好吧，我们直接把glsl用字符串写进程序里的时代结束了……之前我们的glsl代码实际上是这个样子的：
之后我们的代码将会是这个样子的！：
是不是很诱人！！！那么我们就开始吧！
Shader类：
首先：你要新建一个C++类：
复制下面这些代码：（全是原教程的代码，我基本上没改，……也没看…………）
头文件（.h文件）：
#pragma once
#include <glad/glad.h> // include glad to get all the required OpenGL headers
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>
class Shader
{
public:
// the program ID
unsigned int ID;
// constructor reads and builds the shader
Shader(const GLchar* vertexPath, const GLchar* fragmentPath);
// use/activate the shader
//void use();
// utility uniform functions
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;
};
.cpp文件：
#include "Shader.h"
Shader::Shader(const char* vertexPath, const char* fragmentPath)
{
// 1. retrieve the vertex/fragment source code from filePath
std::string vertexCode;
std::string fragmentCode;
std::ifstream vShaderFile;
std::ifstream fShaderFile;
// ensure ifstream objects can throw exceptions:
vShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
fShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
try
{
// open files
vShaderFile.open(vertexPath);
fShaderFile.open(fragmentPath);
std::stringstream vShaderStream, fShaderStream;
// read file's buffer contents into streams
vShaderStream << vShaderFile.rdbuf();
fShaderStream << fShaderFile.rdbuf();
// close file handlers
vShaderFile.close();
fShaderFile.close();
// convert stream into string
vertexCode = vShaderStream.str();
fragmentCode = fShaderStream.str();
}
catch (std::ifstream::failure e)
{
std::cout << "ERROR::SHADER::FILE_NOT_SUCCESFULLY_READ" << std::endl;
}
const char* vShaderCode = vertexCode.c_str();
const char* fShaderCode = fragmentCode.c_str();
// 2. compile shaders
unsigned int vertex, fragment;
int success;
char infoLog[512];
// vertex Shader
vertex = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertex, 1, &vShaderCode, NULL);
glCompileShader(vertex);
// print compile errors if any
glGetShaderiv(vertex, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(vertex, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
};
// similiar for Fragment Shader
fragment = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragment, 1, &fShaderCode, NULL);
glCompileShader(fragment);
// print compile errors if any
glGetShaderiv(fragment, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(fragment, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
};
// shader Program
ID = glCreateProgram();
glAttachShader(ID, vertex);
glAttachShader(ID, fragment);
glLinkProgram(ID);
// print linking errors if any
glGetProgramiv(ID, GL_LINK_STATUS, &success);
if (!success)
{
glGetProgramInfoLog(ID, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
}
// delete the shaders as they're linked into our program now and no longer necessery
glDeleteShader(vertex);
glDeleteShader(fragment);
}
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);
}
使用实例：
首先你需要把Shader.h加到你main.cpp（就是有main函数的.cpp文件）里：
#include "Shader.h"
然后建立一个Shader对象：
Shader myShaderProg("vtx.vs", "frag.fs");
两个初始参数分别是：vertexshader，fragmentshader的路径。我这边就把他们与main.cpp放在了一起。
然后是编辑这两个文件，我用的是vscood，因为里面有好用的高亮插件：
vtx.vs：
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 myC_a;
out vec3 myC;
void main()
{
gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
myC = myC_a;
}
frag.fs：
#version 330 core
in vec3 myC;
out vec4 FragColor;
void main()
{
FragColor = vec4(myC,1.0f);
}
高亮插件：
最后是main.cpp（我的叫test.cpp）:
// 1.头文件：
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <iostream>
#include "Shader.h"
// 5.OpenGL与窗口（main之前）：
void CBK_framebuffer_size(GLFWwindow* window, int w, int h)
{
glViewport(0, 0, w, h);
}
void processInput(GLFWwindow* window)
{
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
glfwSetWindowShouldClose(window, true);
}
int main()
{
// 2.在创建窗口之前……：
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
// 3.创建窗口：
GLFWwindow* window = glfwCreateWindow(800, 600, "LearnOpenGL", NULL, NULL);
if (window == NULL)
{
std::cout << "Failed to create GLFW window" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
// 4.在OpenGL之前……：
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
std::cout << "Failed to initialize GLAD" << std::endl;
return -1;
}
// 5.OpenGL与窗口：
glViewport(0, 0, 800, 600);
glfwSetFramebufferSizeCallback(window, CBK_framebuffer_size);
// OpenGL的配置：
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);//设置背景色
// 绘图需要用的数据：
float vertices[] = {
// positions // colors
0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f, // bottom right
-0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, // bottom left
0.0f, 0.5f, 0.0f, 0.0f, 0.0f, 1.0f // top
};
GLuint VBO;
glGenBuffers(1, &VBO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
GLuint VAO;
glGenVertexArrays(1, &VAO);
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
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);
glBindVertexArray(0);
Shader myShaderProg("vtx.vs", "frag.fs");
// 6.Render Loop：
while (!glfwWindowShouldClose(window))
{
processInput(window);
glClear(GL_COLOR_BUFFER_BIT);//绘制背景色
// 这下面就可以写绘图的代码了
glUseProgram(myShaderProg.ID);
glBindVertexArray(VAO);
glDrawArrays(GL_TRIANGLES,0,3);
// 这上面是绘图的代码
glfwSwapBuffers(window);
glfwPollEvents();
}
// 7.程序结束之前：
glfwTerminate();
return 0;
}
运行结果如下：
