Squashed 'third_party/eigen/' content from commit 61d72f6
Change-Id: Iccc90fa0b55ab44037f018046d2fcffd90d9d025
git-subtree-dir: third_party/eigen
git-subtree-split: 61d72f6383cfa842868c53e30e087b0258177257
diff --git a/demos/opengl/icosphere.cpp b/demos/opengl/icosphere.cpp
new file mode 100644
index 0000000..39444cb
--- /dev/null
+++ b/demos/opengl/icosphere.cpp
@@ -0,0 +1,120 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra.
+//
+// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#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]);
+}
+
+