triangle.h
4.14 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
#ifndef RTS_TRIANGLE_H
#define RTS_TRIANGLE_H
//enable CUDA_CALLABLE macro
#include <stim/cuda/cudatools/callable.h>
#include <stim/math/vector.h>
#include <iostream>
namespace stim{
template <class T>
struct triangle
{
/*
A------>B
| /
| /
| /
| /
| /
| /
C
*/
private:
vec<T> A;
vec<T> B;
vec<T> C;
CUDA_CALLABLE vec<T> _p(T s, T t)
{
//This function returns the point specified by p = A + s(B-A) + t(C-A)
vec<T> E0 = B-A;
vec<T> E1 = C-A;
return A + s*E0 + t*E1;
}
public:
CUDA_CALLABLE triangle()
{
}
CUDA_CALLABLE triangle(vec<T> a, vec<T> b, vec<T> c)
{
A = a;
B = b;
C = c;
}
CUDA_CALLABLE stim::vec<T> operator()(T s, T t)
{
return _p(s, t);
}
CUDA_CALLABLE vec<T> nearest(vec<T> p)
{
//comptue the distance between a point and this triangle
// This code is adapted from: http://www.geometrictools.com/Documentation/DistancePoint3Triangle3.pdf
vec<T> E0 = B-A;
vec<T> E1 = C-A;
vec<T> D = A - p;
T a = E0.dot(E0);
T b = E0.dot(E1);
T c = E1.dot(E1);
T d = E0.dot(D);
T e = E1.dot(D);
//T f = D.dot(D);
T det = a*c - b*b;
T s = b*e - c*d;
T t = b*d - a*e;
/*std::cout<<"E0: "<<E0<<std::endl;
std::cout<<"E1: "<<E1<<std::endl;
std::cout<<"a: "<<a<<std::endl;
std::cout<<"b: "<<b<<std::endl;
std::cout<<"c: "<<c<<std::endl;
std::cout<<"d: "<<d<<std::endl;
std::cout<<"e: "<<e<<std::endl;
std::cout<<"f: "<<f<<std::endl;
std::cout<<"det: "<<det<<std::endl;
std::cout<<"s: "<<s<<std::endl;
std::cout<<"t: "<<t<<std::endl;*/
if( s+t <= det)
{
if(s < 0)
{
if(t < 0)
{
//region 4
//std::cout<<"Region 4"<<std::endl;
s = 0;
t = 0;
//done?
}
else
{
//region 3
//std::cout<<"Region 3"<<std::endl;
s=0;
t = ( e >= 0 ? 0 : ( -e >= c ? 1 : -e/c ) );
//done
}
}
else if(t < 0)
{
//region 5
//std::cout<<"Region 5"<<std::endl;
s = ( d >= 0 ? 0 : ( -d >= a ? 1 : -d/a ) );
t = 0;
//done
}
else
{
//region 0
//std::cout<<"Region 0"<<std::endl;
T invDet = (T)1.0/det;
s *= invDet;
t *= invDet;
//done
}
}
else
{
if(s < 0)
{
//region 2
//std::cout<<"Region 2"<<std::endl;
s = 0;
t = 1;
//done?
}
else if(t < 0)
{
//region 6
//std::cout<<"Region 6"<<std::endl;
s = 1;
t = 0;
//done?
}
else
{
//region 1
//std::cout<<"Region 1"<<std::endl;
T numer = c + e - b - d;
if( numer <= 0 )
s = 0;
else
{
T denom = a - 2 * b + c;
s = ( numer >= denom ? 1 : numer/denom );
}
t = 1 - s;
//done
}
}
//std::cout<<"s: "<<s<<std::endl;
//std::cout<<"t: "<<t<<std::endl;
//std::cout<<"p: "<<_p(s, t)<<std::endl;
return _p(s, t);
}
CUDA_CALLABLE T dist(vec<T> p)
{
vec<T> n = nearest(p);
return (p - n).len();
}
};
}
#endif