update bundled_deps

bundled_deps/libigl/igl/random_dir.cpp

@@ -0,0 +1,52 @@
+// This file is part of libigl, a simple c++ geometry processing library.
+//
+// Copyright (C) 2013 Alec Jacobson <alecjacobson@gmail.com>
+//
+// 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 "random_dir.h"
+#include <igl/PI.h>
+#include <cmath>
+
+IGL_INLINE Eigen::Vector3d igl::random_dir()
+{
+  using namespace Eigen;
+  double z =  (double)rand() / (double)RAND_MAX*2.0 - 1.0;
+  double t =  (double)rand() / (double)RAND_MAX*2.0*PI;
+  // http://www.altdevblogaday.com/2012/05/03/generating-uniformly-distributed-points-on-sphere/
+  double r = sqrt(1.0-z*z);
+  double x = r * cos(t);
+  double y = r * sin(t);
+  return Vector3d(x,y,z);
+}
+
+IGL_INLINE Eigen::MatrixXd igl::random_dir_stratified(const int n)
+{
+  using namespace Eigen;
+  using namespace std;
+  const double m = std::floor(sqrt(double(n)));
+  MatrixXd N(n,3);
+  int row = 0;
+  for(int i = 0;i<m;i++)
+  {
+    const double x = double(i)*1./m;
+    for(int j = 0;j<m;j++)
+    {
+      const double y = double(j)*1./m;
+      double z = (x+(1./m)*(double)rand() / (double)RAND_MAX)*2.0 - 1.0;
+      double t = (y+(1./m)*(double)rand() / (double)RAND_MAX)*2.0*PI;
+      double r = sqrt(1.0-z*z);
+      N(row,0) = r * cos(t);
+      N(row,1) = r * sin(t);
+      N(row,2) = z;
+      row++;
+    }
+  }
+  // Finish off with uniform random directions
+  for(;row<n;row++)
+  {
+    N.row(row) = random_dir();
+  }
+  return N;
+}