Foam::point Foam::polyLine::position
(
const label segment,
const scalar mu
) const
{
// out-of-bounds
if (segment < 0)
{
return points_[0];
}
else if (segment > nSegments())
{
return points_[points_.size()-1];
}
const point& p0 = points()[segment];
const point& p1 = points()[segment+1];
// special cases - no calculation needed
if (mu <= 0.0)
{
return p0;
}
else if (mu >= 1.0)
{
return p1;
}
else
{
// linear interpolation
return points_[segment] + mu * (p1 - p0);
}
}
Foam::label Foam::polyLine::localParameter(scalar& lambda) const
{
// check endpoints
if (lambda < SMALL)
{
lambda = 0;
return 0;
}
else if (lambda > 1 - SMALL)
{
lambda = 1;
return nSegments();
}
// search table of cumulative distances to find which line-segment
// we are on. Check the upper bound.
label segmentI = 1;
while (param_[segmentI] < lambda)
{
segmentI++;
}
segmentI--; // we want the corresponding lower bound
// the local parameter [0-1] on this line segment
lambda =
(
( lambda - param_[segmentI] )
/ ( param_[segmentI+1] - param_[segmentI] )
);
return segmentI;
}
/**
* Returns list of segments that are not empty.
*/
std::vector<UInt> getNonEmptySegList() const
{
std::vector<UInt> non_empties;
for (UInt i = 0; i != _segments.size(); ++i)
if (!_segments[i].empty())
non_empties.push_back(i);
NTA_ASSERT(non_empties.size() == nSegments());
return non_empties;
}
Foam::point Foam::CatmullRomSpline::position
(
const label segment,
const scalar mu
) const
{
// out-of-bounds
if (segment < 0)
{
return points()[0];
}
else if (segment > nSegments())
{
return points()[points().size()-1];
}
const point& p0 = points()[segment];
const point& p1 = points()[segment+1];
// special cases - no calculation needed
if (mu <= 0.0)
{
return p0;
}
else if (mu >= 1.0)
{
return p1;
}
// determine the end points
point e0;
point e1;
if (segment == 0)
{
// end: simple reflection
e0 = 2*p0 - p1;
}
else
{
e0 = points()[segment-1];
}
if (segment+1 == nSegments())
{
// end: simple reflection
e1 = 2*p1 - p0;
}
else
{
e1 = points()[segment+2];
}
return 0.5 *
(
( 2*p0 )
+ mu *
(
( -e0 + p1 )
+ mu *
(
( 2*e0 - 5*p0 + 4*p1 - e1 )
+ mu *
( -e0 + 3*p0 - 3*p1 + e1 )
)
)
);
}
