// Adds a new control point to the arrays CPCenter, CPRight and CPLeft
private void AddControlPoints(Vector3 ca0, Vector3 ox0, Vector3 ca1, int ss, int handedness)
{
Vector3 A, B, C, D, p0, cpt0, cpt1, cpt2;
A = ca1 - ca0;
B = ox0 - ca0;
// Vector normal to the peptide plane (pointing outside in the case of the
// alpha helix).
C = Vector3.Cross(A, B);
// Vector contained in the peptide plane (perpendicular to its direction).
D = Vector3.Cross(C, A);
C.Normalize();
D.Normalize();
// Flipping test (to avoid self crossing in the strands).
if ((ss != HELIX) && (90f < Vector3.Angle(flipTestV, D)))
{
D = D * -1f; // flip detected, the plane vector is inverted
}
// The central control point is constructed
cpt0 = LinearComb(0.5f, ca0, 0.5f, ca1);
splineCenter.SetCPoint(3, cpt0);
if (ss == HELIX)
{
// When residue i is contained in a helix, the control point is moved away
// from the helix axis, along the C direction.
p0 = Vector3.zero;
splineCenter.GetCPoint(3, out p0);
cpt0 = LinearComb(1f, p0, handedness * HELIX_DIAM, C);
splineCenter.SetCPoint(3, cpt0);
}
// The control points for the side ribbons are constructed.
cpt1 = LinearComb(1f, cpt0, ribbonWidth[ss], D);
splineSide1.SetCPoint(3, cpt1);
cpt2 = LinearComb(1f, cpt0, -ribbonWidth[ss], D);
splineSide2.SetCPoint(3, cpt2);
// Saving the plane vector (for the flipping test in the next call)
flipTestV = D;
} // End of AddControlPoints
