Visual Studio 2019 和 qt 5.15.1 下 opengl 的运用 - Getting-started - 03 - Shaders

学习learnopengl文章对应地址:https://learnopengl-cn.github.io/01%20Getting%20started/05%20Shaders/

Visual Studio c++ 文件和 qt 项目链接（在一个包内）：https://download.youkuaiyun.com/download/zzjzmdx/16634484

由于learnopengl此章节有三个代码示例，所以VS、qt版本分别给了三个文件和三个项目，都在同一个包内。

展示图：

三角形颜色渐变

混色

Visual Studio 2019

代码如下:

Shaders-01.cpp

#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <iostream>

void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow* window);

float vertices[] = {
    -0.5f, -0.5f, 0.0f,
     0.5f, -0.5f, 0.0f,
     0.0f,  0.5f, 0.0f
};

//uniform用法
const char* vertexShaderSource = "#version 330 core \n"
"layout (location = 0); \n"
"in vec3 aPos; \n"       
"void main() \n"
"{ \n"
"    gl_Position = vec4(aPos.x+0.3,aPos.y+0.3,aPos.z+0.3,1.0); \n" 
"} \n";

const char* fragmentShaderSource = "#version 330 core\n"
"out vec4 FragColor; \n"
"uniform  vec4 ourColor; \n"
"void main() \n"
"{ \n"
"    FragColor = ourColor; \n"
"} \n";
//uniform用法

int main()
{
    //init
    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, "DrawRectangle02-VAOandVBO", NULL, NULL);
    if (window == NULL)
    {
        std::cout << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);
    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
        std::cout << "Failed to initialize GLAD" << std::endl;
        return -1;
    }
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
    //init

    //vertex shader 顶点着色器
    unsigned int vertexShader;
    vertexShader = glCreateShader(GL_VERTEX_SHADER);//创建顶点着色器
    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);//将着色器中的源代码设置为string指定的字符串数组中的源代码
    glCompileShader(vertexShader);//编译着色器
    //测试编译是否成功
    int success;
    char infoLog[512];
    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
        std::cout << "vertex shader 顶点着色器::编译失败\n" << infoLog << std::endl;
    }
    //测试编译是否成功
    //vertex shader 顶点着色器

    //fragment shader 片段着色器
    unsigned int fragmentShader;
    fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);//创建片段着色器
    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);//将着色器中的源代码设置为string指定的字符串数组中的源代码
    glCompileShader(fragmentShader);//编译着色器
    //测试编译是否成功
    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
    }
    //测试编译是否成功
    //fragment shader 片段着色器

    //链接着色器到program对象
    unsigned int shaderProgram;
    shaderProgram = glCreateProgram();//创建一个program对象
    glAttachShader(shaderProgram, vertexShader);//将顶点着色器对象附加到program对象
    glAttachShader(shaderProgram, fragmentShader);//将着片段色器对象附加到program对象
    glLinkProgram(shaderProgram);//连接一个program对象

    //测试链接是否成功
    glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
    if (!success) {
        glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
    }
    //测试链接是否成功
    //链接着色器到program对象

    //删除片段着色器
    glDeleteShader(vertexShader);
    //删除顶点着色器
    glDeleteShader(fragmentShader);

    //创建VAO   VAO: 顶点数组对象：Vertex Array Object,  
    unsigned int VAO;
    glGenVertexArrays(1, &VAO); // 用来生成缓冲区对象
    glBindVertexArray(VAO);//绑定VAO

       //创建EBO 
    unsigned int VBO;
    glGenBuffers(1, &VBO);// 用来生成缓冲区对象
    //把新创建的缓冲绑定到GL_ARRAY_BUFFER目标上
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    //复制顶点数组到缓冲中供OpenGL使用
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    //告诉OpenGL该如何解析顶点数据
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);

    glEnableVertexAttribArray(0);


    //解绑VAO
    glBindVertexArray(0);
    //解绑VBO
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    //解绑EBO
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);

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

        // 记得激活着色器,使用程序对象作为当前渲染状态的一部分
        glUseProgram(shaderProgram);

        //02 uniform用法
        float timeValue = glfwGetTime();
        float greenValue = (sin(timeValue) / 2.0f) + 0.5f;
        int vertexColorLocation = glGetUniformLocation(shaderProgram, "ourColor"); //glGetUniformLocation返回 - 1就代表没有找到这个位置值
        glUniform4f(vertexColorLocation, 0.0f, greenValue, 0.0f, 1.0f);//设置uniform值
        //glUniform4f(vertexColorLocation, greenValue, 0.0f, 0.0f, 1.0f);
        //02 uniform用法
        //查询uniform地址不要求你之前使用过着色器程序，但是更新一个uniform之前你必须先使用程序

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

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glDeleteVertexArrays(1, &VAO);
    glDeleteProgram(shaderProgram);

    glfwTerminate();
    return 0;
}

void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    glViewport(0, 0, width, height);
}

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

Shaders-02.cpp

#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <iostream>

void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow* window);

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



const char* vertexShaderSource = "#version 330 core\n"
"layout(location = 0) \n"
"in vec3 aPos; \n"   // 位置变量的属性位置值为 0 
"layout(location = 1) \n"
"in vec3 aColor; \n"// 颜色变量的属性位置值为 1
"out vec3 ourColor; \n"// 向片段着色器输出一个颜色
"void main() \n"
"{ \n"
"    gl_Position = vec4(aPos, 1.0); \n"
"    ourColor = aColor; \n"  // 将ourColor设置为我们从顶点数据那里得到的输入颜色
"} \n";

const char* fragmentShaderSource = "#version 330 core \n"
"out vec4 FragColor; \n"
"in vec3 ourColor; \n"
"void main()\n"
"{ \n"
"   FragColor = vec4(ourColor, 1.0); \n"
"} \n";



int main()
{
    //init
    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, "DrawTriangle01", NULL, NULL);
    if (window == NULL)
    {
        std::cout << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);
    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
        std::cout << "Failed to initialize GLAD" << std::endl;
        return -1;
    }
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
    //init

    //vertex shader 顶点着色器
    unsigned int vertexShader;
    vertexShader = glCreateShader(GL_VERTEX_SHADER);//创建顶点着色器
    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);//将着色器中的源代码设置为string指定的字符串数组中的源代码
    glCompileShader(vertexShader);//编译着色器
    //测试编译是否成功
    int success;
    char infoLog[512];
    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
        std::cout << "vertex shader 顶点着色器::编译失败\n" << infoLog << std::endl;
    }
    //测试编译是否成功
    //vertex shader 顶点着色器

    //fragment shader 片段着色器
    unsigned int fragmentShader;
    fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);//创建片段着色器
    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);//将着色器中的源代码设置为string指定的字符串数组中的源代码
    glCompileShader(fragmentShader);//编译着色器
    //测试编译是否成功
    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
    }
    //测试编译是否成功
    //fragment shader 片段着色器

    //链接着色器到program对象
    unsigned int shaderProgram;
    shaderProgram = glCreateProgram();//创建一个program对象
    glAttachShader(shaderProgram, vertexShader);//将顶点着色器对象附加到program对象
    glAttachShader(shaderProgram, fragmentShader);//将着片段色器对象附加到program对象
    glLinkProgram(shaderProgram);//连接一个program对象

    //测试链接是否成功
    glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
    if (!success) {
        glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
    }
    //测试链接是否成功
    //链接着色器到program对象

    //删除片段着色器
    glDeleteShader(vertexShader);
    //删除顶点着色器
    glDeleteShader(fragmentShader);

    //创建VAO   VAO: 顶点数组对象：Vertex Array Object,  
    unsigned int VAO;
    glGenVertexArrays(1, &VAO); // 用来生成缓冲区对象
    glBindVertexArray(VAO);//绑定VAO

    //创建VBO,  VBO:顶点缓冲对象：Vertex Buffer Object
    unsigned int VBO;
    glGenBuffers(1, &VBO);//用来生成缓冲区对象
    //把新创建的缓冲绑定到GL_ARRAY_BUFFER目标上
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    //复制顶点数组到缓冲中供OpenGL使用
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    //位置属性 告诉OpenGL该如何解析顶点数据
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
    //允许顶点着色器读取GPU（服务器端）数据
    glEnableVertexAttribArray(0);

    //颜色属性 告诉OpenGL该如何解析颜色数据
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float)));
    //允许顶点着色器读取GPU（服务器端）数据
    glEnableVertexAttribArray(1);


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

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

        glUseProgram(shaderProgram);//使用程序对象作为当前渲染状态的一部分
        glBindVertexArray(VAO);
        glDrawArrays(GL_TRIANGLES, 0, 3);

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);
    glDeleteProgram(shaderProgram);

    glfwTerminate();
    return 0;
}

void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    glViewport(0, 0, width, height);
}

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

Shaders-03.cpp

#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <iostream>

#include "shader.h"

void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow* window);

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

int main()
{
    //init
    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, "DrawTriangle01", NULL, NULL);
    if (window == NULL)
    {
        std::cout << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);
    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
        std::cout << "Failed to initialize GLAD" << std::endl;
        return -1;
    }
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
    //init

    //创建VAO   VAO: 顶点数组对象：Vertex Array Object,  
    unsigned int VAO;
    glGenVertexArrays(1, &VAO); // 用来生成缓冲区对象
    glBindVertexArray(VAO);//绑定VAO

    //创建VBO,  VBO:顶点缓冲对象：Vertex Buffer Object
    unsigned int VBO;
    glGenBuffers(1, &VBO);//用来生成缓冲区对象
    //把新创建的缓冲绑定到GL_ARRAY_BUFFER目标上
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    //复制顶点数组到缓冲中供OpenGL使用
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    //位置属性 告诉OpenGL该如何解析顶点数据
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
    //允许顶点着色器读取GPU（服务器端）数据
    glEnableVertexAttribArray(0);

    //颜色属性 告诉OpenGL该如何解析颜色数据
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float)));
    //允许顶点着色器读取GPU（服务器端）数据
    glEnableVertexAttribArray(1);

    Shader ourShader("./3.3.shader.vs", "./3.3.shader.fs"); // you can name your shader files however you like

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

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

        // render the triangle
        ourShader.use();

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

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

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

    glfwTerminate();
    return 0;
}

void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    glViewport(0, 0, width, height);
}

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

qt  5.15.1 

代码如下:

由于qt代码较多，直贴关键代码，项目可自行下载

项目Shaders-02-01

Shaders.cpp

#include "Shaders.h"

const char* vertexShaderSource = "#version 330 core \n"
"layout (location = 0); \n"//位置变量的属性位置值为0
"in vec3 aPos; \n"
"void main() \n"
"{ \n"
"    gl_Position = vec4(aPos.x,aPos.y,aPos.z,1.0); \n"
"} \n";

const char* fragmentShaderSource = "#version 330 core\n"
"out vec4 FragColor; \n"
"uniform  vec4 ourColor; \n"
"void main() \n"
"{ \n"
"    FragColor = ourColor; \n"
"} \n";

float vertices[] = {
    -0.5f, -0.5f, 0.0f,
     0.5f, -0.5f, 0.0f,
     0.0f,  0.5f, 0.0f
};

Shaders::Shaders(QWidget *parent)
    : QOpenGLWidget(parent)
{
}

Shaders::~Shaders()
{
    m_vao->release();
    m_vbo->release();
    m_program->release();  //解绑
}

void Shaders::initializeGL()
{
    initializeOpenGLFunctions();
    glEnable(GL_DEPTH_TEST);
    //QOpenGLShaderProgram
    m_program = new QOpenGLShaderProgram(this);
    //vertex shader 顶点着色器
    m_program->addShaderFromSourceCode(QOpenGLShader::Vertex, vertexShaderSource);
    //fragment shader 片段着色器
    m_program->addShaderFromSourceCode(QOpenGLShader::Fragment, fragmentShaderSource);
    m_program->link();
    m_program->bind();//激活Program对象

    m_vao = new QOpenGLVertexArrayObject();
    m_vao->create();
    m_vao->bind();

    //画三角形
    m_vbo = new QOpenGLBuffer(QOpenGLBuffer::Type::VertexBuffer);
    m_vbo->create();
    m_vbo->bind();
    m_vbo->allocate(vertices, sizeof(vertices));
    m_vbo->setUsagePattern(QOpenGLBuffer::StreamDraw);

    //void setAttributeBuffer  (const char *name, GLenum type, int offset, int tupleSize, int stride = 0);
    GLint aPos = m_program->attributeLocation("aPos");        //获取aPos位置
    if(aPos==-1)
    {
        return;
    }
    m_program->setAttributeBuffer(aPos, GL_FLOAT, 0,  3, 0);   //设置顶点属性
    m_program->enableAttributeArray(aPos); //使能顶点属性
    //画三角形


    m_time = QTime::currentTime();
    qDebug()<<"m_time=0="<<m_time;
}

void Shaders::paintGL()
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);

    // 渲染Shader
    m_program->bind(); //绑定激活Program对象
    m_vao->bind();      //绑定激活vao
    float timeValue = m_time.msecsTo(QTime::currentTime())/1000.0f;
    float greenValue = (sin(timeValue) / 2.0f) + 0.5f;
    m_ourColor = m_program->uniformLocation("ourColor");
    m_program->setUniformValue(m_ourColor,  0.0f, greenValue, 0.0f, 1.0f);
    //画三角形
    glDrawArrays(GL_TRIANGLES, 0, 3);    //绘制3个定点,样式为三角形
    //画三角形
    m_vao->release();       //解绑
    update();//注意update才能重复调用paintGL，前面两个例子不涉及动态所以没有添加
}

void Shaders::resizeGL(int w, int h)
{

}

项目Shaders-02-02

Shaders.cpp

#include "Shaders.h"

const char* vertexShaderSource = "#version 330 core\n"
"layout(location = 0) \n"
"in vec3 aPos; \n"   // 位置变量的属性位置值为 0
"layout(location = 1) \n"
"in vec3 aColor; \n"// 颜色变量的属性位置值为 1
"out vec3 ourColor; \n"// 向片段着色器输出一个颜色
"void main() \n"
"{ \n"
"    gl_Position = vec4(aPos, 1.0); \n"
"    ourColor = aColor; \n"  // 将ourColor设置为我们从顶点数据那里得到的输入颜色
"} \n";

const char* fragmentShaderSource = "#version 330 core \n"
"out vec4 FragColor; \n"
"in vec3 ourColor; \n"
"void main()\n"
"{ \n"
"   FragColor = vec4(ourColor, 1.0); \n"
"} \n";

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

Shaders::Shaders(QWidget *parent)
    : QOpenGLWidget(parent)
{
}

Shaders::~Shaders()
{
    m_vao->release();
    m_vbo->release();
    m_program->release();  //解绑
}

void Shaders::initializeGL()
{
    initializeOpenGLFunctions();
    glEnable(GL_DEPTH_TEST);
    //QOpenGLShaderProgram
    m_program = new QOpenGLShaderProgram(this);
    //vertex shader 顶点着色器
    m_program->addShaderFromSourceCode(QOpenGLShader::Vertex, vertexShaderSource);
    //fragment shader 片段着色器
    m_program->addShaderFromSourceCode(QOpenGLShader::Fragment, fragmentShaderSource);
    m_program->link();
    m_program->bind();//激活Program对象

    m_vao = new QOpenGLVertexArrayObject();
    m_vao->create();
    m_vao->bind();

    //画三角形
    m_vbo = new QOpenGLBuffer(QOpenGLBuffer::Type::VertexBuffer);
    m_vbo->create();
    m_vbo->bind();
    m_vbo->allocate(vertices, sizeof(vertices));
    m_vbo->setUsagePattern(QOpenGLBuffer::StreamDraw);

    //void setAttributeBuffer  (const char *name, GLenum type, int offset, int tupleSize, int stride = 0);
    GLint aPos = m_program->attributeLocation("aPos");        //获取aPos位置
    if(aPos==-1)
    {
        return;
    }
    m_program->setAttributeBuffer(aPos, GL_FLOAT, 0,  3, 6*sizeof(GLfloat));   //设置顶点属性
    m_program->enableAttributeArray(aPos); //使能顶点属性

    GLint aColor = m_program->attributeLocation("aColor");        //获取aPos位置
    if(aPos==-1)
    {
        return;
    }
    m_program->setAttributeBuffer(aColor, GL_FLOAT, 3*sizeof(GLfloat),  3, 6*sizeof(GLfloat));   //设置颜色属性
    m_program->enableAttributeArray(aColor); //使能顶点属性
    //画三角形


    m_time = QTime::currentTime();
    qDebug()<<"m_time=0="<<m_time;
}

void Shaders::paintGL()
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);

    // 渲染Shader
    m_program->bind(); //绑定激活Program对象
    m_vao->bind();      //绑定激活vao
    //画三角形
    glDrawArrays(GL_TRIANGLES, 0, 3);    //绘制3个定点,样式为三角形
    //画三角形
    m_vao->release();       //解绑
    update();//注意update才能重复调用paintGL，前面两个例子不涉及动态所以没有添加

}

void Shaders::resizeGL(int w, int h)
{

}

项目Shaders-02-03

Shaders.cpp

#include "Shaders.h"

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

Shaders::Shaders(QWidget *parent)
    : QOpenGLWidget(parent)
{
}

Shaders::~Shaders()
{
    m_vao->release();
    m_vbo->release();
    m_program->release();  //解绑
}

void Shaders::initializeGL()
{
    initializeOpenGLFunctions();
    glEnable(GL_DEPTH_TEST);
    //QOpenGLShaderProgram
    m_program = new QOpenGLShaderProgram(this);
    //vertex shader 顶点着色器
    m_program->addShaderFromSourceFile(QOpenGLShader::Vertex, ":/vshader.glsl");
    //fragment shader 片段着色器
    m_program->addShaderFromSourceFile(QOpenGLShader::Fragment, ":/fshader.glsl");
    m_program->link();
    m_program->bind();//激活Program对象

    m_vao = new QOpenGLVertexArrayObject();
    m_vao->create();
    m_vao->bind();

    //画三角形
    m_vbo = new QOpenGLBuffer(QOpenGLBuffer::Type::VertexBuffer);
    m_vbo->create();
    m_vbo->bind();
    m_vbo->allocate(vertices, sizeof(vertices));
    m_vbo->setUsagePattern(QOpenGLBuffer::StreamDraw);

    //void setAttributeBuffer  (const char *name, GLenum type, int offset, int tupleSize, int stride = 0);
    GLint aPos = m_program->attributeLocation("aPos");        //获取aPos位置
    if(aPos==-1)
    {
        return;
    }
    m_program->setAttributeBuffer(aPos, GL_FLOAT, 0,  3, 6*sizeof(GLfloat));   //设置顶点属性
    m_program->enableAttributeArray(aPos); //使能顶点属性

    GLint aColor = m_program->attributeLocation("aColor");        //获取aPos位置
    if(aPos==-1)
    {
        return;
    }
    m_program->setAttributeBuffer(aColor, GL_FLOAT, 3*sizeof(GLfloat),  3, 6*sizeof(GLfloat));   //设置颜色属性
    m_program->enableAttributeArray(aColor); //使能顶点属性
    //画三角形


    m_time = QTime::currentTime();
    qDebug()<<"m_time=0="<<m_time;
}

void Shaders::paintGL()
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);

    // 渲染Shader
    m_program->bind(); //绑定激活Program对象
    m_vao->bind();      //绑定激活vao
    //画三角形
    glDrawArrays(GL_TRIANGLES, 0, 3);    //绘制3个定点,样式为三角形
    //画三角形
    m_vao->release();       //解绑
    update();//注意update才能重复调用paintGL，前面两个例子不涉及动态所以没有添加

}

void Shaders::resizeGL(int w, int h)
{

}