surface_grid_writer.hpp

// This file is part of the ACTS project.
//
// Copyright (C) 2016 CERN for the benefit of the ACTS project
//
// 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 https://mozilla.org/MPL/2.0/.
 
#pragma once
 
// Project include(s)
#include "detray/core/concepts.hpp"
#include "detray/definitions/indexing.hpp"
#include "detray/io/backend/detail/grid_writer.hpp"
#include "detray/io/frontend/payloads.hpp"
 
// System include(s)
#include <string_view>
 
namespace detray::io {

class surface_grid_writer : public detail::grid_writer {
  using base_type = detail::grid_writer;
  using grid_writer_t = base_type;
 
 public:
  static constexpr std::string_view tag = "surface_grids";

  using payload_type = detector_grids_payload<std::size_t, io::accel_id>;

  using base_type::base_type;

  template <detray::concepts::detector detector_t>
  static auto header_to_payload(const detector_t& det,
                                const std::string_view det_name) {
    return grid_writer_t::header_to_payload(tag, det.accelerator_store(),
                                            det_name);
  }

  template <detray::concepts::detector detector_t>
  static payload_type to_payload(
      const detector_t& det, const typename detector_t::name_map& /*unused*/) {
    using surface_desc_t = typename detector_t::surface_type;
 
    payload_type grids_data;
 
    for (const auto& vol_desc : det.volumes()) {
      // Links to all acceleration data structures in the volume
      const auto& multi_link = vol_desc.accel_link();
 
      // How to convert the surface descriptors in the grid
      auto sf_converter =
          [&vol_desc = std::as_const(vol_desc)](const surface_desc_t& sf_desc) {
            return vol_desc.to_local_sf_index(sf_desc.index());
          };
 
      // Start a 1, because the first acceleration structure is always
      // the brute force method
      for (dindex i = 1u; i < multi_link.size(); ++i) {
        const auto& acc_link = multi_link[i];
        // Don't look at empty links
        if (acc_link.is_invalid()) {
          continue;
        }
 
        // Generate the payload
        grid_writer_t::to_payload(det.accelerator_store(), acc_link,
                                  vol_desc.index(), vol_desc.index(),
                                  grids_data, sf_converter);
      }
    }
 
    return grids_data;
  }
};
 
}  // namespace detray::io