feat(editor): the terrain model loads from a clearer panel and follows the tracks edited

The panel gives the place on the map or typed, the area, one main button, a
progress bar with Stop and a banner over the view while it loads. The terrain
grown ahead of a track goes on at the height of the one beside it and skips
the ground made by hand. The formations follow the tracks moved, laid and
removed, in the same step of the history; a whole load is one step, the
ground grown ahead none.

application/editormode.h

@@ -27,6 +27,7 @@ http://mozilla.org/MPL/2.0/.
 #include "editor/editorTerrainStreamer.hpp"
 #include "editor/editorOrthophoto.hpp"
 #include "editor/editorNmt.hpp"
+#include "editor/editorGeoMap.hpp"
 #include "editor/editorTrack.hpp"
 #include "editor/editorConnections.hpp"
 #include "editor/editorAlignment.hpp"
@@ -323,6 +324,13 @@ class editor_mode : public application_mode, private editor_track::observer, pri
 		double reach{60.0};
 		std::vector<heightmap::chunk_key> pending; // chunks to make once their model is in
 		std::size_t made{0};
+		std::size_t empty{0}; // chunks not made: the model has no data there
+		std::size_t foreign{0}; // chunks not made ahead: the terrain beside isn't of the model
+		std::optional<double> ahead; // how much the terrain made ahead lies over the model
+		std::set<TTrack *> changed; // tracks whose formations are to follow them
+		std::set<std::string> gone; // names of the tracks removed, whose formations go with them
+		double changed_time{0.0};
+		bool restoring{false}; // the history is taken back or forward: the terrain comes back with it
 		std::size_t shaped{0};
 		std::string status;
 		std::string error;
@@ -354,13 +362,14 @@ class editor_mode : public application_mode, private editor_track::observer, pri
 		std::map<std::pair<int, int>, std::vector<std::size_t>> anchor_cells; // the anchors in squares of the plan
 		bool offered{false}; // the terrain was offered to the scenery begun without it
 		bool prompt{false}; // the offer is shown
-		double north{0.0}; // the place typed into the offer, PUWG 1992
-		double east{0.0};
 		int mode{0}; // 0: the tracks go onto the terrain, 1: the terrain is drawn to the tracks
-		bool moving{false}; // the place being typed again
+		bool moving{false}; // the place being picked again
+		char place[96]{}; // typed: degrees or PUWG 1992
+		int shown{-1}; // the frame the terrain panel showed how far the work got
 	};
 	editor_nmt m_nmt;
 	nmt_state m_nmt_state;
+	editor_map m_nmt_map;
 	std::vector<nmt_place> nmt_track_places(double const Step) const override;
 	void nmt_locate() override;
 	bool nmt_choice_card(int const Index, char const *Title, char const *Text, float const Width, float const TextHeight, bool const Chosen) const;
@@ -375,18 +384,50 @@ class editor_mode : public application_mode, private editor_track::observer, pri
 	std::vector<heightmap::chunk_key> nmt_keys_along_tracks() const;
 	// Rebuild: the chunks there already are made anew too, and the formation laid before is forgotten, as when the tracks moved
 	void nmt_make(std::vector<heightmap::chunk_key> const &Keys, bool const Rebuild = false);
-	bool add_chunk_from_nmt(heightmap::chunk_key const &Key);
+	enum class nmt_chunk
+	{
+		waiting, // for its squares of the model
+		made,
+		empty // the model has no data there
+	};
+	// Offset: the heights of the model go up or down by it in the whole chunk, in place of the offsets of the fit
+	nmt_chunk add_chunk_from_nmt(heightmap::chunk_key const &Key, std::optional<double> const Offset = std::nullopt);
+	// how much the terrain lies over the model at the points: none where there's too little terrain at them, nor where it
+	// doesn't follow the model (Foreign), as one made by hand
+	std::optional<double> nmt_terrain_offset(std::vector<glm::dvec2> const &Points, bool &Foreign) const;
+	// the same along the edges the chunk shares with the chunks beside it in memory
+	std::optional<double> nmt_seam_offset(heightmap::chunk_key const &Key, bool &Foreign) const;
+	// the terrain beside the formation of the track is the one made from the model; Waiting: its squares of the model aren't in yet
+	bool nmt_terrain_along(TTrack const &Track, bool &Waiting);
+	// the tracks changed by hand are told to the terrain: their formations laid anew, of the tracks removed taken away, a
+	// track laid onto the terrain of the model given its own, once the mouse lets go; in the step of the history of the change
+	void nmt_track_changed(std::vector<TTrack *> const &Tracks);
+	void nmt_track_gone(TTrack const &Track);
+	void nmt_follow_tracks();
+	// the height the ground will have where the terrain is made ahead of the track laid and isn't there yet
+	bool nmt_ahead(double const X, double const Z, double &Height) const;
+	// the squares of the model under the rectangle are in, none of them waiting to be asked for again
+	bool nmt_ready(glm::dvec2 const &Min, glm::dvec2 const &Max);
 	// Only: the paths of these tracks are shaped anew, the modifiers of those removed taken away; null: all of them. the number
 	// of the modifiers laid
 	std::size_t nmt_shape_tracks(std::vector<TTrack *> const *Only = nullptr);
 	void nmt_update();
 	void nmt_grow();
 	void render_nmt_ui();
+	// where the scenery lies: the map to click on, the place typed; true once it's placed
+	bool render_nmt_place(bool const Moving, bool const Button);
+	// the work under way: what's left of it and the button to stop it; Compact: one line, for the 3d view
+	void render_nmt_progress(bool const Compact);
+	// over the 3d view while the terrain panel isn't seen
+	void render_nmt_banner();
+	bool nmt_busy() const;
+	// the terrain made so far stays, what's waiting is dropped, the grade lines not fitted yet are left
+	void nmt_stop();
 	// a scenery begun from nothing, with no tracks nor terrain, is asked as the first track is laid whether it wants the terrain
 	void nmt_offer();
 	void render_nmt_prompt();
-	// the place typed in the terrain window: the terrain model and the orthophoto take it
-	void nmt_place_scenery();
+	// the place picked in the terrain window: the terrain model and the orthophoto take it
+	void nmt_place_scenery(glm::dvec2 const &Point);
 	void nmt_accept_offer();
 	// the whole scenery: tracks, includes and models, moved up or down as one undo step
 	void nmt_lift_scenery(double const Offset);