Acts/Surfaces/ConvexPolygonBounds.ipp

0001 // This file is part of the Acts project.
0002 //
0003 // Copyright (C) 2019 CERN for the benefit of the Acts project
0004 //
0005 // This Source Code Form is subject to the terms of the Mozilla Public
0006 // License, v. 2.0. If a copy of the MPL was not distributed with this
0007 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
0008
0009 #include "Acts/Utilities/ThrowAssert.hpp"
0010
0011 template <typename coll_t>
0012 void Acts::ConvexPolygonBoundsBase::convex_impl(
0013     const coll_t& vertices) noexcept(false) {
0014   static_assert(std::is_same<typename coll_t::value_type, Vector2>::value,
0015                 "Must be collection of Vector2");
0016
0017   const std::size_t N = vertices.size();
0018   for (std::size_t i = 0; i < N; i++) {
0019     std::size_t j = (i + 1) % N;
0020     const Vector2& a = vertices[i];
0021     const Vector2& b = vertices[j];
0022
0023     const Vector2 ab = b - a;
0024     const Vector2 normal = Vector2(ab.y(), -ab.x()).normalized();
0025
0026     bool first = true;
0027     bool ref = false;
0028     // loop over all other vertices
0029     for (std::size_t k = 0; k < N; k++) {
0030       if (k == i || k == j) {
0031         continue;
0032       }
0033
0034       const Vector2& c = vertices[k];
0035       double dot = normal.dot(c - a);
0036
0037       if (first) {
0038         ref = std::signbit(dot);
0039         first = false;
0040         continue;
0041       }
0042
0043       if (std::signbit(dot) != ref) {
0044         throw std::logic_error(
0045             "ConvexPolygon: Given vertices do not form convex hull");
0046       }
0047     }
0048   }
0049 }
0050
0051 template <typename coll_t>
0052 Acts::RectangleBounds Acts::ConvexPolygonBoundsBase::makeBoundingBox(
0053     const coll_t& vertices) {
0054   Vector2 vmax, vmin;
0055   vmax = vertices[0];
0056   vmin = vertices[0];
0057
0058   for (std::size_t i = 1; i < vertices.size(); i++) {
0059     vmax = vmax.cwiseMax(vertices[i]);
0060     vmin = vmin.cwiseMin(vertices[i]);
0061   }
0062
0063   return {vmin, vmax};
0064 }
0065
0066 template <int N>
0067 Acts::ConvexPolygonBounds<N>::ConvexPolygonBounds(
0068     const std::vector<Acts::Vector2>& vertices) noexcept(false)
0069     : m_vertices(), m_boundingBox(makeBoundingBox(vertices)) {
0070   throw_assert(vertices.size() == N,
0071                "Size and number of given vertices do not match.");
0072   for (std::size_t i = 0; i < N; i++) {
0073     m_vertices[i] = vertices[i];
0074   }
0075   checkConsistency();
0076 }
0077
0078 template <int N>
0079 Acts::ConvexPolygonBounds<N>::ConvexPolygonBounds(
0080     const vertex_array& vertices) noexcept(false)
0081     : m_vertices(vertices), m_boundingBox(makeBoundingBox(vertices)) {
0082   checkConsistency();
0083 }
0084
0085 template <int N>
0086 Acts::ConvexPolygonBounds<N>::ConvexPolygonBounds(
0087     const value_array& values) noexcept(false)
0088     : m_vertices(), m_boundingBox(0., 0.) {
0089   for (std::size_t i = 0; i < N; i++) {
0090     m_vertices[i] = Vector2(values[2 * i], values[2 * i + 1]);
0091   }
0092   makeBoundingBox(m_vertices);
0093   checkConsistency();
0094 }
0095
0096 template <int N>
0097 Acts::SurfaceBounds::BoundsType Acts::ConvexPolygonBounds<N>::type() const {
0098   return SurfaceBounds::eConvexPolygon;
0099 }
0100
0101 template <int N>
0102 bool Acts::ConvexPolygonBounds<N>::inside(
0103     const Acts::Vector2& lposition, const Acts::BoundaryCheck& bcheck) const {
0104   return bcheck.isInside(lposition, m_vertices);
0105 }
0106
0107 template <int N>
0108 std::vector<Acts::Vector2> Acts::ConvexPolygonBounds<N>::vertices(
0109     unsigned int /*lseg*/) const {
0110   return {m_vertices.begin(), m_vertices.end()};
0111 }
0112
0113 template <int N>
0114 const Acts::RectangleBounds& Acts::ConvexPolygonBounds<N>::boundingBox() const {
0115   return m_boundingBox;
0116 }
0117
0118 template <int N>
0119 void Acts::ConvexPolygonBounds<N>::checkConsistency() const noexcept(false) {
0120   convex_impl(m_vertices);
0121 }