(Help please) How to show drawing in QGLWidget on mainwindow?



  • Hello,
    I'm new to QT and OpenGL and need your help for my question. I have created a QT+OpenGL application. I have a mainwindow UI and have place a Widget inherited from QGLWidget on the mainwindow.

    I have write a simple OpenGL code to show points on the screen. The function is called (I had placed a messagebox there) but the app does not display the points I pained on screen. Please help what I should do to have the points display on screen.

    Here is my code in .h file.

    @#include <QGLWidget>

    class MyPanelOpenGL : public QGLWidget
    {
    Q_OBJECT
    public:
    explicit MyPanelOpenGL(QWidget *parent = 0);

    protected:
    void initializeGL();
    void resizeGL(int width, int height);
    void paintGL();
    void draw();

    signals:

    public slots:

    };@

    and here is my implementation .cpp file - in which I draw points in draw()
    @MyPanelOpenGL::MyPanelOpenGL(QWidget *parent) :
    QGLWidget(parent)
    {
    setFormat(QGLFormat(QGL::DoubleBuffer | QGL::DepthBuffer));
    }

    void MyPanelOpenGL::initializeGL()
    {
    qglClearColor(Qt::white);
    glShadeModel(GL_FLAT);
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_CULL_FACE);
    }

    void MyPanelOpenGL::resizeGL(int width, int height)
    {
    glViewport(0,0,width,height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    GLfloat x = GLfloat(width)/height;
    glFrustum(-x, +x, -1.0, +1.0, 4.0, 15.0);
    glMatrixMode(GL_MODELVIEW);

    }

    void MyPanelOpenGL::paintGL()
    {
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    draw();
    }

    void MyPanelOpenGL::draw()
    {
    glColor3f(1.0, 0.0, 0.0);
    glBegin(GL_POINTS);
    glVertex2i(50,100);
    glVertex2i(75,150);
    glVertex2i(100,200);
    glEnd();

    glFlush();
    //updateGL();
    

    }
    @

    Really thanks for your help ^^



  • Hi Fuji,

    My guess is that you can't see the points because they are outside the viewing frustum - try glVertex2i(0,0).

    Regards,



  • Hi Arnaut, Thanks for that but it still doesn't work.


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