64-windows/share/freetype/vcpkg-cmake-wrapper.cmake:5 (_find_package)
vcpkg/scripts/buildsystems/vcpkg.cmake:813 (include)
CMakeLists.txt:24 (find_package)
This warning is for project developers. Use -Wno-dev to suppress it.
-- Configuring done (2.3s)
CMake Error: The following variables are used in this project, but they are set to NOTFOUND.
Please set them or make sure they are set and tested correctly in the CMake files:
IMGUI_LIBRARY
linked by target "MY_PROJECT" in directory C:/Users/gopik/OneDrive/Desktop/my-project
-- Generating done (0.1s)
CMake Generate step failed. Build files cannot be regenerated correctly.
我的项目结构：
`my-project
|-cmake
|- Vcpkg.cmake
|-src
|- main.cpp
|-vcpkg
|-CMakeLists.txt
|-bin`
我的CMakeLists.txt：
`cmake_minimum_required(VERSION 3.16 FATAL_ERROR)
include(cmake/Vcpkg.cmake) # needs to happen before project()
project(
"MY_PROJECT" # replace this with the name of your executable
VERSION 0.1.0
LANGUAGES CXX
)
# add all headers (.h, .hpp) to this
set(PRJ_HEADERS )
# add all source files (.cpp) to this, except the one with main()
set(PRJ_SOURCES )
# set the source file containing main()
set(PRJ_MAIN src/main.cpp)
# add library targets here
set(PRJ_LIBRARIES
freetype
glfw
glad::glad
glm::glm
imgui::imgui
)
# add dependency find_package calls and similar here
find_package(glfw3 REQUIRED)
find_package(glad REQUIRED)
find_package(glm REQUIRED)
find_package(freetype REQUIRED)
find_package(imgui REQUIRED)
add_executable(${PROJECT_NAME} ${PRJ_HEADERS} ${PRJ_SOURCES} ${PRJ_MAIN})
target_link_libraries(${PROJECT_NAME} PRIVATE ${PRJ_LIBRARIES})`
vcpkg.json
`{
"name": "my-project",
"version-string": "0.1.0",
"dependencies": [
"glfw3",
"glad",
"glm",
"freetype",
{
"name": "imgui",
"features": [
"opengl3-binding",
"glfw-binding",
"freetype"
]
}
]
}
`
我的 main.cpp 这是一个例子：
`// 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
#include "imgui.h"
#include "imgui_impl_glfw.h"
#include "imgui_impl_opengl3.h"
#include <stdio.h>
#define GL_SILENCE_DEPRECATION
#if defined(IMGUI_IMPL_OPENGL_ES2)
#include <GLES2/gl2.h>
#endif
#include <GLFW/glfw3.h> // Will drag system OpenGL headers
// [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
// This example can also compile and run with Emscripten! See 'Makefile.emscripten' for details.
#ifdef __EMSCRIPTEN__
#include "../libs/emscripten/emscripten_mainloop_stub.h"
#endif
static void glfw_error_callback(int error, const char* description)
{
fprintf(stderr, "GLFW Error %d: %s\n", error, description);
}
// Main code
int main(int, char**)
{
glfwSetErrorCallback(glfw_error_callback);
if (!glfwInit())
return 1;
// Decide GL+GLSL versions
#if defined(IMGUI_IMPL_OPENGL_ES2)
// GL ES 2.0 + GLSL 100
const char* glsl_version = "#version 100";
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_ES_API);
#elif defined(__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, 0);
//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", nullptr, nullptr);
if (window == nullptr)
return 1;
glfwMakeContextCurrent(window);
glfwSwapInterval(1); // Enable vsync
// 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::StyleColorsLight();
// 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 a nullptr. 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.
// - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
// - 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 \\ !
// - Our Emscripten build process allows embedding fonts to be accessible at runtime from the "fonts/" folder. See Makefile.emscripten for details.
//io.Fonts->AddFontDefault();
//io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
//io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
//io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
//io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
//ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
//IM_ASSERT(font != nullptr);
// Our state
bool show_demo_window = true;
bool show_another_window = false;
ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
// Main loop
#ifdef __EMSCRIPTEN__
// For an Emscripten build we are disabling file-system access, so let's not attempt to do a fopen() of the imgui.ini file.
// You may manually call LoadIniSettingsFromMemory() to load settings from your own storage.
io.IniFilename = nullptr;
EMSCRIPTEN_MAINLOOP_BEGIN
#else
while (!glfwWindowShouldClose(window))
#endif
{
// 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, or clear/overwrite your copy of the mouse data.
// - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application, or clear/overwrite your copy of the keyboard data.
// 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 create 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 / io.Framerate, io.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.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w);
glClear(GL_COLOR_BUFFER_BIT);
ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
glfwSwapBuffers(window);
}
#ifdef __EMSCRIPTEN__
EMSCRIPTEN_MAINLOOP_END;
#endif
// Cleanup
ImGui_ImplOpenGL3_Shutdown();
ImGui_ImplGlfw_Shutdown();
ImGui::DestroyContext();
glfwDestroyWindow(window);
glfwTerminate();
return 0;
}
`
我能够在全局安装 imgui 并在 Visual Studio 中使用它，但这不是本练习的目的。任何帮助将不胜感激。
在加载 glfw 之前，您需要
#include "glad/glad.h"具体来说，glad.h 标头包含
#definestypedef void (APIENTRYP PFNGLVIEWPORTPROC)(GLint x, GLint y, GLsizei width, GLsizei height);
GLAPI PFNGLVIEWPORTPROC glad_glViewport;
#define glViewport glad_glViewport
这使得核心
gladLoadGLLoaderglad_glViewport