Xcode 中搭建 OpenGL 环境
前言
本文主要是讲解如何在 MacOS
下在 Xcode
中搭建 OpenGL
的环境,主要是学习 OpenGL
的时候方便理解,直接可以跑出效果。
所需 Library
GLFW:
一个轻量级的,开源的,跨平台的 library
。支持 OpenGL
及 OpenGL ES
,用来管理窗口,读取输入,处理事件等。因为 OpenGL
没有窗口管理的功能,所以很多热心的人写了工具来支持这些功能,比如早期的 glut
,现在的 freeglut
等。那么 GLFW
有何优势呢? glut
太老了,最后一个版本还是 90
年代的。 freeglut
完全兼容 glut
,算是 glut
的代替品,功能齐全,但是 bug
太多。稳定性也不好(不是我说的啊), GLFW
应运而生。
GLEW:
GLEW
是一个跨平台的 C++
扩展库,基于 OpenGL
图形接口。使用 OpenGL
的朋友都知道,Windows
目前只支持 OpenGL1.1
的涵数,但 OpenGL
现在都发展到 2.0
以上了,要使用这些 OpenGL
的高级特性,就必须下载最新的扩展,另外,不同的显卡公司,也会发布一些只有自家显卡才支 持的扩展函数,你要想用这数涵数,不得不去寻找最新的glext.h,有了GLEW扩展库,你就再也不用为找不到函数的接口而烦恼,因为GLEW能自动识 别你的平台所支持的全部 OpenGL
高级扩展涵数。也就是说,只要包含一个 glew.h
头文件,你就能使用 gl
,glu
,glext
,wgl
,glx
的全 部函数。 GLEW
支持目前流行的各种操作系统( including Windows
,Linux
,Mac OS X
,FreeBSD
,Irix
,andSolaris
)。
安装:
分两种,一种手动编译 GLFW
和 GLEW
的源码,另一种是使用 HomeBrew
1. 手动编译安装:
编译工具 CMake IDE :
CMake
是一个跨平台的安装(编译)工具,可以用简单的语句来描述所有平台的安装(编译过程)。他能够输出各种各样的 makefile
或者 project
文件,能测试编译器所支持的 C++
特性,类似 UNIX
下的 automake
。
GLFW 源码:
GLEW 源码:
编译过程:
打开 CMake
的 IDE
,然后按照下图的配置:
点击 Generate
成功之后我们可以看到目录下有了 Xcode
工程,证明该步骤成功了
2. 使用 HomeBrew 安装:
$ brew install glew $ brew install homebrew/versions/glfw3
执行之前记得先把终端设置代理翻墙,你懂的。
执行完之后,进入 /usr/local/Cellar
查看是否有 glew
和 glfw
文件夹,如果有证明成功了
配置
Locations 加载配置
告诉 Xcode
如何去加载这些库 安装完成后在 Xcode
的 Proferences
> Locations
> Source Trees
中添加刚才安装的 GLFW
, GLEW
的库文件, 通过 brew
安装的库通常放在 /usr/local/Cellar
,然后找相应的 include
, lib
路径进行配置。
Search Path 配置
build Setting
-> Header Search Path
和 Library Search Path
添加相应的配置,以下是我的配置
// library search path $(glew_lib) $(glfw_lib) // header search patch $(glew_header) $(glfw_header)
library search path:
header search patch:
Builed Phases 中添加库:
这两个库就是之前brew的库,路径是
/usr/local/Cellar/glew/2.0.0/lib/ /usr/local/Cellar/glfw/3.2.1/lib/
测试
#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, 4); glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1); glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); 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 GLint 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 GLint 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 GLint 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); }
点击 run
之后出现的效果是如下这样的话
证明成功了,你可以开始你的 OpenGL
之旅!
参考链接:
- 点赞
- 收藏
- 关注作者
评论(0)