Subversion Repositories gelsvn

Rev

Rev 291 | Go to most recent revision | Details | Last modification | View Log | RSS feed

Rev Author Line No. Line
290 jrf 1 
#include "CGLA/Vec4f.h"
2 
#include "Triangle.h"
3 
 
4 
 
5 
using namespace std;
6 
using namespace CGLA;
7 
 
8 
const float EPSILON = 0.000001;
9 
 
10 
Triangle::Triangle(const CGLA::Vec3f& _v0,
11 
									 const CGLA::Vec3f& _v1,
12 
									 const CGLA::Vec3f& _v2,
13 
 
14 
									 const CGLA::Vec3f& _vn0,
15 
									 const CGLA::Vec3f& _vn1,
16 
									 const CGLA::Vec3f& _vn2,
17 
 
18 
									 const CGLA::Vec3f& _en0,
19 
									 const CGLA::Vec3f& _en1,
20 
									 const CGLA::Vec3f& _en2)
21 
{
22 
	vert[0]  =_v0;
23 
	vert[1]  =_v1;
24 
	vert[2]  =_v2;
25 
 
26 
#ifdef COMPUTE_SIGN
27 
	vert_norm[0] = _vn0;
28 
	vert_norm[1] = _vn1;
29 
	vert_norm[2] = _vn2;
30 
 
31 
	edge_norm[0] = _en0;
32 
	edge_norm[1] = _en1;
33 
	edge_norm[2] = _en2;
34 
#endif
35 
 
36 
	face_norm = normalize(cross(vert[1]-vert[0], vert[2]-vert[0]));
37 
	for(int i=0;i<3;++i)
38 
		{
39 
			int j= (i+1)%3;
40 
			edge[i] = vert[j]-vert[i];
41 
			tri_plane_edge_norm[i] = cross(face_norm, edge[i]);
42 
			edge_len[i] = edge[i].length();
43 
		}
44 
}
45 
 
46 
 
47 
// Moellers method
48 
bool Triangle::intersect(const CGLA::Vec3f& orig,
49 
												 const CGLA::Vec3f& dir, float&t) const
50 
{
51 
	Vec3f tvec, pvec, qvec;
52 
	float det,inv_det;
53 
 
54 
   /* begin calculating determinant - also used to calculate U parameter */
55 
   pvec = cross(dir, -edge[2]);
56 
 
57 
   /* if determinant is near zero, ray lies in plane of triangle */
58 
   det = dot(edge[0], pvec);
59 
 
60 
   if (det > -EPSILON && det < EPSILON)
61 
     return 0;
62 
   inv_det = 1.0 / det;
63 
 
64 
   /* calculate distance from v0 to ray origin */
65 
   tvec =  orig - vert[0];
66 
 
67 
   /* calculate U parameter and test bounds */
68 
   float u = dot(tvec, pvec) * inv_det;
69 
   if (u < 0.0 || u > 1.0)
70 
     return false;
71 
 
72 
   /* prepare to test V parameter */
73 
   qvec = cross(tvec, edge[0]);
74 
 
75 
   /* calculate V parameter and test bounds */
76 
   float v = dot(dir, qvec) * inv_det;
77 
   if (v < 0.0 || u + v > 1.0)
78 
     return false;
79 
 
80 
   /* calculate t, ray intersects triangle */
81 
   t = dot(-edge[2], qvec) * inv_det;
82 
 
83 
   return true;
84 
}
85 
 
86 
 
87 
 
88 
 
89 
bool Triangle::signed_distance(const Vec3f& p,
90 
															 float& sq_dist, float& sgn) const
91 
{
92 
	int vertex_scores[3] = {0,0,0};
93 
	Vec3f closest_pnt, normal;
94 
	int idx_0;
95 
 
96 
	// Loop over all three edges.
97 
	for(idx_0=0; idx_0<3; ++idx_0)
98 
		{
99 
			const int idx_1 = (idx_0+1) % 3;
100 
			const Vec3f dir_3d = edge[idx_0]/edge_len[idx_0];
101 
			const float t = dot(p - vert[idx_0], dir_3d);
102 
			if(t <= 0)
103 
				{
104 
					++vertex_scores[idx_0];
105 
					if(vertex_scores[idx_0] == 2)
106 
						{
107 
							closest_pnt = vert[idx_0];
108 
#ifdef COMPUTE_SIGN
109 
							normal = vert_norm[idx_0];
110 
#endif
111 
							break;
112 
						}
113 
				}
114 
			else if(t >= edge_len[idx_0])
115 
				{
116 
					++vertex_scores[idx_1];
117 
					if(vertex_scores[idx_1] == 2)
118 
						{
119 
							closest_pnt = vert[idx_1];
120 
#ifdef COMPUTE_SIGN
121 
							normal = vert_norm[idx_1];
122 
#endif
123 
							break;
124 
						}
125 
				}
126 
			else if(dot(tri_plane_edge_norm[idx_0], p-vert[idx_0]) <=0)
127 
				{
128 
					closest_pnt=vert[idx_0]+t*dir_3d;
129 
#ifdef COMPUTE_SIGN
130 
					normal = edge_norm[idx_0];
131 
#endif
132 
					break;
133 
				}
134 
		}
135 
	if(idx_0 == 3)
136 
		{
137 
			closest_pnt = p - face_norm*(dot(p-vert[0],face_norm));
138 
#ifdef COMPUTE_SIGN
139 
			normal = face_norm;
140 
#endif
141 
		}
142 
	sq_dist = sqr_length(p-closest_pnt);
143 
 
144 
#ifdef COMPUTE_SIGN
145 
	// Compute dot product with angle weighted normal, and
146 
	// assign the sign based on the result.
147 
	if(dot(normal, p-closest_pnt) >=0)
148 
		sgn = 1.0f;
149 
	else
150 
		sgn = -1.0f;
151 
#else
152 
	sgn = 1.0f;
153 
#endif
154 
 
155 
	return true;
156 
}
157 
 
158 
 
159