Qt5使用openGL，進行3d繪圖

https://blog.csdn.net/qq_35703848/article/details/79819854　

　1、

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QOpenGLWindow>
#include <QOpenGLFunctions>

class Widget : public QOpenGLWindow,protected QOpenGLFunctions
{
    Q_OBJECT

public:
  //  Widget(QWidget *parent = 0);
  //使用時，直接Widget w;即可。
    ~Widget(){};

    void initializeGL()
    {
        initializeOpenGLFunctions();
        glClearColor(0.0f,0.0f,0.0f,0.0f);
    }
    void resizeGL(int width, int height){} //若無需對高、寬進行處理，此函數可省
    void paintGL()
    {
        glClear(GL_COLOR_BUFFER_BIT);
    }
};

#endif // WIDGET_H

 

2、使用QGLWidget

#ifndef OPENGLWIDGET_H
#define OPENGLWIDGET_H
#include <QtOpenGL>

class OpenglWidget : public QGLWidget
{
public:
    OpenglWidget(QWidget *parent=0);
protected:
    void initializeGL();
    void initWidget();
    void paintGL();
    void resizeGL(int width, int height);
private:
    GLfloat angle;
    GLfloat angle1;
};
#endif // OPENGLWIDGET_H

 

#include "widget.h"

OpenglWidget::OpenglWidget(QWidget *parent):QGLWidget(parent)
{
    initWidget();
    initializeGL();
}
void OpenglWidget::initializeGL()
{
    //設置着色模式，平滑的
    glShadeModel(GL_SMOOTH);
    //清除掉之前的所有顏色
    glClearColor(0.0,0.0,0.0,0.0);
    //深度緩存,設置初始值為1.0，小於1.0的部分是可見的
    glClearDepth(1.0);
    //啟動OPenGL的相關功能，由參數決定，這里指
    //（啟用了之后，OpenGL在繪制的時候就會檢查，當前像素前面是否有別的像素，如果別的像素擋道了它，那它就不會繪制，也就是說，OpenGL就只繪制最前面的一層）
    glEnable(GL_DEPTH_TEST);
    //制定深度緩存比較值
    //這里參數指的是如果輸入的深度值小於或者等於參考值則通過
    glDepthFunc(GL_LEQUAL);

    glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);

}

void OpenglWidget::initWidget()
{
    //從屏幕上（400，400）為起始點，顯示一個640*400的界面
    setGeometry(400,200,640,480);
    setWindowTitle("My OPenGL");
}

void OpenglWidget::paintGL()
{
    //清除顏色緩沖和深度緩沖
    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
    //將當前點移置屏幕中心，相當於復位的操作
    glLoadIdentity();
    //平移函數,參數指的是分別從X軸，Y軸，Z軸平移
    glTranslatef(-1.5,0.0,-6.0);


    glRotated(angle,0.0,1.0,0.0);
    //創建圖元，是繪制什么圖形的接口，參數是繪制多邊形的意思
    glBegin(GL_QUADS);
    //設置頂點值（f代表浮點），三維空間坐標
    glColor3f( 1.0, 0.0, 0.0 );
    glBegin( GL_QUADS );

       glColor3f(1, 0, 0);
       glVertex3f(-1,1,1);
       glVertex3f(-1,1,-1);
       glVertex3f(-1,-1,-1);
       glVertex3f(-1,-1,1);

       glColor3f(0, 0, 1);
       glVertex3f(-1,1,-1);
       glVertex3f(-1,-1,-1);
       glVertex3f(1,-1,-1);
       glVertex3f(1,1,-1);

       glColor3f(0, 1, 0);
       glVertex3f(1,1,-1);
       glVertex3f(1,-1,-1);
       glVertex3f(1,-1,1);
       glVertex3f(1,1,1);

       glColor3f(0, 0, 1);
       glVertex3f(1,-1,1);
       glVertex3f(1,1,1);
       glVertex3f(-1,1,1);
       glVertex3f(-1,-1,1);

       glColor3f(0, 1, 0);
       glVertex3f(-1,1,1);
       glVertex3f(1,1,1);
       glVertex3f(1,1,-1);
       glVertex3f(-1,1,-1);

       glColor3f(0, 0, 1);
       glVertex3f(-1,-1,1);
       glVertex3f(-1,-1,-1);
       glVertex3f(1,-1,-1);
       glVertex3f(1,-1,1);
       glEnd();

       glLoadIdentity();

      glTranslatef(1.5,0.0,-6.0);
      glRotatef( angle1,0.0,1.0,0.0);

      glBegin( GL_TRIANGLES );

      glColor3f( 1.0, 0.0, 0.0 );
      glVertex3f(  0.0,  1.0,  0.0 );
      glColor3f( 0.0, 0.0, 1.0 );
      glVertex3f( -1.0, -1.0, -1.0 );
      glColor3f( 0.0, 1.0, 0.0 );
      glVertex3f( -1.0, -1.0,  1.0 );

      glColor3f( 1.0, 0.0, 0.0 );
      glVertex3f(  0.0,  1.0,  0.0 );
      glColor3f( 0.0, 0.0, 1.0 );
      glVertex3f(  1.0, -1.0,  1.0 );
      glColor3f( 0.0, 1.0, 0.0 );
      glVertex3f(  1.0, -1.0, -1.0 );

      glColor3f( 1.0, 0.0, 0.0 );
      glVertex3f(  0.0,  1.0,  0.0 );
      glColor3f( 0.0, 1.0, 0.0 );
      glVertex3f( -1.0, -1.0,  1.0 );
      glColor3f( 0.0, 0.0, 1.0 );
      glVertex3f(  1.0, -1.0,  1.0 );


      glColor3f( 1.0, 0.0, 0.0 );
      glVertex3f(  0.0,  1.0,  0.0 );
      glColor3f( 0.0, 1.0, 0.0 );
      glVertex3f(  1.0, -1.0, -1.0 );
      glColor3f( 0.0, 0.0, 1.0 );
      glVertex3f( -1.0, -1.0, -1.0 );

      glEnd();

    angle+=70;
    angle1+=10;

}

void OpenglWidget::resizeGL(int width, int height)
{
    if(0==height)
        height=1;
    //告訴繪制到窗體的哪個位置
    glViewport(0,0,width,height);
    // 設置矩陣模式，參數是設置為投影矩陣
    glMatrixMode(GL_PROJECTION);
    //復位操作
    glLoadIdentity();

    GLdouble aspectRatio=(GLfloat)width/(GLfloat)height;
    GLdouble rFov=45.0*3.14159265/180.0;
    GLdouble zNear=0.1;
    GLdouble zFar=100.0;
    //調用glFrustum，生成矩陣與當前矩陣相乘，生成透視效果
    glFrustum(-zNear*tan(rFov/2.0)*aspectRatio,
              zNear*tan(rFov/2.0)*aspectRatio,
              -zNear*tan(rFov/2.0),
              zNear*tan(rFov/2.0),
              zNear,zFar);
    //切回模型視圖矩陣
    glMatrixMode(GL_MODELVIEW);
    //復位
    glLoadIdentity();
}