鏈接問題C++，glew和SDL

Question

我有一些鏈接器錯誤，我不能真正解讀它們的意思，所以我會感謝一些幫助。我試圖編寫一個簡單的程序，它只是創建一個基本的片段着色器和一個基本的頂點着色器。下面的代碼：

Shader.h〜

#pragma once 
#include <iostream> 
#include <fstream> 
#include <string> 
#include <glew.h> 


class Shader 
{ 
    public: 
    const static unsigned int NUMOFSHADERS = 2; 

    GLuint m_program; 
    GLuint m_shaders[NUMOFSHADERS]; 

    void Bind(); 
    static std::string LoadShader(const std::string& filename); 
    static GLuint CreateShader(const std::string& text, GLenum shadertype); 
    Shader(const std::string& filename); 
    virtual ~Shader(); 
}; 

Shader.cpp〜

#include "Shader.h" 


Shader::Shader(const std::string& filename) 
{ 
    m_program = glCreateProgram(); 
    m_shaders[0] = CreateShader(LoadShader(filename + ".shade_v"),  GL_VERTEX_SHADER); 
    m_shaders[1] = CreateShader(LoadShader(filename + ".shade_f"),  GL_FRAGMENT_SHADER); 

    for (unsigned int i = 0; NUMOFSHADERS; i++) 
    { 
     glAttachShader(m_program, m_shaders[i]); 
    }; 

    glBindAttribLocation(m_program, 0, "position"); 
    glLinkProgram(m_program); 
} 

Shader::~Shader() 
{ 
    for (unsigned int i = 0; NUMOFSHADERS; i++) 
    { 
     glDetachShader(m_program, m_shaders[i]); 
     glDeleteShader(m_shaders[i]); 
    } 

    glDeleteProgram(m_program); 
} 

static std::string LoadShader(const std::string& filename) 
{ 

    std::ifstream file; 
    std::string output; 
    std::string line; 
    file.open(filename.c_str()); 
    if (file.is_open()) 
    { 
     while (file) 
     { 
      std::getline(file, line); 
      output.append(line + "\n"); 
     } 
     file.close(); 
     return output; 
    } 
} 

static GLuint CreateShader(const std::string& text, GLenum shadertype) 
{ 
    GLuint shader = glCreateShader(shadertype); 
    const GLchar* shadersourcestrings[1]; 
    GLint shadersourcelengths[1]; 

    shadersourcestrings[0] = text.c_str(); 
    shadersourcelengths[0] = text.length(); 

    glShaderSource(shader, 1, shadersourcestrings, shadersourcelengths); 
    glCompileShader(shader); 

    return shader; 
} 

void Shader::Bind() 
{ 
    glUseProgram(m_program); 
} 

Display.h〜

#pragma once 
#include <SDL.h> 
#include <glew.h> 
#include <iostream> 

class Display 
{ 
public: 
    void Update(); 
    void Clear(float r, float g, float b, float a); 
    bool isClosed(); 
    Display(int width, int height, const char *title); 
    virtual ~Display(); 
private: 
    bool m_isClosed; 
    SDL_Window* m_window; 
    SDL_GLContext m_context; 
}; 

Display.cpp〜

#pragma once 
#include "Display.h" 

Display::Display(int width, int height, const char *title) 
{ 
    if (SDL_Init(SDL_INIT_EVERYTHING) == 0) 
    { 
     SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1); 

     m_window = SDL_CreateWindow(title, SDL_WINDOWPOS_CENTERED,  SDL_WINDOWPOS_CENTERED, width, height, SDL_WINDOW_OPENGL); 
     m_context = SDL_GL_CreateContext(m_window); 

     GLenum status = glewInit(); 
     if (status != GLEW_OK){ 
      std::cerr << "this is where the problem is" << std::endl; 
     } 
     m_isClosed = false; 
    } 
} 


Display::~Display() 
{ 
     std::cerr << "destructor ran" << std::endl; 
     SDL_GL_DeleteContext(m_context); 
     SDL_DestroyWindow(m_window); 
     SDL_Quit(); 
} 

void Display::Update() 
{ 
    SDL_Event event; 
    SDL_GL_SwapWindow(m_window); 

    while (SDL_PollEvent(&event)) 
    { 
     switch (event.type) 
     { 
     case SDL_QUIT: 
      m_isClosed = true; 
     } 
    } 
} 

void Display::Clear(float r, float g, float b, float a) 
{ 
    glClearColor(r, g, b, a); 
    glClear(GL_COLOR_BUFFER_BIT); 
} 

bool Display::isClosed(){ 
    return m_isClosed; 
} 

的main.cpp〜

#include <iostream> 
#include "Display.h" 
#include "Shader.h" 

int main(int argc, char *argv[]) 
{ 
    Display display(800, 600, "test"); 
    Shader shader("basicshader"); 

    while (!display.isClosed()) 
    { 
     display.Clear(1.0f, 0.0f, 0.0f, 1.0f); 
     shader.Bind(); 
     display.Update(); 
    } 

    return 0; 
} 

這裏是錯誤我recieving：

error LNK2019: unresolved external symbol "public: static unsigned int __cdecl Shader::CreateShader(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &,unsigned int)" (?CreateShader@Shader@@SAIABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@I@Z) referenced in function "public: __thiscall Shader::Shader(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (??0Shader@@QAE@ABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) C:\Users\Nas\documents\visual studio 2013\Projects\Open GL\Open GL\Shader.obj 

error LNK2019: unresolved external symbol "public: static class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > __cdecl Shader::LoadShader(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (?LoadShader@Shader@@SA?AV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@ABV23@@Z) referenced in function "public: __thiscall Shader::Shader(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (??0Shader@@QAE@ABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) C:\Users\Nas\documents\visual studio 2013\Projects\Open GL\Open GL\Shader.obj 

error LNK1120: 2 unresolved externals C:\Users\Nas\documents\visual studio 2013\Projects\Open GL\Debug\Open GL.exe 1 

Answer 1

你缺少一個Shader::在CreateShader實施的前面。此外，您必須刪除static關鍵字在實施：

​​3210

什麼你現在正在定義是在全球範圍內的局部靜態方法::CreateShader，這是完全無關的成員函數Shader::CreateShader。