Qt+OpenGL——通过索引绘制管道模型并使用鼠标控制摄像机镜头

朱雀 2023-03-06 03:50 179阅读 0赞

最终效果  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p1aWN5QWN0aXZlR2lsYmVydA_size_16_color_FFFFFF_t_70]

头文件

#ifndef GLWIDGET_H
    #define GLWIDGET_H
    
    #include <QOpenGLWidget>
    #include <QOpenGLFunctions_4_5_Core>
    #include <QWheelEvent>
    #include <QMouseEvent>
    #include <QOpenGLShaderProgram>
    
    #include "glcamera.h"
    
    class GLWidget : public QOpenGLWidget,public QOpenGLFunctions_4_5_Core
    {
        
        Q_OBJECT
    public:
        explicit GLWidget(QWidget *parent=nullptr);
        ~GLWidget();
    
    protected:
    
        void iniDatas();
    
        void initializeGL(); //初始化相关的操作全在这个函数中完成
        void resizeGL(int w,int h);
        void paintGL();
    
        float *getCylinderVertex(int segment, float r1, float r2, int &count);
        int *getCylinderIndices(int segment, int &count);
    
        void wheelEvent(QWheelEvent *pEvent);
    
        void mousePressEvent(QMouseEvent *pEvent);
        void mouseMoveEvent(QMouseEvent *pEvent);
        void mouseReleaseEvent(QMouseEvent *pEvent);
    private:
        QOpenGLShaderProgram *m_pShaderProgram = nullptr;
        GLCamera *m_pCamera = nullptr;
    
        QMatrix4x4 m_mat4Model;
        QPoint m_pointMouseDown;
    
        Qt::MouseButton m_mouseBtn;
    
        int m_nDataCount = 0;
    
    };
    
    #endif // GLWIDGET_H

#include "glwidget.h"
    #include <QOpenGLBuffer>
    #include <QtMath>
    
    #include <QDebug>
    
    
    #define BUFFER_OFFSET(offset) ((void*)(offset))
    
    
    #define BALL_X_SEGMENT 40
    #define BALL_Y_SEGMENT 50
    
    
    GLuint VAO = -1;
    GLWidget::GLWidget(QWidget *parent):
        QOpenGLWidget(parent)
    {
        
    
    }
    
    GLWidget::~GLWidget()
    {
        
    
    }
    
    void GLWidget::iniDatas()
    {
        
        int nIndicesCount = 0;
        int nDataCount = 0;
        float *vertices = getCylinderVertex(BALL_X_SEGMENT,0.6f,0.8f,nDataCount);
        int *indices = getCylinderIndices(BALL_X_SEGMENT,nIndicesCount);
    
        glGenVertexArrays(1,&VAO);
        glBindVertexArray(VAO);
    
        GLuint VBO;
        glGenBuffers(1,&VBO);
        glBindBuffer(GL_ARRAY_BUFFER,VBO);
        glBufferData(GL_ARRAY_BUFFER,sizeof(vertices) * nDataCount,
                     vertices,GL_STATIC_DRAW);
        glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,sizeof(float) * 3,BUFFER_OFFSET(0));
        glEnableVertexAttribArray(0);
    
        GLuint EBO;
        glGenBuffers(1,&EBO);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,EBO);
        glBufferData(GL_ELEMENT_ARRAY_BUFFER,sizeof(indices) * nIndicesCount,indices,GL_STATIC_DRAW);
    
        glBindVertexArray(0);//解绑
        glBindBuffer(GL_ARRAY_BUFFER,0);
    
        m_nDataCount = nIndicesCount;
    
        //        glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);//填充图
        //            glPolygonMode(GL_FRONT_AND_BACK,GL_POINT);//散点图
        glPolygonMode(GL_FRONT_AND_BACK,GL_LINE);//线框图
    }
    
    void GLWidget::initializeGL()
    {
        
        initializeOpenGLFunctions();
    
        m_pShaderProgram = new QOpenGLShaderProgram(this);
        m_pShaderProgram->addShaderFromSourceFile(QOpenGLShader::Vertex,":/shaders/vertext.vert");
        m_pShaderProgram->addShaderFromSourceFile(QOpenGLShader::Fragment,":/shaders/fragment.frag");
        m_pShaderProgram->link();
        m_pShaderProgram->bind();
    
        m_pCamera = new GLCamera(this->width() * 1.0/this->height());
        iniDatas();
    }
    
    void GLWidget::resizeGL(int w, int h)
    {
        
        glViewport(0,0,w,h);
    }
    
    void GLWidget::paintGL()
    {
        
        static const GLfloat color[] = {
        0.0f,0.0f,0.0f,1.0f};
    
        glClearBufferfv(GL_COLOR,0,color);
    
        if(VAO == -1){
        
            return;
        }
    
        m_pShaderProgram->setUniformValue("model",m_mat4Model);
        m_pShaderProgram->setUniformValue("view",m_pCamera->getCameraMatrix());
    
        glUseProgram(m_pShaderProgram->programId());
        glBindVertexArray(VAO);
        glDrawElements(GL_TRIANGLES,m_nDataCount,GL_UNSIGNED_INT,0);
    
        glBindVertexArray(0);
    
        update();
    }
    
    
    float *GLWidget::getCylinderVertex(int segment, float r1, float r2,int &count)
    {
        
        float alpha = 2 * M_PI / segment;
    
        count = (segment + 1) * 3 * 4;
        float *data = new float[count];
    
        int a = 2;
        int b = 1;
        int c = 0;
    
        int nIndex = 0;
        for (int i = 0; i <= segment; ++i) {
        
            data[nIndex + a] = r1 * qSin(alpha * i);
            data[nIndex + b] = r1 * qCos(alpha * i);
            data[nIndex + c] = -r2;
            nIndex += 3;
    
        }
    
        for (int i = 0; i <= segment; ++i) {
        
            data[nIndex + a] = r2 * qSin(alpha * i);
            data[nIndex + b] = r2 * qCos(alpha * i);
            data[nIndex + c] = -r2;
            nIndex += 3;
        }
    
        for (int i = 0; i <= segment; ++i) {
        
            data[nIndex + a] = r1 * qSin(alpha * i);
            data[nIndex + b] = r1 * qCos(alpha * i);
            data[nIndex + c] = r2;
            nIndex += 3;
    
        }
    
        for (int i = 0; i <= segment; ++i) {
        
            data[nIndex + a] = r2 * qSin(alpha * i);
            data[nIndex + b] = r2 * qCos(alpha * i);
            data[nIndex + c] = r2;
            nIndex += 3;
        }
    
    
        return data;
    }
    
    int *GLWidget::getCylinderIndices(int segment,int &count)
    {
        
        count = segment * 6 * 4;
        int *indices = new int[count];
    
        int nIndex = 0;
        //第一个圆环
        for (int i = 0; i < segment; ++i) {
        
            indices[nIndex] = i;
            indices[nIndex + 1] = segment + (i + 1);
            indices[nIndex + 2] = i + 1;
            indices[nIndex + 3] = i + 1;
            indices[nIndex + 4] = segment + (i + 1);
            indices[nIndex + 5] = segment + (i + 2);
    
            nIndex += 6;
        }
    
        //第一层形成柱 0,2
        for (int i = 0; i < segment; ++i) {
        
            indices[nIndex] = i;
            indices[nIndex + 1] = segment * 2 + i + 2;
            indices[nIndex + 2] = i + 1;
            indices[nIndex + 3] = i + 1;
            indices[nIndex + 4] = segment * 2 + (i + 2);
            indices[nIndex + 5] = segment * 2 + (i + 3);
    
            nIndex += 6;
        }
    
    
        //第二个圆环
        for (int i = 0; i < segment; ++i) {
        
            indices[nIndex] = i + (segment * 2 + 2);
            indices[nIndex + 1] = segment * 3 + (i + 3);
            indices[nIndex + 2] = i + 1 + (segment * 2 + 2);
            indices[nIndex + 3] = i + 1 + (segment * 2 + 2);
            indices[nIndex + 4] = segment * 3 + (i + 3);
            indices[nIndex + 5] = segment * 3 + (i + 4);
    
            nIndex += 6;
        }
    
    
        //第二层形成柱 1,3
        for (int i = 0; i < segment; ++i) {
        
            indices[nIndex] = i + segment + 1;
            indices[nIndex + 1] = segment * 3 + (i + 3);
            indices[nIndex + 2] = i + 1 + segment + 1;
            indices[nIndex + 3] = i + 1 + segment + 1;
            indices[nIndex + 4] = segment * 3 + (i + 3);
            indices[nIndex + 5] = segment * 3 + (i + 4);
            nIndex += 6;
        }
    
        return indices;
    }
    
    void GLWidget::wheelEvent(QWheelEvent *pEvent)
    {
        
        if(!m_pCamera){
        
            return;
        }
    
        if(pEvent->delta() > 0){
        //向上滚动，放大
            m_pCamera->adjustFocus(1.2f);
        }else{
        
            m_pCamera->adjustFocus(1/1.2f);
        }
    
        update();
        QOpenGLWidget::wheelEvent(pEvent);
    }
    
    void GLWidget::mousePressEvent(QMouseEvent *pEvent)
    {
        
        m_pointMouseDown = pEvent->pos();
        m_mouseBtn = pEvent->button();
    }
    
    void GLWidget::mouseMoveEvent(QMouseEvent *pEvent)
    {
        
        QPoint pos = pEvent->pos();
        QVector2D offset(pos.x() - m_pointMouseDown.x(),
                         pos.y() - m_pointMouseDown.y());
    
        m_pointMouseDown = pos;
    
        if(m_mouseBtn == Qt::LeftButton){
        
            int angleX = offset.x() / width() * 180;
            int angleY = offset.y() / width() * 90;
    
            m_pCamera->rotate(angleX,angleY);
        }else{
        
            m_pCamera->translate(-offset.x() / this->width() * 5,-offset.y() / this->height() * 5);
        }
    
    }
    
    void GLWidget::mouseReleaseEvent(QMouseEvent *pEvent)
    {
        
        m_pointMouseDown = pEvent->pos();
        m_mouseBtn = Qt::NoButton;
    }

shader文件

#version 450 core
    
    layout(location=0) in vec3 aPos;
    uniform mat4 model;
    uniform mat4 view;
    void main()
    {
        
            gl_Position = view * model * vec4(aPos,1);
    }

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p1aWN5QWN0aXZlR2lsYmVydA_size_16_color_FFFFFF_t_70]: /images/20230208/3178713511404078bed3989e84737469.png