Gabriele Cosmo
132 lines
3.0 KiB
Plaintext
132 lines
3.0 KiB
Plaintext
inline void G4Ellipse::Init(const G4Axis2Placement3D& position0,
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G4double semiAxis10, G4double semiAxis20) {
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position= position0;
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semiAxis1= semiAxis10;
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semiAxis2= semiAxis20;
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ratioAxis2Axis1= semiAxis2/semiAxis1;
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SetBounds(0, 0);
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// needed only for 2D ellipses
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toUnitCircle = G4Scale3D(1/semiAxis1, 1/semiAxis2, 0)
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* position.GetToPlacementCoordinates();
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forTangent= -semiAxis1*semiAxis1/(semiAxis2*semiAxis2);
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}
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inline G4double G4Ellipse::GetSemiAxis1() const {
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return semiAxis1;
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}
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inline G4double G4Ellipse::GetSemiAxis2() const {
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return semiAxis2;
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}
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/////////////////////////////////////////////////////////////////////////////
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inline G4double G4Ellipse::GetPMax() {
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return twopi;
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}
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inline G4Point3D G4Ellipse::GetPoint(G4double param) {
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param-= GetPShift();
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return position.GetLocation()
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+ semiAxis1*cos(param)*position.GetPX()
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+ semiAxis2*sin(param)*position.GetPY();
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}
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inline G4double G4Ellipse::GetPPoint(const G4Point3D& pt) {
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G4Point3D ptLocal= position.GetToPlacementCoordinates()*pt;
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G4double angle= atan2(ptLocal.y(), ptLocal.x()*ratioAxis2Axis1);
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G4double r= (angle<0)? angle+twopi: angle;
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return r+GetPShift();
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}
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/////////////////////////////////////////////////////////////////////////////
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#include "G4CurveRayIntersection.hh"
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/*
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inline void G4Ellipse::IntersectRay2D(const G4Ray& ray,
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G4CurveRayIntersection& is)
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{
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is.Init(*this, ray);
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// transform s.t. the ellipse becomes the unit circle
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// with the center at the origin
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// 2D operations would be faster
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G4Point3D s= toUnitCircle*ray.GetStart();
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G4Vector3D d= toUnitCircle*ray.GetDir();
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// solve (s+i*t)^2 = 1 for i (the distance)
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G4double sd= s*d;
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G4double dd= d.mag2(); // never 0
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G4double ss= s.mag2();
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G4double discr= sd*sd-dd*(ss-1);
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if (discr >= 0) {
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// 2 intersections (maybe 1, but this case is rare)
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G4double sqrtdiscr= sqrt(discr);
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// find the smallest positive i
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G4double i= -sd-sqrtdiscr;
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if (i<kCarTolerance) {
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i= -sd+sqrtdiscr;
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if (i<kCarTolerance) {
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return;
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}
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}
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i/= dd;
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G4CurveRayIntersection isTmp(*this, ray);
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isTmp.ResetDistance(i);
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is.Update(isTmp);
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}
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}
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*/
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inline G4int G4Ellipse::IntersectRay2D(const G4Ray& ray)
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{
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// transform s.t. the ellipse becomes the unit circle
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// with the center at the origin
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// 2D operations would be faster
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G4Point3D s= toUnitCircle*ray.GetStart();
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G4Vector3D d= toUnitCircle*ray.GetDir();
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// solve (s+i*t)^2 = 1 for i (the distance)
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G4double sd= s*d;
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G4double dd= d.mag2(); // never 0
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G4double ss= s.mag2();
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G4double discr= sd*sd-dd*(ss-1);
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G4int nbinter = 0;
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G4double i;
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if (discr > 0)
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{
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// 2 intersections
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G4double sqrtdiscr= sqrt(discr);
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// if i is positive, we have an intersection
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i= -sd-sqrtdiscr;
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if (i > kCarTolerance)
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nbinter++;
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i= -sd+sqrtdiscr;
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if (i > kCarTolerance)
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nbinter++;
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}
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// if the ray is tangent on the circle
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if (discr == 0)
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nbinter = 1;
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return nbinter;
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}
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