dMatrix clSpline::GetCoordinates(const dMatrix &uSpec)
{
dMatrix coord;
if(uSpec.GetNumberColumns() != 1 || uSpec.GetNumberRows() == 0)
{
throw clException("clSpline", "GetCoordinates", "Invalid dimensions of matrix uSpec.");
}
else
{
coord.SetNumberRows(uSpec.GetNumberRows());
coord.SetNumberColumns(3);
if(!initialised)
{
Initialise();
}
// Do for all specified u's
for(int i=1; i<=uSpec.GetNumberRows(); i++)
{
if(uSpec(i, 1) < 0 || uSpec(i, 1) > 1)
{
throw clException("clSpline", "GetCoordinates", "Invalid value for uSpec.");
}
else
{
// Now find the position of uSpec
double uu = uSpec(i, 1)*GetSplineLength();
int j = 1;
while((uu - u(j+1, 1) > 0) && (j<u.GetNumberRows()-1))
{
j++;
}
// Now calculate the coefficients
double A = (u(j+1, 1)-uu)/(u(j+1, 1)-u(j,1));
double B = 1-A;
double C = (A*A*A-A)/6 * (u(j+1, 1)-u(j, 1))*(u(j+1, 1)-u(j, 1));
double D = (B*B*B-B)/6 * (u(j+1, 1)-u(j, 1))*(u(j+1, 1)-u(j, 1));
// Finally calculate the coordinates
coord.SetElement(i, 1, A*X(j, 1) + B*X(j+1, 1) + C*X2(j, 1) + D*X2(j+1, 1));
coord.SetElement(i, 2, A*Y(j, 1) + B*Y(j+1, 1) + C*Y2(j, 1) + D*Y2(j+1, 1));
coord.SetElement(i, 3, A*Z(j, 1) + B*Z(j+1, 1) + C*Z2(j, 1) + D*Z2(j+1, 1));
}
}
}
return (coord);
}
void clSpline::SetControlPoints(const dMatrix &cPointsX, const dMatrix &cPointsY, const dMatrix &cPointsZ)
{
// Check if dimensions are correct
if((cPointsX.GetNumberColumns() != 1 || cPointsY.GetNumberColumns() != 1 || cPointsZ.GetNumberColumns() != 1) ||
(cPointsX.GetNumberRows() != cPointsY.GetNumberRows()) ||
(cPointsX.GetNumberRows() != cPointsZ.GetNumberRows()))
{
throw clException("clSpline", "SetControlPoints", "Dimensions of matrices do not match.");
}
else
{
X = cPointsX;
Y = cPointsY;
Z = cPointsZ;
}
}