Surfaces/detail/AnnulusBoundsHelper.cpp

0001 // This file is part of the ACTS project.
0002 //
0003 // Copyright (C) 2016 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 https://mozilla.org/MPL/2.0/.
0008
0009 #include "Acts/Surfaces/detail/AnnulusBoundsHelper.hpp"
0010
0011 #include "Acts/Surfaces/AnnulusBounds.hpp"
0012 #include "Acts/Utilities/VectorHelpers.hpp"
0013
0014 #include <numbers>
0015
0016 namespace Acts::detail {
0017
0018 std::tuple<std::shared_ptr<AnnulusBounds>, Transform3>
0019 AnnulusBoundsHelper::create(const Transform3& transform, double rMin,
0020                             double rMax, std::vector<Vector2> vertices) {
0021   using Line2D = Eigen::Hyperplane<double, 2>;
0022
0023   // Construct the bound lines
0024   std::vector<std::pair<Vector2, Vector2>> boundLines;
0025   for (std::size_t i = 0; i < vertices.size(); ++i) {
0026     Vector2 a = vertices.at(i);
0027     Vector2 b = vertices.at((i + 1) % vertices.size());
0028     Vector2 ab = b - a;
0029     double phi = VectorHelpers::phi(ab);
0030
0031     if (std::abs(phi) > 3 * std::numbers::pi / 4. ||
0032         std::abs(phi) < std::numbers::pi / 4.) {
0033       if (a.norm() < b.norm()) {
0034         boundLines.push_back(std::make_pair(a, b));
0035       } else {
0036         boundLines.push_back(std::make_pair(b, a));
0037       }
0038     }
0039   }
0040
0041   if (boundLines.size() != 2) {
0042     throw std::logic_error(
0043         "Input DiscPoly bounds type does not have sensible edges.");
0044   }
0045
0046   Line2D lA = Line2D::Through(boundLines[0].first, boundLines[0].second);
0047   Line2D lB = Line2D::Through(boundLines[1].first, boundLines[1].second);
0048   Vector2 ix = lA.intersection(lB);
0049
0050   const Eigen::Translation3d originTranslation(ix.x(), ix.y(), 0.);
0051   const Vector2 originShift = -ix;
0052
0053   // Update transform by prepending the origin shift translation
0054   Transform3 boundsTransform = transform * originTranslation;
0055   // Transform phi line point to new origin and get phi
0056   double phi1 = VectorHelpers::phi(boundLines[0].second - boundLines[0].first);
0057   double phi2 = VectorHelpers::phi(boundLines[1].second - boundLines[1].first);
0058   double phiMax = std::max(phi1, phi2);
0059   double phiMin = std::min(phi1, phi2);
0060   double phiShift = 0.;
0061
0062   // Create the bounds
0063   auto annulusBounds = std::make_shared<AnnulusBounds>(
0064       rMin, rMax, phiMin, phiMax, originShift, phiShift);
0065
0066   return {annulusBounds, boundsTransform};
0067 }
0068
0069 }  // namespace Acts::detail