Qt3d timer and texture binding

[sunil.nair]

I am trying to update the texture image which will be bound to the cube. Bu, when I do this I cannot see anything on the screen.

a. Constructor has a timer which calls the update action slot every 10 ms
b. this slot gets the cursor position and reads a Mat image
c. Now this function calls Mat to QImage function which sets the grayscale value of the image and returns a QImage
d. This QImage is taken and binded on the cube in the paintgl code
e. but the code doesn't work

@QImage Mat2QImage(cv::Mat const& src, int i, int j)
{
//temp.at<uchar>(i, j) = 255; //white
cv::Mat temp, result; // make the same cv::Mat
//cv::cvtColor(src, temp,CV_BGR2RGB); // cvtColor Makes a copt, that what i need
cv::cvtColor(src,temp,CV_BGR2GRAY);
for(int row=i-10; row<i+10; row++)
{
for(int col=j-10;col<j+10;col++)
{
temp.at<uchar>(i,j)=255;
}
}
cv::cvtColor(temp,result,CV_GRAY2RGB);
QImage dest((const uchar *) result.data, result.cols, result.rows, result.step, QImage::Format_RGB888);
dest.bits(); // enforce deep copy, see documentation
// of QImage::QImage ( const uchar * data, int width, int height, Format format )
return dest;
}
//! [1] constructor, initialize the cube, cursor and camera
CubeView::CubeView(QWidget *parent)
{
//! [1]
QVector3D *cube1_pos= new QVector3D(0.0,0.0,-1.5);
QGLBuilder builder1;
builder1 << QGL::Faceted;
builder1 << QGLCube(3.25);
cube = builder1.finalizedSceneNode();
cube->setPosition(*cube1_pos);

QGLBuilder cursor_builder;
cursor_builder <<QGL::Faceted;
cursor_builder <<QGLCube(0.25);
cursor=cursor_builder.finalizedSceneNode();

//camera setup
camera()->setFieldOfView(25);
camera()->setNearPlane(1);
camera()->setFarPlane(15);

//! [2] set texture for cube and cursor
//QImage image(QLatin1String(":/bluecircle.jpg"));

cv::Mat mat=cv::imread("C:/Qt/qt-qt3d/tutorials/qt3d/cube4/bluecircle.jpg");

handcursor.setImage(QImage(QLatin1String(":/hand.jpg")));


//timer to call the update action slot
QTimer *timer = new QTimer(this);
connect(timer, SIGNAL(timeout()), this, SLOT(update_action()));
timer->start(50);
std::cout<<i<<j<<"\n";

}
//! [2] update the cursor based on the haptic position
void CubeView::update_action()
{
//QMatrix4x4 mat;
double position[3];
drawcursor(position);//updating the new cursor co-ordinates
QVector3D *p2=new QVector3D(position[0],position[1],position[2]);
cursor->setPosition(*p2);

int i=((position[0]+(gCubeEdgeLength/2))/gCubeEdgeLength)*imageDim;
int j=((position[1]+(gCubeEdgeLength/2))/gCubeEdgeLength)*imageDim;
cv::imshow("image",source);

//QImage image  = Mat2QImage(source, i, j);
//image.scaled(256,256,Qt::IgnoreAspectRatio);
//logo.setImage(image);
update();

}@