Mac下配置OpenGL环境

zhangMo Blog

2019-09-11 (Updated: 2019-09-11)

计算机图形学

OpenGL, 计算机图形学

Mac下配置OpenGL环境。

Mac下配置OpenGL

安装homebrew

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
安装GLEW与GLFW

brew install glew

brew install glfw3

CLion法（推荐）

在CLion:A cross-platform IDE for C and C++下载CLion

配置GLAD：

打开在线服务（点击这个链接），API选择3.3及以上，Profile选择Core，勾选Options中的Generate a loader，点击GENERATE，会生成一个压缩包，下载。
将子目录中的/include/glad与/include/KHR复制到/usr/Local/include文件夹下。（如果/usr文件夹隐藏，可用快捷键command+shift+G输入访问）

新建一个项目，配置对应的Cmake文件：

cmake_minimum_required(VERSION 3.12)
project(OpenGL)

set(CMAKE_CXX_STANDARD 14)

set(GLEW_H /usr/local/Cellar/glew/2.1.0/include/GL)
set(GLFW_H /usr/local/Cellar/glfw/3.2.1/include/GLFW)
set(GLAD_H /usr/local/include/glad)
set(KH_H /usr/local/include/KHR)
include_directories(${GLEW_H} ${GLFW_H} ${GLAD_H} ${KH_H})

# 添加目标链接
set(GLEW_LINK /usr/local/Cellar/glew/2.1.0/lib/libGLEW.2.1.dylib)
set(GLFW_LINK /usr/local/Cellar/glfw/3.2.1/lib/libglfw.3.dylib)
link_libraries(${OPENGL} ${GLEW_LINK} ${GLFW_LINK})

# 执行编译命令
# 这个glad.c在第2步中说过要拉到项目中，注意路径
set(SOURCE_FILES "src/glad.c" "main.cpp")
add_executable(OpenGL ${SOURCE_FILES})

# mac下这步很重要
if (APPLE)
    target_link_libraries(OpenGL "-framework OpenGL")
    target_link_libraries(OpenGL "-framework GLUT")
endif()

4. 注意这样配置之后需要更改`/usr/local/include/glad文件夹下的glad.h`中的`#include <KHR/khrplatform.h>`更改为`#include <khrplatform.h>`，具体步骤：

   1. 在CLion中打开`glad.c`文件，command+点按`#include <glad.h>`会跳到`glad.h`
   2. 然后在`glad.h`中command+f找到`#include <KHR/khrplatform.h>`，将它改为`#include <khrplatform.h>`

5. 运行测试代码（把下列代码复制到main.cpp中）：

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#include <glew.h>
#include <glfw3.h>
#include <iostream>
using namespace std;

void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
{
    //如果按下ESC，把windowShouldClose设置为True，外面的循环会关闭应用
    if(key==GLFW_KEY_ESCAPE && action == GLFW_PRESS)
        glfwSetWindowShouldClose(window, GL_TRUE);
    std::cout<<"ESC"<<mode;
}

int main(void)
{
    //初始化GLFW库
    if(!glfwInit())
        return -1;
    //创建窗口以及上下文
    GLFWwindow* window = glfwCreateWindow(640, 480, "hello world", NULL, NULL);
    if(!window)
    {
        //创建失败会返回NULL
        glfwTerminate();
    }
    //建立当前窗口的上下文
    glfwMakeContextCurrent(window);

    glfwSetKeyCallback(window, key_callback); //注册回调函数
    //循环，直到用户关闭窗口
    while(!glfwWindowShouldClose(window))
    {
        /*******轮询事件*******/
        glfwPollEvents();

        /*******渲染*******/
        //选择清空的颜色RGBA
        glClearColor(0.2, 0.3, 0.3, 1);
        glClear(GL_COLOR_BUFFER_BIT);

        //开始画一个三角形
        glBegin(GL_TRIANGLES);
        glColor3f(1, 0, 0); //Red
        glVertex3f(0, 1, 1);

        glColor3f(0, 1, 0); //Green
        glVertex3f(-1, -1, 0);

        glColor3f(0, 0, 1); //Blue
        glVertex3f(1, -1, 0);
        //结束一个画图步骤
        glEnd();

        glBegin(GL_POLYGON);
        //再画个梯形，需要注意笔顺
        glColor3f(0.5, 0.5, 0.5); //Grey
        glVertex2d(0.5, 0.5);
        glVertex2d(1, 1);
        glVertex2d(1, 0);
        glVertex2d(0.5, 0);
        glEnd();


        /******交换缓冲区，更新window上的内容******/
        glfwSwapBuffers(window);
    }
    glfwTerminate();
    return 0;
}

如果出现如下窗口说明配置成功：
屏幕快照 2019-09-11 下午9.45.32.png

XCode法

在App Store中搜索XCode并安装。
新建Xcode的Command Line C++项目，在build settings中设置Header Search Path与Library Search Path，在其中添加对应的glew与glfw的头文件(include)与库文件(lib)路径。

在build Phases中添加库文件屏幕快照 2018-07-28 下午5.27.39

        （在对应的文件夹中将两个/.dylib的文件直接拖拽进来）

配置GLAD：
1. 打开在线服务（点击这个链接），API选择3.3及以上，Profile选择Core，勾选Options中的Generate a loader，点击GENERATE，会生成一个压缩包，下载。
2. 将子目录中的/include/glad与/include/KHR复制到/usr/Local/include文件夹下。（如果/usr文件夹隐藏，可用快捷键command+shift+G输入访问）
3. 将/src中的glad.c复制到Xcode工程文件夹下。
4. 在build settings中添加路径/usr/local/include

此时如果不出意外的话，你的第一个测试程序已经可以运行了，点击测试代码，复制到自己的.cpp文件中执行，会出现一个黑色窗口。(或者直接复制下面的代码)

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

#include <iostream>

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

// settings
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;

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); // uncomment this statement to fix compilation on OS X
#endif

    // glfw window creation
    // --------------------
    GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", 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;
    }    

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

        // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
        // -------------------------------------------------------------------------------
        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    // glfw: terminate, clearing all previously allocated GLFW resources.
    // ------------------------------------------------------------------
    glfwTerminate();
    return 0;
}

// process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
// ---------------------------------------------------------------------------------------------------------
void processInput(GLFWwindow *window)
{
    if(glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
        glfwSetWindowShouldClose(window, true);
}

// glfw: whenever the window size changed (by OS or user resize) this callback function executes
// ---------------------------------------------------------------------------------------------
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    // make sure the viewport matches the new window dimensions; note that width and 
    // height will be significantly larger than specified on retina displays.
    glViewport(0, 0, width, height);
}

如果运行出现如下窗口，说明配置成功：
屏幕快照 2019-09-11 下午9.47.29.png

参考：

https://www.cnblogs.com/shayue/p/Mac-CLion-xiaOpenGL-huan-jing-pei-zhi.html