【小沐学OpenGL】Ubuntu环境下glfw的安装和使用

文章目录

1、简介
- 1.1 OpenGL简介
- 1.2 glfw简介
2、安装glfw
- 2.1 直接命令二进制安装
- 2.2 源码安装
3、测试glfw
- 3.1 测试1，glfw+glew
- 3.2 测试2，glfw+glad
- 3.3 测试3
结语

1、简介

1.1 OpenGL简介

OpenGL作为图形界的工业标准，其仅仅定义了一组2D和3D图形接口API，而对于窗口管理、IO消息响应等并没有规定。也就是说，OpenGL依赖各平台提供用于渲染的context以及具体实现方式，而各平台提供的实现不尽相同。这些实现主要有：Windows平台下的WGL、Linux下的Mesa/GLX、Mac OS X下的Cocoa/NSGL，以及跨平台的GLUT、GLFW、SDL等等。

安装OpenGL库：

sudo apt-get install build-essential
sudo apt-get install libgl1-mesa-dev

使用如下的命令来查看对应显卡的OpenGL版本：

glxinfo | grep -i opengl

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1.2 glfw简介

GLFW 是一个开源的多平台库，适用于 OpenGL、OpenGL ES 和桌面上的 Vulkan 开发。它提供了一个简单的 API 来创建窗口、上下文和表面，接收输入和事件。
GLFW 是用 C 语言编写的，支持 Windows、macOS、Wayland 和 X11。
GLFW 根据 zlib/libpng 许可证获得许可。

https://www.glfw.org/
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查看glfw安装情况如下：

locate glfw

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2、安装glfw

2.1 直接命令二进制安装

使用包管理器安装。

安装glfw:

sudo apt-get update
sudo apt-get -y install libglfw3

# 或者
sudo apt-get install libglfw3
sudo apt-get install libglfw3-dev

# 或者
sudo apt update
sudo apt -y install libglfw3

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卸载glfw

# 要仅卸载包libglfw3
sudo apt-get remove libglfw3

# 卸载 libglfw3 及其依赖项
sudo apt-get -y autoremove libglfw3

# 删除 libglfw3 配置和数据
sudo apt-get -y purge libglfw3

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2.2 源码安装

官方地址：
https://github.com/glfw/glfw

从 GLFW 的官方网站下载源代码并编译安装，依次执行如下命令：

# git clone git@github.com:glfw/glfw.git
# wget https://github.com/glfw/glfw/archive/refs/tags/3.4.tar.gz
wget http://github.com/glfw/glfw/releases/download/3.4/glfw-3.4.zip
cd glfw-3.4
mkdir build && cd build
sudo apt-get install libxrandr-dev
sudo apt-get install libxinerama-dev
sudo apt-get install libxcursor-dev
sudo apt-get install libxi-dev
cmake .. -DGLFW_BUILD_WAYLAND:BOOL=OFF
make -j4
sudo make install

通过wget下载glfw源码。
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通过cmake编译glfw代码。

通过make install安装glfw库文件。

3、测试glfw

3.1 测试1，glfw+glew

要在 Linux 系统上配置 OpenGL 开发环境并使用 GLFW 和 GLEW，你可以按照以下步骤操作。
使用 GLEW 加载所有 OpenGL 函数指针。通过cmake构建测试工程。

CMakeLists.txt

cmake_minimum_required(VERSION 2.8.1)

project(my_project)

find_package(OpenGL REQUIRED)
find_package(GLEW REQUIRED)
find_package(glfw3 REQUIRED)

add_executable(main main.cpp)
target_link_libraries(main OpenGL::GL  GLEW::GLEW glfw)

main.cpp

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

int main(void)
{
    GLFWwindow* window;

    /* Initialize the library */
    if (!glfwInit())
        return -1;

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

    /* Make the window's context current */
    glfwMakeContextCurrent(window);

	if(glewInit() != GLEW_OK){
        std::cerr << "Failed to initalize GLEW" << std::endl;
        return -1;
    }
    
    /* Loop until the user closes the window */
    while (!glfwWindowShouldClose(window))
    {
        /* Render here */
        glClear(GL_COLOR_BUFFER_BIT);
        glClearColor(0, 1, 0, 1);

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

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

    glfwTerminate();
    return 0;
}

编译如下：
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3.2 测试2，glfw+glad

GLAD 是一个用于加载 OpenGL 函数指针的库，它简化了 OpenGL 函数的调用。你可以从 GLAD 的官方网站下载并生成适合你需求的 GLAD 配置。通常，你需要指定 OpenGL 的版本和配置文件类型（通常是核心模式）。生成后，将包含的头文件和源文件添加到你的项目中。

在你的项目中，你需要包含 GLAD 和 GLFW 的头文件，并链接到相应的库。如果你使用 CMake，你可能需要在你的 CMakeLists.txt 文件中添加相应的链接指令。

CMakeLists.txt

cmake_minimum_required(VERSION 2.8.1)

project(my_project)
set(CMAKE_C_STANDARD 11)
set(CMAKE_CXX_STANDARD 14)

find_package(glfw3 REQUIRED)

file(GLOB SOURCE_FILES glad.c main.cpp)
add_executable(${PROJECT_NAME} ${SOURCE_FILES})

target_link_libraries(${PROJECT_NAME} glfw)

main.cpp

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

void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow *window);

int main() {
    // Intialize GLFW
    glfwInit();

    // Configure GLFW (v3.3)
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    // Create a window object
    GLFWwindow* window = glfwCreateWindow(800, 600, "LearnOpenGL, yxy", NULL, NULL);
    if (window == NULL) {
        std::cout << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return -1;
    }

    // Make our window the main context on the current thread
    glfwMakeContextCurrent(window);

    // Initialize GLAD
    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
        std::cout << "Failed to initialize GLAD" << std::endl;
        return -1;
    }

    // Set size of the rendering window (dimensions)
    glViewport(0, 0, 800, 600);

    // Register a callback function on the window that gets called
    // each time the window is resized
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

    // Render loop that keeps on running until we tell GLFW to stop
    while(!glfwWindowShouldClose(window)) {
        // Check input close window if it is the escape key
        processInput(window);

        // Rendering commands here
        // Set a color to clear the screen with (state-setting function)
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        // Clear the screen with the color (state-using function)
        glClear(GL_COLOR_BUFFER_BIT);

        // Swap the color buffer and show output to the screen
        glfwSwapBuffers(window);

        // Check if any events are triggered
        glfwPollEvents();
    }

    // Clean/delete all GLFW's resources
    glfwTerminate();

    return 0;
}

void framebuffer_size_callback(GLFWwindow* window, int width, int height) {
    // Update width and height
    glViewport(0, 0, width, height);
}

void processInput(GLFWwindow *window) {
    // Check whether the user has pressed the escape key and close GLFW
    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
        glfwSetWindowShouldClose(window, true);
}

编译如下：
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3.3 测试3

CMakeLists.txt

cmake_minimum_required(VERSION 2.8.1)

project(my_project)
set(CMAKE_C_STANDARD 11)
set(CMAKE_CXX_STANDARD 14)

find_package(glfw3 REQUIRED)

file(GLOB SOURCE_FILES glad.c main.cpp)
add_executable(${PROJECT_NAME} ${SOURCE_FILES})

target_link_libraries(${PROJECT_NAME} glfw)

main.cpp

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

#include <iostream>

void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow *window);
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;

// 顶点着色器，GLSL语言
const char *vertexShaderSource = "#version 330 core\n"
                                 "layout (location = 0) in vec3 aPos;\n"
                                 "void main()\n"
                                 "{\n"
                                 "   gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
                                 "}\0";
// 片元着色器
const char *fragmentShaderSource = "#version 330 core\n"
                                   "out vec4 FragColor;\n"
                                   "void main()\n"
                                   "{\n"
                                   "   FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
                                   "}\n\0";

int main()
{
    // glfw: initialize and configure
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
#ifdef __APPLE__
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endif

    // glfw window creation
    GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL, yxy", NULL, NULL);
    if (window == NULL)
    {
        std::cout << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

    // glad: load all OpenGL function pointers
    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
        std::cout << "Failed to initialize GLAD" << std::endl;
        return -1;
    }

    // build and compile our shader program
    // ------------------------------------
    // vertex shader
    int vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
    glCompileShader(vertexShader);
    // check for shader compile errors
    int success;
    char 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
    int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
    glCompileShader(fragmentShader);
    // check for shader compile 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
    int 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);


    float vertices[] = {
        -0.5f, -0.5f, 0.0f, // left
        0.5f, -0.5f, 0.0f, // right
        0.0f,  0.5f, 0.0f  // top
    };

    unsigned int VBO, VAO;
    //创建VAO对象
    glGenVertexArrays(1, &VAO);
    glBindVertexArray(VAO);
    //创建VBO对象，把顶点数组复制到一个顶点缓冲中，供OpenGL使用
    glGenBuffers(1, &VBO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO); // 缓冲绑定到GL_ARRAY_BUFFER
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW); // 顶点数据复制到缓冲的内存中

    //解释顶点数据方式
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0); // 顶点数据的解释
    glEnableVertexAttribArray(0);

    // 解绑VAO
    glBindVertexArray(0);
    // 解绑VBO
    glBindBuffer(GL_ARRAY_BUFFER, 0);

    // render loop
    // -----------
    while (!glfwWindowShouldClose(window))
    {
        // input
        // -----
        processInput(window);

        // render
        // ------
        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, 3);

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    // optional: de-allocate all resources
    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);
    glDeleteProgram(shaderProgram);
    glfwTerminate();

    return 0;
}

//键盘按键回调函数
void processInput(GLFWwindow *window)
{
    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
        glfwSetWindowShouldClose(window, true);
}

//调整窗口大小回调函数
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    glViewport(0, 0, width, height);
}

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结语

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