• QT中学习Opengl---（摄像机2）

    前言：

    本文的代码是 LearnOpenGL 中对应代码，这里提供学习，大家喜欢的可去官方网站去看看:

     LearnOpenGL-CNhttps://learnopengl-cn.readthedocs.io/zh/latest/

     本章讲解摄像机的移动。

    欧拉角

          欧拉角是表示3D空间中可以表示任何旋转的三个值， 由莱昂哈德·欧拉在18世纪提出。 有三种
    欧拉角： 俯仰角(Pitch)、 偏航角(Yaw)和滚转角(Roll)， 下面的图片展示了它们的含义：

     下面看看添加鼠标，键盘，视角的变化吧。

    代码部分

     顶点着色器：

    1. #version 330 core
    2. layout (location = 0) in vec3 aPos;
    3. layout (location = 1) in vec2 aTexCoord;
    4.  
    5. out vec2 TexCoord;
    6. uniform mat4 model;
    7. uniform mat4 view;
    8. uniform mat4 projection;
    9. void main()
    10. {
    11.         gl_Position =projection*view*model* vec4(aPos, 1.0);
    12.         TexCoord = vec2(aTexCoord.x, aTexCoord.y);
    13. }

    片段着色器：

    1. #version 330 core
    2. out vec4 FragColor;
    3.  
    4. in vec2 TexCoord;
    5.  
    6. // texture samplers
    7. uniform sampler2D texture1;
    8. uniform sampler2D texture2;
    9.  
    10. void main()
    11. {
    12.         // linearly interpolate between both textures (80% container, 20% awesomeface)
    13.         FragColor = mix(texture(texture1, TexCoord), texture(texture2, TexCoord), 0.2);
    14.         //FragColor =texture(texture2,TexCoord);
    15. }

    源码部分：

    1. #ifndef BKQOPENGLW_H
    2. #define BKQOPENGLW_H
    3.  
    4. #include 
    5. #include 
    6. #include 
    7. #include 
    8. #include 
    9. #include 
    10. #include 
    11. #include 
    12. #include 
    13. class BKQOpenglW : public QOpenGLWidget, QOpenGLFunctions_3_3_Core
    14. {
    15.     Q_OBJECT
    16. public:
    17.     enum Shape{None,Rect,circle,Triangle};
    18.     explicit BKQOpenglW(QWidget *parent = nullptr);
    19.     ~BKQOpenglW();
    20.     void drawShapes(Shape shape);
    21.     void setWireFrame(bool b);
    22. protected:
    23.     //设置OpenGL资源和状态。在第一次调用resizeGL或paintGL之前被调用一次
    24.     virtual void initializeGL() override;
    25.     //渲染OpenGL场景，每当需要更新小部件时使用
    26.     virtual void resizeGL(int w, int h) override;
    27.     //设置OpenGL视口、投影等，每当尺寸大小改变时调用
    28.     virtual void paintGL() override;
    29.     //键盘操作重载Qt的事件处理
    30.     virtual void keyPressEvent(QKeyEvent *event) override;
    31.     //鼠标操作,重载Qt的事件处理
    32.     void mousePressEvent(QMouseEvent *event) override;
    33.     void mouseReleaseEvent(QMouseEvent *event) override;
    34.     void mouseMoveEvent(QMouseEvent *event) override;
    35.     void wheelEvent(QWheelEvent *event) override;
    36. private:
    37.     //计算
    38.     void calculateCamera();
    39.     QMatrix4x4 getViewMatrix();
    40. signals:
    41.  
    42. public slots:
    43.  
    44. private:
    45.     unsigned int VBO, VAO,EBO;
    46.     Shape m_Shape;
    47.     QOpenGLShaderProgram shaderProgram;
    48.     unsigned int texture;
    49.     QOpenGLTexture *pTexture;
    50.     QOpenGLTexture *pTexture2;
    51.  
    52.     QTimer timer;
    53.     int rotate{ 0 };
    54.  
    55.     //鼠标位置
    56.     QPoint mousePos;
    57.     QVector3D cameraPos{ 0.0f, 0.0f, 3.0f };
    58.     QVector3D cameraFront{ 0.0f, 0.0f, -1.0f };
    59.     QVector3D cameraUp{ 0.0f, 1.0f, 0.0f };
    60.     QVector3D cameraRight{ 1.0f, 0.0f, 0.0f };
    61.     //Euler Angles
    62.     //偏航角如果是0.0f,指向的是 x轴正方向，即右方向，所以向里转90度，初始方向指向z轴负方向
    63.     float eulerYaw{ -90.0f }; //偏航角，绕y左右转
    64.     float eulerPitch{ 0.0f }; //俯仰角，绕x上下转
    65.     //Camera options
    66.     float cameraSpeed{ 0.5f }; //移动速度
    67.     float cameraSensitivity{ 0.1f }; //鼠标拖动灵敏度
    68.     float projectionFovy{ 45.0f }; //透视投影的fovy参数，视野范围
    69.  
    70.  
    71. };
    72.  
    73. #endif // BKQOPENGLW_H

    对应cpp

    1. #include "bkqopenglw.h"
    2. #include
    3. #include 
    4. #include 
    5. #include 
    6. #include 
    7. #define STB_IMAGE_IMPLEMENTATION
    8. #include "stb_image.h"
    9.  
    10. #if 0
    11. float vertices[] = {
    12.         // positions          // colors           // texture coords
    13.          0.8f,  0.8f, 0.0f,   1.0f, 0.0f, 0.0f,   2.0f, 2.0f, // top right
    14.          0.8f, -0.8f, 0.0f,   0.0f, 1.0f, 0.0f,   2.0f, 0.0f, // bottom right
    15.         -0.8f, -0.8f, 0.0f,   0.0f, 0.0f, 1.0f,   0.0f, 0.0f, // bottom left
    16.         -0.8f,  0.8f, 0.0f,   1.0f, 1.0f, 0.0f,   0.0f, 2.0f  // top left
    17.     };
    18.  
    19. #endif
    20.  
    21. //顶点数据（盒子六个面，一个面两个三角）
    22. float vertices[] = {
    23.     -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
    24.     0.5f, -0.5f, -0.5f,  1.0f, 0.0f,
    25.     0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
    26.     0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
    27.     -0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
    28.     -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
    29.  
    30.     -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
    31.     0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
    32.     0.5f,  0.5f,  0.5f,  1.0f, 1.0f,
    33.     0.5f,  0.5f,  0.5f,  1.0f, 1.0f,
    34.     -0.5f,  0.5f,  0.5f,  0.0f, 1.0f,
    35.     -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
    36.  
    37.     -0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
    38.     -0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
    39.     -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
    40.     -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
    41.     -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
    42.     -0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
    43.  
    44.     0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
    45.     0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
    46.     0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
    47.     0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
    48.     0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
    49.     0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
    50.  
    51.     -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
    52.     0.5f, -0.5f, -0.5f,  1.0f, 1.0f,
    53.     0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
    54.     0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
    55.     -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
    56.     -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
    57.  
    58.     -0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
    59.     0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
    60.     0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
    61.     0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
    62.     -0.5f,  0.5f,  0.5f,  0.0f, 0.0f,
    63.     -0.5f,  0.5f, -0.5f,  0.0f, 1.0f
    64. };
    65.  
    66.  
    67. unsigned int indices[] = {  // note that we start from 0!
    68.     0, 1, 3,  // first Triangle
    69.     1, 2, 3   // second Triangle
    70. };
    71.  
    72.  
    73. //绘制多个盒子
    74. static QVector3D cubePositions[] = {
    75.     QVector3D( 0.0f,  0.0f,  0.0f),
    76.     QVector3D( 2.0f,  5.0f, -15.0f),
    77.     QVector3D(-1.5f, -2.2f, -2.5f),
    78.     QVector3D(-3.8f, -2.0f, -12.3f),
    79.     QVector3D( 2.4f, -0.4f, -3.5f),
    80.     QVector3D(-1.7f,  3.0f, -7.5f),
    81.     QVector3D( 1.3f, -2.0f, -2.5f),
    82.     QVector3D( 1.5f,  2.0f, -2.5f),
    83.     QVector3D( 1.5f,  0.2f, -1.5f),
    84.     QVector3D(-1.3f,  1.0f, -1.5f)
    85. };
    86.  
    87.  
    88. BKQOpenglW::BKQOpenglW(QWidget *parent) : QOpenGLWidget(parent)
    89. {
    90.     setFocusPolicy(Qt::StrongFocus);
    91. //    QSurfaceFormat fmt = format();
    92. //    fmt.setRenderableType(QSurfaceFormat::OpenGL);
    93. //    fmt.setProfile(QSurfaceFormat::CoreProfile);
    94.     fmt.setVersion(3, 3);
    95. //    //当启用多重采样时，将每个像素的首选样本数设置为numSamples
    96. //    fmt.setSamples(4);
    97. //    setFormat(fmt);
    98.  
    99.  
    100.     connect(&timer,&QTimer::timeout,this,[this](){
    101.             rotate+=2;
    102.             if(isVisible()){
    103.                 update();
    104.             }
    105.         });
    106.         timer.setInterval(50);
    107.      //弧度转换
    108.      calculateCamera();
    109.  
    110. }
    111.  
    112. BKQOpenglW::~BKQOpenglW()
    113. {
    114.     makeCurrent();
    115.     glDeleteVertexArrays(1,&VAO);
    116.     glDeleteBuffers(1,&VBO);
    117.     doneCurrent();
    118. }
    119.  
    120. void BKQOpenglW::drawShapes(BKQOpenglW::Shape shape)
    121. {
    122.     m_Shape = shape;
    123.     update();
    124. }
    125.  
    126. void BKQOpenglW::setWireFrame(bool b)
    127. {
    128.     makeCurrent();
    129.     if(b)
    130.     {
    131.        glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
    132.     }
    133.     else {
    134.        glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
    135.     }
    136.     update();
    137.     doneCurrent();
    138. }
    139.  
    140. void BKQOpenglW::initializeGL()
    141. {
    142.     initializeOpenGLFunctions();
    143.  
    144.     //    shaderProgram.addShaderFromSourceCode(QOpenGLShader::Vertex,vertexShaderSource);
    145.     //    shaderProgram.addShaderFromSourceCode(QOpenGLShader::Fragment,fragmentShaderSource);
    146.     shaderProgram.addShaderFromSourceFile(QOpenGLShader::Vertex,":/shader/shader.vs");
    147.     shaderProgram.addShaderFromSourceFile(QOpenGLShader::Fragment,":/shader/shader.fs");
    148.     shaderProgram.link();
    149.     glGenVertexArrays(1, &VAO);
    150.     glGenBuffers(1, &VBO);
    151.     // bind the Vertex Array Object first, then bind and set vertex buffer(s), and then configure vertex attributes(s).
    152.     glBindVertexArray(VAO);
    153.  
    154.     glBindBuffer(GL_ARRAY_BUFFER, VBO);
    155.     glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    156.  
    157.     //绑定ebo
    158.     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,EBO);
    159.     glBufferData(GL_ELEMENT_ARRAY_BUFFER,sizeof(indices),indices,GL_STATIC_DRAW);
    160.  
    161.     glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), nullptr);
    162.     glEnableVertexAttribArray(0);
    163.  
    164.     // texture coord attribute
    165.     glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
    166.     glEnableVertexAttribArray(1);
    167.  
    168.     //绑定纹理
    169.     glEnable(GL_BLEND);
    170.     glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
    171.     pTexture = new QOpenGLTexture(QImage(":/images/images/brickwall.jpg").mirrored());
    172.     pTexture2 = new QOpenGLTexture(QImage(":/images/images/awesomeface.png").mirrored());
    173.     shaderProgram.bind();
    174.     shaderProgram.setUniformValue("texture1",0);
    175.     shaderProgram.setUniformValue("texture2",1);
    176.     //默认为GL_REPEAT 重复 GL_MIRRORED_REPEAT镜像  GL_CLAMP_TO_EDGE 边缘拉伸 GL_CLAMP_TO_BORDER 超出部分使用用户定义
    177.     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S,GL_REPEAT);	// we want to repeat the awesomeface pattern so we kept it at GL_REPEAT
    178.     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T,GL_REPEAT);
    179.  
    180.  
    181.     QMatrix4x4 projection; //透视投影
    182.     //坐标到达观察空间之后，我们需要将其投影到裁剪坐标。
    183.     //裁剪坐标会被处理至-1.0到1.0的范围内，并判断哪些顶点将会出现在屏幕上
    184.     //参数1：指定视景体的视野的角度
    185.     //参数2：指定你的视景体的宽高比
    186.     //参数3：指定观察者到视景体的最近的裁剪面的距离（正数）
    187.     //参数4：指定观察者到视景体最远的裁剪面距离（正数）
    188.     projection.perspective(45.0f, 1.0f * width() / height(), 0.1f, 100.0f);
    189.     shaderProgram.setUniformValue("projection", projection);
    190.     shaderProgram.release();
    191.  
    192.     timer.start();
    193.  
    194.     // note that this is allowed, the call to glVertexAttribPointer registered VBO as the vertex attribute's bound vertex buffer object so afterwards we can safely unbind
    195.     glBindBuffer(GL_ARRAY_BUFFER, 0);
    196.  
    197.     // You can unbind the VAO afterwards so other VAO calls won't accidentally modify this VAO, but this rarely happens. Modifying other
    198.     // VAOs requires a call to glBindVertexArray anyways so we generally don't unbind VAOs (nor VBOs) when it's not directly necessary.
    199.     glBindVertexArray(0);
    200.  
    201. }
    202.  
    203. void BKQOpenglW::resizeGL(int w, int h)
    204. {
    205.        glViewport(0,0,w,h);
    206. }
    207.  
    208. void BKQOpenglW::paintGL()
    209. {
    210.  
    211.     glEnable(GL_DEPTH_TEST);
    212.     glClearColor(0.2f, 0.3f, 0.3f, 0.0f);
    213.     glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
    214.  
    215.  
    216.     shaderProgram.setUniformValue("view", getViewMatrix());
    217.  
    218.  
    219.     shaderProgram.bind();
    220.     glBindVertexArray(VAO);
    221.     switch (m_Shape) {
    222.     case Triangle:
    223.         glDrawArrays(GL_TRIANGLES,0,3);
    224.         break;
    225.     case Rect:
    226.         pTexture->bind(0);
    227.         pTexture2->bind(1);
    228.  
    229.         for (unsigned int i = 0; i < 10; i++) {
    230.                //计算模型矩阵
    231.                QMatrix4x4 model;
    232.                //平移
    233.                model.translate(cubePositions[i]);
    234.                //这样每个箱子旋转的速度就不一样
    235.                float angle = (i + 1.0f) * rotate;
    236.                //旋转
    237.                model.rotate(angle, QVector3D(1.0f, 0.3f, 0.5f));
    238.                //传入着色器并绘制
    239.                shaderProgram.setUniformValue("model", model);
    240.                glDrawArrays(GL_TRIANGLES, 0, 36);
    241.            }
    242.         break;
    243.     default:
    244.         break;
    245.     }
    246.  
    247. }
    248.  
    249. void BKQOpenglW::keyPressEvent(QKeyEvent *event)
    250. {
    251.      event->accept();
    252.      //横向是移动，不是绕0点
    253.      switch (event->key()) {
    254.      case Qt::Key_W: //摄像机往上，场景往下
    255.          cameraPos -= QVector3D::crossProduct(cameraFront, cameraRight).normalized() * cameraSpeed;
    256.          break;
    257.      case Qt::Key_S: //摄像机往下，场景往上
    258.          cameraPos += QVector3D::crossProduct(cameraFront, cameraRight).normalized() * cameraSpeed;
    259.          break;
    260.      case Qt::Key_A: //摄像机往左，场景往右
    261.          cameraPos -= QVector3D::crossProduct(cameraFront, cameraUp).normalized() * cameraSpeed;
    262.          break;
    263.      case Qt::Key_D: //摄像机往右，场景往左
    264.          cameraPos += QVector3D::crossProduct(cameraFront, cameraUp).normalized() * cameraSpeed;
    265.          break;
    266.      case Qt::Key_E: //远
    267.          cameraPos -= cameraFront * cameraSpeed;
    268.          break;
    269.      case Qt::Key_Q: //近
    270.          cameraPos += cameraFront * cameraSpeed;
    271.          break;
    272.      default:
    273.          break;
    274.      }
    275.      update();
    276.  
    277. }
    278.  
    279. void BKQOpenglW::mousePressEvent(QMouseEvent *event)
    280. {
    281.     event->accept();
    282.     mousePos = event->pos();
    283. }
    284.  
    285. void BKQOpenglW::mouseReleaseEvent(QMouseEvent *event)
    286. {
    287.      event->accept();
    288. }
    289.  
    290. void BKQOpenglW::mouseMoveEvent(QMouseEvent *event)
    291. {
    292.     event->accept();
    293.     int x_offset = event->pos().x()-mousePos.x();
    294.     int y_offset = event->pos().y()-mousePos.y();
    295.     mousePos = event->pos();
    296.     //y轴的坐标是从下往上，所以相反
    297.     //我这里移动的是摄像机，所以场景往相反方向动
    298.     eulerYaw += x_offset*cameraSensitivity;
    299.     eulerPitch -= y_offset*cameraSensitivity;
    300.  
    301.     if (eulerPitch > 89.0f)
    302.         eulerPitch = 89.0f;
    303.     else if (eulerPitch < -89.0f)
    304.         eulerPitch = -89.0f;
    305.     calculateCamera();
    306.     update();
    307. }
    308.  
    309. void BKQOpenglW::wheelEvent(QWheelEvent *event)
    310. {
    311.     event->accept();
    312.         //fovy越小，模型看起来越大
    313.     if(event->delta() < 0){
    314.         //鼠标向下滑动为-，这里作为zoom out
    315.         projectionFovy += cameraSpeed;
    316.         if(projectionFovy > 90)
    317.             projectionFovy = 90;
    318.     }else{
    319.         //鼠标向上滑动为+，这里作为zoom in
    320.         projectionFovy -= cameraSpeed;
    321.         if(projectionFovy < 1)
    322.             projectionFovy = 1;
    323.     }
    324.     update();
    325.  
    326. }
    327.  
    328. void BKQOpenglW::calculateCamera()
    329. {
    330.     const float yaw = qDegreesToRadians(eulerYaw);
    331.     const float pitch = qDegreesToRadians(eulerPitch);
    332.     QVector3D front;
    333.     front.setX(std::cos(yaw) * std::cos(pitch));
    334.     front.setY(std::sin(pitch));
    335.     front.setZ(std::sin(yaw) * std::cos(pitch));
    336.     cameraFront = front.normalized();
    337. }
    338.  
    339. QMatrix4x4 BKQOpenglW::getViewMatrix()
    340. {
    341.     QMatrix4x4 view; //观察矩阵
    342.     view.lookAt(cameraPos, cameraPos+cameraFront, cameraUp);
    343.     return view;
    344. }

    后面的话

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  • 原文地址：https://blog.csdn.net/weixin_42126427/article/details/126147705