[831] | 1 | // |
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| 2 | // ******************************************************************** |
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| 3 | // * License and Disclaimer * |
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| 4 | // * * |
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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| 7 | // * conditions of the Geant4 Software License, included in the file * |
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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| 9 | // * include a list of copyright holders. * |
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| 10 | // * * |
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| 11 | // * Neither the authors of this software system, nor their employing * |
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| 12 | // * institutes,nor the agencies providing financial support for this * |
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| 13 | // * work make any representation or warranty, express or implied, * |
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| 14 | // * regarding this software system or assume any liability for its * |
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| 15 | // * use. Please see the license in the file LICENSE and URL above * |
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| 16 | // * for the full disclaimer and the limitation of liability. * |
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| 17 | // * * |
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| 18 | // * This code implementation is the result of the scientific and * |
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| 19 | // * technical work of the GEANT4 collaboration. * |
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| 20 | // * By using, copying, modifying or distributing the software (or * |
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| 21 | // * any work based on the software) you agree to acknowledge its * |
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| 22 | // * use in resulting scientific publications, and indicate your * |
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| 23 | // * acceptance of all terms of the Geant4 Software license. * |
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| 24 | // ******************************************************************** |
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| 25 | // |
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| 26 | // |
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| 27 | // $Id: G4EllipticalTube.cc,v 1.27 2006/10/20 13:45:21 gcosmo Exp $ |
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[1058] | 28 | // GEANT4 tag $Name: geant4-09-02-ref-02 $ |
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[831] | 29 | // |
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| 30 | // |
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| 31 | // -------------------------------------------------------------------- |
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| 32 | // GEANT 4 class source file |
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| 33 | // |
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| 34 | // |
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| 35 | // G4EllipticalTube.cc |
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| 36 | // |
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| 37 | // Implementation of a CSG volume representing a tube with elliptical cross |
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| 38 | // section (geant3 solid 'ELTU') |
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| 39 | // |
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| 40 | // -------------------------------------------------------------------- |
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| 41 | |
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| 42 | #include "G4EllipticalTube.hh" |
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| 43 | |
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| 44 | #include "G4ClippablePolygon.hh" |
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| 45 | #include "G4AffineTransform.hh" |
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| 46 | #include "G4SolidExtentList.hh" |
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| 47 | #include "G4VoxelLimits.hh" |
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| 48 | #include "meshdefs.hh" |
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| 49 | |
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| 50 | #include "Randomize.hh" |
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| 51 | |
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| 52 | #include "G4VGraphicsScene.hh" |
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| 53 | #include "G4Polyhedron.hh" |
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| 54 | #include "G4VisExtent.hh" |
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| 55 | |
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| 56 | using namespace CLHEP; |
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| 57 | |
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| 58 | // |
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| 59 | // Constructor |
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| 60 | // |
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| 61 | G4EllipticalTube::G4EllipticalTube( const G4String &name, |
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| 62 | G4double theDx, |
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| 63 | G4double theDy, |
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| 64 | G4double theDz ) |
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| 65 | : G4VSolid( name ), fCubicVolume(0.), fSurfaceArea(0.), fpPolyhedron(0) |
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| 66 | { |
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| 67 | dx = theDx; |
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| 68 | dy = theDy; |
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| 69 | dz = theDz; |
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| 70 | } |
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| 71 | |
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| 72 | |
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| 73 | // |
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| 74 | // Fake default constructor - sets only member data and allocates memory |
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| 75 | // for usage restricted to object persistency. |
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| 76 | // |
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| 77 | G4EllipticalTube::G4EllipticalTube( __void__& a ) |
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| 78 | : G4VSolid(a), fCubicVolume(0.), fSurfaceArea(0.), fpPolyhedron(0) |
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| 79 | { |
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| 80 | } |
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| 81 | |
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| 82 | |
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| 83 | // |
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| 84 | // Destructor |
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| 85 | // |
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| 86 | G4EllipticalTube::~G4EllipticalTube() |
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| 87 | { |
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| 88 | delete fpPolyhedron; |
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| 89 | } |
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| 90 | |
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| 91 | |
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| 92 | // |
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| 93 | // CalculateExtent |
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| 94 | // |
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| 95 | G4bool |
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| 96 | G4EllipticalTube::CalculateExtent( const EAxis axis, |
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| 97 | const G4VoxelLimits &voxelLimit, |
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| 98 | const G4AffineTransform &transform, |
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| 99 | G4double &min, G4double &max ) const |
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| 100 | { |
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| 101 | G4SolidExtentList extentList( axis, voxelLimit ); |
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| 102 | |
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| 103 | // |
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| 104 | // We are going to divide up our elliptical face into small |
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| 105 | // pieces |
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| 106 | // |
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| 107 | |
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| 108 | // |
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| 109 | // Choose phi size of our segment(s) based on constants as |
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| 110 | // defined in meshdefs.hh |
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| 111 | // |
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| 112 | G4int numPhi = kMaxMeshSections; |
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| 113 | G4double sigPhi = twopi/numPhi; |
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| 114 | |
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| 115 | // |
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| 116 | // We have to be careful to keep our segments completely outside |
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| 117 | // of the elliptical surface. To do so we imagine we have |
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| 118 | // a simple (unit radius) circular cross section (as in G4Tubs) |
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| 119 | // and then "stretch" the dimensions as necessary to fit the ellipse. |
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| 120 | // |
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| 121 | G4double rFudge = 1.0/std::cos(0.5*sigPhi); |
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| 122 | G4double dxFudge = dx*rFudge, |
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| 123 | dyFudge = dy*rFudge; |
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| 124 | |
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| 125 | // |
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| 126 | // As we work around the elliptical surface, we build |
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| 127 | // a "phi" segment on the way, and keep track of two |
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| 128 | // additional polygons for the two ends. |
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| 129 | // |
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| 130 | G4ClippablePolygon endPoly1, endPoly2, phiPoly; |
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| 131 | |
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| 132 | G4double phi = 0, |
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| 133 | cosPhi = std::cos(phi), |
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| 134 | sinPhi = std::sin(phi); |
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| 135 | G4ThreeVector v0( dxFudge*cosPhi, dyFudge*sinPhi, +dz ), |
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| 136 | v1( dxFudge*cosPhi, dyFudge*sinPhi, -dz ), |
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| 137 | w0, w1; |
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| 138 | transform.ApplyPointTransform( v0 ); |
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| 139 | transform.ApplyPointTransform( v1 ); |
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| 140 | do |
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| 141 | { |
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| 142 | phi += sigPhi; |
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| 143 | if (numPhi == 1) phi = 0; // Try to avoid roundoff |
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| 144 | cosPhi = std::cos(phi), |
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| 145 | sinPhi = std::sin(phi); |
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| 146 | |
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| 147 | w0 = G4ThreeVector( dxFudge*cosPhi, dyFudge*sinPhi, +dz ); |
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| 148 | w1 = G4ThreeVector( dxFudge*cosPhi, dyFudge*sinPhi, -dz ); |
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| 149 | transform.ApplyPointTransform( w0 ); |
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| 150 | transform.ApplyPointTransform( w1 ); |
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| 151 | |
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| 152 | // |
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| 153 | // Add a point to our z ends |
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| 154 | // |
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| 155 | endPoly1.AddVertexInOrder( v0 ); |
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| 156 | endPoly2.AddVertexInOrder( v1 ); |
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| 157 | |
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| 158 | // |
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| 159 | // Build phi polygon |
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| 160 | // |
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| 161 | phiPoly.ClearAllVertices(); |
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| 162 | |
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| 163 | phiPoly.AddVertexInOrder( v0 ); |
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| 164 | phiPoly.AddVertexInOrder( v1 ); |
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| 165 | phiPoly.AddVertexInOrder( w1 ); |
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| 166 | phiPoly.AddVertexInOrder( w0 ); |
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| 167 | |
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| 168 | if (phiPoly.PartialClip( voxelLimit, axis )) |
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| 169 | { |
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| 170 | // |
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| 171 | // Get unit normal |
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| 172 | // |
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| 173 | phiPoly.SetNormal( (v1-v0).cross(w0-v0).unit() ); |
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| 174 | |
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| 175 | extentList.AddSurface( phiPoly ); |
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| 176 | } |
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| 177 | |
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| 178 | // |
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| 179 | // Next vertex |
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| 180 | // |
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| 181 | v0 = w0; |
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| 182 | v1 = w1; |
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| 183 | } while( --numPhi > 0 ); |
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| 184 | |
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| 185 | // |
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| 186 | // Process the end pieces |
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| 187 | // |
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| 188 | if (endPoly1.PartialClip( voxelLimit, axis )) |
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| 189 | { |
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| 190 | static const G4ThreeVector normal(0,0,+1); |
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| 191 | endPoly1.SetNormal( transform.TransformAxis(normal) ); |
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| 192 | extentList.AddSurface( endPoly1 ); |
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| 193 | } |
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| 194 | |
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| 195 | if (endPoly2.PartialClip( voxelLimit, axis )) |
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| 196 | { |
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| 197 | static const G4ThreeVector normal(0,0,-1); |
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| 198 | endPoly2.SetNormal( transform.TransformAxis(normal) ); |
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| 199 | extentList.AddSurface( endPoly2 ); |
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| 200 | } |
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| 201 | |
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| 202 | // |
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| 203 | // Return min/max value |
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| 204 | // |
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| 205 | return extentList.GetExtent( min, max ); |
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| 206 | } |
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| 207 | |
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| 208 | |
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| 209 | // |
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| 210 | // Inside |
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| 211 | // |
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| 212 | // Note that for this solid, we've decided to define the tolerant |
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| 213 | // surface as that which is bounded by ellipses with axes |
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| 214 | // at +/- 0.5*kCarTolerance. |
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| 215 | // |
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| 216 | EInside G4EllipticalTube::Inside( const G4ThreeVector& p ) const |
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| 217 | { |
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| 218 | static const G4double halfTol = 0.5*kCarTolerance; |
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| 219 | |
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| 220 | // |
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| 221 | // Check z extents: are we outside? |
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| 222 | // |
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| 223 | G4double absZ = std::fabs(p.z()); |
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| 224 | if (absZ > dz+halfTol) return kOutside; |
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| 225 | |
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| 226 | // |
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| 227 | // Check x,y: are we outside? |
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| 228 | // |
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| 229 | // G4double x = p.x(), y = p.y(); |
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| 230 | |
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| 231 | if (CheckXY(p.x(), p.y(), +halfTol) > 1.0) return kOutside; |
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| 232 | |
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| 233 | // |
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| 234 | // We are either inside or on the surface: recheck z extents |
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| 235 | // |
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| 236 | if (absZ > dz-halfTol) return kSurface; |
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| 237 | |
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| 238 | // |
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| 239 | // Recheck x,y |
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| 240 | // |
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| 241 | if (CheckXY(p.x(), p.y(), -halfTol) > 1.0) return kSurface; |
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| 242 | |
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| 243 | return kInside; |
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| 244 | } |
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| 245 | |
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| 246 | |
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| 247 | // |
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| 248 | // SurfaceNormal |
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| 249 | // |
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| 250 | G4ThreeVector G4EllipticalTube::SurfaceNormal( const G4ThreeVector& p ) const |
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| 251 | { |
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| 252 | // |
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| 253 | // Which of the three surfaces are we closest to (approximately)? |
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| 254 | // |
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| 255 | G4double distZ = std::fabs(p.z()) - dz; |
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| 256 | |
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| 257 | G4double rxy = CheckXY( p.x(), p.y() ); |
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| 258 | G4double distR2 = (rxy < DBL_MIN) ? DBL_MAX : 1.0/rxy; |
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| 259 | |
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| 260 | // |
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| 261 | // Closer to z? |
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| 262 | // |
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| 263 | if (distZ*distZ < distR2) |
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| 264 | return G4ThreeVector( 0.0, 0.0, p.z() < 0 ? -1.0 : 1.0 ); |
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| 265 | |
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| 266 | // |
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| 267 | // Closer to x/y |
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| 268 | // |
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| 269 | return G4ThreeVector( p.x()*dy*dy, p.y()*dx*dx, 0.0 ).unit(); |
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| 270 | } |
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| 271 | |
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| 272 | |
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| 273 | // |
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| 274 | // DistanceToIn(p,v) |
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| 275 | // |
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| 276 | // Unlike DistanceToOut(p,v), it is possible for the trajectory |
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| 277 | // to miss. The geometric calculations here are quite simple. |
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| 278 | // More difficult is the logic required to prevent particles |
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| 279 | // from sneaking (or leaking) between the elliptical and end |
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| 280 | // surfaces. |
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| 281 | // |
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| 282 | // Keep in mind that the true distance is allowed to be |
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| 283 | // negative if the point is currently on the surface. For oblique |
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| 284 | // angles, it can be very negative. |
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| 285 | // |
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| 286 | G4double G4EllipticalTube::DistanceToIn( const G4ThreeVector& p, |
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| 287 | const G4ThreeVector& v ) const |
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| 288 | { |
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| 289 | static const G4double halfTol = 0.5*kCarTolerance; |
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| 290 | |
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| 291 | // |
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| 292 | // Check z = -dz planer surface |
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| 293 | // |
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| 294 | G4double sigz = p.z()+dz; |
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| 295 | |
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| 296 | if (sigz < halfTol) |
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| 297 | { |
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| 298 | // |
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| 299 | // We are "behind" the shape in z, and so can |
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| 300 | // potentially hit the rear face. Correct direction? |
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| 301 | // |
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| 302 | if (v.z() <= 0) |
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| 303 | { |
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| 304 | // |
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| 305 | // As long as we are far enough away, we know we |
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| 306 | // can't intersect |
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| 307 | // |
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| 308 | if (sigz < 0) return kInfinity; |
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| 309 | |
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| 310 | // |
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| 311 | // Otherwise, we don't intersect unless we are |
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| 312 | // on the surface of the ellipse |
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| 313 | // |
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| 314 | if (CheckXY(p.x(),p.y(),-halfTol) <= 1.0) return kInfinity; |
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| 315 | } |
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| 316 | else |
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| 317 | { |
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| 318 | // |
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| 319 | // How far? |
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| 320 | // |
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| 321 | G4double s = -sigz/v.z(); |
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| 322 | |
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| 323 | // |
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| 324 | // Where does that place us? |
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| 325 | // |
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| 326 | G4double xi = p.x() + s*v.x(), |
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| 327 | yi = p.y() + s*v.y(); |
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| 328 | |
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| 329 | // |
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| 330 | // Is this on the surface (within ellipse)? |
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| 331 | // |
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| 332 | if (CheckXY(xi,yi) <= 1.0) |
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| 333 | { |
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| 334 | // |
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| 335 | // Yup. Return s, unless we are on the surface |
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| 336 | // |
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| 337 | return (sigz < -halfTol) ? s : 0; |
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| 338 | } |
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| 339 | else if (xi*dy*dy*v.x() + yi*dx*dx*v.y() >= 0) |
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| 340 | { |
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| 341 | // |
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| 342 | // Else, if we are traveling outwards, we know |
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| 343 | // we must miss |
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| 344 | // |
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| 345 | return kInfinity; |
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| 346 | } |
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| 347 | } |
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| 348 | } |
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| 349 | |
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| 350 | // |
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| 351 | // Check z = +dz planer surface |
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| 352 | // |
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| 353 | sigz = p.z() - dz; |
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| 354 | |
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| 355 | if (sigz > -halfTol) |
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| 356 | { |
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| 357 | if (v.z() >= 0) |
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| 358 | { |
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| 359 | if (sigz > 0) return kInfinity; |
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| 360 | if (CheckXY(p.x(),p.y(),-halfTol) <= 1.0) return kInfinity; |
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| 361 | } |
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| 362 | else { |
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| 363 | G4double s = -sigz/v.z(); |
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| 364 | |
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| 365 | G4double xi = p.x() + s*v.x(), |
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| 366 | yi = p.y() + s*v.y(); |
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| 367 | |
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| 368 | if (CheckXY(xi,yi) <= 1.0) |
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| 369 | { |
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| 370 | return (sigz > -halfTol) ? s : 0; |
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| 371 | } |
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| 372 | else if (xi*dy*dy*v.x() + yi*dx*dx*v.y() >= 0) |
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| 373 | { |
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| 374 | return kInfinity; |
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| 375 | } |
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| 376 | } |
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| 377 | } |
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| 378 | |
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| 379 | // |
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| 380 | // Check intersection with the elliptical tube |
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| 381 | // |
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| 382 | G4double s[2]; |
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| 383 | G4int n = IntersectXY( p, v, s ); |
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| 384 | |
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| 385 | if (n==0) return kInfinity; |
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| 386 | |
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| 387 | // |
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| 388 | // Is the original point on the surface? |
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| 389 | // |
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| 390 | if (std::fabs(p.z()) < dz+halfTol) { |
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| 391 | if (CheckXY( p.x(), p.y(), halfTol ) < 1.0) |
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| 392 | { |
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| 393 | // |
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| 394 | // Well, yes, but are we traveling inwards at this point? |
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| 395 | // |
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| 396 | if (p.x()*dy*dy*v.x() + p.y()*dx*dx*v.y() < 0) return 0; |
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| 397 | } |
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| 398 | } |
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| 399 | |
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| 400 | // |
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| 401 | // We are now certain that point p is not on the surface of |
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| 402 | // the solid (and thus std::fabs(s[0]) > halfTol). |
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| 403 | // Return kInfinity if the intersection is "behind" the point. |
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| 404 | // |
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| 405 | if (s[0] < 0) return kInfinity; |
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| 406 | |
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| 407 | // |
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| 408 | // Check to see if we intersect the tube within |
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| 409 | // dz, but only when we know it might miss |
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| 410 | // |
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| 411 | G4double zi = p.z() + s[0]*v.z(); |
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| 412 | |
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| 413 | if (v.z() < 0) |
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| 414 | { |
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| 415 | if (zi < -dz) return kInfinity; |
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| 416 | } |
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| 417 | else if (v.z() > 0) |
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| 418 | { |
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| 419 | if (zi > +dz) return kInfinity; |
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| 420 | } |
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| 421 | |
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| 422 | return s[0]; |
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| 423 | } |
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| 424 | |
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| 425 | |
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| 426 | // |
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| 427 | // DistanceToIn(p) |
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| 428 | // |
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| 429 | // The distance from a point to an ellipse (in 2 dimensions) is a |
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| 430 | // surprisingly complicated quadric expression (this is easy to |
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| 431 | // appreciate once one understands that there may be up to |
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| 432 | // four lines normal to the ellipse intersecting any point). To |
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| 433 | // solve it exactly would be rather time consuming. This method, |
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| 434 | // however, is supposed to be a quick check, and is allowed to be an |
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| 435 | // underestimate. |
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| 436 | // |
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| 437 | // So, I will use the following underestimate of the distance |
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| 438 | // from an outside point to an ellipse. First: find the intersection "A" |
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| 439 | // of the line from the origin to the point with the ellipse. |
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| 440 | // Find the line passing through "A" and tangent to the ellipse |
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| 441 | // at A. The distance of the point p from the ellipse will be approximated |
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| 442 | // as the distance to this line. |
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| 443 | // |
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| 444 | G4double G4EllipticalTube::DistanceToIn( const G4ThreeVector& p ) const |
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| 445 | { |
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| 446 | static const G4double halfTol = 0.5*kCarTolerance; |
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| 447 | |
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| 448 | if (CheckXY( p.x(), p.y(), +halfTol ) < 1.0) |
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| 449 | { |
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| 450 | // |
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| 451 | // We are inside or on the surface of the |
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| 452 | // elliptical cross section in x/y. Check z |
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| 453 | // |
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| 454 | if (p.z() < -dz-halfTol) |
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| 455 | return -p.z()-dz; |
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| 456 | else if (p.z() > dz+halfTol) |
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| 457 | return p.z()-dz; |
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| 458 | else |
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| 459 | return 0; // On any surface here (or inside) |
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| 460 | } |
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| 461 | |
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| 462 | // |
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| 463 | // Find point on ellipse |
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| 464 | // |
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| 465 | G4double qnorm = CheckXY( p.x(), p.y() ); |
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| 466 | if (qnorm < DBL_MIN) return 0; // This should never happen |
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| 467 | |
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| 468 | G4double q = 1.0/std::sqrt(qnorm); |
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| 469 | |
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| 470 | G4double xe = q*p.x(), ye = q*p.y(); |
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| 471 | |
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| 472 | // |
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| 473 | // Get tangent to ellipse |
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| 474 | // |
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| 475 | G4double tx = -ye*dx*dx, ty = +xe*dy*dy; |
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| 476 | G4double tnorm = std::sqrt( tx*tx + ty*ty ); |
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| 477 | |
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| 478 | // |
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| 479 | // Calculate distance |
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| 480 | // |
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| 481 | G4double distR = ( (p.x()-xe)*ty - (p.y()-ye)*tx )/tnorm; |
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| 482 | |
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| 483 | // |
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| 484 | // Add the result in quadrature if we are, in addition, |
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| 485 | // outside the z bounds of the shape |
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| 486 | // |
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| 487 | // We could save some time by returning the maximum rather |
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| 488 | // than the quadrature sum |
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| 489 | // |
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| 490 | if (p.z() < -dz) |
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| 491 | return std::sqrt( (p.z()+dz)*(p.z()+dz) + distR*distR ); |
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| 492 | else if (p.z() > dz) |
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| 493 | return std::sqrt( (p.z()-dz)*(p.z()-dz) + distR*distR ); |
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| 494 | |
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| 495 | return distR; |
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| 496 | } |
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| 497 | |
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| 498 | |
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| 499 | // |
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| 500 | // DistanceToOut(p,v) |
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| 501 | // |
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| 502 | // This method can be somewhat complicated for a general shape. |
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| 503 | // For a convex one, like this, there are several simplifications, |
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| 504 | // the most important of which is that one can treat the surfaces |
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| 505 | // as infinite in extent when deciding if the p is on the surface. |
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| 506 | // |
---|
| 507 | G4double G4EllipticalTube::DistanceToOut( const G4ThreeVector& p, |
---|
| 508 | const G4ThreeVector& v, |
---|
| 509 | const G4bool calcNorm, |
---|
| 510 | G4bool *validNorm, |
---|
| 511 | G4ThreeVector *norm ) const |
---|
| 512 | { |
---|
| 513 | static const G4double halfTol = 0.5*kCarTolerance; |
---|
| 514 | |
---|
| 515 | // |
---|
| 516 | // Our normal is always valid |
---|
| 517 | // |
---|
| 518 | if (calcNorm) *validNorm = true; |
---|
| 519 | |
---|
| 520 | G4double sBest = kInfinity; |
---|
| 521 | const G4ThreeVector *nBest=0; |
---|
| 522 | |
---|
| 523 | // |
---|
| 524 | // Might we intersect the -dz surface? |
---|
| 525 | // |
---|
| 526 | if (v.z() < 0) |
---|
| 527 | { |
---|
| 528 | static const G4ThreeVector normHere(0.0,0.0,-1.0); |
---|
| 529 | // |
---|
| 530 | // Yup. What distance? |
---|
| 531 | // |
---|
| 532 | sBest = -(p.z()+dz)/v.z(); |
---|
| 533 | |
---|
| 534 | // |
---|
| 535 | // Are we on the surface? If so, return zero |
---|
| 536 | // |
---|
| 537 | if (p.z() < -dz+halfTol) { |
---|
| 538 | if (calcNorm) *norm = normHere; |
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| 539 | return 0; |
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| 540 | } |
---|
| 541 | else |
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| 542 | nBest = &normHere; |
---|
| 543 | } |
---|
| 544 | |
---|
| 545 | // |
---|
| 546 | // How about the +dz surface? |
---|
| 547 | // |
---|
| 548 | if (v.z() > 0) |
---|
| 549 | { |
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| 550 | static const G4ThreeVector normHere(0.0,0.0,+1.0); |
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| 551 | // |
---|
| 552 | // Yup. What distance? |
---|
| 553 | // |
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| 554 | G4double s = (dz-p.z())/v.z(); |
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| 555 | |
---|
| 556 | // |
---|
| 557 | // Are we on the surface? If so, return zero |
---|
| 558 | // |
---|
| 559 | if (p.z() > +dz-halfTol) { |
---|
| 560 | if (calcNorm) *norm = normHere; |
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| 561 | return 0; |
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| 562 | } |
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| 563 | |
---|
| 564 | // |
---|
| 565 | // Best so far? |
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| 566 | // |
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| 567 | if (s < sBest) { sBest = s; nBest = &normHere; } |
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| 568 | } |
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| 569 | |
---|
| 570 | // |
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| 571 | // Check furthest intersection with ellipse |
---|
| 572 | // |
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| 573 | G4double s[2]; |
---|
| 574 | G4int n = IntersectXY( p, v, s ); |
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| 575 | |
---|
| 576 | if (n == 0) |
---|
| 577 | { |
---|
| 578 | if (sBest == kInfinity) |
---|
| 579 | { |
---|
| 580 | G4cout.precision(16) ; |
---|
| 581 | G4cout << G4endl ; |
---|
| 582 | DumpInfo(); |
---|
| 583 | G4cout << "Position:" << G4endl << G4endl ; |
---|
| 584 | G4cout << "p.x() = " << p.x()/mm << " mm" << G4endl ; |
---|
| 585 | G4cout << "p.y() = " << p.y()/mm << " mm" << G4endl ; |
---|
| 586 | G4cout << "p.z() = " << p.z()/mm << " mm" << G4endl << G4endl ; |
---|
| 587 | G4cout << "Direction:" << G4endl << G4endl; |
---|
| 588 | G4cout << "v.x() = " << v.x() << G4endl; |
---|
| 589 | G4cout << "v.y() = " << v.y() << G4endl; |
---|
| 590 | G4cout << "v.z() = " << v.z() << G4endl << G4endl; |
---|
| 591 | G4cout << "Proposed distance :" << G4endl << G4endl; |
---|
| 592 | G4cout << "snxt = " << sBest/mm << " mm" << G4endl << G4endl; |
---|
| 593 | G4Exception( "G4EllipticalTube::DistanceToOut(p,v,...)", |
---|
| 594 | "Notification", JustWarning, "Point p is outside !?" ); |
---|
| 595 | } |
---|
| 596 | if (calcNorm) *norm = *nBest; |
---|
| 597 | return sBest; |
---|
| 598 | } |
---|
| 599 | else if (s[n-1] > sBest) |
---|
| 600 | { |
---|
| 601 | if (calcNorm) *norm = *nBest; |
---|
| 602 | return sBest; |
---|
| 603 | } |
---|
| 604 | sBest = s[n-1]; |
---|
| 605 | |
---|
| 606 | // |
---|
| 607 | // Intersection with ellipse. Get normal at intersection point. |
---|
| 608 | // |
---|
| 609 | if (calcNorm) |
---|
| 610 | { |
---|
| 611 | G4ThreeVector ip = p + sBest*v; |
---|
| 612 | *norm = G4ThreeVector( ip.x()*dy*dy, ip.y()*dx*dx, 0.0 ).unit(); |
---|
| 613 | } |
---|
| 614 | |
---|
| 615 | // |
---|
| 616 | // Do we start on the surface? |
---|
| 617 | // |
---|
| 618 | if (CheckXY( p.x(), p.y(), -halfTol ) > 1.0) |
---|
| 619 | { |
---|
| 620 | // |
---|
| 621 | // Well, yes, but are we traveling outwards at this point? |
---|
| 622 | // |
---|
| 623 | if (p.x()*dy*dy*v.x() + p.y()*dx*dx*v.y() > 0) return 0; |
---|
| 624 | } |
---|
| 625 | |
---|
| 626 | return sBest; |
---|
| 627 | } |
---|
| 628 | |
---|
| 629 | |
---|
| 630 | // |
---|
| 631 | // DistanceToOut(p) |
---|
| 632 | // |
---|
| 633 | // See DistanceToIn(p) for notes on the distance from a point |
---|
| 634 | // to an ellipse in two dimensions. |
---|
| 635 | // |
---|
| 636 | // The approximation used here for a point inside the ellipse |
---|
| 637 | // is to find the intersection with the ellipse of the lines |
---|
| 638 | // through the point and parallel to the x and y axes. The |
---|
| 639 | // distance of the point from the line connecting the two |
---|
| 640 | // intersecting points is then used. |
---|
| 641 | // |
---|
| 642 | G4double G4EllipticalTube::DistanceToOut( const G4ThreeVector& p ) const |
---|
| 643 | { |
---|
| 644 | static const G4double halfTol = 0.5*kCarTolerance; |
---|
| 645 | |
---|
| 646 | // |
---|
| 647 | // We need to calculate the distances to all surfaces, |
---|
| 648 | // and then return the smallest |
---|
| 649 | // |
---|
| 650 | // Check -dz and +dz surface |
---|
| 651 | // |
---|
| 652 | G4double sBest = dz - std::fabs(p.z()); |
---|
| 653 | if (sBest < halfTol) return 0; |
---|
| 654 | |
---|
| 655 | // |
---|
| 656 | // Check elliptical surface: find intersection of |
---|
| 657 | // line through p and parallel to x axis |
---|
| 658 | // |
---|
| 659 | G4double radical = 1.0 - p.y()*p.y()/dy/dy; |
---|
| 660 | if (radical < +DBL_MIN) return 0; |
---|
| 661 | |
---|
| 662 | G4double xi = dx*std::sqrt( radical ); |
---|
| 663 | if (p.x() < 0) xi = -xi; |
---|
| 664 | |
---|
| 665 | // |
---|
| 666 | // Do the same with y axis |
---|
| 667 | // |
---|
| 668 | radical = 1.0 - p.x()*p.x()/dx/dx; |
---|
| 669 | if (radical < +DBL_MIN) return 0; |
---|
| 670 | |
---|
| 671 | G4double yi = dy*std::sqrt( radical ); |
---|
| 672 | if (p.y() < 0) yi = -yi; |
---|
| 673 | |
---|
| 674 | // |
---|
| 675 | // Get distance from p to the line connecting |
---|
| 676 | // these two points |
---|
| 677 | // |
---|
| 678 | G4double xdi = p.x() - xi, |
---|
| 679 | ydi = yi - p.y(); |
---|
| 680 | |
---|
| 681 | G4double normi = std::sqrt( xdi*xdi + ydi*ydi ); |
---|
| 682 | if (normi < halfTol) return 0; |
---|
| 683 | xdi /= normi; |
---|
| 684 | ydi /= normi; |
---|
| 685 | |
---|
| 686 | G4double s = 0.5*(xdi*(p.y()-yi) - ydi*(p.x()-xi)); |
---|
| 687 | if (xi*yi < 0) s = -s; |
---|
| 688 | |
---|
| 689 | if (s < sBest) sBest = s; |
---|
| 690 | |
---|
| 691 | // |
---|
| 692 | // Return best answer |
---|
| 693 | // |
---|
| 694 | return sBest < halfTol ? 0 : sBest; |
---|
| 695 | } |
---|
| 696 | |
---|
| 697 | |
---|
| 698 | // |
---|
| 699 | // IntersectXY |
---|
| 700 | // |
---|
| 701 | // Decide if and where the x/y trajectory hits the elliptical cross |
---|
| 702 | // section. |
---|
| 703 | // |
---|
| 704 | // Arguments: |
---|
| 705 | // p - (in) Point on trajectory |
---|
| 706 | // v - (in) Vector along trajectory |
---|
| 707 | // s - (out) Up to two points of intersection, where the |
---|
| 708 | // intersection point is p + s*v, and if there are |
---|
| 709 | // two intersections, s[0] < s[1]. May be negative. |
---|
| 710 | // Returns: |
---|
| 711 | // The number of intersections. If 0, the trajectory misses. If 1, the |
---|
| 712 | // trajectory just grazes the surface. |
---|
| 713 | // |
---|
| 714 | // Solution: |
---|
| 715 | // One needs to solve: ( (p.x + s*v.x)/dx )**2 + ( (p.y + s*v.y)/dy )**2 = 1 |
---|
| 716 | // |
---|
| 717 | // The solution is quadratic: a*s**2 + b*s + c = 0 |
---|
| 718 | // |
---|
| 719 | // a = (v.x/dx)**2 + (v.y/dy)**2 |
---|
| 720 | // b = 2*p.x*v.x/dx**2 + 2*p.y*v.y/dy**2 |
---|
| 721 | // c = (p.x/dx)**2 + (p.y/dy)**2 - 1 |
---|
| 722 | // |
---|
| 723 | G4int G4EllipticalTube::IntersectXY( const G4ThreeVector &p, |
---|
| 724 | const G4ThreeVector &v, |
---|
| 725 | G4double s[2] ) const |
---|
| 726 | { |
---|
| 727 | G4double px = p.x(), py = p.y(); |
---|
| 728 | G4double vx = v.x(), vy = v.y(); |
---|
| 729 | |
---|
| 730 | G4double a = (vx/dx)*(vx/dx) + (vy/dy)*(vy/dy); |
---|
| 731 | G4double b = 2.0*( px*vx/dx/dx + py*vy/dy/dy ); |
---|
| 732 | G4double c = (px/dx)*(px/dx) + (py/dy)*(py/dy) - 1.0; |
---|
| 733 | |
---|
| 734 | if (a < DBL_MIN) return 0; // Trajectory parallel to z axis |
---|
| 735 | |
---|
| 736 | G4double radical = b*b - 4*a*c; |
---|
| 737 | |
---|
| 738 | if (radical < -DBL_MIN) return 0; // No solution |
---|
| 739 | |
---|
| 740 | if (radical < DBL_MIN) |
---|
| 741 | { |
---|
| 742 | // |
---|
| 743 | // Grazes surface |
---|
| 744 | // |
---|
| 745 | s[0] = -b/a/2.0; |
---|
| 746 | return 1; |
---|
| 747 | } |
---|
| 748 | |
---|
| 749 | radical = std::sqrt(radical); |
---|
| 750 | |
---|
| 751 | G4double q = -0.5*( b + (b < 0 ? -radical : +radical) ); |
---|
| 752 | G4double sa = q/a; |
---|
| 753 | G4double sb = c/q; |
---|
| 754 | if (sa < sb) { s[0] = sa; s[1] = sb; } else { s[0] = sb; s[1] = sa; } |
---|
| 755 | return 2; |
---|
| 756 | } |
---|
| 757 | |
---|
| 758 | |
---|
| 759 | // |
---|
| 760 | // GetEntityType |
---|
| 761 | // |
---|
| 762 | G4GeometryType G4EllipticalTube::GetEntityType() const |
---|
| 763 | { |
---|
| 764 | return G4String("G4EllipticalTube"); |
---|
| 765 | } |
---|
| 766 | |
---|
| 767 | |
---|
| 768 | // |
---|
| 769 | // GetCubicVolume |
---|
| 770 | // |
---|
| 771 | G4double G4EllipticalTube::GetCubicVolume() |
---|
| 772 | { |
---|
| 773 | if(fCubicVolume != 0.) {;} |
---|
| 774 | else { fCubicVolume = G4VSolid::GetCubicVolume(); } |
---|
| 775 | return fCubicVolume; |
---|
| 776 | } |
---|
| 777 | |
---|
| 778 | // |
---|
| 779 | // GetSurfaceArea |
---|
| 780 | // |
---|
| 781 | G4double G4EllipticalTube::GetSurfaceArea() |
---|
| 782 | { |
---|
| 783 | if(fSurfaceArea != 0.) {;} |
---|
| 784 | else { fSurfaceArea = G4VSolid::GetSurfaceArea(); } |
---|
| 785 | return fSurfaceArea; |
---|
| 786 | } |
---|
| 787 | |
---|
| 788 | // |
---|
| 789 | // Stream object contents to an output stream |
---|
| 790 | // |
---|
| 791 | std::ostream& G4EllipticalTube::StreamInfo(std::ostream& os) const |
---|
| 792 | { |
---|
| 793 | os << "-----------------------------------------------------------\n" |
---|
| 794 | << " *** Dump for solid - " << GetName() << " ***\n" |
---|
| 795 | << " ===================================================\n" |
---|
| 796 | << " Solid type: G4EllipticalTube\n" |
---|
| 797 | << " Parameters: \n" |
---|
| 798 | << " length Z: " << dz/mm << " mm \n" |
---|
| 799 | << " surface equation in X and Y: \n" |
---|
| 800 | << " (X / " << dx << ")^2 + (Y / " << dy << ")^2 = 1 \n" |
---|
| 801 | << "-----------------------------------------------------------\n"; |
---|
| 802 | |
---|
| 803 | return os; |
---|
| 804 | } |
---|
| 805 | |
---|
| 806 | |
---|
| 807 | // |
---|
| 808 | // GetPointOnSurface |
---|
| 809 | // |
---|
| 810 | // Randomly generates a point on the surface, |
---|
| 811 | // with ~ uniform distribution across surface. |
---|
| 812 | // |
---|
| 813 | G4ThreeVector G4EllipticalTube::GetPointOnSurface() const |
---|
| 814 | { |
---|
| 815 | G4double xRand, yRand, zRand, phi, cosphi, sinphi, zArea, cArea,p, chose; |
---|
| 816 | |
---|
| 817 | phi = RandFlat::shoot(0., 2.*pi); |
---|
| 818 | cosphi = std::cos(phi); |
---|
| 819 | sinphi = std::sin(phi); |
---|
| 820 | |
---|
| 821 | // the ellipse perimeter from: "http://mathworld.wolfram.com/Ellipse.html" |
---|
| 822 | // m = (dx - dy)/(dx + dy); |
---|
| 823 | // k = 1.+1./4.*m*m+1./64.*sqr(m)*sqr(m)+1./256.*sqr(m)*sqr(m)*sqr(m); |
---|
| 824 | // p = pi*(a+b)*k; |
---|
| 825 | |
---|
| 826 | // perimeter below from "http://www.efunda.com/math/areas/EllipseGen.cfm" |
---|
| 827 | |
---|
| 828 | p = 2.*pi*std::sqrt(0.5*(dx*dx+dy*dy)); |
---|
| 829 | |
---|
| 830 | cArea = 2.*dz*p; |
---|
| 831 | zArea = pi*dx*dy; |
---|
| 832 | |
---|
| 833 | xRand = dx*cosphi; |
---|
| 834 | yRand = dy*sinphi; |
---|
| 835 | zRand = RandFlat::shoot(dz, -1.*dz); |
---|
| 836 | |
---|
| 837 | chose = RandFlat::shoot(0.,2.*zArea+cArea); |
---|
| 838 | |
---|
| 839 | if( (chose>=0) && (chose < cArea) ) |
---|
| 840 | { |
---|
| 841 | return G4ThreeVector (xRand,yRand,zRand); |
---|
| 842 | } |
---|
| 843 | else if( (chose >= cArea) && (chose < cArea + zArea) ) |
---|
| 844 | { |
---|
| 845 | xRand = RandFlat::shoot(-1.*dx,dx); |
---|
| 846 | yRand = std::sqrt(1.-sqr(xRand/dx)); |
---|
| 847 | yRand = RandFlat::shoot(-1.*yRand, yRand); |
---|
| 848 | return G4ThreeVector (xRand,yRand,dz); |
---|
| 849 | } |
---|
| 850 | else |
---|
| 851 | { |
---|
| 852 | xRand = RandFlat::shoot(-1.*dx,dx); |
---|
| 853 | yRand = std::sqrt(1.-sqr(xRand/dx)); |
---|
| 854 | yRand = RandFlat::shoot(-1.*yRand, yRand); |
---|
| 855 | return G4ThreeVector (xRand,yRand,-1.*dz); |
---|
| 856 | } |
---|
| 857 | } |
---|
| 858 | |
---|
| 859 | |
---|
| 860 | // |
---|
| 861 | // CreatePolyhedron |
---|
| 862 | // |
---|
| 863 | G4Polyhedron* G4EllipticalTube::CreatePolyhedron() const |
---|
| 864 | { |
---|
| 865 | // create cylinder with radius=1... |
---|
| 866 | // |
---|
| 867 | G4Polyhedron* eTube = new G4PolyhedronTube(0.,1.,dz); |
---|
| 868 | |
---|
| 869 | // apply non-uniform scaling... |
---|
| 870 | // |
---|
| 871 | eTube->Transform(G4Scale3D(dx,dy,1.)); |
---|
| 872 | return eTube; |
---|
| 873 | } |
---|
| 874 | |
---|
| 875 | |
---|
| 876 | // |
---|
| 877 | // GetPolyhedron |
---|
| 878 | // |
---|
| 879 | G4Polyhedron* G4EllipticalTube::GetPolyhedron () const |
---|
| 880 | { |
---|
| 881 | if (!fpPolyhedron || |
---|
| 882 | fpPolyhedron->GetNumberOfRotationStepsAtTimeOfCreation() != |
---|
| 883 | fpPolyhedron->GetNumberOfRotationSteps()) |
---|
| 884 | { |
---|
| 885 | delete fpPolyhedron; |
---|
| 886 | fpPolyhedron = CreatePolyhedron(); |
---|
| 887 | } |
---|
| 888 | return fpPolyhedron; |
---|
| 889 | } |
---|
| 890 | |
---|
| 891 | |
---|
| 892 | // |
---|
| 893 | // DescribeYourselfTo |
---|
| 894 | // |
---|
| 895 | void G4EllipticalTube::DescribeYourselfTo( G4VGraphicsScene& scene ) const |
---|
| 896 | { |
---|
| 897 | scene.AddSolid (*this); |
---|
| 898 | } |
---|
| 899 | |
---|
| 900 | |
---|
| 901 | // |
---|
| 902 | // GetExtent |
---|
| 903 | // |
---|
| 904 | G4VisExtent G4EllipticalTube::GetExtent() const |
---|
| 905 | { |
---|
| 906 | return G4VisExtent( -dx, dx, -dy, dy, -dz, dz ); |
---|
| 907 | } |
---|