LearnOpenGL笔记（2）三角形

这是学习LearnOpenGL CN教程的笔记，包括我遇到的问题和我的烂笔头。文章名与网站小节对应。

------------------------------------分割线--------------------------------------------------------------------------------------------

摆张重要的图先，蓝色的是可以编写着色器控制的部分。

 

着色器在C++字符串中的形式

 

"#version 330 core\n"

"layout (location = 0) in vec3 aPos;\n"

"void main()\n"

"{\n"

"gl_Position=vec4(aPos.x,aPos.y,aPos.z,1.0);\n"

"}\n";

绘制流程

//初始化缓冲数组对象
unsigned int VAO;            //顶点数组对象VAO
unsigned int VBO;            //顶点缓冲对象VBO
    //创建VAO
    glGenVertexArrays(1, &VAO);
    //绑定VAO
    glBindVertexArray(VAO);

    //创建VBO
    glGenBuffers(1, &VBO);  //生成vbo和缓冲ID
    //缓冲绑定
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    //将数据传输到当前绑定缓冲
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    //第四个参数：如何管理给定的数据
    //  GL_STATIC_DRAW ：数据不会或几乎不会改变。
    //    GL_DYNAMIC_DRAW：数据会被改变很多。
    //    GL_STREAM_DRAW ：数据每次绘制时都会改变。

    //解析顶点数据,设置顶点属性指针
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);
//创建着色器程序
//顶点着色器
    unsigned int vertexShader;
    vertexShader = glCreateShader(GL_VERTEX_SHADER);
    //附加
    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
    //编译
    glCompileShader(vertexShader);
    //检测失败
    int  success;
    char infoLog[512];
    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
    }
    //片段着色器
    unsigned int fragmentShader;
    fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
    glCompileShader(fragmentShader);

    //片段着色器
    unsigned int fragmentShaderY;
    fragmentShaderY = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShaderY, 1, &fragmentShaderYellowSource, NULL);
    glCompileShader(fragmentShaderY);

    shaderProgram = glCreateProgram();
    //附加
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    //链接
    glLinkProgram(shaderProgram);
    shaderYellowProram = glCreateProgram();
    //附加
    glAttachShader(shaderYellowProram, vertexShader);
    glAttachShader(shaderYellowProram, fragmentShaderY);
    //链接
    glLinkProgram(shaderYellowProram);
    //链接成功后，释放着色器对象
    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);
    glDeleteShader(fragmentShaderY);
//在循环渲染中绘制
    //渲染循环
    while (!glfwWindowShouldClose(window)) {
        //渲染指令
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        glUseProgram(shaderProgram);
        glBindVertexArray(VAO);
        glDrawArrays(GL_TRIANGLES, 0, 3);



        //交换颜色缓冲，绘制显示
        glfwSwapBuffers(window);    
    }