Developer Documentation
BezierCurveT_impl.hh
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41 
42 
43 
44 
45 
46 //=============================================================================
47 //
48 // CLASS BezierCurve - IMPLEMENTATION
49 //
50 //=============================================================================
51 
52 #define ACG_BEZIERCURVE_C
53 
54 //== INCLUDES =================================================================
55 
56 
57 #include "BezierCurveT.hh"
58 
59 
60 //== IMPLEMENTATION ==========================================================
61 
62 
63 namespace ACG {
64 
65 
66 //-----------------------------------------------------------------------------
67 
68 
69 template <class Point>
70 Point
72 operator()(Scalar _t) const
73 {
74  // copy controll points
75  std::vector<Point> b(*this);
76 
77  unsigned int n = b.size()-1, k;
78  Scalar t0(1.0-_t), t1(_t);
79 
80 
81  // de Casteljau
82  unsigned int i, j;
83  for (i=0; i<n; ++i)
84  for (j=0, k=n-i; j<k; ++j)
85  b[j] = t0*b[j] + t1*b[j+1];
86 
87 
88  return b[0];
89 }
90 
91 
92 //-----------------------------------------------------------------------------
93 
94 
95 template <class Point>
96 void
98 subdivide(Scalar _t, Self& _curve0, Self& _curve1) const
99 {
100  // copy controll points
101  std::vector<Point> b(*this);
102 
103  int n = degree();
104  Scalar t0(1.0-_t), t1(_t);
105 
106 
107  _curve0.clear();
108  _curve0.reserve(n+1);
109  _curve1.clear();
110  _curve1.reserve(n+1);
111 
112  std::vector<Point> tmp;
113  tmp.reserve(n+1);
114 
115 
116  // de Casteljau
117  int i, j, k;
118  for (i=0; i<n; ++i)
119  {
120  _curve0.push_back(b[0]);
121  tmp.push_back(b[n-i]);
122 
123  for (j=0, k=n-i; j<k; ++j)
124  b[j] = t0*b[j] + t1*b[j+1];
125  }
126 
127  _curve0.push_back(b[0]);
128  tmp.push_back(b[0]);
129 
130 
131  for (i=n; i>=0; --i)
132  _curve1.push_back(tmp[i]);
133 
134 
135  assert(_curve0.degree() == n);
136  assert(_curve1.degree() == n);
137 }
138 
139 
140 //=============================================================================
141 } // namespace ACG
142 //=============================================================================
Namespace providing different geometric functions concerning angles.
void subdivide(Scalar _t, Self &_curve0, Self &_curve1) const
unsigned int degree() const
return degree (= size()-1)
Definition: BezierCurveT.hh:94
Point operator()(Scalar _t) const
evaluate curve at parameter _t using deCasteljau