LearningOpenGL学习总结Day03

编写一个Shader类

为了方便日后复习文章都是以笔记形式记录。

由于每次创建shader都要经过繁琐的修改字符串、创建、合并这样的重复工作，因此将其抽象为一个类对象以方便代码的重复利用。

Shader.h

#ifndef SHADER_H
#define SHADER_H
#include 

#include 
#include 
#include 
#include 

class Shader {
public:
	
	Shader(const char* vertexPath, const char* fragmentPath);
	void use();
	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;
private:
	unsigned int m_ID;
};
#endif

Shader.cpp

#include "Shader.h"

Shader::Shader(const char* vertexPath, const char* fragmentPath) {
	std::string vertexCode;
	std::string fragmentCode;
	std::ifstream vShaderFile;
	std::ifstream fShaderFile;
	vShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
	fShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
	try {
		vShaderFile.open(vertexPath);		//打开文件
		fShaderFile.open(fragmentPath);
		std::stringstream vShaderStream, fShaderStream;
		vShaderStream << vShaderFile.rdbuf();		//将文件缓冲区的内容读入字符串流中
		fShaderStream << fShaderFile.rdbuf();
		vertexCode = vShaderStream.str();		//将流转换为字符串
		fragmentCode = fShaderStream.str();
		
	}
	catch(std::ifstream::failure e) {
		std::cout << "ERROR::SHADER::FILE_NOT_SUCCESFULLY_READ" << std::endl;
	}

	const char* vShaderCode = vertexCode.c_str();		//将字符串转换c的字符指针
	const char* fShaderCode = fragmentCode.c_str();

	
	int success;
	char infoLog[512];	

	//vertex shader
	unsigned int vertex = glCreateShader(GL_VERTEX_SHADER);
	glShaderSource(vertex, 1, &vShaderCode, nullptr);
	glCompileShader(vertex);
	glGetShaderiv(vertex, GL_COMPILE_STATUS, &success);		//编译检错
	if (!success)
	{
		glGetShaderInfoLog(vertex, 512, NULL, infoLog);
		std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
	};
	
	//fragment shader
	unsigned int fragment = glCreateShader(GL_FRAGMENT_SHADER);
	glShaderSource(fragment, 1, &fShaderCode, nullptr);
	glCompileShader(fragment);
	glGetShaderiv(fragment, GL_COMPILE_STATUS, &success);	//编译检错
	if (!success)
	{
		glGetShaderInfoLog(fragment, 512, NULL, infoLog);
		std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
	};

	//合并着色器成为着色器程序
	Shader::m_ID = glCreateProgram();
	glAttachShader(m_ID, vertex);
	glAttachShader(m_ID, fragment);
	glLinkProgram(m_ID);
	//检查错误
	glGetProgramiv(m_ID, GL_LINK_STATUS, &success);
	if (!success)
	{
		glGetProgramInfoLog(m_ID, 512, NULL, infoLog);
		std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
	}

	glDeleteShader(vertex);
	glDeleteShader(fragment);
}

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

void Shader::setBool(const std::string& name, bool value) const {
	glUniform1i(glGetUniformLocation(m_ID, name.c_str()), value);
}

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

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