c++ - OpenGL为什么会给我错误:错误:0:1: '':不支持 '330'版本？

Question

我在Mac上并且正在使用Xcode 10.1，因为我的Mac在10.13.6上，所以我无法获得新版本。我是C++和OpenGL的新手，所以我遵循了有关如何执行此操作的教程，但它在Windows 10上适用，所以也许是问题所在？它使用都随Homebrew一起安装的GLFW和GLEW。
这是我的代码:

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

#include <iostream>

static unsigned int CompileShader(unsigned int type, const std::string& source)
{
    unsigned int id = glCreateShader(type);
    const char* src = source.c_str();
    glShaderSource(id, 1, &src, nullptr);
    glCompileShader(id);
    
    int result;
    glGetShaderiv(id, GL_COMPILE_STATUS, &result);
    if(result == GL_FALSE)
    {
        int length;
        glGetShaderiv(id, GL_INFO_LOG_LENGTH, &length);
        char* message = (char*)alloca(length * sizeof(char));
        glGetShaderInfoLog(id, length, &length, message);
        std::cout << "Failed to compile " << (type == GL_VERTEX_SHADER ? "vertex" : "fragment") << " shader!" << std::endl;
        std::cout << message << std::endl;
        glDeleteShader(id);
        return 0;
    }
    
    return id;
}

static unsigned int CreateShader(const std::string& vertexShader, const std::string& fragmentShader)
{
    unsigned int program = glCreateProgram();
    unsigned int vs = CompileShader(GL_VERTEX_SHADER, vertexShader);
    unsigned int fs = CompileShader(GL_FRAGMENT_SHADER, fragmentShader);
    
    glAttachShader(program, vs);
    glAttachShader(program, fs);
    glLinkProgram(program);
    glValidateProgram(program);
    
    glDeleteShader(vs);
    glDeleteShader(fs);
    
    return program;
}

int main(void)
{
    GLFWwindow* window;
    
    if (!glfwInit())
        return -1;
    
    window = glfwCreateWindow(640, 480, "Window", NULL, NULL);
    if (!window)
    {
        glfwTerminate();
        return -1;
    }
    
    glfwMakeContextCurrent(window);
    
    if(glewInit() != GLEW_OK)
        std::cout << "Error!" << std::endl;
    
    std::cout << glGetString(GL_VERSION) << std::endl;
    
    float positions[6] = {
        -0.5f, -0.5f,
        0.0f, 0.5f,
        0.5f, -0.5f
    };
    
    unsigned int buffer;
    glGenBuffers(1, &buffer);
    glBindBuffer(GL_ARRAY_BUFFER, buffer);
    glBufferData(GL_ARRAY_BUFFER, 6 * sizeof(float), positions, GL_STATIC_DRAW);
    
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 2, 0);
    
    std::string vertexShader =
    "#version 330 core\n"
    "\n"
    "layout(location = 0) in vec4 position;\n"
    "\n"
    "void main()\n"
    "{\n"
    "   glPosition = position;\n"
    "}\n";
    
    std::string fragmentShader =
    "#version 450 core\n"
    "\n"
    "layout(location = 0) out vec4 colour;\n"
    "\n"
    "void main()\n"
    "{\n"
    "   colour = vec4(1.0, 0.0, 0.0, 1.0);\n"
    "}\n";
    
    unsigned int shader = CreateShader(vertexShader, fragmentShader);
    glUseProgram(shader);
    
    while (!glfwWindowShouldClose(window))
    {
        glClear(GL_COLOR_BUFFER_BIT);
        
        glDrawArrays(GL_TRIANGLES, 0, 3);
        
        glfwSwapBuffers(window);
        
        glfwPollEvents();
    }

    glfwTerminate();
    return 0;
}

当我运行此代码时，控制台将这样写:

2.1 NVIDIA-10.4.14 310.90.30.05b27
Failed to compile vertex shader!
ERROR: 0:1: '' :  version '330' is not supported
ERROR: 0:1: '' : syntax error: #version
ERROR: 0:3: 'layout' : syntax error: syntax error

Failed to compile fragment shader!
ERROR: 0:1: '' :  version '450' is not supported
ERROR: 0:1: '' : syntax error: #version
ERROR: 0:3: 'layout' : syntax error: syntax error

Program ended with exit code: 0

我怎样才能解决这个问题？

Answer 1

您的c++代码样式与opengl的旧版本(3.2和更早版本)相同，并且与着色器不兼容。您有两个选择。一种是将着色器降级到旧版本。另一种方法是更新C++代码。 opengl 3.30的正确示例如下所示:

#include <iostream>

// GLEW
#define GLEW_STATIC
#include <GL/glew.h>

// GLFW
#include <GLFW/glfw3.h>


// Function prototypes
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);

// Window dimensions
const GLuint WIDTH = 800, HEIGHT = 600;

// Shaders
const GLchar* vertexShaderSource = "#version 330 core\n"
    "layout (location = 0) in vec3 position;\n"
    "void main()\n"
    "{\n"
    "gl_Position = vec4(position.x, position.y, position.z, 1.0);\n"
    "}\0";
const GLchar* fragmentShaderSource = "#version 330 core\n"
    "out vec4 color;\n"
    "void main()\n"
    "{\n"
    "color = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
    "}\n\0";

// The MAIN function, from here we start the application and run the game loop
int main()
{
    std::cout << "Starting GLFW context, OpenGL 3.3" << std::endl;
    // Init GLFW
    glfwInit();
    // Set all the required options for GLFW
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);

    // Create a GLFWwindow object that we can use for GLFW's functions
    GLFWwindow* window = glfwCreateWindow(WIDTH, HEIGHT, "LearnOpenGL", nullptr, nullptr);
    glfwMakeContextCurrent(window);

    // Set the required callback functions
    glfwSetKeyCallback(window, key_callback);

    // Set this to true so GLEW knows to use a modern approach to retrieving function pointers and extensions
    glewExperimental = GL_TRUE;
    // Initialize GLEW to setup the OpenGL Function pointers
    glewInit();

    // Define the viewport dimensions
    int width, height;
    glfwGetFramebufferSize(window, &width, &height);  
    glViewport(0, 0, width, height);


    // Build and compile our shader program
    // Vertex shader
    GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
    glCompileShader(vertexShader);
    // Check for compile time errors
    GLint success;
    GLchar infoLog[512];
    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
    }
    // Fragment shader
    GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
    glCompileShader(fragmentShader);
    // Check for compile time errors
    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
    }
    // Link shaders
    GLuint shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);
    // Check for linking errors
    glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
    if (!success) {
        glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
    }
    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);


    // Set up vertex data (and buffer(s)) and attribute pointers
    //GLfloat vertices[] = {
    //  // First triangle
    //   0.5f,  0.5f,  // Top Right
    //   0.5f, -0.5f,  // Bottom Right
    //  -0.5f,  0.5f,  // Top Left 
    //  // Second triangle
    //   0.5f, -0.5f,  // Bottom Right
    //  -0.5f, -0.5f,  // Bottom Left
    //  -0.5f,  0.5f   // Top Left
    //}; 
    GLfloat vertices[] = {
         0.5f,  0.5f, 0.0f,  // Top Right
         0.5f, -0.5f, 0.0f,  // Bottom Right
        -0.5f, -0.5f, 0.0f,  // Bottom Left
        -0.5f,  0.5f, 0.0f   // Top Left 
    };
    GLuint indices[] = {  // Note that we start from 0!
        0, 1, 3,  // First Triangle
        1, 2, 3   // Second Triangle
    };
    GLuint VBO, VAO, EBO;
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);
    glGenBuffers(1, &EBO);
    // Bind the Vertex Array Object first, then bind and set vertex buffer(s) and attribute pointer(s).
    glBindVertexArray(VAO);

    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), (GLvoid*)0);
    glEnableVertexAttribArray(0);

    glBindBuffer(GL_ARRAY_BUFFER, 0); // Note that this is allowed, the call to glVertexAttribPointer registered VBO as the currently bound vertex buffer object so afterwards we can safely unbind

    glBindVertexArray(0); // Unbind VAO (it's always a good thing to unbind any buffer/array to prevent strange bugs), remember: do NOT unbind the EBO, keep it bound to this VAO


    // Uncommenting this call will result in wireframe polygons.
    //glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);

    // Game loop
    while (!glfwWindowShouldClose(window))
    {
        // Check if any events have been activiated (key pressed, mouse moved etc.) and call corresponding response functions
        glfwPollEvents();

        // Render
        // Clear the colorbuffer
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        // Draw our first triangle
        glUseProgram(shaderProgram);
        glBindVertexArray(VAO);
        //glDrawArrays(GL_TRIANGLES, 0, 6);
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
        glBindVertexArray(0);

        // Swap the screen buffers
        glfwSwapBuffers(window);
    }
    // Properly de-allocate all resources once they've outlived their purpose
    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);
    glDeleteBuffers(1, &EBO);
    // Terminate GLFW, clearing any resources allocated by GLFW.
    glfwTerminate();
    return 0;
}

// Is called whenever a key is pressed/released via GLFW
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
{
    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
        glfwSetWindowShouldClose(window, GL_TRUE);
}

新版本与旧版本之间的最大区别是在新版本中需要使用VAO。