shader-增加shader类

shader类
1.读取shader文件，从文件中读取最终获取字符数组

2.创建 编译 链接 使用着色器

3.shader运行相关错误打印方法

#pragma once
#include 

class Shader
{
public:
	Shader(const char* vertextPath, const char* fragmentPath);
	std::string vertexString;
	std::string fragmentStrimg;
	const char* vertexSource;
	const char* fragmentSource;

	unsigned int ID; //shader program id

	void Use();
private:
	void checkComplieErrors(unsigned int ID, std::string type);
};

#include "Shader.h"
#include 
#include 
#include 
#include 
#include 
using namespace std;

Shader::Shader(const char* vertextPath,const char* fragmentPath )
{
	ifstream vertexFile;
	ifstream fragmentFile;

	vertexFile.open(vertextPath);
	fragmentFile.open(fragmentPath);
	stringstream vertexSStream;
	stringstream fragmentSStream;

	vertexFile.exceptions(ifstream::failbit || ifstream::badbit);
	fragmentFile.exceptions(ifstream::failbit || ifstream::badbit);
	try
	{
		if (!vertexFile.is_open() || !fragmentFile.is_open())
		{
			throw exception("open file error");
		}
		vertexSStream << vertexFile.rdbuf();
		fragmentSStream << fragmentFile.rdbuf();

		vertexString = vertexSStream.str();
		fragmentStrimg = fragmentSStream.str();

		vertexSource = vertexString.c_str();
		fragmentSource = fragmentStrimg.c_str();

		unsigned vertex, frag;
		vertex = glCreateShader(GL_VERTEX_SHADER);
		glShaderSource(vertex, 1, &vertexSource, NULL);
		glCompileShader(vertex);
		checkComplieErrors(vertex, "VERTEX");

		frag = glCreateShader(GL_FRAGMENT_SHADER);
		glShaderSource(frag, 1, &fragmentSource, NULL);
		glCompileShader(frag);
		checkComplieErrors(frag, "FRAGMENT");

		ID = glCreateProgram();
		glAttachShader(ID, vertex);
		glAttachShader(ID, frag);

		glLinkProgram(ID);
		checkComplieErrors(ID, "PROGRAM");
		glDeleteShader(vertex);
		glDeleteShader(frag);
	}
	catch (const std::exception& ex)
	{
		printf(ex.what());
	}
}

void Shader::Use()
{
	glUseProgram(ID);
}
void Shader::checkComplieErrors(unsigned int ID, std::string type)
{
	int success;
	char infoLog[512];

	if (type != "PROGRAM")
	{
		glGetShaderInfoLog(ID, 512, NULL, infoLog);
		cout << "shader complie error:" << infoLog << endl;
	}
	else
	{
		glGetProgramiv(ID, GL_LINK_STATUS, &success);
		if (!success)
		{
			glGetProgramInfoLog(ID, 512, NULL, infoLog);
			cout << "shader link error:" << infoLog << endl;
		}
		
	}
}

#include 
using namespace std;
#include 
#include 
#include "Shader.h"

void processInput(GLFWwindow *window);

float vertices[] = {
		 0.5f,  0.5f, 0.0f, 1.0f,0,0, // top right
		 0.5f, -0.5f, 0.0f,0,1,0, // bottom right
		-0.5f, -0.5f, 0.0f, 0,0,1, // bottom left
		-0.5f,  0.5f, 0.0f,1.0f,0.0f,1.0f   // top left 
};
unsigned int indices[] = {  // note that we start from 0!
	0, 1, 3,  // first Triangle
	1, 2, 3   // second Triangle
};

int main()
{
	glfwInit();  //初始化glfw库
	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, "OpenGL Window", NULL, NULL);

	if (window == NULL)
	{
		cout << "init window error" << endl;
		glfwTerminate();
		return -1;
	}
	glfwMakeContextCurrent(window);


	//init glew
	//glewExperimental = GL_TRUE; //使用有问题 注释掉
	if (glewInit() != GLEW_OK)
	{
		cout << "glewInit error" << endl;
		glfwTerminate();
		return -1;
	}

	glViewport(0, 0, 800, 600);
	//glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
	//创建VAO并且绑定
	unsigned int VAO;
	glGenVertexArrays(1, &VAO);
	glBindVertexArray(VAO);

	//创建VBO
	unsigned int VBO;
	glGenBuffers(1, &VBO);
	glBindBuffer(GL_ARRAY_BUFFER, VBO);

	//数据写入内存
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

	//创建EBO
	unsigned int EBO;
	glGenBuffers(1, &EBO);
	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);

	//数据写入内存
	glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

	//顶点位置属性
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
	glEnableVertexAttribArray(0);

	//顶点颜色属性
	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*) (3 * sizeof(float)));
	glEnableVertexAttribArray(1);

	while (!glfwWindowShouldClose(window))
	{
		glfwPollEvents();

		glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
		glClear(GL_COLOR_BUFFER_BIT);

		glBindVertexArray(VAO);
		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);

		//float timeValue = glfwGetTime();
		//float greenValue = (sin(timeValue) / 2.0f) + 0.5f;
		Shader shader = Shader("vertexSource.txt", "fragSource.txt");
		shader.Use();
		//glDrawArrays(GL_TRIANGLES, 0, 3);
		glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
		glfwSwapBuffers(window); //双缓存防止闪烁

		processInput(window);
	}
	return 0;
}

void processInput(GLFWwindow *window)
{
	if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
	{
		glfwSetWindowShouldClose(window, true);
	}
}