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BezierCurveT.cc
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40 \*===========================================================================*/
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42 /*===========================================================================*\
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48 \*===========================================================================*/
49
50
51
52 //=============================================================================
53 //
54 // CLASS BezierCurve - IMPLEMENTATION
55 //
56 //=============================================================================
57
58 #define ACG_BEZIERCURVE_C
59
60 //== INCLUDES =================================================================
61
62
63 #include "BezierCurveT.hh"
64
65
66 //== IMPLEMENTATION ==========================================================
67
68
69 namespace ACG {
70
71
72 //-----------------------------------------------------------------------------
73
74
75 template <class Point>
76 Point
77 BezierCurveT<Point>::
78 operator()(Scalar _t) const
79 {
80 // copy controll points
81 std::vector<Point> b(*this);
82
83 unsigned int n = b.size()-1, k;
84 Scalar t0(1.0-_t), t1(_t);
85
86
87 // de Casteljau
88 unsigned int i, j;
89 for (i=0; i<n; ++i)
90 for (j=0, k=n-i; j<k; ++j)
91 b[j] = t0*b[j] + t1*b[j+1];
92
93
94 return b[0];
95 }
96
97
98 //-----------------------------------------------------------------------------
99
100
101 template <class Point>
102 void
103 BezierCurveT<Point>::
104 subdivide(Scalar _t, Self& _curve0, Self& _curve1) const
105 {
106 // copy controll points
107 std::vector<Point> b(*this);
108
109 int n = degree();
110 Scalar t0(1.0-_t), t1(_t);
111
112
113 _curve0.clear();
114 _curve0.reserve(n+1);
115 _curve1.clear();
116 _curve1.reserve(n+1);
117
118 std::vector<Point> tmp;
119 tmp.reserve(n+1);
120
121
122 // de Casteljau
123 int i, j, k;
124 for (i=0; i<n; ++i)
125 {
126 _curve0.push_back(b[0]);
127 tmp.push_back(b[n-i]);
128
129 for (j=0, k=n-i; j<k; ++j)
130 b[j] = t0*b[j] + t1*b[j+1];
131 }
132
133 _curve0.push_back(b[0]);
134 tmp.push_back(b[0]);
135
136
137 for (i=n; i>=0; --i)
138 _curve1.push_back(tmp[i]);
139
140
141 assert(_curve0.degree() == n);
142 assert(_curve1.degree() == n);
143 }
144
145
146 //=============================================================================
147 } // namespace ACG
148 //=============================================================================
ACG::BezierCurveT::degree
unsigned int degree() const
return degree (= size()-1)
Definition: BezierCurveT.hh:100
ACG::BezierCurveT::operator()
Point operator()(Scalar _t) const
evaluate curve at parameter _t using deCasteljau
Definition: BezierCurveT.cc:78
ACG
Namespace providing different geometric functions concerning angles.
Definition: DBSCANT.cc:51
ACG::BezierCurveT
Definition: BezierCurveT.hh:83
ACG::BezierCurveT::subdivide
void subdivide(Scalar _t, Self &_curve0, Self &_curve1) const
Definition: BezierCurveT.cc:104