GlWidget in Plugin crash on destroy

CatBehemoth

Hi there,

I recently implemented a simple opengl widget to display the 3D point cloud into the plugin. The widget works fine, but when I load the plugin and don't show it, only destroy at the end of application run i got a segmentation fault in the destructor of the plugin. The GlWidget class has been used in the form editor to subclass a widget object (but it happens when I create the window manually). The Plugin crashes in the area of a secondary display too.

When I use the GlWidget class like a normal form the problem doesn't occur. Do I forget some initialization?

Below is the opengl widget class and lik to simple Qt5.4 project where the problem occurs.

here is the link to the sample project

(header)
*#ifndef GLWIDGET_H
#define GLWIDGET_H

#include <QGLWidget>
#include <QGLShaderProgram>

class GlWidget : public QGLWidget
{
Q_OBJECT

public:
explicit GlWidget(QWidget *parent = 0);
~GlWidget();
QSize sizeHint() const;

void addVertices(QVector<QVector3D> &vertices, QVector<QVector3D> colors);
void setVertices(const QVector<QVector3D> &vertices, const QVector<QVector3D> &colors);
void remVertices();

protected:
void initializeGL();
void resizeGL(int width, int height);
void paintGL();
void mousePressEvent(QMouseEvent *event);
void mouseMoveEvent(QMouseEvent *event);
void wheelEvent(QWheelEvent *event);

private:

QMatrix4x4 pMatrix;
QGLShaderProgram shaderProgram;
QVector<QVector3D> m_vertices;
QVector<QVector3D> m_colors;

double alpha;
double beta;
double distance;
QPoint lastMousePosition;

QVector<QVector3D> m_grid;

};

#endif // GLWIDGET_H*

(source)

*#include "glwidget.h"
#include <QMouseEvent>
#include <QWheelEvent>

GlWidget::GlWidget(QWidget parent)
: QGLWidget(QGLFormat(/ Additional format options */), parent)
{
alpha = 25;
beta = -25;
distance = 10.0;

// define the grid
m_grid << QVector3D(-50, 0,  0) << QVector3D( 50, 0,  0) // X
       << QVector3D(0, -50,  0) << QVector3D( 0, 50,  0)// Y
       << QVector3D(0, 0, -50) << QVector3D( 0, 0,  50);// Z

}

GlWidget::~GlWidget()
{
qDebug () << this;
}

QSize GlWidget::sizeHint() const
{
return QSize(640, 480);
}

void GlWidget::remVertices()
{
m_vertices.clear();
m_colors.clear();

updateGL();

}

void GlWidget::addVertices(QVector<QVector3D> &vertices, QVector<QVector3D> colors)
{
for (QVector<QVector3D>::iterator i=vertices.begin();i!=vertices.end();i++)
{
m_vertices.append(*i);
}

for (QVector<QVector3D>::iterator i=colors.begin();i!=colors.end();i++)
{
    m_colors.append(*i);
}

updateGL();

}

void GlWidget::setVertices(const QVector<QVector3D> &vertices, const QVector<QVector3D> & colors)
{
m_vertices.clear();
m_colors.clear();

m_vertices  = vertices;
m_colors = colors;

updateGL();

}

//! [0]
void GlWidget::initializeGL()
{
//! [0]
glEnable(GL_DEPTH_TEST);
glEnable(GL_CULL_FACE);

qglClearColor(QColor(Qt::gray));

shaderProgram.addShaderFromSourceFile(QGLShader::Vertex, ":/vertexShader.vsh");
shaderProgram.addShaderFromSourceFile(QGLShader::Fragment, ":/fragmentShader.fsh");

shaderProgram.link();

}
//! [1]

void GlWidget::resizeGL(int width, int height)
{
if (height == 0) {
height = 1;
}

pMatrix.setToIdentity();
pMatrix.perspective(60.0, (float) width / (float) height, 0.001, 1000);

glViewport(0, 0, width, height);

}

//! [2]
void GlWidget::paintGL()
{
//! [2]
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

QMatrix4x4 mMatrix;
QMatrix4x4 vMatrix;

QMatrix4x4 cameraTransformation;
cameraTransformation.rotate(alpha, 0, 1, 0);
cameraTransformation.rotate(beta, 1, 0, 0);

QVector3D cameraPosition = cameraTransformation * QVector3D(0, 0, distance);
QVector3D cameraUpDirection = cameraTransformation * QVector3D(0, 1, 0);

vMatrix.lookAt(cameraPosition, QVector3D(0, 1, 0), cameraUpDirection);

//! [3]
shaderProgram.bind();

shaderProgram.setUniformValue("mvpMatrix", pMatrix * vMatrix * mMatrix);

shaderProgram.setAttributeArray("vertex", m_grid.constData());
shaderProgram.enableAttributeArray("vertex");

glDrawArrays(GL_LINES, 0, m_grid.size());

shaderProgram.disableAttributeArray("vertex");

shaderProgram.setAttributeArray("vertex", m_vertices.constData());
shaderProgram.enableAttributeArray("vertex");

shaderProgram.setAttributeArray("color", m_colors.constData());
shaderProgram.enableAttributeArray("color");

glDrawArrays(GL_POINTS, 0, m_vertices.size());

shaderProgram.disableAttributeArray("vertex");

shaderProgram.disableAttributeArray("color");

shaderProgram.release();

}
//! [3]

void GlWidget::mousePressEvent(QMouseEvent *event)
{
lastMousePosition = event->pos();

event->accept();

}

void GlWidget::mouseMoveEvent(QMouseEvent *event)
{
int deltaX = event->x() - lastMousePosition.x();
int deltaY = event->y() - lastMousePosition.y();

if (event->buttons() & Qt::LeftButton)
{
    alpha -= deltaX;
    while (alpha < 0) {
        alpha += 360;
    }
    while (alpha >= 360) {
        alpha -= 360;
    }

    beta -= deltaY;
    if (beta < -90) {
        beta = -90;
    }
    if (beta > 90) {
        beta = 90;
    }

    updateGL();
}

lastMousePosition = event->pos();

event->accept();

}

void GlWidget::wheelEvent(QWheelEvent *event)
{
int delta = event->delta();

if (event->orientation() == Qt::Vertical) {
    if (delta < 0) {
        distance *= 1.1;
    } else if (delta > 0) {
        distance *= 0.9;
    }

    updateGL();
}

event->accept();

}*

And the crash occurs here:

    Function: QScopedPointer<QObjectData, QScopedPointerDeleter<QObjectData> >::data() const

0xc074ec 55 push %ebp
0xc074ed <+0x0001> 89 e5 mov %esp,%ebp
0xc074ef <+0x0003> 83 ec 04 sub $0x4,%esp
0xc074f2 <+0x0006> 89 4d fc mov %ecx,-0x4(%ebp)
0xc074f5 <+0x0009> 8b 45 fc mov -0x4(%ebp),%eax
*** 0xc074f8 <+0x000c> 8b 00 mov (%eax),%eax ***
0xc074fa <+0x000e> c9 leave
0xc074fb <+0x000f> c3 ret

CatBehemoth

[SOLVED]

My bad... I took an obsolete old class. O:)

QGLWidget
This class is obsolete. It is provided to keep old source code working. We strongly advise against using it in new code.

i should use
QOpenGLWidget