MAC OS下使用Xcode进行GLSL编程的配置过程

整理自之前使用的163博客原创文章。

GLSL项目中需要使用GLEW库，因此先要安装GLEW库和在Xcode中配置GLEW。要使GLEW在Xcode中被正确链接，又需要通过MacPorts来安装GLEW。下文以MacPorts-->GLEW-->GLSL的顺序来阐述。
环境：系统 OS X 10.9.2 (13C64)，工具 Xcode 5.1，图形卡 Intel Iris 1024 MB

1 MacPorts安装

MacPorts是与apt-get和yum类似的软件管理包，下载与系统对应的安装包后进行安装（安装过程中会联网进行更新，导致安装过程很久，建议断网安装）。安装之后打开终端运行

$ sudo port -v selfupdate

进行更新。如果更新时在如下状态下卡的时间很久，

--->  Updating the ports tree
Synchronizing local ports tree from rsync://rsync.macports.org/release/tarballs/ports.tar
receiving file list ... done
ports.tar

使用control+z终止更新，终端输入

$ sudo vim /opt/local/etc/macports/sources.conf

打开配置文件，更改最后一行的默认下载地址（参考“解决安装macports，不能更新的问题”，参考下载网址列表），如可修改为韩国镜像：

#rsync://rsync.macports.org/release/tarballs/ports.tar [default]
#http://www.macports.org/files/ports.tar.gz [default]
rsync://cjj.kr.rsync.macports.org/macports/release/tarballs/ports.tar

改好后wq保存退出，再次运行

$ sudo port -v selfupdate

进行更新，更新成功后会显示如下信息：

--->  MacPorts base is already the latest version
The ports tree has been updated. To upgrade your installed ports, you should run  port upgrade outdated

安装过程中遇到其它问题请戳：

Mac OS X Lion安装MacPorts（让你在Mac的Shell下更加游刃有余）

Mac中MacPorts安装和使用

Mac OS X中MacPorts安装和使用

2 GLEW库安装

glew库主要有如下三种安装方式：1）在Xcode中直接导入framework（下载地址）；2）编译glew源代码进行安装（参考“Installing GLEW in Mac OS X (Leopard)”）；3）通过MacPorts进行安装。

实测了三种方式，均可成功安装glew库，但前两种方式在Xcode中链接不成功，本文通过MacPorts进行安装（参考“GLEW: Apple Mach-O Linker (Id) Error”）。

终端输入

$ sudo port install glew

进行安装，安装成功后显示：

--->  Installing glew @1.10.0_0
--->  Activating glew @1.10.0_0
--->  Cleaning glew
--->  Updating database of binaries: 100.0%
--->  Scanning binaries for linking errors: 100.0%
--->  No broken files found.

安装过程中遇到其它问题请戳

cannot link glew under xcode4, macosx lion

3 Xcode中GLSL的配置

Mac系统中已内置openGL、GLUT和GLSL，无需安装。

启动Xcode，新建Cocoa Application工程，删除“TriangleAppDelegate.*”文件、“*main.m”文件和“MainMenu.xib”文件。右键单击"Supporting Files"添加新文件，选择"C++ File"。添加后，删除对应的头文件。右键单击"Frameworks"，添加"OpenGL.framework"和"GLUT.framework"（参考“MAC OS X And Win7 vs2010 搭建OpenGL”，参考“在Xcode中使用GLUT开发OpenGL应用程序”）。

下面是添加对GLEW库的链接，在build setting中添加如下参数即可：

other linker flags: -lGLEW
header search paths: /opt/local/include/
library search paths: /opt/local/lib/

4 Hello World

在supporting files下添加basic.vert：

 void main(){
     gl_Position = ftransform();
 }

在supporting files下添加basic.frag：

 void main() {
     gl_FragColor = vec4(0.4,0.4,0.8,1.0);
 }

在supporting files下添加textfile.h：

 #ifndef macGL_textfile_h
 #define macGL_textfile_h

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>

 char *textFileRead(const char *fn);
 int textFileWrite(char *fn, char *s);
 unsigned char *readDataFromFile(char *fn);
 #endif

在supporting files下添加textfile.cpp：

 #include "textfile.h"

 unsigned char * readDataFromFile(char *fn){
     FILE *fp;
     unsigned char *content = NULL;
     int count=;

     if (fn != NULL) {
         fp = fopen(fn,"rb");
         if (fp != NULL) {
             fseek(fp, , SEEK_END);
             count = ftell(fp);
             rewind(fp);
             if (count > ) {
                 content = (unsigned char *)malloc(sizeof(unsigned char) * (count+));
                 count = fread(content,sizeof(unsigned char),count,fp);
                 content[count] = '\0';
             }
             fclose(fp);
         }
     }

     return content;
 }

 char *textFileRead(const char *fn) {
     FILE *fp;
     char *content = NULL;
     int count=;

     if (fn != NULL) {
             fp = fopen(fn,"rt");
             if (fp != NULL) {
                 fseek(fp, , SEEK_END);
                 count = ftell(fp);
                 rewind(fp);
                 if (count > ) {
                     content = (char *)malloc(sizeof(char) * (count+));
                     count = fread(content,sizeof(char),count,fp);
                     content[count] = '\0';
                 }
                 fclose(fp);
             }
         }
     return content;
 }

 int textFileWrite(char *fn, char *s) {
     FILE *fp;
     int status  = ;
     if (fn != NULL){
         fp = fopen(fn,"w");
         if (fp != NULL) {
             if (fwrite(s,sizeof(char),strlen(s),fp) == strlen(s))
                 status = ;
             fclose(fp);
         }
     }
     return(status);
 }

在supporting files下添加GLSLTest.cpp。其中display函数中的glutWireTeapot()是glut内置的画茶壶的函数。注意MAC下特有的glBindVertexArrayAPPLE，glBindVertexArrayAPPLE，glGenVertexArraysAPPLE：

 //#pragma comment(lib,"libGLEW.a")

 #include <GL/glew.h>

 #include "textfile.h"

 #include <glut/glut.h>
 #include <iostream>
 using namespace std;

 GLuint vShader,fShader;//顶点着色器对象

 //顶点位置数组
 float positionData[] = {
     -0.8f, -0.8f, 0.0f,
     0.8f, -0.8f, 0.0f,
     0.0f,  0.8f, 0.0f };
 //颜色数组
 float colorData[] = {
     1.0f, 0.0f, 0.0f,
     0.0f, 1.0f, 0.0f,
     0.0f, 0.0f, 1.0f };

 GLuint vaoHandle;//vertex array object

 void initShader(const char *VShaderFile,const char *FShaderFile)
 {
     //1、查看GLSL和OpenGL的版本
     const GLubyte *renderer = glGetString( GL_RENDERER );
     const GLubyte *vendor = glGetString( GL_VENDOR );
     const GLubyte *version = glGetString( GL_VERSION );
     const GLubyte *glslVersion =
     glGetString( GL_SHADING_LANGUAGE_VERSION );
     GLint major, minor;
     glGetIntegerv(GL_MAJOR_VERSION, &major);
     glGetIntegerv(GL_MINOR_VERSION, &minor);
     cout << "GL Vendor    :" << vendor << endl;
     cout << "GL Renderer  : " << renderer << endl;
     cout << "GL Version (string)  : " << version << endl;
     cout << "GL Version (integer) : " << major << "." << minor << endl;
     cout << "GLSL Version : " << glslVersion << endl;

     //2、编译着色器
     //创建着色器对象：顶点着色器
     vShader = glCreateShader(GL_VERTEX_SHADER);
     //错误检测
     if ( == vShader)
     {
         cerr << "ERROR : Create vertex shader failed" << endl;
         exit();
     }

     //把着色器源代码和着色器对象相关联
     const GLchar *vShaderCode = textFileRead(VShaderFile);
     const GLchar *vCodeArray[] = {vShaderCode};
     glShaderSource(vShader,,vCodeArray,NULL);

     //编译着色器对象
     glCompileShader(vShader);

     //检查编译是否成功
     GLint compileResult;
     glGetShaderiv(vShader,GL_COMPILE_STATUS,&compileResult);
     if (GL_FALSE == compileResult)
     {
         GLint logLen;
         //得到编译日志长度
         glGetShaderiv(vShader,GL_INFO_LOG_LENGTH,&logLen);
         if (logLen > )
         {
             char *log = (char *)malloc(logLen);
             GLsizei written;
             //得到日志信息并输出
             glGetShaderInfoLog(vShader,logLen,&written,log);
             cerr << "vertex shader compile log : " << endl;
             cerr << log << endl;
             free(log);//释放空间
         }
     }

     //创建着色器对象：片断着色器
     fShader = glCreateShader(GL_FRAGMENT_SHADER);
     //错误检测
     if ( == fShader)
     {
         cerr << "ERROR : Create fragment shader failed" << endl;
         exit();
     }

     //把着色器源代码和着色器对象相关联
     const GLchar *fShaderCode = textFileRead(FShaderFile);
     const GLchar *fCodeArray[] = {fShaderCode};
     glShaderSource(fShader,,fCodeArray,NULL);

     //编译着色器对象
     glCompileShader(fShader);

     //检查编译是否成功
     glGetShaderiv(fShader,GL_COMPILE_STATUS,&compileResult);
     if (GL_FALSE == compileResult)
     {
         GLint logLen;
         //得到编译日志长度
         glGetShaderiv(fShader,GL_INFO_LOG_LENGTH,&logLen);
         if (logLen > )
         {
             char *log = (char *)malloc(logLen);
             GLsizei written;
             //得到日志信息并输出
             glGetShaderInfoLog(fShader,logLen,&written,log);
             cerr << "fragment shader compile log : " << endl;
             cerr << log << endl;
             free(log);//释放空间
         }
     }

     //3、链接着色器对象
     //创建着色器程序
     GLuint programHandle = glCreateProgram();
     if (!programHandle)
     {
         cerr << "ERROR : create program failed" << endl;
         exit();
     }
     //将着色器程序链接到所创建的程序中
     glAttachShader(programHandle,vShader);
     glAttachShader(programHandle,fShader);
     //将这些对象链接成一个可执行程序
     glLinkProgram(programHandle);
     //查询链接的结果
     GLint linkStatus;
     glGetProgramiv(programHandle,GL_LINK_STATUS,&linkStatus);
     if (GL_FALSE == linkStatus)
     {
         cerr << "ERROR : link shader program failed" << endl;
         GLint logLen;
         glGetProgramiv(programHandle,GL_INFO_LOG_LENGTH,
                        &logLen);
         if (logLen > )
         {
             char *log = (char *)malloc(logLen);
             GLsizei written;
             glGetProgramInfoLog(programHandle,logLen,
                                 &written,log);
             cerr << "Program log : " << endl;
             cerr << log << endl;
         }
     }
     else//链接成功，在OpenGL管线中使用渲染程序
     {
         glUseProgram(programHandle);
     }
 }

 void initVBO()
 {
     // Create and populate the buffer objects
     GLuint vboHandles[];
     glGenBuffers(, vboHandles);
     GLuint positionBufferHandle = vboHandles[];
     GLuint colorBufferHandle = vboHandles[];

     //绑定VBO以供使用
     glBindBuffer(GL_ARRAY_BUFFER,positionBufferHandle);
     //加载数据到VBO
     glBufferData(GL_ARRAY_BUFFER, * sizeof(float),
                  positionData,GL_STATIC_DRAW);

     //绑定VBO以供使用
     glBindBuffer(GL_ARRAY_BUFFER,colorBufferHandle);
     //加载数据到VBO
     glBufferData(GL_ARRAY_BUFFER, * sizeof(float),
                  colorData,GL_STATIC_DRAW);

     glGenVertexArraysAPPLE(,&vaoHandle);
     glBindVertexArrayAPPLE(vaoHandle);

     glEnableVertexAttribArray();//顶点坐标
     glEnableVertexAttribArray();//顶点颜色

     //调用glVertexAttribPointer之前需要进行绑定操作
     glBindBuffer(GL_ARRAY_BUFFER, positionBufferHandle);
     glVertexAttribPointer( , , GL_FLOAT, GL_FALSE, , (GLubyte *)NULL );

     glBindBuffer(GL_ARRAY_BUFFER, colorBufferHandle);
     glVertexAttribPointer( , , GL_FLOAT, GL_FALSE, , (GLubyte *)NULL );
 }

 void init()
 {
     //初始化glew扩展库
     GLenum err = glewInit();
     if( GLEW_OK != err )
     {
         cout <<"Error initializing GLEW: " << glewGetErrorString(err) << endl;
     }

     initShader("basic.vert","basic.frag");

     initVBO();

     glClearColor(0.0,0.0,0.0,0.0);
     //glShadeModel(GL_SMOOTH);

 }

 void display()
 {
     glClear(GL_COLOR_BUFFER_BIT);

     ////绘制一个三角形(使用普通方法)
     //glBegin(GL_TRIANGLES);
     //glColor3f(0.0f,1.0f,0.0f);
     //glVertex3f(0.0f,1.0f,0.0f);

     //glColor3f(0.0f,1.0f,0.0f);
     //glVertex3f(-1.0f,-1.0f,0.0f);

     //glColor3f(0.0f,0.0f,1.0f);
     //glVertex3f(1.0f,-1.0f,0.0f);
     //glEnd();

     //使用VAO、VBO绘制
     glBindVertexArrayAPPLE(vaoHandle);
     //glDrawArrays(GL_TRIANGLES,0,3);
     glutWireTeapot(0.5);
     GLint tiz = glGetUniformLocation(vaoHandle, "iz");
     glUniform1iARB(tiz, );
     glBindVertexArrayAPPLE();
     glutWireTeapot(1.0);

     glutSwapBuffers();
 }

 void keyboard(unsigned char key,int x,int y)
 {
     switch(key)
     {
         case :
             glDeleteShader(vShader);
             glUseProgram();
             break;
     }
 }

 int main(int argc,char** argv)
 {
     glutInit(&argc,argv);
     glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
     glutInitWindowSize(,);
     glutInitWindowPosition(,);
     glutCreateWindow("GLSL Test : Draw a triangle");
     init();
     glutDisplayFunc(display);
     glutKeyboardFunc(keyboard);

     glutMainLoop();
     return ;
 }

运行成功后的效果图：

其它参考网址：

【GLSL教程】（四）shder的简单示例

GLSL Tutorial

How to link glew in xcode

【GLSL教程】（二）在OpenGL中使用GLSL

GLSL.Refract & Reflect & Diffraction