How can I detect collision among QPixmaps and QGraphicsItems objects

DSlim

If I change to a QGraphicsPixmapItem can I make another list and collide the two. i.e. collideWithItem?

Asperamanca

Yes, it should work that way.

DSlim

I understand what you're saying about collision but the issues is I have the images stored in an array.

@ main_targets[0] = QPixmap(":images/darkbluelogo.jpg");
main_targets[1] = QPixmap(":images/graylogo.jpg");
main_targets[2] = QPixmap(":images/lightbluelogo.jpg");
main_targets[3] = QPixmap(":images/lime.jpg");
main_targets[4] = QPixmap(":images/pink.jpg");
main_targets[5] = QPixmap(":images/purple.jpg");
main_targets[6] = QPixmap(":images/redlogo.jpg");
main_targets[7] = QPixmap(":images/yellow.jpg");
main_targets[8] = QPixmap(":images/brown.jpg");@

I ran into alot of errors trying to store this array in a QGraphicsPixmapItem

andreyc

@
QVector<QGraphicsPixmapItem*> targetItems;
foreach(QPixmap pix, main_targets) {
QGraphicsPixmapItem* item = QGraphicsPixmapItem(pix);
targetItems.append(item);
}
@

Hope it help.

DSlim

Thanks it helps but implementation throws @In instantiation of 'class QForeachContainer<QPixmap [9]>':@
The main_target array, QPixmap and targetitems array, QGraphicsPixmapItem seem to not play well together.

andreyc

How did you define main_targets?
Is it
@
QVector<QPixmap> main_targets;
or
QPixmap main_targets[9];
@

Qt specific keyword foreach works only with container classes like first definition. If you have second definition then you should use standard C++ for or while loop.

SGaist

Hi,

foreach must be used with a containers. A c array is not considered a container.

In your case you can use a classic for loop or change your array to a QList of QPixmap

Hope it helps

DSlim

Changing to containers I get the index is out of range error. Can I not assign each QPixmap an array value?

andreyc

If you use containers then you should use append() method to add pixmaps to your container.

DSlim

I thought the @QVector<QGraphicsPixmapItem*> targetItems;
foreach(QPixmap pix, main_targets) {
QGraphicsPixmapItem* item = QGraphicsPixmapItem(pix);
targetItems.append(item);
}@ takes each instance of the main_targets array, and creates QGraphicsPixmapItems of them.

andreyc

Could you show the code where you are getting "index is out of range" error.

DSlim

I pass the pmap to the MainTarget class by pointer, which was previously by reference. There isn't a specific line that the compiler is showing. It crashes on execution. I replaced main_targets[index] with targetItems since that should hold the QGraphicsPixmapItem items.

@void Dialog::setPixmaps()
{
//Targets are delivered every 1sec
Five_timer->start(1000);

QList<QGraphicsPixmapItem*> targetItems;
foreach(QPixmap pix, main_targets) {
QGraphicsPixmapItem* p_item = new QGraphicsPixmapItem(pix);
targetItems.append(p_item);
}

int StartY = 0;

//Random starting Y point between -140 and -389
StartY = (qrand() % (-400 + 150) -140);

index = (qrand() % 9);
{
    if(index % 2 == 0)
    {
        //When even is selected start at far right
        pmap = new MainTargets(targetItems[index], 0);
        pmap->setPos(345,StartY);
    }

    else
    {
        //When odd is selected start at far left
        pmap = new MainTargets(targetItems[index], 1);
        pmap->setPos(-325,StartY);

    }
}

scene->addItem(pmap);

}@

andreyc

Does it always crash on the same place?
Try to step through the function using a debugger.

What is the type of main_targets in line #9?

DSlim

QList<QPixmap> main_targets is the type.

Seems to fail at the QList::operator[].

That is why I think the main_target array seems to be the issue.

andreyc

How do you fill main_target?

DSlim

Guess that is where the problem is I thought the @ QList<QGraphicsPixmapItem*> targetItems;
foreach(QPixmap pix, main_targets) {
QGraphicsPixmapItem* p_item = new QGraphicsPixmapItem(pix);
targetItems.append(p_item);@ fills the main_target list. If not what is the purpose of this line?

andreyc

In this code you take the pixmaps from main_target and create qlist of qgraphicsitems.
So, the main_target must be populated by the qpixmaps before this code.

DSlim

@ main_targets[0] = QPixmap(":images/darkbluelogo.jpg");
main_targets[1] = QPixmap(":images/graylogo.jpg");
main_targets[2] = QPixmap(":images/lightbluelogo.jpg");
main_targets[3] = QPixmap(":images/lime.jpg");
main_targets[4] = QPixmap(":images/pink.jpg");
main_targets[5] = QPixmap(":images/purple.jpg");
main_targets[6] = QPixmap(":images/redlogo.jpg");
main_targets[7] = QPixmap(":images/yellow.jpg");
main_targets[8] = QPixmap(":images/brown.jpg");@

The main_targets are created and stored in the constructor initially before anything is done. So the qlist should have 9 qpixmaps.

andreyc

If I'm not mistaken you need to use .append() method to add elements to the QList. QList::opeartor[] does not work for adding new elements.

EDIT: Yep, you have to use append() or operator+=() to extend a list "operator[]":http://qt-project.org/doc/qt-5/qlist.html#operator-5b-5d requires an index to be valid (0 <= i < qlist.size())

DSlim

Thank you finally have it switched over to QGraphicsPixmapItems. Now the initial problem and see if I can get the collision working.