Openglで三角形を描き、shaderで色を変えます

/*
glew.h           
typedef unsigned int GLenum;
typedef unsigned int GLbitfield;
typedef unsigned int GLuint;
typedef int GLint;
typedef int GLsizei;
typedef unsigned char GLboolean;
typedef signed char GLbyte;
typedef short GLshort;
typedef unsigned char GLubyte;
typedef unsigned short GLushort;
typedef unsigned long GLulong;
typedef float GLfloat;
typedef float GLclampf;
typedef double GLdouble;
typedef double GLclampd;
typedef void GLvoid;
 */

#include 

#define GLEW_STATIC

#include 
#include 

void key_callback(GLFWwindow *windows, int key, int scancode, int actin, int mode);

const GLuint WIDTH = 800, HEIGHT = 600;

//Shaders
const GLchar *vertexShaderSource = "#version 330 core
"
        "  
"
        "layout (location = 0) in vec3 position;
"
        "
"
        "void main()
"
        "{
"
        "    gl_Position = vec4(position.x, position.y, position.z, 1.0);
"
        "}";


const GLchar *fragmentShaderSource = "#version 330 core
"
        "out vec4 color;
"
        "void main()
"
        "{
"
        "color = vec4(1.0f, 0.5f, 0.2f, 1.0f);
"
        "}
\0";
const GLchar* fragmentShaderSource2 = "#version 330 core
"
        "out vec4 color;
"
        "void main()
"
        "{
"
        "color = vec4(1.0f, 1.0f, 0.0f, 1.0f); // The color yellow 
"
        "}
\0";

int main() {
    glfwInit();

    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);

    //     GLFWwindow      ，     ，       ，        ，            ，
    //     null，    nullptr   c++11    
    GLFWwindow *window = glfwCreateWindow(WIDTH, HEIGHT, "OpenGL", nullptr, nullptr);
    glfwMakeContextCurrent(window);  //  GLFW           

    glewExperimental = GL_TRUE;//     true    glew           opengl   

    glewInit();//   glew

    //  viewport             dpi          
    int width, height;
    glfwGetFramebufferSize(window, &width, &height);
    glViewport(0, 0, width, height);

    //   vertexShader,glShaderSource   shader           shader  ，      ID
    //glCompileShader    .
    GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
    glCompileShader(vertexShader);

    //    Shader      
    GLint success;
    GLchar infoLog[512];
    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
    if (!success) {
        glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED
" << infoLog << std::endl;
    }

    // Fragment shader ，  
    GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
    glCompileShader(fragmentShader);
    //       
    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
    if (!success) {
        glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED
" << infoLog << std::endl;
    }

    // Fragment shader ，  
    GLuint fragmentShader2 = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader2, 1, &fragmentShaderSource2, NULL);
    glCompileShader(fragmentShader2);
    // Check for compile time errors
    glGetShaderiv(fragmentShader2, GL_COMPILE_STATUS, &success);
    if (!success) {
        glGetShaderInfoLog(fragmentShader2, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED
" << infoLog << std::endl;
    }

    // Link shaders
    GLuint shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);

    //   link     
    glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
    if (!success) {
        glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED
" << infoLog << std::endl;
    }

    GLuint shaderProgram2 = glCreateProgram();
    glAttachShader(shaderProgram2, vertexShader);
    glAttachShader(shaderProgram2, fragmentShader2);
    glLinkProgram(shaderProgram2);

    //   link     
    glGetProgramiv(shaderProgram2, GL_LINK_STATUS, &success);
    if (!success) {
        glGetProgramInfoLog(shaderProgram2, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED
" << infoLog << std::endl;
    }

    //      Shader
    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);
    glDeleteShader(fragmentShader2);

    //     
    GLfloat vertices1[] = {
            0.0f, -0.5f, 0.0f,
            1.0f, -0.5f, 0.0f,
            0.5f, 0.5f, 0.0f,
    };

    GLfloat vertices2[] = {
            0.0f, -0.5f, 0.0f,
            -1.0, -0.5f, 0.0f,
            -0.5f, 0.5f, 0.0f
    };
    GLuint VBOs[2], VAOs[2];
    //      
    glGenVertexArrays(1, &VAOs[0]);
    glGenBuffers(1, &VBOs[0]);

    glBindVertexArray(VAOs[0]);

    glBindBuffer(GL_ARRAY_BUFFER, VBOs[0]); //   VBO
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices1), vertices1, GL_STATIC_DRAW);//           ,
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat),
                          (GLvoid *) 0);//         ，       location，            
    glEnableVertexAttribArray(0); //  location   0         ，      

    glBindBuffer(GL_ARRAY_BUFFER, 0);//   VBO
    glBindVertexArray(0);//   VAO

    //      
    glGenVertexArrays(1, &VAOs[1]);
    glGenBuffers(1, &VBOs[1]);

    glBindVertexArray(VAOs[1]);

    glBindBuffer(GL_ARRAY_BUFFER, VBOs[1]); //   VBO
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices2), vertices2, GL_STATIC_DRAW);//           ,
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat),
                          (GLvoid *) 0);//         ，       location，            
    glEnableVertexAttribArray(0); //  location   0         ，      

    glBindBuffer(GL_ARRAY_BUFFER, 0);//   VBO
    glBindVertexArray(0);//   VAO
    //    
    while (!glfwWindowShouldClose(window)) {
        //         
        glfwPollEvents();

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

        //  shaderProgram
        glUseProgram(shaderProgram);
        glBindVertexArray(VAOs[0]);
        //     
        glDrawArrays(GL_TRIANGLES, 0, 3);

        glUseProgram(shaderProgram2);
        glBindVertexArray(VAOs[1]);
        //     
        glDrawArrays(GL_TRIANGLES, 0, 3);
        glBindVertexArray(0);
        //    
        glfwSwapBuffers(window);

    }

    glDeleteVertexArrays(2, VAOs);
    glDeleteBuffers(2, VBOs);

    glfwTerminate();
    return 0;
}

void key_callback(GLFWwindow *window, int key, int scancode, int action, int mode) {
    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
        glfwSetWindowShouldClose(window, GL_TRUE);
}

   learnopengl