坐标系统

原文：https://www.jianshu.com/p/45122bdaae77

opengl核心函数版

#include "corefunctionwidget.h"
#include <QDebug>
#include <QTimer>

static GLuint VAO,VBO,texture1,texture2;

CoreFunctionWidget::CoreFunctionWidget(QWidget *parent)
    : QOpenGLWidget (parent)
{
    m_timer = new QTimer(this);
    connect(m_timer,&QTimer::timeout,this,[=]{
        m_nTimeValue += 1;
        update();
    });
    m_timer->start(50);
}

CoreFunctionWidget::~CoreFunctionWidget()
{
    glDeleteVertexArrays(1,&VAO);
    glDeleteBuffers(1,&VBO);
}

void CoreFunctionWidget::initializeGL()
{
    this->initializeOpenGLFunctions();

    bool success = m_program.addShaderFromSourceFile(QOpenGLShader::Vertex,":/shader/textures.vert");
    if (!success) {
        qDebug() << "m_program addShaderFromSourceFile failed!" << m_program.log();
        return;
    }
    success = m_program.addShaderFromSourceFile(QOpenGLShader::Fragment, ":/shader/textures.frag");
    if (!success) {
        qDebug() << "m_program addShaderFromSourceFile failed!" << m_program.log();
        return;
    }

    success = m_program.link();
    if(!success) {
        qDebug() << "m_program link failed!" << m_program.log();
    }

    // configure global opengl state
    // -----------------------------
    glEnable(GL_DEPTH_TEST);

    //VAO，VBO data
    float vertices[] = {
        -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
         0.5f, -0.5f, -0.5f,  1.0f, 0.0f,
         0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
         0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
        -0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
        -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,

        -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
         0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
         0.5f,  0.5f,  0.5f,  1.0f, 1.0f,
         0.5f,  0.5f,  0.5f,  1.0f, 1.0f,
        -0.5f,  0.5f,  0.5f,  0.0f, 1.0f,
        -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,

        -0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
        -0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
        -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
        -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
        -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
        -0.5f,  0.5f,  0.5f,  1.0f, 0.0f,

         0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
         0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
         0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
         0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
         0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
         0.5f,  0.5f,  0.5f,  1.0f, 0.0f,

        -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
         0.5f, -0.5f, -0.5f,  1.0f, 1.0f,
         0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
         0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
        -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
        -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,

        -0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
         0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
         0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
         0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
        -0.5f,  0.5f,  0.5f,  0.0f, 0.0f,
        -0.5f,  0.5f, -0.5f,  0.0f, 1.0f
    };

     glGenVertexArrays(1, &VAO);
     glGenBuffers(1, &VBO);
     // bind the Vertex Array Object first, then bind and set vertex buffer(s), and then configure vertex attributes(s).
     glBindVertexArray(VAO);

     glBindBuffer(GL_ARRAY_BUFFER, VBO);
     glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

     // position attribute
     glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
     glEnableVertexAttribArray(0);
     // texture coord attribute
     glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
     glEnableVertexAttribArray(1);

    // texture1
    glGenTextures(1,&texture1);
    glBindTexture(GL_TEXTURE_2D,texture1);

    // set texture wrapping parameters
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT);
    // SET texture filting parameters
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    // load image,create texture,generate mipmaps
    QImage image1 = QImage(":/image/container.jpg").convertToFormat(QImage::Format_RGB888);
    if (!image1.isNull()){
        glTexImage2D(GL_TEXTURE_2D,0,GL_RGB,image1.width(),image1.height(),0,GL_RGB,GL_UNSIGNED_BYTE,image1.bits());
        glGenerateMipmap(GL_TEXTURE_2D);
    }

    // texture2
    glGenTextures(1,&texture2);
    glBindTexture(GL_TEXTURE_2D,texture2);

    // set texture wrapping parameters
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT);
    // SET texture filting parameters
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    // load image,create texture,generate mipmaps
    QImage image2 = QImage(":/image/awesomeface.png").convertToFormat(QImage::Format_RGBA8888).mirrored(true, true);
    if (!image2.isNull()){
        // note that the awesomeface.png has transparency and thus an alpha channel, so make sure to tell OpenGL the data type is of GL_RGBA
        glTexImage2D(GL_TEXTURE_2D,0,GL_RGBA,image2.width(),image2.height(),0,GL_RGBA,GL_UNSIGNED_BYTE,image2.bits());
        glGenerateMipmap(GL_TEXTURE_2D);
    }

    // tell opengl for each sampler to which texture unit it belongs to (only has to be done once)
    m_program.bind();   // don't forget to activate/use the shader before setting uniforms!
    glUniform1i(m_program.uniformLocation("texture1"),0);
    glUniform1i(m_program.uniformLocation("texture2"),1);

    QMatrix4x4 view;
    view.translate(QVector3D(0.0f,0.0f,-3.0f));
    m_program.setUniformValue("view",view);
    QMatrix4x4 projection;
    projection.perspective(45.0f,1.0f*width()/height(),0.1f,100.0f);
    m_program.setUniformValue("projection",projection);

    m_program.release();

}

void CoreFunctionWidget::resizeGL(int w, int h)
{
    glViewport(0,0,w,h);
}

static QVector3D cubePositions[] = {
  QVector3D( 0.0f,  0.0f,  0.0f),
  QVector3D( 2.0f,  5.0f, -15.0f),
  QVector3D(-1.5f, -2.2f, -2.5f),
  QVector3D(-3.8f, -2.0f, -12.3f),
  QVector3D( 2.4f, -0.4f, -3.5f),
  QVector3D(-1.7f,  3.0f, -7.5f),
  QVector3D( 1.3f, -2.0f, -2.5f),
  QVector3D( 1.5f,  2.0f, -2.5f),
  QVector3D( 1.5f,  0.2f, -1.5f),
  QVector3D(-1.3f,  1.0f, -1.5f)
};

void CoreFunctionWidget::paintGL()
{
    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // also clear the depth buffer now!

    // bind textures on corresponding texture units
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, texture1);
    glActiveTexture(GL_TEXTURE1);
    glBindTexture(GL_TEXTURE_2D, texture2);

    m_program.bind();
    // render boxes
    glBindVertexArray(VAO);
    for (unsigned int i = 0; i < 10; i++) {
       // calculate the model matrix for each object and pass it to shader before drawing
       QMatrix4x4 model;
       model.translate(cubePositions[i]);
       float angle = (i + 1.0f) * m_nTimeValue;
       model.rotate(angle, QVector3D(1.0f, 0.3f, 0.5f));
       m_program.setUniformValue("model", model);
       glDrawArrays(GL_TRIANGLES, 0, 36);
    }

    m_program.release();

}

CoreFunction.cpp

#ifndef COREFUNCTIONWIDGET_H
#define COREFUNCTIONWIDGET_H

#include <QWidget>
#include <QOpenGLWidget>
#include <QOpenGLFunctions_3_3_Core>
#include <QOpenGLShader>
#include <QOpenGLShaderProgram>

class CoreFunctionWidget : public QOpenGLWidget,protected QOpenGLFunctions_3_3_Core
{
    Q_OBJECT

public:
    CoreFunctionWidget(QWidget *parent = nullptr);
    ~CoreFunctionWidget() Q_DECL_OVERRIDE;
protected:
    virtual void initializeGL() Q_DECL_OVERRIDE;
    virtual void resizeGL(int w,int h) Q_DECL_OVERRIDE;
    virtual void paintGL() Q_DECL_OVERRIDE;
private:
    QOpenGLShaderProgram m_program;
    QTimer *m_timer;
    int m_nTimeValue{0};
};

.hpp

#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec2 aTexCoord;
 
out vec2 TexCoord;
 
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
 
void main(){
  gl_Position = projection * view * model * vec4(aPos, 1.0f);
  TexCoord = aTexCoord;
}

vert

#version 330 core
out vec4 FragColor;
 
in vec2 TexCoord;
 
uniform sampler2D texture1;
uniform sampler2D texture2;
 
void main()
{
    FragColor = mix(texture2D(texture1, TexCoord), texture2D(texture2, TexCoord), 0.2f);
}

frag

Qt封装函数版本

#include "qtfunwidget.h"
#include <QTimer>
#include <QDebug>

QtFunWidget::QtFunWidget(QWidget *parent)
    : QOpenGLWidget(parent)
{
    m_timer = new QTimer(this);
    connect(m_timer,&QTimer::timeout,this,[=]{
        m_nTimeValue += 1;
        update();
    });
    m_timer->start(40);
}

QtFunWidget::~QtFunWidget()
{
    makeCurrent();

    vbo.destroy();
    vao.destroy();

    delete texture1;
    delete texture2;

    doneCurrent();
}

void QtFunWidget::initializeGL()
{
    this->initializeOpenGLFunctions();

    bool success = m_program.addShaderFromSourceFile(QOpenGLShader::Vertex,":/shader/textures.vert");
    if(!success) {
        qDebug() << "add vertex shader failed." << m_program.log();
        return;
    }
    m_program.addShaderFromSourceFile(QOpenGLShader::Fragment,":/shader/textures.frag");
    if(!success) {
        qDebug() << "add frag shader failed." << m_program.log();
        return;
    }

    m_program.link();
    if(!success) {
        qDebug() << "link shader failed." << m_program.log();
        return;
    }

    // configure global opengl state
    // -----------------------------
    glEnable(GL_DEPTH_TEST);

    //VAO，VBO data
    float vertices[] = {
        -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
         0.5f, -0.5f, -0.5f,  1.0f, 0.0f,
         0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
         0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
        -0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
        -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,

        -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
         0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
         0.5f,  0.5f,  0.5f,  1.0f, 1.0f,
         0.5f,  0.5f,  0.5f,  1.0f, 1.0f,
        -0.5f,  0.5f,  0.5f,  0.0f, 1.0f,
        -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,

        -0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
        -0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
        -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
        -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
        -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
        -0.5f,  0.5f,  0.5f,  1.0f, 0.0f,

         0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
         0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
         0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
         0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
         0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
         0.5f,  0.5f,  0.5f,  1.0f, 0.0f,

        -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
         0.5f, -0.5f, -0.5f,  1.0f, 1.0f,
         0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
         0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
        -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
        -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,

        -0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
         0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
         0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
         0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
        -0.5f,  0.5f,  0.5f,  0.0f, 0.0f,
        -0.5f,  0.5f, -0.5f,  0.0f, 1.0f
    };

    QOpenGLVertexArrayObject::Binder vaoBind(&vao);

    vbo.create();
    vbo.bind();
    vbo.allocate(vertices,sizeof(vertices));

    //position attribute
    int attr = -1;
    attr = m_program.attributeLocation("aPos");
    m_program.setAttributeBuffer(attr,GL_FLOAT,0,3,5*sizeof(GL_FLOAT));
    m_program.enableAttributeArray(attr);

    // coord attribute
    attr = m_program.attributeLocation("aTexCoord");
    m_program.setAttributeBuffer(attr,GL_FLOAT,3*sizeof(GL_FLOAT),2,5*sizeof(GL_FLOAT));
    m_program.enableAttributeArray(attr);

    // texture1
    texture1 = new QOpenGLTexture(QImage(":/image/container.jpg"));
    if(!texture1->isCreated()) {
        qDebug() << "failed to load texture1";
    }
    // set the texture wrapping parameters
    texture1->setWrapMode(QOpenGLTexture::DirectionS, QOpenGLTexture::Repeat);
    texture1->setWrapMode(QOpenGLTexture::DirectionT, QOpenGLTexture::Repeat);
    // set texture filtering parameters
    texture1->setMinificationFilter(QOpenGLTexture::Linear);
    texture1->setMagnificationFilter(QOpenGLTexture::Linear);

    // texture 2
    // ---------
    texture2 = new QOpenGLTexture(QImage(":/image/awesomeface.png").mirrored(true, true), QOpenGLTexture::GenerateMipMaps);
    if(!texture2->isCreated()){
        qDebug() << "Failed to load texture";
    }

    texture2->setWrapMode(QOpenGLTexture::DirectionS,QOpenGLTexture::Repeat);
    texture2->setWrapMode(QOpenGLTexture::DirectionT,QOpenGLTexture::Repeat);

    texture2->setMinificationFilter(QOpenGLTexture::Linear);
    texture2->setMagnificationFilter(QOpenGLTexture::Linear);

    m_program.bind();
    m_program.setUniformValue("texture1",0);
    m_program.setUniformValue("texture2",1);

    QMatrix4x4 view;
    view.translate(QVector3D(0.0f,0.0f,-3.0f));
    m_program.setUniformValue("view",view);
    QMatrix4x4 projection;
    projection.perspective(45.0f, 1.0f * width() / height(), 0.1f, 100.0f);
    m_program.setUniformValue("projection", projection);
    m_program.release();

    vbo.release();
}


void QtFunWidget::resizeGL(int w, int h)
{
    glViewport(0,0,w,h);
}

static QVector3D cubePositions[] = {
  QVector3D( 0.0f,  0.0f,  0.0f),
  QVector3D( 2.0f,  5.0f, -15.0f),
  QVector3D(-1.5f, -2.2f, -2.5f),
  QVector3D(-3.8f, -2.0f, -12.3f),
  QVector3D( 2.4f, -0.4f, -3.5f),
  QVector3D(-1.7f,  3.0f, -7.5f),
  QVector3D( 1.3f, -2.0f, -2.5f),
  QVector3D( 1.5f,  2.0f, -2.5f),
  QVector3D( 1.5f,  0.2f, -1.5f),
  QVector3D(-1.3f,  1.0f, -1.5f)
};

void QtFunWidget::paintGL()
{
    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // also clear the depth buffer now!

    // bind textures on corresponding texture units
    glActiveTexture(GL_TEXTURE0);
    texture1->bind();
    glActiveTexture(GL_TEXTURE1);
    texture2->bind();

    m_program.bind();

    {
        QOpenGLVertexArrayObject::Binder vaoBind(&vao);
        for(int i = 0; i< 10; ++i){
            QMatrix4x4 model;
           model.translate(cubePositions[i]);
           float angle = (i + 1.0f) * m_nTimeValue;
           model.rotate(angle, QVector3D(1.0f, 0.3f, 0.5f));
           m_program.setUniformValue("model", model);
           glDrawArrays(GL_TRIANGLES, 0, 36);

        }
    }

    texture1->release();
    texture2->release();
    m_program.release();

}

.cpp

#ifndef QTFUNWIDGET_H
#define QTFUNWIDGET_H

#include <QWidget>
#include <QOpenGLWidget>
#include <QOpenGLFunctions>
#include <QOpenGLShader>
#include <QOpenGLShaderProgram>
#include <QOpenGLBuffer>
#include <QOpenGLVertexArrayObject>
#include <QOpenGLTexture>

class QtFunWidget : public QOpenGLWidget,protected QOpenGLFunctions
{
    Q_OBJECT

public:
    QtFunWidget(QWidget *parent = 0);
    ~QtFunWidget() Q_DECL_OVERRIDE;
protected:
    virtual void initializeGL() Q_DECL_OVERRIDE;
    virtual void resizeGL(int w,int h) Q_DECL_OVERRIDE;
    virtual void paintGL() Q_DECL_OVERRIDE;
private:
    QOpenGLShaderProgram m_program;
    QOpenGLBuffer vbo;
    QOpenGLVertexArrayObject vao;

    QOpenGLTexture *texture1{nullptr};
    QOpenGLTexture *texture2{nullptr};

    QTimer *m_timer;
    int m_nTimeValue;
};

#endif // QTFUNWIDGET_H

.hpp

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原文地址：https://www.cnblogs.com/xiangtingshen/p/12075902.html