QOpenGLContext::SwapBuffer error when using different widgets

[miyoku157]

Hi,

I have a strange problem with my qt application. I have a custom QGLWidget which get a stream video from a camera. Like this:
sans.jpg

Ans as soon i put an other widget in an other layout, my custom widget stop rendering. Like this:
avec.png

And i got the error :

QOpenGLContext::swapBuffers() called with non-exposed window, behaviour is undefined.

QOpenGLContext::swapBuffers() called with non-exposed window, behaviour is undefined.

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Here is the code of my custom widget:

#include "widget.h"
#include "ui_widget.h"
 
Widget::Widget(QWidget *parent) :
    QGLWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
}
 
Widget::~Widget()
{
    wglMakeCurrent(GetDC((HWND)this->winId()), this->contextGL);
    cu.ClearProcess(nvGl.m_videoBuffer);
    nvGl.cleanupVideo(GetDC((HWND)this->winId()));
    delete ui;
}
 
void Widget::initializeGL(){
    glewInit();
    rec = Recorder();
    this->contextGL =wglGetCurrentContext();
    nvC = NVConfig();
    nvC.GlobalInit();
    nvGl = NVGL(nvC.l_vioConfig,GetDC((HWND)this->winId()));
    cu= CUGL();
    cu.InitProcess(nvGl.m_videoBuffer);
    QTimer::singleShot(16,this,SLOT(Tick()));
}
 
void Widget::resizeGL(int w, int h){
    this->resize(w,h);
    if(h==0)
        h =1;
    glViewport(0,0,w,h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    perspectiveGL(45.0f,w/h,0.1f,100.0f);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
 
}
void  Widget::Tick(){
        nvC.DetectIStatus();
        nvC.setCaptureDevice();
        nvGl.StartCapture();
        cu.ProcessVideo(nvGl.m_videoBuffer);
        rec.RecordShot(nvGl.m_videoTexture);
        paintGL();
 
    QTimer::singleShot(16,this,SLOT(Tick()));
}
 
void Widget::paintGL(){
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
    glLoadIdentity();
    glTranslatef(-0.5f,-.5f,-1.1f);
    glBegin(GL_QUADS);
    glTexCoord2f(0,0);
    glVertex3f(0,0,0);
    glTexCoord2f(0,1.0f);
    glVertex3f(0,1.0f,0);
    glTexCoord2f(1.0f,1.0f);
    glVertex3f(1.0f,1.0f,0);
    glTexCoord2f(1.0f,0);
    glVertex3f(1.0f,0,0);
    glEnd();
}
void Widget::Record(){
    rec.Start_StopRecord(nvGl.m_videoTexture);
}
 
 
void Widget::perspectiveGL(GLdouble fovY, GLdouble aspect, GLdouble zNear, GLdouble zFar){
    const GLdouble pi = 3.1415926535897932384626433832795;
    GLdouble fW, fH;
    fH = tan( fovY / 360 * pi) * zNear;
    fW = fH * aspect;
    glFrustum( -fW,fW,-fH,fH,zNear,zFar);
}

#include "widget.h"
#include "ui_widget.h"

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

Widget::~Widget()
{
    wglMakeCurrent(GetDC((HWND)this->winId()), this->contextGL);
    cu.ClearProcess(nvGl.m_videoBuffer);
    nvGl.cleanupVideo(GetDC((HWND)this->winId()));
    delete ui;
}

void Widget::initializeGL(){
    glewInit();
    rec = Recorder();
    this->contextGL =wglGetCurrentContext();
    nvC = NVConfig();
    nvC.GlobalInit();
    nvGl = NVGL(nvC.l_vioConfig,GetDC((HWND)this->winId()));
    cu= CUGL();
    cu.InitProcess(nvGl.m_videoBuffer);
    QTimer::singleShot(16,this,SLOT(Tick()));
}

void Widget::resizeGL(int w, int h){
    this->resize(w,h);
    if(h==0)
        h =1;
    glViewport(0,0,w,h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    perspectiveGL(45.0f,w/h,0.1f,100.0f);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

}
void  Widget::Tick(){
        nvC.DetectIStatus();
        nvC.setCaptureDevice();
        nvGl.StartCapture();
        cu.ProcessVideo(nvGl.m_videoBuffer);
        rec.RecordShot(nvGl.m_videoTexture);
        paintGL();

    QTimer::singleShot(16,this,SLOT(Tick()));
}

void Widget::paintGL(){
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glLoadIdentity();
    glTranslatef(-0.5f,-.5f,-1.1f);
    glBegin(GL_QUADS);
    glTexCoord2f(0,0);
    glVertex3f(0,0,0);
    glTexCoord2f(0,1.0f);
    glVertex3f(0,1.0f,0);
    glTexCoord2f(1.0f,1.0f);
    glVertex3f(1.0f,1.0f,0);
    glTexCoord2f(1.0f,0);
    glVertex3f(1.0f,0,0);
    glEnd();
}
void Widget::Record(){
    rec.Start_StopRecord(nvGl.m_videoTexture);
}


void Widget::perspectiveGL(GLdouble fovY, GLdouble aspect, GLdouble zNear, GLdouble zFar){
    const GLdouble pi = 3.1415926535897932384626433832795;
    GLdouble fW, fH;
    fH = tan( fovY / 360 * pi) * zNear;
    fW = fH * aspect;
    glFrustum( -fW,fW,-fH,fH,zNear,zFar);
}

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If you have any idea.
thanks in advance

[miyoku157]

Hi,

So i've managed to draw something on my window (you can see it here :New.png )
But I only get a white screen, during the creation of the QmainApllication, how does the different QGLWidget are handled? In the same thread? With only one GL Context?

I can't find these informations on internet and it could be the reason of the white screen. Do you have any idea?