[1097] | 1 | /************************************************************************
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| 2 |
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| 3 | 2D Quadric Error Metric
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| 4 |
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| 5 | Copyright (C) 1998 Michael Garland. See "COPYING.txt" for details.
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| 6 |
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| 7 | $Id: MxQMetric2.cxx,v 1.1 2002/09/24 16:53:54 wimmer Exp $
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| 8 |
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| 9 | ************************************************************************/
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| 10 |
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| 11 | #include "stdmix.h"
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| 12 | #include "MxQMetric2.h"
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| 13 |
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| 14 |
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| 15 | void MxQuadric2::init(double a, double b, double c, double len)
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| 16 | {
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| 17 | a2 = a*a; ab = a*b; ac = a*c;
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| 18 | b2 = b*b; bc = b*c;
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| 19 | c2 = c*c;
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| 20 |
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| 21 | r = len;
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| 22 | }
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| 23 |
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| 24 | Mat2 MxQuadric2::tensor() const
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| 25 | {
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| 26 | return Mat2(a2, ab, ab, b2);
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| 27 | }
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| 28 |
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| 29 | Mat3 MxQuadric2::homogeneous() const
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| 30 | {
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| 31 | return Mat3(Vec3(a2, ab, ac),
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| 32 | Vec3(ab, b2, bc),
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| 33 | Vec3(ac, bc, c2));
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| 34 | }
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| 35 |
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| 36 | MxQuadric2& MxQuadric2::operator=(const MxQuadric2& Q)
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| 37 | {
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| 38 | r = Q.r;
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| 39 |
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| 40 | a2 = Q.a2; ab = Q.ab; ac = Q.ac;
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| 41 | b2 = Q.b2; bc = Q.bc;
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| 42 | c2 = Q.c2;
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| 43 |
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| 44 | return *this;
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| 45 | }
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| 46 |
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| 47 | MxQuadric2& MxQuadric2::operator+=(const MxQuadric2& Q)
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| 48 | {
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| 49 | r += Q.r;
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| 50 |
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| 51 | a2 += Q.a2; ab += Q.ab; ac += Q.ac;
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| 52 | b2 += Q.b2; bc += Q.bc;
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| 53 | c2 += Q.c2;
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| 54 |
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| 55 | return *this;
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| 56 | }
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| 57 |
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| 58 | MxQuadric2& MxQuadric2::operator-=(const MxQuadric2& Q)
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| 59 | {
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| 60 | r -= Q.r;
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| 61 |
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| 62 | a2 -= Q.a2; ab -= Q.ab; ac -= Q.ac;
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| 63 | b2 -= Q.b2; bc -= Q.bc;
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| 64 | c2 -= Q.c2;
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| 65 |
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| 66 | return *this;
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| 67 | }
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| 68 |
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| 69 | MxQuadric2& MxQuadric2::operator*=(double s)
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| 70 | {
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| 71 | // Don't scale area
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| 72 |
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| 73 | a2 *= s; ab *= s; ac *= s;
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| 74 | b2 *= s; bc *= s;
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| 75 | c2 *= s;
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| 76 |
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| 77 | return *this;
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| 78 | }
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| 79 |
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| 80 | double MxQuadric2::evaluate(double x, double y) const
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| 81 | {
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| 82 | // Evaluate vAv + 2bv + c
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| 83 |
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| 84 | return x*x*a2 + 2*x*y*ab + 2*x*ac
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| 85 | + y*y*b2 + 2*y*bc
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| 86 | + c2;
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| 87 | }
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| 88 |
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| 89 | bool MxQuadric2::optimize(Vec2& v) const
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| 90 | {
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| 91 | Mat2 Ainv;
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| 92 | double det = tensor().invert(Ainv);
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| 93 | if( FEQ(det, 0.0, 1e-12) )
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| 94 | return false;
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| 95 |
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| 96 | v = -(Ainv*vector());
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| 97 |
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| 98 | return true;
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| 99 | }
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| 100 |
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| 101 | bool MxQuadric2::optimize(float *x, float *y) const
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| 102 | {
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| 103 | Vec2 v;
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| 104 |
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| 105 | bool success = optimize(v);
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| 106 | if( success )
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| 107 | {
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| 108 | *x = (float)v[X];
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| 109 | *y = (float)v[Y];
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| 110 | }
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| 111 | return success;
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| 112 | }
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