使用核心 OpenGL 版本

Question

我在 glsl 中编写一个着色器，当我运行遇到一个问题，我需要的功能在我使用的版本中不可用。我运行 glxinfo | grep 'OpenGL' 得到了这个输出：

OpenGL vendor string: Intel Open Source Technology Center
OpenGL renderer string: Mesa DRI Intel(R) Sandybridge Mobile 
OpenGL core profile version string: 3.3 (Core Profile) Mesa 18.3.6
OpenGL core profile shading language version string: 3.30
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile
OpenGL core profile extensions:
OpenGL version string: 3.0 Mesa 18.3.6
OpenGL shading language version string: 1.30
OpenGL context flags: (none)
OpenGL extensions:
OpenGL ES profile version string: OpenGL ES 3.0 Mesa 18.3.6
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.00

根据输出，我可以访问 OpenGL 核心 3.3 和 GLSL 核心 3.30，如下所示：

OpenGL core profile version string: 3.3 (Core Profile) Mesa 18.3.6
OpenGL core profile shading language version string: 3.30

唯一的问题是，每当我尝试使用 GLSL 核心 330 时，都会收到一条错误消息： GLSL 3.30 is not supported. Supported versions are: 1.10, 1.20, 1.30, 1.00 ES, and 3.00 ES.

我正在使用 GLFW 创建 OpenGL 上下文。创建上下文的行是：glfwMakeContextCurrent(window);

有谁知道允许我访问 OpenGL 核心或以某种方式更新驱动程序以使我能够访问更高版本的 OpenGL 的方法吗？

____________________________________________________________________________

额外信息：

格式：Code : output

glGetString(GL_VERSION) : 3.0 Mesa 18.3.6
glGetString (GL_SHADING_LANGUAGE_VERSION) : 1.30

着色器：

    vertex shader:
    #version 330 core
    
    layout(location = 0) in vec4 position;
    
    void main(){
       gl_Position = position;
    };
    


    fragment shader:
    #version 330 core
    
    layout(location = 0) out vec4 color;
    
    void main(){
       color = vec4(1.0, 0.0, 0.0, 1.0);
    };

这是我正在尝试的代码运行:

#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;

    /* Initialize the library */
    if (!glfwInit())
        return -1;
        
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    /* Create a windowed mode window and its OpenGL context */
    window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
    if (!window)
    {
        glfwTerminate();
        return -1;
    }

    /* Make the window's context  current */
    glfwMakeContextCurrent(window);
    
    if(glewInit() != GLEW_OK){
        std::cout << "REEEEEEEEEEE" << std::endl;
    }
    
    std::cout << glGetString(GL_VERSION) << std::endl;
    std::cout << glGetString (GL_SHADING_LANGUAGE_VERSION) << std::endl;

    
    float vertices[6] = {
        -0.5f, -0.5f,
         0.0f,  0.5f,
        -0.5f, -0.5f
    };
    
    unsigned int buf;
    glGenBuffers(1, &buf);
    glBindBuffer(GL_ARRAY_BUFFER, buf);
    glBufferData(GL_ARRAY_BUFFER, 6 * sizeof(float), vertices, GL_STATIC_DRAW);
    
    glEnableVertexAttribArray(buf); // try replacing buf with 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"
    "   gl_Position = position;\n"
    "}\n";
    
    std::string fragmentshader = 
    "#version 330 core\n"
    "\n"
    "out vec4 color;\n"
    "\n"
    "void main(){\n"
    "   color = vec4(1.0, 0.0, 0.0, 1.0);\n"
    "}\n";
    
    unsigned int shader = CreateShader(vertexshader, fragmentshader);
    glUseProgram(shader);
    
    /* Loop until the user closes the window */
    while (!glfwWindowShouldClose(window))
    {
        /* Render here */
        glClear(GL_COLOR_BUFFER_BIT);
        
        glDrawArrays(GL_TRIANGLES, 0, 3);

        /* Swap front and back buffers */
        glfwSwapBuffers(window);

        /* Poll for and process events */
        glfwPollEvents();
    }

    glfwTerminate();
    return 0;
}

OS: LINUX DEBIAN

Answer 1

通过添加

glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

在 window 创建之前，我能够让它工作。如果您不知道 MAJOR 和 MINOR 是什么意思，请看这里：

TLDR： “主要”和“次要”是单个版本号的两个组成部分，以点分隔。

因此，将主要版本和次要版本都设置为 3，我就能够请求 OpenGL 3.3 Core Profile。

现在当我运行:

std::cout << glGetString(GL_VERSION) << std::endl;
std::cout << glGetString (GL_SHADING_LANGUAGE_VERSION) << std::endl;

我得到：

3.3 (Core Profile) Mesa 18.3.6
3.30

使用核心 OpenGL 版本

Use core OpenGL version

c++

opengl

shader

rendering

glsl