On 27/4/09 7:03 PM, Ulrich Hertlein wrote:
please find attached a patch for TrackballManipulator to fix zooming
using the MBP touchpad. The old code would always zoom-in even when
using the gesture to zoom-out.
I just realised I left some debug printf() in the code. Attached is the
cleaned version.
/ulrich
#include <osgGA/TrackballManipulator>
#include <osg/Quat>
#include <osg/Notify>
#include <osg/BoundsChecking>
using namespace osg;
using namespace osgGA;
TrackballManipulator::TrackballManipulator()
{
_modelScale = 0.01f;
_minimumZoomScale = 0.05f;
_allowThrow = true;
_thrown = false;
_distance = 1.0f;
_trackballSize = 0.8f;
_zoomDelta = 0.1f;
}
TrackballManipulator::~TrackballManipulator()
{
}
void TrackballManipulator::setNode(osg::Node* node)
{
_node = node;
if (_node.get())
{
const osg::BoundingSphere& boundingSphere=_node->getBound();
_modelScale = boundingSphere._radius;
}
if (getAutoComputeHomePosition()) computeHomePosition();
}
const osg::Node* TrackballManipulator::getNode() const
{
return _node.get();
}
osg::Node* TrackballManipulator::getNode()
{
return _node.get();
}
void TrackballManipulator::home(double /*currentTime*/)
{
if (getAutoComputeHomePosition()) computeHomePosition();
computePosition(_homeEye, _homeCenter, _homeUp);
_thrown = false;
}
void TrackballManipulator::home(const GUIEventAdapter& ea ,GUIActionAdapter& us)
{
home(ea.getTime());
us.requestRedraw();
us.requestContinuousUpdate(false);
}
void TrackballManipulator::init(const GUIEventAdapter& ,GUIActionAdapter& )
{
flushMouseEventStack();
}
void TrackballManipulator::getUsage(osg::ApplicationUsage& usage) const
{
usage.addKeyboardMouseBinding("Trackball: Space","Reset the viewing
position to home");
usage.addKeyboardMouseBinding("Trackball: +","When in stereo, increase the
fusion distance");
usage.addKeyboardMouseBinding("Trackball: -","When in stereo, reduce the
fusion distance");
}
bool TrackballManipulator::handle(const GUIEventAdapter& ea,GUIActionAdapter&
us)
{
switch(ea.getEventType())
{
case(GUIEventAdapter::FRAME):
if (_thrown && _allowThrow)
{
if (calcMovement()) us.requestRedraw();
}
return false;
default:
break;
}
if (ea.getHandled()) return false;
switch(ea.getEventType())
{
case(GUIEventAdapter::PUSH):
{
flushMouseEventStack();
addMouseEvent(ea);
if (calcMovement()) us.requestRedraw();
us.requestContinuousUpdate(false);
_thrown = false;
return true;
}
case(GUIEventAdapter::RELEASE):
{
if (ea.getButtonMask()==0)
{
double timeSinceLastRecordEvent = _ga_t0.valid() ?
(ea.getTime() - _ga_t0->getTime()) : DBL_MAX;
if (timeSinceLastRecordEvent>0.02) flushMouseEventStack();
if (isMouseMoving())
{
if (calcMovement())
{
us.requestRedraw();
us.requestContinuousUpdate(true);
_thrown = _allowThrow;
}
}
else
{
flushMouseEventStack();
addMouseEvent(ea);
if (calcMovement()) us.requestRedraw();
us.requestContinuousUpdate(false);
_thrown = false;
}
}
else
{
flushMouseEventStack();
addMouseEvent(ea);
if (calcMovement()) us.requestRedraw();
us.requestContinuousUpdate(false);
_thrown = false;
}
return true;
}
case(GUIEventAdapter::DRAG):
case(GUIEventAdapter::SCROLL):
{
addMouseEvent(ea);
if (calcMovement()) us.requestRedraw();
us.requestContinuousUpdate(false);
_thrown = false;
return true;
}
case(GUIEventAdapter::MOVE):
{
return false;
}
case(GUIEventAdapter::KEYDOWN):
if (ea.getKey()== GUIEventAdapter::KEY_Space)
{
flushMouseEventStack();
_thrown = false;
home(ea,us);
return true;
}
return false;
case(GUIEventAdapter::FRAME):
if (_thrown)
{
if (calcMovement()) us.requestRedraw();
}
return false;
default:
return false;
}
}
bool TrackballManipulator::isMouseMoving()
{
if (_ga_t0.get()==NULL || _ga_t1.get()==NULL) return false;
static const float velocity = 0.1f;
float dx = _ga_t0->getXnormalized()-_ga_t1->getXnormalized();
float dy = _ga_t0->getYnormalized()-_ga_t1->getYnormalized();
float len = sqrtf(dx*dx+dy*dy);
float dt = _ga_t0->getTime()-_ga_t1->getTime();
return (len>dt*velocity);
}
void TrackballManipulator::flushMouseEventStack()
{
_ga_t1 = NULL;
_ga_t0 = NULL;
}
void TrackballManipulator::addMouseEvent(const GUIEventAdapter& ea)
{
_ga_t1 = _ga_t0;
_ga_t0 = &ea;
}
void TrackballManipulator::setByMatrix(const osg::Matrixd& matrix)
{
_center = osg::Vec3(0.0f,0.0f,-_distance)*matrix;
_rotation = matrix.getRotate();
}
osg::Matrixd TrackballManipulator::getMatrix() const
{
return
osg::Matrixd::translate(0.0,0.0,_distance)*osg::Matrixd::rotate(_rotation)*osg::Matrixd::translate(_center);
}
osg::Matrixd TrackballManipulator::getInverseMatrix() const
{
return
osg::Matrixd::translate(-_center)*osg::Matrixd::rotate(_rotation.inverse())*osg::Matrixd::translate(0.0,0.0,-_distance);
}
void TrackballManipulator::computePosition(const osg::Vec3& eye,const
osg::Vec3& center,const osg::Vec3& up)
{
osg::Vec3 lv(center-eye);
osg::Vec3 f(lv);
f.normalize();
osg::Vec3 s(f^up);
s.normalize();
osg::Vec3 u(s^f);
u.normalize();
osg::Matrix rotation_matrix(s[0], u[0], -f[0], 0.0f,
s[1], u[1], -f[1], 0.0f,
s[2], u[2], -f[2], 0.0f,
0.0f, 0.0f, 0.0f, 1.0f);
_center = center;
_distance = lv.length();
_rotation = rotation_matrix.getRotate().inverse();
}
bool TrackballManipulator::calcMovement()
{
// mouse scroll is only a single event
if (_ga_t0.get()==NULL) return false;
float dx=0.0f;
float dy=0.0f;
unsigned int buttonMask=osgGA::GUIEventAdapter::NONE;
if (_ga_t0->getEventType()==GUIEventAdapter::SCROLL)
{
switch (_ga_t0->getScrollingMotion()) {
case osgGA::GUIEventAdapter::SCROLL_UP:
dy = _zoomDelta;
break;
case osgGA::GUIEventAdapter::SCROLL_DOWN:
dy = -_zoomDelta;
break;
case osgGA::GUIEventAdapter::SCROLL_LEFT:
case osgGA::GUIEventAdapter::SCROLL_RIGHT:
// pass
break;
case osgGA::GUIEventAdapter::SCROLL_2D:
// normalize scrolling delta
dx = _ga_t0->getScrollingDeltaX() /
((_ga_t0->getXmax()-_ga_t0->getXmin()) * 0.5f);
dy = _ga_t0->getScrollingDeltaY() /
((_ga_t0->getYmax()-_ga_t0->getYmin()) * 0.5f);
dx *= _zoomDelta;
dy *= _zoomDelta;
break;
default:
break;
}
buttonMask=GUIEventAdapter::SCROLL;
}
else
{
if (_ga_t1.get()==NULL) return false;
dx = _ga_t0->getXnormalized()-_ga_t1->getXnormalized();
dy = _ga_t0->getYnormalized()-_ga_t1->getYnormalized();
float distance = sqrtf(dx*dx + dy*dy);
// return if movement is too fast, indicating an error in event values
or change in screen.
if (distance>0.5)
{
return false;
}
// return if there is no movement.
if (distance==0.0f)
{
return false;
}
buttonMask = _ga_t1->getButtonMask();
}
if (buttonMask==GUIEventAdapter::LEFT_MOUSE_BUTTON)
{
// rotate camera.
osg::Vec3 axis;
float angle;
float px0 = _ga_t0->getXnormalized();
float py0 = _ga_t0->getYnormalized();
float px1 = _ga_t1->getXnormalized();
float py1 = _ga_t1->getYnormalized();
trackball(axis,angle,px1,py1,px0,py0);
osg::Quat new_rotate;
new_rotate.makeRotate(angle,axis);
_rotation = _rotation*new_rotate;
return true;
}
else if (buttonMask==GUIEventAdapter::MIDDLE_MOUSE_BUTTON ||
buttonMask==(GUIEventAdapter::LEFT_MOUSE_BUTTON|GUIEventAdapter::RIGHT_MOUSE_BUTTON))
{
// pan model.
float scale = -0.3f*_distance;
osg::Matrix rotation_matrix;
rotation_matrix.makeRotate(_rotation);
osg::Vec3 dv(dx*scale,dy*scale,0.0f);
_center += dv*rotation_matrix;
return true;
}
else if ((buttonMask==GUIEventAdapter::RIGHT_MOUSE_BUTTON) ||
(buttonMask==GUIEventAdapter::SCROLL))
{
// zoom model.
float fd = _distance;
float scale = 1.0f+dy;
if (fd*scale>_modelScale*_minimumZoomScale)
{
_distance *= scale;
}
else
{
// notify(DEBUG_INFO) << "Pushing forward"<<std::endl;
// push the camera forward.
float scale = -fd;
osg::Matrix rotation_matrix(_rotation);
osg::Vec3 dv =
(osg::Vec3(0.0f,0.0f,-1.0f)*rotation_matrix)*(dy*scale);
_center += dv;
}
return true;
}
return false;
}
/*
* This size should really be based on the distance from the center of
* rotation to the point on the object underneath the mouse. That
* point would then track the mouse as closely as possible. This is a
* simple example, though, so that is left as an Exercise for the
* Programmer.
*/
void TrackballManipulator::setTrackballSize(float size)
{
_trackballSize = size;
osg::clampBetweenRange(_trackballSize,0.1f,1.0f,"TrackballManipulator::setTrackballSize(float)");
}
/*
* Ok, simulate a track-ball. Project the points onto the virtual
* trackball, then figure out the axis of rotation, which is the cross
* product of P1 P2 and O P1 (O is the center of the ball, 0,0,0)
* Note: This is a deformed trackball-- is a trackball in the center,
* but is deformed into a hyperbolic sheet of rotation away from the
* center. This particular function was chosen after trying out
* several variations.
*
* It is assumed that the arguments to this routine are in the range
* (-1.0 ... 1.0)
*/
void TrackballManipulator::trackball(osg::Vec3& axis,float& angle, float p1x,
float p1y, float p2x, float p2y)
{
/*
* First, figure out z-coordinates for projection of P1 and P2 to
* deformed sphere
*/
osg::Matrix rotation_matrix(_rotation);
osg::Vec3 uv = osg::Vec3(0.0f,1.0f,0.0f)*rotation_matrix;
osg::Vec3 sv = osg::Vec3(1.0f,0.0f,0.0f)*rotation_matrix;
osg::Vec3 lv = osg::Vec3(0.0f,0.0f,-1.0f)*rotation_matrix;
osg::Vec3 p1 = sv * p1x + uv * p1y - lv *
tb_project_to_sphere(_trackballSize, p1x, p1y);
osg::Vec3 p2 = sv * p2x + uv * p2y - lv *
tb_project_to_sphere(_trackballSize, p2x, p2y);
/*
* Now, we want the cross product of P1 and P2
*/
// Robert,
//
// This was the quick 'n' dirty fix to get the trackball doing the right
// thing after fixing the Quat rotations to be right-handed. You may want
// to do something more elegant.
// axis = p1^p2;
axis = p2^p1;
axis.normalize();
/*
* Figure out how much to rotate around that axis.
*/
float t = (p2 - p1).length() / (2.0 * _trackballSize);
/*
* Avoid problems with out-of-control values...
*/
if (t > 1.0) t = 1.0;
if (t < -1.0) t = -1.0;
angle = inRadians(asin(t));
}
/*
* Project an x,y pair onto a sphere of radius r OR a hyperbolic sheet
* if we are away from the center of the sphere.
*/
float TrackballManipulator::tb_project_to_sphere(float r, float x, float y)
{
float d, t, z;
d = sqrt(x*x + y*y);
/* Inside sphere */
if (d < r * 0.70710678118654752440)
{
z = sqrt(r*r - d*d);
} /* On hyperbola */
else
{
t = r / 1.41421356237309504880;
z = t*t / d;
}
return z;
}
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