Re: [osg-users] Qt mouse wheel zoom howto
Hi Paulo,
Possible the easiest way to do this would be modify the
osgGA::TrackballManipulator itself (and see in the changes so we can
all benefit :-), or subclass from it and override the handle method to
add the handling of the mouse wheel events. Once you've done this
you'd need to pass in the mouse wheel events via the
osgGA::EventQueue.
Robert.
On Thu, Feb 26, 2009 at 1:00 PM, Paulo Jnkml paulo.jn...@gmail.com wrote:
Hi,
I was writing an application using Qt and osg.
I would like to zoom in and out on mouse scroll.
I could not find a good way to do this, so I came up with:
void osgWidget::wheelEvent(QWheelEvent *event) {
const float delta(event-delta() / (8.0f * 15.0f));
const float x(event-x());
const float y(event-y());
const float ydy(y + delta);
const int b(osgGA::GUIEventAdapter::LEFT_MOUSE_BUTTON
| osgGA::GUIEventAdapter::MIDDLE_MOUSE_BUTTON);
_gw-getEventQueue()-mouseButtonPress(x, y, b);
_gw-getEventQueue()-mouseMotion(x, ydy);
_gw-getEventQueue()-mouseButtonRelease(x, ydy, b);
}
which actually works but it's not so elegant.
Is there a obj-zoom(0.9f); to get 10% closer or obj-zoom(1.1f); to get 10%
further for example?
thank you.
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Re: [osg-users] Qt mouse wheel zoom howto
Hi Martin,
I had a try at doing this through TrackBallManipulator
This seems to work, tested on Windows with viewerQT and viewer.Each mouseWheel
click zooms in/out by 10%
I'm not an expert and would welcome any suggestions about better ways to do
this.
That looks a bit like how we did it in our local codebase, except that
instead of acting directly on _distance, in our case we set dy to 0.1 or
-0.1 (depending on scroll up or down) and then let the normal mouse
zooming functionality do the zooming calculations:
if (_ga_t0-getEventType() == osgGA::GUIEventAdapter::SCROLL)
{
dy = _ga_t0-getScrollingMotion() ==
osgGA::GUIEventAdapter::SCROLL_DOWN ? 0.1 : -0.1;
}
It works well too, perhaps you can compare the two and see which one you
like best in terms of behavior. I don't know if zooming in/out by 10%
per mouse wheel click is too much or too little, I haven't tested your
code directly...
And in our case, we didn't add a completely separate case for SCROLL in
the handle() method, just piggybacked on top of the DRAG case:
case (osgGA::GUIEventAdapter::SCROLL):
case (osgGA::GUIEventAdapter::DRAG):
{
// ...
}
J-S
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Re: [osg-users] Qt mouse wheel zoom howto
I had a try at doing this through TrackBallManipulator This seems to work, tested on Windows with viewerQT and viewer.Each mouseWheel click zooms in/out by 10% I'm not an expert and would welcome any suggestions about better ways to do this. -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=7522#7522 TrackballManipulator.cpp Description: Binary data ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Qt mouse wheel zoom howto
Thanks Jean-Sébastien, You can't reuse (osgGA::GUIEventAdapter::DRAG) case in handle() because the scroll event needs to be cleared. I like the idea of reusing the drag and 'dy' - I have rewritten it with that approach. It does lead to having to declare a couple of variables before they can be set which seems to be against OSG house style (and is generally a bad idea) I can only test on windows, but so long as the other windows toolkits add mouse wheel events to the GUIEventAdapter it should just work. -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=7534#7534 TrackballManipulator.cpp Description: Binary data ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Qt mouse wheel zoom howto
Hi Martin,
You can't reuse (osgGA::GUIEventAdapter::DRAG) case in handle() because the scroll event needs to be cleared.
That's how we do it, and I didn't see any problems... Our code is quite
close to:
case (osgGA::GUIEventAdapter::SCROLL):
case (osgGA::GUIEventAdapter::DRAG):
{
addMouseEvent(ea);
if (calcMovement()) aa.requestRedraw();
aa.requestContinuousUpdate(false);
_thrown = false;
return true;
}
and it works great. Perhaps there's something else that is different.
We've subclassed TrackballManipulator and replaced most of its
functionality with similar (but not quite identical) code...
I like the idea of reusing the drag and 'dy' - I have rewritten it with that
approach. It does lead to having to declare a couple of variables before they
can be set which seems to be against OSG house style (and is generally a bad
idea)
It's not that bad, since you only have an if and an else it can't really
fall through the cracks. As with any programming convention I tend to be
pragmatic...
J-S
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Re: [osg-users] Qt mouse wheel zoom howto
Skylark wrote:
case (osgGA::GUIEventAdapter::SCROLL):
case (osgGA::GUIEventAdapter::DRAG):
{
addMouseEvent(ea);
if (calcMovement()) aa.requestRedraw();
aa.requestContinuousUpdate(false);
_thrown = false;
return true;
}
On Windows at least with viewer/viewerQT if you don't call
flushMouseEventStack() the handle() gets called repeatedly.
I suppose because there isn't really an end event for a mouse scroll.
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Re: [osg-users] Qt mouse wheel zoom howto
Hi Martin, On Windows at least with viewer/viewerQT if you don't call flushMouseEventStack() the handle() gets called repeatedly. I suppose because there isn't really an end event for a mouse scroll. We're on Windows, and we have a Qt-based application running this (among others)... But we don't need to call flushMouseEventStack()... I don't know what to say. :-) J-S -- __ Jean-Sebastien Guayjean-sebastien.g...@cm-labs.com http://www.cm-labs.com/ http://whitestar02.webhop.org/ ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Qt mouse wheel zoom howto
Aha - I had _thrown=true in my scroll case ! For simplicity I will have SCROLL and DRAG together as you do. If somebody needs scroll to do more/different it is easy to add as a special case. -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=7549#7549 TrackballManipulator.cpp Description: Binary data ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
