1 // This file is part of Eigen, a lightweight C++ template library
2 // for linear algebra.
3 //
4 // Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
5 //
6 // This Source Code Form is subject to the terms of the Mozilla
7 // Public License v. 2.0. If a copy of the MPL was not distributed
8 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
9
10 #include "icosphere.h"
11
12 #include <GL/gl.h>
13 #include <map>
14
15 using namespace Eigen;
16
17 //--------------------------------------------------------------------------------
18 // icosahedron data
19 //--------------------------------------------------------------------------------
20 #define X .525731112119133606
21 #define Z .850650808352039932
22
23 static GLfloat vdata[12][3] = {
24 {-X, 0.0, Z}, {X, 0.0, Z}, {-X, 0.0, -Z}, {X, 0.0, -Z},
25 {0.0, Z, X}, {0.0, Z, -X}, {0.0, -Z, X}, {0.0, -Z, -X},
26 {Z, X, 0.0}, {-Z, X, 0.0}, {Z, -X, 0.0}, {-Z, -X, 0.0}
27 };
28
29 static GLint tindices[20][3] = {
30 {0,4,1}, {0,9,4}, {9,5,4}, {4,5,8}, {4,8,1},
31 {8,10,1}, {8,3,10}, {5,3,8}, {5,2,3}, {2,7,3},
32 {7,10,3}, {7,6,10}, {7,11,6}, {11,0,6}, {0,1,6},
33 {6,1,10}, {9,0,11}, {9,11,2}, {9,2,5}, {7,2,11} };
34 //--------------------------------------------------------------------------------
35
IcoSphere(unsigned int levels)36 IcoSphere::IcoSphere(unsigned int levels)
37 {
38 // init with an icosahedron
39 for (int i = 0; i < 12; i++)
40 mVertices.push_back(Map<Vector3f>(vdata[i]));
41 mIndices.push_back(new std::vector<int>);
42 std::vector<int>& indices = *mIndices.back();
43 for (int i = 0; i < 20; i++)
44 {
45 for (int k = 0; k < 3; k++)
46 indices.push_back(tindices[i][k]);
47 }
48 mListIds.push_back(0);
49
50 while(mIndices.size()<levels)
51 _subdivide();
52 }
53
indices(int level) const54 const std::vector<int>& IcoSphere::indices(int level) const
55 {
56 while (level>=int(mIndices.size()))
57 const_cast<IcoSphere*>(this)->_subdivide();
58 return *mIndices[level];
59 }
60
_subdivide(void)61 void IcoSphere::_subdivide(void)
62 {
63 typedef unsigned long long Key;
64 std::map<Key,int> edgeMap;
65 const std::vector<int>& indices = *mIndices.back();
66 mIndices.push_back(new std::vector<int>);
67 std::vector<int>& refinedIndices = *mIndices.back();
68 int end = indices.size();
69 for (int i=0; i<end; i+=3)
70 {
71 int ids0[3], // indices of outer vertices
72 ids1[3]; // indices of edge vertices
73 for (int k=0; k<3; ++k)
74 {
75 int k1 = (k+1)%3;
76 int e0 = indices[i+k];
77 int e1 = indices[i+k1];
78 ids0[k] = e0;
79 if (e1>e0)
80 std::swap(e0,e1);
81 Key edgeKey = Key(e0) | (Key(e1)<<32);
82 std::map<Key,int>::iterator it = edgeMap.find(edgeKey);
83 if (it==edgeMap.end())
84 {
85 ids1[k] = mVertices.size();
86 edgeMap[edgeKey] = ids1[k];
87 mVertices.push_back( (mVertices[e0]+mVertices[e1]).normalized() );
88 }
89 else
90 ids1[k] = it->second;
91 }
92 refinedIndices.push_back(ids0[0]); refinedIndices.push_back(ids1[0]); refinedIndices.push_back(ids1[2]);
93 refinedIndices.push_back(ids0[1]); refinedIndices.push_back(ids1[1]); refinedIndices.push_back(ids1[0]);
94 refinedIndices.push_back(ids0[2]); refinedIndices.push_back(ids1[2]); refinedIndices.push_back(ids1[1]);
95 refinedIndices.push_back(ids1[0]); refinedIndices.push_back(ids1[1]); refinedIndices.push_back(ids1[2]);
96 }
97 mListIds.push_back(0);
98 }
99
draw(int level)100 void IcoSphere::draw(int level)
101 {
102 while (level>=int(mIndices.size()))
103 const_cast<IcoSphere*>(this)->_subdivide();
104 if (mListIds[level]==0)
105 {
106 mListIds[level] = glGenLists(1);
107 glNewList(mListIds[level], GL_COMPILE);
108 glVertexPointer(3, GL_FLOAT, 0, mVertices[0].data());
109 glNormalPointer(GL_FLOAT, 0, mVertices[0].data());
110 glEnableClientState(GL_VERTEX_ARRAY);
111 glEnableClientState(GL_NORMAL_ARRAY);
112 glDrawElements(GL_TRIANGLES, mIndices[level]->size(), GL_UNSIGNED_INT, &(mIndices[level]->at(0)));
113 glDisableClientState(GL_VERTEX_ARRAY);
114 glDisableClientState(GL_NORMAL_ARRAY);
115 glEndList();
116 }
117 glCallList(mListIds[level]);
118 }
119
120
121