void
JX3DWidget::ContinueDrag
(
const JPoint& pt
)
{
if (itsDragType == kRotateDrag)
{
const JVector delta(3, - pt.x + itsStartPt.x, pt.y - itsStartPt.y, 0.0);
const JVector& o = itsCamera->GetAttentionPt();
JVector v = itsStartPos - o;
const JFloat r = v.GetLength();
const JFloat lat = asin(v.GetElement(3) / r);
const JFloat lon = atan2(v.GetElement(2), v.GetElement(1));
// direction of drag relative to screen x-axis
const JFloat alpha = atan2(delta.GetElement(2), delta.GetElement(1));
// delta along the sphere in drag direction
const JFloat phi = delta.GetLength() / (r * 50);
JVector p(3, r*cos(phi), r*sin(phi), 0.0);
// inverse: rotate around z-axis for partial alignment of x-axis
JMatrix r1(3, 3);
r1.SetElements(
cos(lon), -sin(lon), 0.0,
sin(lon), cos(lon), 0.0,
0.0, 0.0, 1.0);
// inverse: rotate around y-axis for complete alignment of x-axis towards viewer
JMatrix r2(3, 3);
r2.SetElements(
cos(lat), 0.0, -sin(lat),
0.0, 1.0, 0.0,
sin(lat), 0.0, cos(lat));
// inverse: rotate around x-axis to align y-axis with drag direction
JMatrix r3(3, 3);
r3.SetElements(
1.0, 0.0, 0.0,
0.0, cos(alpha), -sin(alpha),
0.0, sin(alpha), cos(alpha));
// transform delta long the sphere to our coordinate system
p = (r1 * r2 * r3 * p).GetColVector(1);
itsCamera->SetPosition(p + o);
}
}
JBoolean
JX3DWidget::HandleRotationKeyPress
(
const int key,
const JXKeyModifiers& modifiers
)
{
if (modifiers.meta() && key == kJUpArrow)
{
return ZoomForWheel(kJXButton4, modifiers);
}
else if (modifiers.meta() && key == kJDownArrow)
{
return ZoomForWheel(kJXButton5, modifiers);
}
const JVector& o = itsCamera->GetAttentionPt();
JVector v = itsCamera->GetPosition() - o;
const JFloat r = v.GetLength();
JFloat lat = asin(v.GetElement(3) / r);
JFloat lon = atan2(v.GetElement(2), v.GetElement(1));
const JFloat delta =
(modifiers.shift() ? kSmallDeltaAngle :
(modifiers.control() ? kBigDeltaAngle :
kDeltaAngle));
JBoolean moved = kJFalse;
if (key == kJUpArrow)
{
lat += delta;
moved = kJTrue;
}
else if (key == kJDownArrow)
{
lat -= delta;
moved = kJTrue;
}
else if (key == kJLeftArrow)
{
lon += delta;
moved = kJTrue;
}
else if (key == kJRightArrow)
{
lon -= delta;
moved = kJTrue;
}
if (moved)
{
itsCamera->SetPosition(JVector(3,
r * cos(lat) * cos(lon),
r * cos(lat) * sin(lon),
r * sin(lat)));
Redraw(); // key repeats can delay Refresh()
return kJTrue;
}
else
{
return kJFalse;
}
}