libigl_Martin/include/igl/cylinder_with_caps.cpp

// This file is part of libigl, a simple c++ geometry processing library.
//
// Copyright (C) 2018 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 "cylinder_with_caps.h"
#include "PI.h"
#include <cassert>
#include <cmath>

template <typename DerivedV, typename DerivedF>
IGL_INLINE void igl::cylinder_with_caps(
    const int axis_devisions,
    const int height_devisions,
    Eigen::PlainObjectBase<DerivedV> &V,
    Eigen::PlainObjectBase<DerivedF> &F)
{
  V.resize(axis_devisions * height_devisions, 3);
  F.resize(2 * (axis_devisions * height_devisions) - 4, 3);
  int f = 0;
  typedef typename DerivedV::Scalar Scalar;
  for (int th = 0; th < axis_devisions; th++)
  {
    Scalar x = cos(2. * igl::PI * Scalar(th) / Scalar(axis_devisions));
    Scalar y = sin(2. * igl::PI * Scalar(th) / Scalar(axis_devisions));
    for (int h = 0; h < height_devisions; h++)
    {
      Scalar z = Scalar(h) / Scalar(height_devisions - 1);
      V(th + h * axis_devisions, 0) = x;
      V(th + h * axis_devisions, 1) = y;
      V(th + h * axis_devisions, 2) = z;
      if (h > 0)
      {
        F(f, 0) = ((th + 0) % axis_devisions) + (h - 1) * axis_devisions;
        F(f, 1) = ((th + 1) % axis_devisions) + (h - 1) * axis_devisions;
        F(f, 2) = ((th + 0) % axis_devisions) + (h + 0) * axis_devisions;
        f++;
        F(f, 0) = ((th + 1) % axis_devisions) + (h - 1) * axis_devisions;
        F(f, 1) = ((th + 1) % axis_devisions) + (h + 0) * axis_devisions;
        F(f, 2) = ((th + 0) % axis_devisions) + (h + 0) * axis_devisions;
        f++;
      }
    }
  }

  for (int i = 0; i < axis_devisions - 2; ++i)
  {
    F(f, 2) = 0;
    F(f, 1) = ((i + 1) % axis_devisions);
    F(f, 0) = ((i + 2) % axis_devisions);
    f++;
  }

  for (int i = 0; i < axis_devisions - 2; ++i)
  {
    F(f, 0) = (height_devisions - 1) * axis_devisions;
    F(f, 1) = ((i + 1) % axis_devisions) + (height_devisions - 1) * axis_devisions;
    F(f, 2) = ((i + 2) % axis_devisions) + (height_devisions - 1) * axis_devisions;
    f++;
  }
  assert(f == F.rows());
}

#ifdef IGL_STATIC_LIBRARY
template void igl::cylinder_with_caps<Eigen::Matrix<double, -1, -1, 0, -1, -1>, Eigen::Matrix<int, -1, -1, 0, -1, -1>>(int, int, Eigen::PlainObjectBase<Eigen::Matrix<double, -1, -1, 0, -1, -1>> &, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, -1, 0, -1, -1>> &);
#endif