feat(editor): the signalling mode finds the station of a switch, lays it out as a schematic along its main track and keeps its name, code and line in the scenery

editor/editorStation.hpp

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+/*
+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/.
+*/
+
+#pragma once
+
+#include <optional>
+#include <vector>
+
+#include <glm/glm.hpp>
+
+class TTrack;
+
+// a station as the signalling sees it: its switches, the tracks between them and the lines leading out, and its schematic,
+// the tracks laid out along the main track through it
+namespace station
+{
+
+struct options
+{
+	double link{1500.0}; // m, switches joined by plain track no longer than this belong to the same station
+	double approach{400.0}; // m, of each line leading out, taken beyond the outermost switch
+};
+
+struct path
+{
+	TTrack *track{nullptr};
+	int index{0}; // of the path of the track
+	std::vector<glm::dvec3> points; // along the path, world space
+	std::vector<glm::dvec2> schematic; // the chainage along the axis and the offset to the left of it, as the map shows it
+	double length{0.0}; // in the plan
+	bool approach{false}; // on a line leading out of the station
+};
+
+struct layout
+{
+	std::vector<TTrack *> switches; // switches, crossings and turntables, by the chainage of their start
+	std::vector<path> paths;
+	std::vector<glm::dvec3> axis; // the main route through the station
+	std::vector<double> chainage; // of the points of the axis
+	double from{0.0}; // the chainage over which the switches lie
+	double to{0.0};
+	double low{0.0}; // the offsets of the outermost tracks of the station
+	double high{0.0};
+	bool kilometrage{false}; // the chainage runs with the km of the switches
+	double km{0.0}; // at chainage 0, when it does
+};
+
+// the station of the switch, or of the plain track near one
+std::optional<layout> find(TTrack &From, options const &Options = {});
+// the chainage along the axis and the offset to the left of it, as the map shows it
+glm::dvec2 project(layout const &Layout, glm::dvec3 const &Point);
+// km at the chainage, when the station knows its kilometrage
+double km_of(layout const &Layout, double const Chainage);
+// one switch of each station of the scenery
+std::vector<TTrack *> stations(options const &Options = {});
+// the switches of the station of the switch, without laying it out
+std::vector<TTrack *> switches_of(TTrack &Switch, options const &Options = {});
+
+} // namespace station