Qt5与现代OpenGL学习（三）纹理

把第一张图放到D盘的1文件夹里面：1.png
triangle.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QOpenGLWidget>
#include <QOpenGLFunctions>
#include <QOpenGLVertexArrayObject>
#include <QOpenGLShaderProgram>
#include <QOpenGLBuffer>

#include <QDebug>
#include <QOpenGLFunctions_3_3_Core>
#include "shader.h"
#include <QOpenGLTexture>  //新添项

class Triangle : public QOpenGLWidget,protected QOpenGLFunctions
{
    Q_OBJECT
public:
    Triangle(QWidget* parent=0);
    GLuint a;
    ~Triangle();
protected:
    virtual void initializeGL();
    virtual void resizeGL(int w, int h);
    virtual void paintGL();
private:
    Shader *ourShader;
    QOpenGLTexture *texture;//新添项
    QOpenGLFunctions_3_3_Core *core;

};

#endif // WIDGET_H

triangle.cpp

#include "triangle.h"
GLuint VBO, VAO, EBO;

Triangle::Triangle(QWidget* parent)
    :QOpenGLWidget(parent)
{
    this->setWindowTitle("Texture");
}

Triangle::~Triangle(){
    delete ourShader;
    core->glDeleteVertexArrays(1, &VAO);
    core->glDeleteBuffers(1, &VBO);
    core->glDeleteBuffers(1, &EBO);
    texture->destroy(); //纹理使用完 进行删除
}

void Triangle::initializeGL(){

    //着色器部分
    core = QOpenGLContext::currentContext()->versionFunctions<QOpenGLFunctions_3_3_Core>();
    ourShader = new Shader(":/triangle.vert", ":/triangle.frag");

    //VAO，VBO数据部分
    GLfloat vertices[] = {
        0.5f,  0.5f, 0.0f,   1.0f, 0.0f, 0.0f,   1.0f, 1.0f, // top right //注意新的数据，有纹理单元
        0.5f, -0.5f, 0.0f,   0.0f, 1.0f, 0.0f,   1.0f, 0.0f, // bottom right
       -0.5f, -0.5f, 0.0f,   0.0f, 0.0f, 1.0f,   0.0f, 0.0f, // bottom left
       -0.5f,  0.5f, 0.0f,   1.0f, 1.0f, 0.0f,   0.0f, 1.0f  // top left
    };

    GLuint indices[] = {
        0, 1, 3, // first triangle
        1, 2, 3  // second triangle
    };

    core->glGenVertexArrays(1, &VAO);//两个参数，第一个为需要创建的缓存数量。第二个为用于存储单一ID或多个ID的GLuint变量或数组的地址
    core->glGenBuffers(1, &VBO);
    core->glGenBuffers(1, &EBO);

    core->glBindVertexArray(VAO);

    core->glBindBuffer(GL_ARRAY_BUFFER, VBO);
    core->glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    core->glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
    core->glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

    core->glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
    core->glEnableVertexAttribArray(0);
    // color attribute
    core->glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
    core->glEnableVertexAttribArray(1);
    // texture coord attribute
    core->glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
    core->glEnableVertexAttribArray(2);

    //纹理
    texture = new QOpenGLTexture(QImage("D://1//1.png").mirrored(), QOpenGLTexture::GenerateMipMaps); //直接生成绑定一个2d纹理, 并生成多级纹理MipMaps
    if(!texture->isCreated()){
        qDebug() << "Failed to load texture" << endl;
    }
    texture->setWrapMode(QOpenGLTexture::DirectionS, QOpenGLTexture::Repeat);// 等于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    texture->setWrapMode(QOpenGLTexture::DirectionT, QOpenGLTexture::Repeat);//    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);


    texture->setMinificationFilter(QOpenGLTexture::Linear);   //等价于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    texture->setMagnificationFilter(QOpenGLTexture::Linear);  //     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    texture->setFormat(QOpenGLTexture::RGBFormat); //将纹理储存为rgb值


    core->glClearColor(0.2f, 0.3f, 0.3f, 1.0f);

}

void Triangle::resizeGL(int w, int h){
    core->glViewport(0, 0, w, h);
}

void Triangle::paintGL(){
    core->glClear(GL_COLOR_BUFFER_BIT);

    texture->bind();
    ourShader->use();
    core->glBindVertexArray(VAO);
    core->glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

}

shader.h

#ifndef SHADER_H
#define SHADER_H

#include <QDebug>
#include <QOpenGLShader>
#include <QOpenGLShaderProgram>
#include <QString>

class Shader {
public:
  Shader(const QString& vertexSourcePath, const QString& fragmentSourcePath);
  ~Shader();
  QOpenGLShaderProgram shaderProgram;

  void use(){
    shaderProgram.bind();
  }


};

#endif // SHADER_H

shader.cpp

#include "shader.h"

Shader::Shader(const QString& vertexPath, const QString& fragmentPath){
    QOpenGLShader vertexShader(QOpenGLShader::Vertex);
    bool success = vertexShader.compileSourceFile(vertexPath);
    if(!success){
        qDebug() << "ERROR::SHADER::VERTEX::COMPILATION_FAILED" << endl;
        qDebug() << vertexShader.log() << endl;
    }

    QOpenGLShader fragmentShader(QOpenGLShader::Fragment);
    success  =fragmentShader.compileSourceFile(fragmentPath);
    if(!success){
        qDebug() << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED" << endl;
        qDebug() << fragmentShader.log() << endl;
    }

   shaderProgram.addShader(&vertexShader);
   shaderProgram.addShader(&fragmentShader);
   success = shaderProgram.link();
   if(!success){
        qDebug() << "ERROR::SHADER::PROGRAM::LINKING_FAILED" << endl;
        qDebug() << shaderProgram.log() << endl;
   }
}

Shader::~Shader(){
}

triangle.frag

#version 330 core
out vec4 FragColor;

in vec3 ourColor;
in vec2 TexCoord;

uniform sampler2D ourTexture;

void main()
{
    FragColor = texture2D(ourTexture, TexCoord);
}

triangle.vert

#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aColor;
layout (location = 2) in vec2 aTexCoord;

out vec3 ourColor;
out vec2 TexCoord;

void main(){
  gl_Position = vec4(aPos, 1.0f);
  ourColor = aColor;
  TexCoord = aTexCoord;
}

在mainwindow.ui中，添加QWidget，并提升为：Triangle