未定义对`LoadShaders（char const *，char const *）的引用

Question

我是c ++ openGL的初学者，刚刚编译了openGL 2.1教程的第一个程序，但是第二个程序给出了错误。我已将shader.cpp和shader.hpp放在文件夹/usr/include/common中。我正在使用Ubuntu 18.04。 这是我要编译的代码。我正在使用代码块

{
    // Create and compile our GLSL program from the shaders

    GLuint programID = LoadShaders( "SimpleVertexShader.vertexshader", "SimpleFragmentShader.fragmentshader" );

    // Get a handle for our buffers
    GLuint vertexPosition_modelspaceID = glGetAttribLocation(programID, "vertexPosition_modelspace");

    static const GLfloat g_vertex_buffer_data[] = {
        -1.0f, -1.0f, 0.0f,
         1.0f, -1.0f, 0.0f,
         0.0f,  1.0f, 0.0f,
    };

    GLuint vertexbuffer;
    glGenBuffers(1, &vertexbuffer);
    glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertex_buffer_data), g_vertex_buffer_data, GL_STATIC_DRAW);

    do{

        // Clear the screen
        glClear( GL_COLOR_BUFFER_BIT );

        // Use our shader
        glUseProgram(programID);

        // 1rst attribute buffer : vertices
        glEnableVertexAttribArray(vertexPosition_modelspaceID);
        glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
        glVertexAttribPointer(
            vertexPosition_modelspaceID, // The attribute we want to configure
            3,                  // size
            GL_FLOAT,           // type
            GL_FALSE,           // normalized?
            0,                  // stride
            (void*)0            // array buffer offset
        );

        // Draw the triangle !
        glDrawArrays(GL_TRIANGLES, 0, 3); // 3 indices starting at 0 -> 1 triangle

        glDisableVertexAttribArray(vertexPosition_modelspaceID);

        // Swap buffers
        glfwSwapBuffers(window);
        glfwPollEvents();

    } // Check if the ESC key was pressed or the window was closed
    while( glfwGetKey(window, GLFW_KEY_ESCAPE ) != GLFW_PRESS &&
           glfwWindowShouldClose(window) == 0 );


    // Cleanup VBO
    glDeleteBuffers(1, &vertexbuffer);
    glDeleteProgram(programID);

    // Close OpenGL window and terminate GLFW
    glfwTerminate();

    return 0;
}