double GLWidget::DistanceToFiniteLine(AVector v, AVector w, AVector p)
{
float zero_epsilon = std::numeric_limits<float>::epsilon();
// Return minimum distance between line segment vw and point p
double l2 = v.DistanceSquared(w); // i.e. |w-v|^2 - avoid a sqrt
if (l2 > -zero_epsilon && l2 < zero_epsilon) return p.Distance(v); // v == w case
// Consider the line extending the segment, parameterized as v + t (w - v).
// We find projection of point p onto the line.
// It falls where t = [(p-v) . (w-v)] / |w-v|^2
double t = (p - v).Dot(w - v) / l2;
if (t < 0.0) { return p.Distance(v); } // Beyond the 'v' end of the segment
else if (t > 1.0) { return p.Distance(w); } // Beyond the 'w' end of the segment
AVector projection = v + (w - v) * t; // Projection falls on the segment
return p.Distance(projection);
}
// not compatible with dirichlet boundary condition
AVector QuadMesh::GetClosestPointFromBorders(AVector pt)
{
AVector closestPt = pt;
float dist = std::numeric_limits<float>::max();
std::vector<ALine> borderLines;
borderLines.push_back(ALine(_leftStartPt, _rightStartPt));
borderLines.push_back(ALine(_leftEndPt, _rightEndPt));
borderLines.push_back(ALine(_leftStartPt, _leftEndPt));
borderLines.push_back(ALine(_rightStartPt, _rightEndPt));
for(uint a = 0; a < borderLines.size(); a++)
{
AVector cPt = UtilityFunctions::GetClosestPoint(borderLines[a].GetPointA(), borderLines[a].GetPointB(), pt);
if(pt.Distance(cPt) < dist)
{
dist = pt.Distance(cPt);
closestPt = cPt;
}
}
return closestPt;
}