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geant4/source/geometry/benchmarks/f77cppcomparison/G4Box_fastfabs.cc
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2016-06-08 15:09:25 +02:00

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// This code implementation is the intellectual property of
// the RD44 GEANT4 collaboration.
//
// By copying, distributing or modifying the Program (or any work
// based on the Program) you indicate your acceptance of this statement,
// and all its terms.
//
// $Id: G4Box_fastfabs.cc,v 1.1 1999/01/08 16:31:33 gunter Exp $
// GEANT4 tag $Name: geant4-00-01 $
//
//
// Implementation for G4Box class
//
#include "G4Box.hh"
//#include "G4VoxelLimits.hh"
//#include "G4Transform.hh"
//#ifdef G4VISUALIZE
//#include "G4VWindow.hh"
//#include "G4Polyline.hh"
//#endif
//#include <math.h>
inline G4double fastfabs(const G4double p)
{
return (p>=0) ? p : -p ;
}
// Private (implementation) enum: Not for external use
// Codes for faces (kPX=plus x face,kMY= minus y face etc)
enum ESide {kPX,kMX,kPY,kMY,kPZ,kMZ};
// Constructor - check & set half widths
G4Box::G4Box(const G4double pX,
const G4double pY,
const G4double pZ)
{
fDx=pX; fDy=pY; fDz=pZ;
}
// Return whether point inside/outside/on surface, using tolerance
EInside G4Box::Inside(const G4ThreeVector& p) const
{
EInside in=kOutside;
if (fastfabs(p.x())<=fDx-kCarTolerance*0.5)
{
if (fastfabs(p.y())<=fDy-kCarTolerance*0.5)
{
if (fastfabs(p.z())<=fDz-kCarTolerance*0.5)
{
in=kInside;
}
else if (fastfabs(p.z())<=fDz+kCarTolerance*0.5)
{
in=kSurface;
}
}
else if (fastfabs(p.y())<=fDy+kCarTolerance*0.5)
{
if (fastfabs(p.z())<=fDz+kCarTolerance*0.5)
{
in=kSurface;
}
}
}
else if (fastfabs(p.x())<=fDx+kCarTolerance*0.5)
{
if (fastfabs(p.y())<=fDy+kCarTolerance*0.5)
{
if (fastfabs(p.z())<=fDz+kCarTolerance*0.5)
{
in=kSurface;
}
}
}
return in;
}
// Calculate side nearest to p, and return normal
// If two sides are equidistant, normal of first side (x/y/z)
// encountered returned
G4ThreeVector G4Box::SurfaceNormal( const G4ThreeVector& p) const
{
G4double distx,disty,distz;
G4ThreeVector norm;
// Calculate distances as if in 1st octant
distx=fastfabs(fastfabs(p.x())-fDx);
disty=fastfabs(fastfabs(p.y())-fDy);
distz=fastfabs(fastfabs(p.z())-fDz);
if (distx<=disty)
{
if (distx<=distz)
{
// Closest to X
if (p.x()<0) norm=G4ThreeVector(-1.0,0,0);
else norm=G4ThreeVector(1.0,0,0);
}
else
{
// Closest to Z
if (p.z()<0) norm=G4ThreeVector(0,0,-1.0);
else norm=G4ThreeVector(0,0,1.0);
}
}
else
{
if (disty<=distz)
{
// Closest to Y
if (p.y()<0) norm=G4ThreeVector(0,-1.0,0);
else norm=G4ThreeVector(0,1.0,0);
}
else
{
// Closest to Z
if (p.z()<0) norm=G4ThreeVector(0,0,-1.0);
else norm=G4ThreeVector(0,0,1.0);
}
}
return norm;
}
// Calculate distance to box from an outside point
// - return kInfinity if no intersection.
//
// ALGORITHM:
//
// Check that if point lies outside x/y/z extent of box, travel is towards
// the box (ie. there is a possiblity of an intersection)
//
// Calculate pairs of minimum and maximum distances for x/y/z travel for
// intersection with the box's x/y/z extent.
// If there is a valid intersection, it is given by the maximum min distance
// (ie. distance to satisfy x/y/z intersections) *if* <= minimum max distance
// (ie. distance after which 1+ of x/y/z intersections not satisfied)
//
// NOTE:
//
// `Inside' safe - meaningful answers given if point is inside the exact
// shape.
G4double G4Box::DistanceToIn(const G4ThreeVector& p,const G4ThreeVector& v) const
{
G4double safx,safy,safz;
G4double smin,sminy,sminz;
G4double smax,smaxy,smaxz;
G4double stmp;
safx=fastfabs(p.x())-fDx; // minimum distance to x surface of shape
safy=fastfabs(p.y())-fDy;
safz=fastfabs(p.z())-fDz;
// Will we intersect?
// If safx/y/z is >-tol/2 the point is outside/on the box's x/y/z extent.
// If both p.x/y/z and v.x/y/z repectively are both positive/negative,
// travel is in a direction away from the shape.
if ( ((p.x()*v.x()>=0.0) && safx>-kCarTolerance*0.5)
|| ((p.y()*v.y()>=0.0) && safy>-kCarTolerance*0.5)
|| ((p.z()*v.z()>=0.0) && safz>-kCarTolerance*0.5)) return kInfinity;
// Compute min / max distances for x/y/z travel:
// X Planes
if (v.x())
{
stmp=1.0/fastfabs(v.x());
smin=safx*stmp;
smax=(fDx+fastfabs(p.x()))*stmp;
}
else
{
if (safx<=0.0)
{
smin=0.0;
smax=kInfinity;
}
else
{
return kInfinity; // Travel parallel
}
}
// Y Planes
if (v.y())
{
stmp=1.0/fastfabs(v.y());
sminy=safy*stmp;
smaxy=(fDy+fastfabs(p.y()))*stmp;
if (sminy>smin) smin=sminy;
if (smaxy<smax) smax=smaxy;
if (smin>smax) return kInfinity;
}
else
{
if (safy>0.0)
{
return kInfinity; // Travel parallel
}
}
// Z planes
if (v.z())
{
stmp=1.0/fastfabs(v.z());
sminz=safz*stmp;
smaxz=(fDz+fastfabs(p.z()))*stmp;
if (sminz>smin) smin=sminz;
if (smaxz<smax) smax=smaxz;
if (smin>smax) return kInfinity;
}
else
{
if (safz>0.0)
{
return kInfinity; // Travel parallel
}
}
if (smin<0)
{
return 0.0;
}
return smin;
}
// Appoximate distance to box.
// Returns largest perpendicular distance to the closest x/y/z sides of
// the box.
// - If inside return 0
G4double G4Box::DistanceToIn(const G4ThreeVector& p) const
{
G4double safex,safey,safez,safe=0.0;
safex=fastfabs(p.x())-fDx;
safey=fastfabs(p.y())-fDy;
safez=fastfabs(p.z())-fDz;
if (safex>safe) safe=safex;
if (safey>safe) safe=safey;
if (safez>safe) safe=safez;
return safe;
}
// Calcluate distance to surface of box from inside
// by calculating distances to box's x/y/z planes.
// Smallest distance is exact distance to exiting.
// - Eliminate one side of each pair by considering direction of v
// - when leaving a surface & v.close, return 0
G4double G4Box::DistanceToOut(const G4ThreeVector& p,const G4ThreeVector& v,
const G4bool calcNorm,
G4bool *validNorm,G4ThreeVector *n) const
{
ESide side;
G4double pdist,stmp,snxt;
if (calcNorm) *validNorm=true; // All normals are valid
if (v.x()>0)
{
pdist=fDx-p.x();
if (pdist>kCarTolerance*0.5)
{
snxt=pdist/v.x();
side=kPX;
}
else
{
if (calcNorm)
{
*n=G4ThreeVector(1,0,0);
}
return snxt=0;
}
}
else if (v.x()<0)
{
pdist=fDx+p.x();
if (pdist>kCarTolerance*0.5)
{
snxt=-pdist/v.x();
side=kMX;
}
else
{
if (calcNorm)
{
*n=G4ThreeVector(-1,0,0);
}
return snxt=0;
}
}
else
{
snxt=kInfinity;
}
if (v.y()>0)
{
pdist=fDy-p.y();
if (pdist>kCarTolerance*0.5)
{
stmp=pdist/v.y();
if (stmp<snxt)
{
snxt=stmp;
side=kPY;
}
}
else
{
if (calcNorm)
{
*n=G4ThreeVector(0,1,0);
}
return snxt=0;
}
}
else if (v.y()<0)
{
pdist=fDy+p.y();
if (pdist>kCarTolerance*0.5)
{
stmp=-pdist/v.y();
if (stmp<snxt)
{
snxt=stmp;
side=kMY;
}
}
else
{
if (calcNorm)
{
*n=G4ThreeVector(0,-1,0);
}
return snxt=0;
}
}
if (v.z()>0)
{
pdist=fDz-p.z();
if (pdist>kCarTolerance*0.5)
{
stmp=pdist/v.z();
if (stmp<snxt)
{
snxt=stmp;
side=kPZ;
}
}
else
{
if (calcNorm)
{
*n=G4ThreeVector(0,0,1);
}
return snxt=0;
}
}
else if (v.z()<0)
{
pdist=fDz+p.z();
if (pdist>kCarTolerance*0.5)
{
stmp=-pdist/v.z();
if (stmp<snxt)
{
snxt=stmp;
side=kMZ;
}
}
else
{
if (calcNorm)
{
*n=G4ThreeVector(0,0,-1);
}
return snxt=0;
}
}
if (calcNorm)
{
switch (side)
{
case kPX:
*n=G4ThreeVector(1,0,0);
break;
case kMX:
*n=G4ThreeVector(-1,0,0);
break;
case kPY:
*n=G4ThreeVector(0,1,0);
break;
case kMY:
*n=G4ThreeVector(0,-1,0);
break;
case kPZ:
*n=G4ThreeVector(0,0,1);
break;
case kMZ:
*n=G4ThreeVector(0,0,-1);
break;
}
}
return snxt;
}
// Calculate exact shortest distance to any boundary from inside
// - If outside return 0
G4double G4Box::DistanceToOut(const G4ThreeVector& p) const
{
G4double safx1,safx2,safy1,safy2,safz1,safz2,safe;
safx1=fDx-p.x();
safx2=fDx+p.x();
safy1=fDy-p.y();
safy2=fDy+p.y();
safz1=fDz-p.z();
safz2=fDz+p.z();
// shortest Dist to any boundary now MIN(safx1,safx2,safy1..)
if (safx2<safx1) safe=safx2;
else safe=safx1;
if (safy1<safe) safe=safy1;
if (safy2<safe) safe=safy2;
if (safz1<safe) safe=safz1;
if (safz2<safe) safe=safz2;
if (safe<0) safe=0;
return safe;
}