makeCurrent crash

Stacktrace

0  QScopedPointer<QObjectData,QScopedPointerDeleter<QObjectData> >::data	qscopedpointer.h	132	0x60a20bda	
1	qGetPtrHelper<QScopedPointer<QObjectData,QScopedPointerDeleter<QObjectData> > >	qglobal.h	886	0x60a519ab	
2	QOpenGLContext::d_func	qopenglcontext.h	145	0x60a57503	
3	QOpenGLContext::makeCurrent	qopenglcontext.cpp	746	0x60a9ded2	
4	QGLContext::makeCurrent	qgl_qpa.cpp	218	0x64031446	
5	QGLWidget::makeCurrent	qgl.cpp	3713	0x63fe806d	
6	VizWidget::paintEvent	vizwidget.cpp	83	0x2861b0	
7	QWidget::event	qwidget.cpp	8029	0x612062cf	
8	QGLWidget::event	qgl_qpa.cpp	366	0x64031c04	
9	QApplicationPrivate::notify_helper	qapplication.cpp	3442	0x611c120e	
10	QApplication::notify	qapplication.cpp	3407	0x611bf2d5	
11	QCoreApplication::notifyInternal	qcoreapplication.cpp	871	0x604bddc4	
12	QCoreApplication::sendSpontaneousEvent	qcoreapplication.h	235	0x605da7c8	
13	QWidgetPrivate::drawWidget	qwidget.cpp	5129	0x6120bb5e	
14	QWidgetPrivate::repaint_sys	qwidgetbackingstore.cpp	1330	0x611ce52b	
15	QWidgetPrivate::syncBackingStore	qwidget.cpp	1680	0x6120da74	
16	QWidgetWindow::handleExposeEvent	qwidgetwindow.cpp	654	0x61240091	
17	QWidgetWindow::event	qwidgetwindow.cpp	204	0x6123eab9	
18	QApplicationPrivate::notify_helper	qapplication.cpp	3442	0x611c120e	
19	QApplication::notify	qapplication.cpp	2845	0x611bd3d2	
...	<More>				

vizwidget.cpp

#include "vizwidget.h"

VizWidget::VizWidget(QWidget *parent) :
    QGLWidget(parent)
{
    playbackWidget = NULL;
    vertShader = "./shaders/basic.vert";
    fragShader = "./shaders/basic.frag";
    needsResize = false;
    frameCount = 0;

    makeCurrent();
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glEnable(GL_DEPTH_TEST);
    frameCount = 0;

    // Prepare a complete shader program...
    if ( !prepareShaders(vertShader, fragShader) )
        return;
    // Bind the shader program so that we can associate variables from
    // our application to the shaders
    if ( !shaderProgram.bind() )
    {
        qWarning() << "Could not bind shader program to context";
        return;
    }

    // Make the background quad and bind it to the vertex buffer
    GLfloat vertices[] = {-1, -1, 0, //bottom left corner
                          -1,  1, 0, //top left corner
                           1,  1, 0, //top right corner
                           1, -1, 0}; // bottom right corner

    vertexBuffer.create();
    vertexBuffer.setUsagePattern( QOpenGLBuffer::StaticDraw );
    if ( !vertexBuffer.bind() )
    {
        qWarning() << "Could not bind vertex buffer to the context";
        return;
    }
    vertexBuffer.allocate(vertices, 3 * 4 * sizeof( float ));
    shaderProgram.setAttributeBuffer("vertex", GL_FLOAT, 0, 3);
    shaderProgram.enableAttributeArray("vertex");


    // Setup the fft buffer
    fftBuffer.create();
    fftBuffer.bind(shaderProgram.programId(), "fftBlock");
    fftBuffer.allocate(FFT_SIZE);
}

VizWidget::~VizWidget()
{
}

void VizWidget::setPlayBackPointer(PlaybackWidget *p)
{
    playbackWidget = p;
}

void VizWidget::updateShaders()
{
    shaderProgram.setUniformValue("winSize", winWidth, winHeight);
    shaderProgram.setUniformValue("time", frameCount);
    fftBuffer.write(0, &fftData, FFT_SIZE);
}

void VizWidget::resizeEvent(QResizeEvent *e)
{
    glViewport(0, 0, (GLint)winWidth, (GLint)winHeight);
}

void VizWidget::closeEvent(QCloseEvent *evt)
{
    QGLWidget::closeEvent(evt);
}

void VizWidget::paintEvent(QPaintEvent *)
{
    makeCurrent();

    // Clear the buffer with the current clearing color
    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
    //Update the fft buffer
    updateFFT();
    updateShaders();
    // Draw stuff
    glDrawArrays(GL_QUADS, 0, 4);

    parent->swapBuffers();
    ++frameCount;
}

void VizWidget::showEvent(QShowEvent *e)
{
    QGLWidget::showEvent(e);
}

void VizWidget::hideEvent(QHideEvent *e)
{
    QGLWidget::hideEvent(e);
}

bool VizWidget::prepareShaders(const QString &vertShaderPath, const QString &fragShaderPath)
{
    // First we load and compile the vertex shader...
    bool result = shaderProgram.addShaderFromSourceFile(QOpenGLShader::Vertex, vertShaderPath);
    if ( !result )
        qWarning() << shaderProgram.log();

    // ...now the fragment shader...
    result = shaderProgram.addShaderFromSourceFile(QOpenGLShader::Fragment, fragShaderPath);
    if ( !result )
        qWarning() << shaderProgram.log();

    // ...and finally we link them to resolve any references.
    result = shaderProgram.link();
    if ( !result )
        qWarning() << "Could not link shader program:" << shaderProgram.log();

    return result;
}

void VizWidget::updateFFT()
{
    if(playbackWidget != NULL)
        playbackWidget->getFFT(&fftData);
}