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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008 Gael Guennebaud <g.gael@free.fr>
//
// Eigen is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 3 of the License, or (at your option) any later version.
//
// Alternatively, you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of
// the License, or (at your option) any later version.
//
// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License and a copy of the GNU General Public License along with
// Eigen. If not, see <http://www.gnu.org/licenses/>.
#include "icosphere.h"
#include <GL/gl.h>
#include <map>
using namespace Eigen;
//--------------------------------------------------------------------------------
// icosahedron data
//--------------------------------------------------------------------------------
#define X .525731112119133606
#define Z .850650808352039932
static GLfloat vdata[12][3] = {
{-X, 0.0, Z}, {X, 0.0, Z}, {-X, 0.0, -Z}, {X, 0.0, -Z},
{0.0, Z, X}, {0.0, Z, -X}, {0.0, -Z, X}, {0.0, -Z, -X},
{Z, X, 0.0}, {-Z, X, 0.0}, {Z, -X, 0.0}, {-Z, -X, 0.0}
};
static GLint tindices[20][3] = {
{0,4,1}, {0,9,4}, {9,5,4}, {4,5,8}, {4,8,1},
{8,10,1}, {8,3,10}, {5,3,8}, {5,2,3}, {2,7,3},
{7,10,3}, {7,6,10}, {7,11,6}, {11,0,6}, {0,1,6},
{6,1,10}, {9,0,11}, {9,11,2}, {9,2,5}, {7,2,11} };
//--------------------------------------------------------------------------------
IcoSphere::IcoSphere(unsigned int levels)
{
// init with an icosahedron
for (int i = 0; i < 12; i++)
mVertices.push_back(Map<Vector3f>(vdata[i]));
mIndices.push_back(new std::vector<int>);
std::vector<int>& indices = *mIndices.back();
for (int i = 0; i < 20; i++)
{
for (int k = 0; k < 3; k++)
indices.push_back(tindices[i][k]);
}
mListIds.push_back(0);
while(mIndices.size()<levels)
_subdivide();
}
const std::vector<int>& IcoSphere::indices(int level) const
{
while (level>=int(mIndices.size()))
const_cast<IcoSphere*>(this)->_subdivide();
return *mIndices[level];
}
void IcoSphere::_subdivide(void)
{
typedef unsigned long long Key;
std::map<Key,int> edgeMap;
const std::vector<int>& indices = *mIndices.back();
mIndices.push_back(new std::vector<int>);
std::vector<int>& refinedIndices = *mIndices.back();
int end = indices.size();
for (int i=0; i<end; i+=3)
{
int ids0[3], // indices of outer vertices
ids1[3]; // indices of edge vertices
for (int k=0; k<3; ++k)
{
int k1 = (k+1)%3;
int e0 = indices[i+k];
int e1 = indices[i+k1];
ids0[k] = e0;
if (e1>e0)
std::swap(e0,e1);
Key edgeKey = Key(e0) | (Key(e1)<<32);
std::map<Key,int>::iterator it = edgeMap.find(edgeKey);
if (it==edgeMap.end())
{
ids1[k] = mVertices.size();
edgeMap[edgeKey] = ids1[k];
mVertices.push_back( (mVertices[e0]+mVertices[e1]).normalized() );
}
else
ids1[k] = it->second;
}
refinedIndices.push_back(ids0[0]); refinedIndices.push_back(ids1[0]); refinedIndices.push_back(ids1[2]);
refinedIndices.push_back(ids0[1]); refinedIndices.push_back(ids1[1]); refinedIndices.push_back(ids1[0]);
refinedIndices.push_back(ids0[2]); refinedIndices.push_back(ids1[2]); refinedIndices.push_back(ids1[1]);
refinedIndices.push_back(ids1[0]); refinedIndices.push_back(ids1[1]); refinedIndices.push_back(ids1[2]);
}
mListIds.push_back(0);
}
void IcoSphere::draw(int level)
{
while (level>=int(mIndices.size()))
const_cast<IcoSphere*>(this)->_subdivide();
if (mListIds[level]==0)
{
mListIds[level] = glGenLists(1);
glNewList(mListIds[level], GL_COMPILE);
glVertexPointer(3, GL_FLOAT, 0, mVertices[0].data());
glNormalPointer(GL_FLOAT, 0, mVertices[0].data());
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_NORMAL_ARRAY);
glDrawElements(GL_TRIANGLES, mIndices[level]->size(), GL_UNSIGNED_INT, &(mIndices[level]->at(0)));
glDisableClientState(GL_VERTEX_ARRAY);
glDisableClientState(GL_NORMAL_ARRAY);
glEndList();
}
glCallList(mListIds[level]);
}
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