头文件 .h

#pragma once

#include <glad/glad.h> //包含glad来获取所有必须的 OpenGL头文件

#include <string>
#include <fstream>
#include <sstream>
#include <iostream>

class Shader
{
public:
 unsigned int ID;

public:
 Shader(const GLchar* vertexPath, const GLchar* fragmentPath);

 void use();//激活Shader

 //uniform工具函数
 void setBool(const std::string& name, bool value) const;
 void setInt(const std::string& name, int value) const;
 void setFloat(const std::string& name, float value) const;
};

源文件 .cpp

#include "Shader.h"

using namespace std;

Shader::Shader(const GLchar* vertexPath, const GLchar* fragmentPath)
{
 //从文件中读取Shader代码，即GLSL代码
 string vertexCode;
 string fragmentCode;
 ifstream vShaderFile;
 ifstream fShaderFile;

 //保证ifstream对象可以抛出异常
 vShaderFile.exceptions(ifstream::failbit | ifstream::badbit);
 fShaderFile.exceptions(ifstream::failbit | ifstream::badbit);
 try
 {
     //打开文件流
     vShaderFile.open(vertexPath);
     fShaderFile.open(fragmentPath);

     //将文件缓冲内容读取到流中
     stringstream vShaderStream, fShaderStream;
     vShaderStream << vShaderFile.rdbuf();
     fShaderStream << fShaderFile.rdbuf();

     //关闭文件流
     vShaderFile.close();
     fShaderFile.close();

     //将流中的数据转换到string变量中
     vertexCode = vShaderStream.str();
     fragmentCode = fShaderStream.str();
 }
 catch(ifstream::failure e)
 {
     cout << "ERROR::SHADER::FILE_NOT_SUCCESSFULLY_READ" << endl;
 }
 const char* vShaderCode = vertexCode.c_str();
 const char* fShaderCode = fragmentCode.c_str();

 //编译Shader
 unsigned int vertex, fragment;
 int success;
 char infoLog[512];

 //vertex shader
 vertex = glCreateShader(GL_VERTEX_SHADER);
 glShaderSource(vertex, 1, &vShaderCode, NULL);
 glCompileShader(vertex);
 glGetShaderiv(vertex, GL_COMPILE_STATUS, &success);
 if (!success)
 {
     glGetShaderInfoLog(vertex, 512, NULL, infoLog);
     cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << endl;
 }

 //fragment shader
 fragment = glCreateShader(GL_FRAGMENT_SHADER);
 glShaderSource(fragment, 1, &fShaderCode, NULL);
 glCompileShader(fragment);
 glGetShaderiv(fragment, GL_COMPILE_STATUS, &success);
 if (!success)
 {
     glGetShaderInfoLog(fragment, 512, NULL, infoLog);
     cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << endl;
 }

 //shader program
 ID = glCreateProgram();
 glAttachShader(ID, vertex);
 glAttachShader(ID, fragment);
 glLinkProgram(ID);
 glGetProgramiv(ID, GL_LINK_STATUS, &success);
 if (!success)
 {
     glGetProgramInfoLog(ID, 512, NULL, infoLog);
     cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << endl;
 }

 //free(delete) shader
 glDeleteShader(vertex);
 glDeleteShader(fragment);
}

void Shader::use()
{
 glUseProgram(ID);
}

//设定Shader中传入的uniform变量
void Shader::setBool(const std::string& name, bool value) const
{
 glUniform1i(glGetUniformLocation(ID, name.c_str()), (int)value);
}

void Shader::setInt(const std::string& name, int value) const
{
 glUniform1i(glGetUniformLocation(ID, name.c_str()), value);
}

void Shader::setFloat(const std::string& name, float value) const
{
 glUniform1f(glGetUniformLocation(ID, name.c_str()), value);
}

简要解释

• glCreateShader：创建OpenGL可用的shader对象，参数用于指定shader的类型
• glShaderSource：将shader的代码（字符数组）传入shader对象中，第一个参数是shader对象，第二个参数是传递的源码字符数组的数量，第三个参数是shader源码字符数组，第四个参数设为NULL，暂且不做追究
• glCompileShader：对shader对象进行编译