Hi,
Am 13.09.10 10:39, schrieb Robert Osfield:
> I kinda like this idea, it's not too intrusive w.r.t osgGA. However,
> in terms of event handlers receiving events I would have thought you'd
> want to get all the events for a single multi-touch together, since if
> you are getting them one by one you'd need to have a start and stop
> event so you'd know how to accumulate.
>
> How about a composite GUIEventType, or one that forms a linked list,
> and you just pass the head around.
Yes you are right, that's a problem with my last approach. Perhaps it's
best to add a ref_ptr to GuiEventAdapter holding a custom structure with
all touch-points with their positions, tapCounts and Ids.
(after a while)
So I tried that approach, I did not use a linked list of
GUIEventAdapters, as they would store too much information for a single
touchpoint (like scrolling and tablet-information, etc).
Instead I added a new class called TouchData which basically holds a
list of structs of { touch-id, touch-phase, x, y, tap-count}. The
GUIEventAdapter holds only a ref_ptr to this class, so the overhead for
osgGUIEventAdapter is not too much. I added some convenience-methods to
EventQueue and GUIEventAdapter.
To add multiple touch-points to a GUIEventAdapter you'll basically do
something along these lines:
osg::ref_ptr<osgGA::GUIEventAdapter> osg_event(NULL);
for(int i=0; i<numTouches; i++)
{
float x = ...
float y = ...
float id = ...
osgGA::GUIEventAdapter::TouchPhase phase = ...
if (!osg_event) {
// touchBegan, touchMoved, or touchEnded
osg_event = _win->getEventQueue()->touchMoved(id, phase,x, y);
} else {
osg_event->addTouchPoint(id, phase, x, y);
}
}
The current implementations set the x and y properties of the
GUIEventAdapter from the first touch point, so we get some basic
compatibility to existing manipulators (basically a one button mouse).
To get the touch-points from inside your event-handler:
if (ea.isMultiTouchEvent())
{
osgGA::GUIEventAdapter::TouchData* data = ea.getTouchData();
for(
osgGA::GUIEventAdapter::TouchData::iterator i = data->begin();
i != data->end();
++i)
{
std::cout
<< " id: " << i->id
<< " phase: " << i->phase
<< " pos: " << i->x << "/" << i->y
<< " tapCount:" << i->tapCount
<< std::endl;
}
}
I hope this design makes more sense. You can find this approach in the
git-repository / iphone-branch.
cheers,
Stephan
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