前言：

这一篇说了opengl三角形是怎么画出来的

我们现在把着色器的代码读取，编译，链接，以及检查错误封装成一个类，不然的话 写起来麻烦臃肿
这里就不详细说了 直接上代码了

Shader

shader.h

shader.cpp

#include "Shader.h"




Shader::Shader(const GLchar * vertexPath, const GLchar * 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);
		fShaderFile.open(fragmentPath);

		std::stringstream vShaderStream, fShaderStream;

		vShaderStream << vShaderFile.rdbuf();
		fShaderStream << fShaderFile.rdbuf();

		vShaderFile.close();
		fShaderFile.close();

		vertexCode = vShaderStream.str();
		fragmentCode = fShaderStream.str();

	}
	catch (std::ifstream::failure e)
	{
		std::cerr << "Failed read file" << std::endl;
	}
		
	const char* vShaderCode = vertexCode.c_str();
	const char* fShaderCode = fragmentCode.c_str();

	unsigned int vertex, fragment;

	vertex = glCreateShader(GL_VERTEX_SHADER);
	glShaderSource(vertex, 1, &vShaderCode, NULL);
	glCompileShader(vertex);
	checkComplileError(vertex, "VERTEX");

	fragment = glCreateShader(GL_FRAGMENT_SHADER);
	glShaderSource(fragment, 1, &fShaderCode, NULL);
	glCompileShader(fragment);
	checkComplileError(fragment,"FRAGMENT");

	ID = glCreateProgram();
	glAttachShader(ID, vertex);
	glAttachShader(ID, fragment);
	glLinkProgram(ID);
	checkComplileError(ID, "PROGRAM");

	glDeleteShader(vertex);
	glDeleteShader(fragment);

}

Shader::~Shader()
{
}

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

void Shader::checkComplileError(unsigned int shader, std::string type)
{
	int success;
	char infoLog[1024];

	if (type != "PROGRAM")
	{
		glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
		if (!success)
		{
			glGetShaderInfoLog(shader, 1024, NULL, infoLog);
			std::cerr << "Failed to complie shader:" << infoLog << std::endl;
		}
	}
	else
	{
		glGetProgramiv(shader, GL_LINK_STATUS, &success);
		if (!success)
		{
			glGetProgramInfoLog(shader, 1024, NULL, infoLog);
			std::cout << "Failed to link shader:" << infoLog << std::endl;
		}
	}
}

默认的构造就是传着色器的路径，然后读取代码进行编译链接以及检错，这样就方便多了

这两个就是我创建的着色器的文件，后缀和名字没有限制 想怎么命名都可以

使用shader

// testOpenGl_2shaderClass.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//


#include <glad/glad.h>
#include <iostream>
#include "openGL/include/GLFW/glfw3.h"
#include "Shader.h"

inline void frameBuffer_size_callback(GLFWwindow* w, int width, int height)
{
	glViewport(0, 0, width, height);

}

int main()
{
    std::cout << "Hello opengl!\n"; 

	glfwInit();
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

	GLFWwindow* window = glfwCreateWindow(800, 600, "learnOpengl", NULL, NULL);
	if (window == NULL)
	{
		std::cout << "opengl window failed" << std::endl;
		glfwTerminate();
		return -1;
	}
	glfwMakeContextCurrent(window);
	glfwSetFramebufferSizeCallback(window, frameBuffer_size_callback);

	/*glad:load all opengl function pointer */
	if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
	{
		std::cout << "failed to initalize glad" << std::endl;
		return -1;
	}

	//读取 编译 连接 shader
	Shader m_shader("vertexShader.vs","fragmentShader.fs");

	float vertices[] =
	{
		//位置			//颜色
		0.5f,-0.5f,0.0f, 1.0f,0.5f,1.0f,
		-0.5f,-0.5f,0.0f, 0.0f,1.0f,0.0f,
		0.0f,0.5f,0.0f,0.0f,0.0f,1.0f
	};

	unsigned int VBO, VAO;
	//创建vertex array 绑定设置 vertex buffer 配置 verter 属性
	glGenVertexArrays(1, &VAO);
	glGenBuffers(1, &VBO);
	glBindVertexArray(VAO);
	glBindBuffer(GL_ARRAY_BUFFER,VBO);
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
	glEnableVertexAttribArray(0);

	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float)));
	glEnableVertexAttribArray(1);


	while (!glfwWindowShouldClose(window))
	{
		glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
		glClear(GL_COLOR_BUFFER_BIT);

		m_shader.use();
		glBindVertexArray(VAO);
		glDrawArrays(GL_TRIANGLES, 0, 3);

		glfwSwapBuffers(window);
		glfwPollEvents();

	}
	glDeleteVertexArrays(1, &VAO);
	glDeleteBuffers(1, &VBO);

	glfwTerminate();

	system("pause");
}