Can't link QOpenGLWidget into a Form

JesusM

Hi guys, I have an application that uses QOpenGLWidget to show a scene.
Now, I want to add an interface to it so I created a Form and I added to it a QOpenGLWidget element:

Now I am trying to link the QOpenGLWidget I had created to this QOpenGlWidget that is into the Form but I cant. It shows a black screen.

This is the main class where I initialized the QOpenGLWidget:

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    QSurfaceFormat format;
    format.setDepthBufferSize(24);
    format.setStencilBufferSize(8);
    format.setVersion(4, 1);
    format.setProfile(QSurfaceFormat::CoreProfile);
    QSurfaceFormat::setDefaultFormat(format);

    glwindow *ventana = new glwindow();
    ventana->setFormat(format);
    ventana->show();
    std::cout<<"Ventana lanzada"<<std::endl;
    ventana->setMouseTracking(true);
    ventana->installEventFilter(ventana);

That shows me a window like this:

Now I added code to link this window to the frame I have created:
int main(int argc, char *argv[])
{
QApplication app(argc, argv);

QSurfaceFormat format;
format.setDepthBufferSize(24);
format.setStencilBufferSize(8);
format.setVersion(4, 1);
format.setProfile(QSurfaceFormat::CoreProfile);
QSurfaceFormat::setDefaultFormat(format);

glwindow *ventana = new glwindow();
ventana->setFormat(format);
ventana->show();
std::cout<<"Ventana lanzada"<<std::endl;
Form *ui = new Form();
ui->setQOpenGLWindow(ventana);
ui->show();
ventana->setMouseTracking(true);
ventana->installEventFilter(ventana);

and this is the result. On the left there is the form and on the right there is the window that I shown you before.

The black screen is a QOpenGLWidget that should show what is in the right window.
What is happening?
I leave here the form classes too:

#ifndef FORM_H
#define FORM_H

#include <QWidget>
#include "glwindow.h"

namespace Ui {
class Form;
}

class Form : public QWidget
{
    Q_OBJECT

public:
    explicit Form(QWidget *parent = nullptr);
    void setQOpenGLWindow(glwindow *window);
    ~Form();

private:
    Ui::Form *ui;
};

#endif // FORM_H

#include "form.h"
#include "ui_form.h"

Form::Form(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Form)
{
    ui->setupUi(this);

}

void Form::setQOpenGLWindow(glwindow *window)
{
    ui->openGLWidget = window;
}
Form::~Form()
{
    delete ui;
}

SGaist

Hi,

You are just replacing a pointer. That won't automagically replace the original widget by yours.

You should rather use the promote feature.

JesusM

@SGaist ok now I added a promote to my class glwindow which is the QopenglWidget class and my app crashes.
It says :

This is my glwindow.cpp:

#include "glwindow.h"

glwindow::glwindow(QWidget *parent): QOpenGLWidget (parent)
{

}
glwindow::~glwindow()
{

}

void glwindow::initializeGL()
    {
        // Set up the rendering context, load shaders and other resources, etc.:
       initializeOpenGLFunctions();
       printContextInformation();
       glClearColor(0.5f, 0.5f, 0.5f, 1.0f);

       // - Le decimos a OpenGL que tenga en cuenta la profundidad a la hora de dibujar.
       // No tiene por qué ejecutarse en cada paso por el ciclo de eventos.
       glEnable(GL_DEPTH_TEST);
       glDepthFunc(GL_LEQUAL);
    }

void glwindow::paintGL()
{
       // Draw the scene:
       glClear(GL_COLOR_BUFFER_BIT);
       renderer::getInstance()->dibujar();

}

 void glwindow::resizeGL(int w, int h)
 {
     renderer::getInstance()->redimensionarAreaDibujo(w,h);
     window_refresh();
 }

 bool glwindow::eventFilter(QObject *obj, QEvent *event)
 {

   if (event->type() == QEvent::KeyPress)
   {
     QKeyEvent* keyEvent = static_cast<QKeyEvent*>(event);

     if(keyEvent->key()==Qt::Key_Escape)
     {
         this->close();
     }
     if(keyEvent->key()==Qt::Key_P)
     {
         renderer::getInstance()->setModoDibujo(0);
     }
     if(keyEvent->key()==Qt::Key_W)
     {
         renderer::getInstance()->setModoDibujo(1);
     }
     if(keyEvent->key()==Qt::Key_T)
     {
         renderer::getInstance()->setModoDibujo(2);
     }
     if(keyEvent->key()==Qt::Key_A)
     {
         renderer::getInstance()->setModoDibujo(3);
     }
     if(keyEvent->key()==Qt::Key_Z)
     {
         renderer::getInstance()->setModoDibujo(4);
     }
     if(keyEvent->key()==Qt::Key_X)
     {
         renderer::getInstance()->setModoDibujo(5);
     }
     if(keyEvent->key()==Qt::Key_C)
     {
         renderer::getInstance()->setModoDibujo(6);
     }
     if(keyEvent->key()==Qt::Key_V)
     {
         renderer::getInstance()->setModoDibujo(7);
     }
     if(keyEvent->key()==Qt::Key_J)
     {
         renderer::getInstance()->setModoTextura(false);
     }
     if(keyEvent->key()==Qt::Key_K)
     {
         renderer::getInstance()->setModoTextura(true);
     }
     if(keyEvent->key()==Qt::Key_1)
     {
         renderer::getInstance()->camaraSiguiente();
     }
     if(keyEvent->key()==Qt::Key_2)
     {
         renderer::getInstance()->camaraAnterior();
     }
     if(keyEvent->key()==Qt::Key_N)
     {
         float posX, posY, posZ,lookX,lookY,lookZ,fovX;
         std::cout << "Proceso de creacion de una nueva camara virtual" << std::endl;
         std::cout << "Por favor, especifique su posicion en los ejes: " << std::endl;
         std::cout << "Eje X: ";
         std::cin >> posX;
         std::cout << std::endl;
         std::cout << "Eje Y: ";
         std::cout << std::endl;
         std::cin >> posY;
         std::cout << "Eje Z: ";
         std::cin >> posZ;
         std::cout << std::endl;
         std::cout << "Especifique hacia donde desea mirar: " << std::endl;
         std::cout << "Eje X: ";
         std::cin >> lookX;
         std::cout << std::endl;
         std::cout << "Eje Y: ";
         std::cin >> lookY;
         std::cout << std::endl;
         std::cout << "Eje Z: ";
         std::cin >> lookZ;
         std::cout << std::endl;
         std::cout << "Por ultimo especifique su angulo de vision: " << std::endl;
         std::cout << "Angulo de vision: ";
         std::cin >> fovX;
         renderer::getInstance()->crearCamara(QVector3D(posX, posY, posZ), QVector3D(lookX, lookY, lookZ), fovX);
     }
     if(keyEvent->key()==Qt::Key_Alt)
     {
         pan = true;
     }
     if(keyEvent->key()==Qt::Key_Control)
     {
         tilt=true;
     }
     if(keyEvent->key()==Qt::Key_Right)
     {
         renderer::getInstance()->moverCamara(TRUCK, 0.3f);
     }
     if(keyEvent->key()==Qt::Key_Left)
     {
         renderer::getInstance()->moverCamara(TRUCK, -0.3f);
     }
     if(keyEvent->key()==Qt::Key_Up)
     {
         renderer::getInstance()->moverCamara(CRANE, -0.3f);
     }
     if(keyEvent->key()==Qt::Key_Down)
     {
         renderer::getInstance()->moverCamara(BOOM, 0.3f);
     }
     if(keyEvent->key()==Qt::Key_F1)
     {
         renderer::getInstance()->moverCamara(DOLLY, -0.3f);
     }
     if(keyEvent->key()==Qt::Key_F2)
     {
         renderer::getInstance()->moverCamara(DOLLY, 0.3f);
         std::cout<<"Realizando DOLLY"<<std::endl;
     }

     window_refresh();
     return true;
   }
   if (event->type() == QEvent::KeyRelease)
   {
          pan = false;
          tilt = false;
          window_refresh();
          return true;
   }
   if(event->type() == QEvent::MouseButtonPress)
   {
        arrastrar = true;
        window_refresh();
        return true;
   }
   if(event->type() == QEvent::MouseButtonRelease)
   {
        arrastrar = false;
        window_refresh();
        return true;
   }
   if(event->type() == QEvent::Wheel)
   {
       QWheelEvent* wheelEvent = static_cast<QWheelEvent*>(event);
       if(wheelEvent->delta()> 0)
       {
           renderer::getInstance()->modificarZoom(-2);
       }else
       {
           renderer::getInstance()->modificarZoom(2);
       }

       window_refresh();
       return true;
   }
   if(event->type() == QEvent::MouseMove)
   {
       QMouseEvent* mouseEvent = static_cast<QMouseEvent*>(event);
       int xpos = mouseEvent->x();
       int ypos = mouseEvent->y();
       if (arrastrar)
            {
                if (pan)
                {
                    renderer::getInstance()->moverCamara(PAN, (posX - xpos)/2);
                    posX = xpos;
                    posY = ypos;

                }
                else if (tilt)
                {
                    renderer::getInstance()->moverCamara(TILT, (posY - ypos)/2);
                    posX = xpos;
                    posY = ypos;

                }
                else
                {
                    renderer::getInstance()->moverCamara(ORBIT_HORIZONTAL, (xpos - posX));
                    renderer::getInstance()->moverCamara(ORBIT_VERTICAL, ((ypos - posY) / 2));
                    posX = xpos;
                    posY = ypos;
                }
            }
            else {
                posX = xpos;
                posY = ypos;
            }
       window_refresh();
       return true;
   }

   return QObject::eventFilter(obj, event);
 }

 void glwindow::window_refresh()
 {
     renderer::getInstance()->refreshCallback();
     update();
 }

 void glwindow::printContextInformation()
 {
   QString glType;
   QString glVersion;
   QString glProfile;

   // Get Version Information
   glType = (context()->isOpenGLES()) ? "OpenGL ES" : "OpenGL";
   glVersion = reinterpret_cast<const char*>(glGetString(GL_VERSION));

   // Get Profile Information
 #define CASE(c) case QSurfaceFormat::c: glProfile = #c; break
   switch (format().profile())
   {
     CASE(NoProfile);
     CASE(CoreProfile);
     CASE(CompatibilityProfile);
   }
 #undef CASE

   // qPrintable() will print our QString w/o quotes around it.
   qDebug() << qPrintable(glType) << qPrintable(glVersion) << "(" << qPrintable(glProfile) << ")";
 }

and this is the code of the binding:

bool shaderProgram::use() {
    // Antes de activar un shader program para su uso, hay que comprobar
     // si se ha creado bien y se ha enlazado bien
    if ((handler) && (linked)) {
        shaderP->bind();
        return true;
    }
    else {
        std::cout << "Cannot use shader program";
        return false;
    }
}

Without the promote added it works in a different window as you can see in my first post but now I think I have to d something with the context but I dont know what.

Thanks

SGaist

In that case, let's take another way. Put a layout in your UI and add your OpenGL widget to it. This will likely be simpler in the short run.

JesusM

@SGaist How an I add my OpenGLWIdget to the UI instead of adding an empty one?. I am adding the widgets from here:

It has to be something with the context, I was not using any function related with the context when I hadn't the UI but It seems that now I need to use it and I don't know how.

jsulm

@JesusM said in Can't link QOpenGLWidget into a Form:

How an I add my OpenGLWIdget to the UI instead of adding an empty one?

@SGaist suggested to do it in your code manually (not using Designer).

JesusM

@jsulm ok I will try it now.

JesusM

@SGaist ok, It works but it creates the widget at the bottom:

and I need to have it on the left side, as I had it before creating it manually:

This is my hierarchy (with the empty QOpenGLWidget):

I added the widget to the centralWidget which has a grid layout. With the Qt Designer I just needed to drag my widget to the left margin to move it to the left but now I can't do it as I created the widget by code.

jsulm

@JesusM said in Can't link QOpenGLWidget into a Form:

I added the widget to the centralWidget

You should add it to the layout at desired position.

JesusM

@jsulm this is the layout where I want to add it. I had the QOpenGLWidget in that layout and it was ok as you can see in the second image.

jsulm

@JesusM I'm a bit lost now. You should remove that QOpenGLWidget you added in the Designer and instead add one via code and insert it in same layout.

JesusM

@jsulm I think I didn't explain myself well, sorry. The hierarchy that I posted is before I added the QOpenGLWidget by code, just to show you where I had it added. When I added it by code I removed that component from the Qt Designer so, now, my hierarchy in the Qt Designer hasn't got that component.

I added this code to the constructor of my UI to add the QOpenGLWidget:

QSurfaceFormat format;
    format.setDepthBufferSize(24);
    format.setStencilBufferSize(8);
    format.setVersion(4, 1);
    format.setProfile(QSurfaceFormat::CoreProfile);
    QSurfaceFormat::setDefaultFormat(format);

    glwindow *ventana = new glwindow();
    ventana->setFormat(format);
    ventana->show();
    ventana->setMouseTracking(true);
    ventana->installEventFilter(ventana);
    std::cout<<"Ventana lanzada"<<std::endl;
    ui->gridLayout->addWidget(ventana);

This code add the QOpenGLWidget but at the bottom of the grid layout.

jsulm

@JesusM said in Can't link QOpenGLWidget into a Form:

ui->gridLayout->addWidget(ventana);

You don't specify where exactly you want this widget to be in the layout. Take a look at https://doc.qt.io/qt-5/qgridlayout.html#addWidget

JesusM

@jsulm all the values I have tried make my program crash. I think I don't understand well how to use the addWidget function.
I tried all of this:

ui->gridLayout->addWidget(ventana,0,0); // This doesn't crash but the widget is still at the bottom;
    ui->gridLayout->addWidget(ventana,1,0); //Same here
//From here all make my program crash.
    ui->gridLayout->addWidget(ventana,0,1);
    ui->gridLayout->addWidget(ventana,1,1);
    ui->gridLayout->addWidget(ventana,0,0, Qt::AlignLeft);
    ui->gridLayout->addWidget(ventana,0,1, Qt::AlignLeft);
    ui->gridLayout->addWidget(ventana,1,0, Qt::AlignLeft);
    ui->gridLayout->addWidget(ventana,1,1, Qt::AlignLeft);

JesusM

I found the solution. I had to set the QSizePolicy of my widget and then place the widget at the top-left side:

    ventana->setSizePolicy(QSizePolicy::MinimumExpanding,QSizePolicy::Expanding);
    ui->gridLayout->addWidget(ventana,0,0);

Thanks all for helping :)

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