包含标头时的 C++ OpenGL LNK2001

Posted 2023-02-22

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【中文标题】包含标头时的 C++ OpenGL LNK2001【英文标题】：C++ OpenGL LNK2001 when header is included 【发布时间】：2012-11-06 16:46:24 【问题描述】：

我已经 28 岁了

错误 LNK2001：无法解析的外部符号

消息。例如，我知道一个事实，即

glBindVertexArray

在 _int_gl_exts.h 中，果然我已经包含了它。

#include <glload\_int_gl_exts.h>

不知道是不是这个问题，但是我的错误信息中有三个下划线字符

symbol ___gleBindVertexArray

而在文件中，它前面只有两个下划线。这是包含文件中的确切行

extern PFNGLBINDVERTEXARRAYPROC __gleBindVertexArray;
#define glBindVertexArray __gleBindVertexArray

我直接从教程中提取了很多东西，即使我的包含和功能相同，我仍然有问题。如有必要，我会发布完整的代码，但在这里停留了大约 2 天后我没有想法。

编辑：事实上我两者都有

#pragma comment(lib, "opengl32.lib")

以及我尝试更改链接器中的项目属性以将其添加到其他库。

我的整个代码如下。我知道还有很多其他的东西需要改变，但这是我首先要克服的。

#include <algorithm>
#include <string>
#include <vector>
#include <fstream>
#include <sstream>
#include <exception>
#include <stdexcept>
#include <string.h>
#include <glload/gl_3_3.h>
#include <glload/gll.hpp>
#include <glutil/Shader.h>
#include <GL/freeglut.h>
#include "framework.h"
#include "directories.h"
#include <glload/_int_gl_exts.h>

#ifdef LOAD_X11
#define APIENTRY
#endif

namespace Framework

GLuint LoadShader(GLenum eShaderType, const std::string &strShaderFilename)

    std::string strFilename = FindFileOrThrow(strShaderFilename);
    std::ifstream shaderFile(strFilename.c_str());
    std::stringstream shaderData;
    shaderData << shaderFile.rdbuf();
    shaderFile.close();

    try
    
        return glutil::CompileShader(eShaderType, shaderData.str());
    
    catch(std::exception &e)
    
        fprintf(stderr, "%s\n", e.what());
        throw;
    


GLuint CreateProgram(const std::vector<GLuint> &shaderList)

    try
    
        GLuint prog = glutil::LinkProgram(shaderList);
        std::for_each(shaderList.begin(), shaderList.end(), glDeleteShader);
        return prog;
    
    catch(std::exception &e)
    
        std::for_each(shaderList.begin(), shaderList.end(), glDeleteShader);
        fprintf(stderr, "%s\n", e.what());
        throw;
    


float DegToRad(float fAngDeg)

    const float fDegToRad = 3.14159f * 2.0f / 360.0f;
    return fAngDeg * fDegToRad;


std::string FindFileOrThrow( const std::string &strBasename )

    std::string strFilename = LOCAL_FILE_DIR + strBasename;
    std::ifstream testFile(strFilename.c_str());
    if(testFile.is_open())
        return strFilename;


    strFilename = GLOBAL_FILE_DIR + strBasename;
    testFile.open(strFilename.c_str());
    if(testFile.is_open())
        return strFilename;

    throw std::runtime_error("Could not find the file " + strBasename);




void init();
void display();
void reshape(int w, int h);
void keyboard(unsigned char key, int x, int y);

unsigned int defaults(unsigned int displayMode, int &width, int &height);

void APIENTRY DebugFunc(GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length,
           const GLchar* message, GLvoid* userParam)

std::string srcName;
switch(source)

case GL_DEBUG_SOURCE_API_ARB: srcName = "API"; break;
case GL_DEBUG_SOURCE_WINDOW_SYSTEM_ARB: srcName = "Window System"; break;
case GL_DEBUG_SOURCE_SHADER_COMPILER_ARB: srcName = "Shader Compiler"; break;
case GL_DEBUG_SOURCE_THIRD_PARTY_ARB: srcName = "Third Party"; break;
case GL_DEBUG_SOURCE_APPLICATION_ARB: srcName = "Application"; break;
case GL_DEBUG_SOURCE_OTHER_ARB: srcName = "Other"; break;


std::string errorType;
switch(type)

case GL_DEBUG_TYPE_ERROR_ARB: errorType = "Error"; break;
case GL_DEBUG_TYPE_DEPRECATED_BEHAVIOR_ARB: errorType = "Deprecated Functionality"; break;
case GL_DEBUG_TYPE_UNDEFINED_BEHAVIOR_ARB: errorType = "Undefined Behavior"; break;
case GL_DEBUG_TYPE_PORTABILITY_ARB: errorType = "Portability"; break;
case GL_DEBUG_TYPE_PERFORMANCE_ARB: errorType = "Performance"; break;
case GL_DEBUG_TYPE_OTHER_ARB: errorType = "Other"; break;


std::string typeSeverity;
switch(severity)

case GL_DEBUG_SEVERITY_HIGH_ARB: typeSeverity = "High"; break;
case GL_DEBUG_SEVERITY_MEDIUM_ARB: typeSeverity = "Medium"; break;
case GL_DEBUG_SEVERITY_LOW_ARB: typeSeverity = "Low"; break;


printf("%s from %s,\t%s priority\nMessage: %s\n",
    errorType.c_str(), srcName.c_str(), typeSeverity.c_str(), message);


int main(int argc, char** argv)

glutInit(&argc, argv);

int width = 500;
int height = 500;
unsigned int displayMode = GLUT_DOUBLE | GLUT_ALPHA | GLUT_DEPTH | GLUT_STENCIL;
displayMode = defaults(displayMode, width, height);

glutInitDisplayMode (displayMode);
glutInitContextVersion (3, 3);
glutInitContextProfile(GLUT_CORE_PROFILE);
#ifdef DEBUG
glutInitContextFlags(GLUT_DEBUG);
#endif
glutInitWindowSize (width, height); 
glutInitWindowPosition (300, 200);
int window = glutCreateWindow (argv[0]);

glload::LoadFunctions();

glutSetOption(GLUT_ACTION_ON_WINDOW_CLOSE, GLUT_ACTION_CONTINUE_EXECUTION);

if(!glload::IsVersionGEQ(3, 3))

    printf("Your OpenGL version is %i, %i. You must have at least OpenGL 3.3 to run this tutorial.\n",
        glload::GetMajorVersion(), glload::GetMinorVersion());
    glutDestroyWindow(window);
    return 0;


if(glext_ARB_debug_output)

    glEnable(GL_DEBUG_OUTPUT_SYNCHRONOUS_ARB);
    glDebugMessageCallbackARB(DebugFunc, (void*)15);


init();

glutDisplayFunc(display); 
glutReshapeFunc(reshape);
glutKeyboardFunc(keyboard);
glutMainLoop();
return 0;


#pragma comment(lib, "opengl32.lib")

#include <string>
#include <vector>
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <glload/gl_3_3.h>
#include <glload\_int_gl_exts.h>
#include <GL/freeglut.h>
#include <glload\_int_gl_1_5.h>
#include <glload\_int_gl_1_1_rem_3_1.h>
#include "../../framework/framework.h"

#define GL_GLEXT_PROTOTYPES
#ifdef __APPLE__
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif

GLuint theProgram;
GLuint elapsedTimeUniform;

void InitializeProgram()

std::vector<GLuint> shaderList;

shaderList.push_back(Framework::LoadShader(GL_VERTEX_SHADER, "calcOffset.vert"));
shaderList.push_back(Framework::LoadShader(GL_FRAGMENT_SHADER, "calcColor.frag"));

theProgram = Framework::CreateProgram(shaderList);

elapsedTimeUniform = glGetUniformLocation(theProgram, "time");

GLuint loopDurationUnf = glGetUniformLocation(theProgram, "loopDuration");
GLuint fragLoopDurUnf = glGetUniformLocation(theProgram, "fragLoopDuration");


glUseProgram(theProgram);
glUniform1f(loopDurationUnf, 5.0f);
glUniform1f(fragLoopDurUnf, 10.0f);
glUseProgram(0);


const float vertexPositions[] = 
0.25f, 0.25f, 0.0f, 1.0f,
0.25f, -0.25f, 0.0f, 1.0f,
-0.25f, -0.25f, 0.0f, 1.0f,
;

GLuint positionBufferObject;
GLuint vao;

void createCube() 
  glBegin(GL_LINES);
  glLineWidth(99.0);

  glColor3f(   1.0,  0.0, 1.0 );

  glVertex3f(  0.5,0.5,0.5 );
  glVertex3f(  0.5,0.5,-0.5 );

  glVertex3f( 0.5,0.5,-0.5 );
  glVertex3f( -0.5,0.5,-0.5 );

  glVertex3f( -0.5,0.5,-0.5 );
  glVertex3f( -0.5,0.5,0.5 );

  glVertex3f( -0.5,0.5,0.5 );
  glVertex3f( 0.5,0.5,0.5 );

  glVertex3f(  0.5,-0.5,0.5 );
  glVertex3f(  0.5,-0.5,-0.5 );

  glVertex3f( 0.5,-0.5,-0.5 );
  glVertex3f( -0.5,-0.5,-0.5 );

  glVertex3f( -0.5,-0.5,-0.5 );
  glVertex3f( -0.5,-0.5,0.5 );

  glVertex3f( -0.5,-0.5,0.5 );
  glVertex3f( 0.5,-0.5,0.5 );

  glVertex3f( 0.5,0.5,0.5 );
  glVertex3f( 0.5,-0.5,0.5 );

  glVertex3f( -0.5,-0.5,-0.5 );
  glVertex3f( -0.5,0.5,-0.5 );

  glVertex3f( 0.5,0.5,-0.5 );
  glVertex3f( 0.5,-0.5,-0.5 );

  glVertex3f( -0.5,0.5,0.5 );
  glVertex3f( -0.5,-0.5,0.5 );

  glEnd();


void InitializeVertexBuffer()

glGenBuffers(1, &positionBufferObject);

glBindBuffer(GL_ARRAY_BUFFER, positionBufferObject);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertexPositions), vertexPositions, GL_STREAM_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);


//Called after the window and OpenGL are initialized. Called exactly once, before the main loop.
void init()

InitializeProgram();
InitializeVertexBuffer();

glGenVertexArrays(1, &vao);
glBindVertexArray(vao);


//Called to update the display.
//You should call glutSwapBuffers after all of your rendering to display what you rendered.
//If you need continuous updates of the screen, call glutPostRedisplay() at the end of the function.
void display()

glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT);

glUseProgram(theProgram);

glUniform1f(elapsedTimeUniform, glutGet(GLUT_ELAPSED_TIME) / 1000.0f);

glBindBuffer(GL_ARRAY_BUFFER, positionBufferObject);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0, 0);


createCube();
glColor3f(1.0,0.0,0.0);
glutSolidSphere(0.04,10,10);

glDrawArrays(GL_TRIANGLES, 0, 3);

glDisableVertexAttribArray(0);
glUseProgram(0);

glutSwapBuffers();
glutPostRedisplay();


    //Called whenever the window is resized. The new window size is given, in pixels.
    //This is an opportunity to call glViewport or glScissor to keep up with the change in size.
void reshape (int w, int h)

glViewport(0, 0, (GLsizei) w, (GLsizei) h);


//Called whenever a key on the keyboard was pressed.
//The key is given by the ''key'' parameter, which is in ASCII.
//It's often a good idea to have the escape key (ASCII value 27) call glutLeaveMainLoop() to 
//exit the program.
void keyboard(unsigned char key, int x, int y)

switch (key)

case 27:
    glutLeaveMainLoop();
    return;




unsigned int defaults(unsigned int displayMode, int &width, int &height) return displayMode;

【问题讨论】：

***.com/questions/12573816/… 有帮助吗？ 【参考方案1】：

如果你真的说what library you were trying to link to就好了。我知道它是哪一个的唯一原因是因为我认识自己的工作；）

无论如何，the documentation makes it clear what library you should link to。如果您使用的是 Premake4 构建系统，那么您的 premake4.lua 项目中应该只有 UseLibs "glload"。如果您使用其他东西，那么您需要分别在调试和发布中手动链接到glloadD 或glload。在 Windows 上，您需要一个 .lib 后缀；在 Linux 上，您可以使用 libglloadD 等。

是否使用编译指示链接或使用项目设置无关紧要。

【讨论】：

我已经包含了所有的库，但我忘记了需要调试版本和发布版本。谢谢。【参考方案2】：

包含声明是一回事；他们的定义是另一个。

在构建可执行文件时，您必须链接 OpenGL 库。

按照您的 OpenGL 书籍或参考资料中的说明进行操作，但通常您会将 -lopengl32 之类的内容传递给您的构建命令；看起来您可能正在使用 Visual Studio，它为您处理特定的构建命令，在这种情况下，您应该将 OpenGL 库添加到您的项目属性or use #pragma：