学习OpenGL时找不到glClear

Posted 2023-02-22

【中文标题】学习OpenGL时找不到glClear

【英文标题】：Cannot find glClear while learning OpenGL

【发布时间】：2017-02-28 01:34:09

【问题描述】：

我正在尝试学习 OpenGL。我使用 Clion 作为 IDE，它使用 CMakeLists.txt 文件来组织/编译项目。

编译器由于某种原因找不到glClear：

Undefined symbols for architecture x86_64:
  "_glClear", referenced from:
      _main in main.cpp.o
  "_glClearColor", referenced from:
      _main in main.cpp.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [GraphicsPractice] Error 1
make[1]: *** [CMakeFiles/GraphicsPractice.dir/all] Error 2
make: *** [all] Error 2

我能够成功链接GLEW 和GLFW，但是，当我调用glClear(GL_COLOR_BUFFER_BIT) 时，我的代码会中断。我不确定为什么。如果有人能帮助我指出正确的方向，那就太好了。

CMakeList.txt

cmake_minimum_required(VERSION 3.6)
project(GraphicsPractice)

set(CMAKE_CXX_STANDARD 14)

set(SOURCE_FILES src/main.cpp)

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(deps/glfw)

find_package(OpenGl REQUIRED)
find_package(GLEW REQUIRED)

include_directories("deps/glfw/include/")

add_executable($PROJECT_NAME $SOURCE_FILES)

target_link_libraries($PROJECT_NAME glfw glew)

main.cpp

#define GLEW_STATIC
#include <GL/glew.h>
#include <GL/glew.h>
#include <GLFW/glfw3.h>

int main() 

    glfwInit();

    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
    glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);

    GLFWwindow* window = glfwCreateWindow(800, 600, "OpenGL", 0, nullptr);

    glfwMakeContextCurrent(window);

    glewExperimental = GL_TRUE;
    glewInit();


    while (!glfwWindowShouldClose(window)) 
        glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
            glfwSetWindowShouldClose(window, GL_TRUE);

        glfwSwapBuffers(window);
        glfwPollEvents();
    

    glfwTerminate();
    return 0;

【问题讨论】：

这是一个链接器错误，而不是编译器错误。您没有链接到 opengl 库。

你在使用OSX吗？

@genpfault 是的，我是。

【参考方案1】：

您需要链接 OpenGL 库。即：

target_link_libraries($PROJECT_NAME $OPENGL_LIBRARIES glfw glew etc...)