path: Portals between fields.

libopenage/pathfinding/CMakeLists.txt

@@ -8,6 +8,7 @@ add_sources(libopenage
 	integration_field.cpp
     integrator.cpp
 	path.cpp
+	portal.cpp
 	tests.cpp
     types.cpp
 )

libopenage/pathfinding/portal.cpp

@@ -0,0 +1,104 @@
+// Copyright 2024-2024 the openage authors. See copying.md for legal info.
+
+#include "portal.h"
+
+#include "error/error.h"
+
+
+namespace openage::path {
+
+Portal::Portal(std::shared_ptr<CostField> sector0,
+               std::shared_ptr<CostField> sector1,
+               std::vector<std::shared_ptr<Portal>> sector0_exits,
+               std::vector<std::shared_ptr<Portal>> sector1_exits,
+               PortalDirection direction,
+               size_t cell_start_x,
+               size_t cell_start_y,
+               size_t cell_end_x,
+               size_t cell_end_y) :
+	sector0{sector0},
+	sector1{sector1},
+	sector0_exits{sector0_exits},
+	sector1_exits{sector1_exits},
+	direction{direction},
+	cell_start_x{cell_start_x},
+	cell_start_y{cell_start_y},
+	cell_end_x{cell_end_x},
+	cell_end_y{cell_end_y} {
+}
+
+const std::vector<std::shared_ptr<Portal>> &Portal::get_exits(const std::shared_ptr<CostField> &entry_sector) const {
+	ENSURE(entry_sector == this->sector0 || entry_sector == this->sector1, "Invalid entry sector");
+
+	if (entry_sector == this->sector0) {
+		return this->sector1_exits;
+	}
+	return this->sector0_exits;
+}
+
+const std::shared_ptr<CostField> &Portal::get_exit_sector(const std::shared_ptr<CostField> &entry_sector) const {
+	ENSURE(entry_sector == this->sector0 || entry_sector == this->sector1, "Invalid entry sector");
+
+	if (entry_sector == this->sector0) {
+		return this->sector1;
+	}
+	return this->sector0;
+}
+
+std::pair<size_t, size_t> Portal::get_entry_start(const std::shared_ptr<CostField> &entry_sector) const {
+	ENSURE(entry_sector == this->sector0 || entry_sector == this->sector1, "Invalid entry sector");
+
+	if (entry_sector == this->sector0) {
+		return this->get_sector0_start();
+	}
+
+	return this->get_sector1_start();
+}
+
+std::pair<size_t, size_t> Portal::get_entry_end(const std::shared_ptr<CostField> &entry_sector) const {
+	ENSURE(entry_sector == this->sector0 || entry_sector == this->sector1, "Invalid entry sector");
+
+	if (entry_sector == this->sector0) {
+		return this->get_sector0_end();
+	}
+
+	return this->get_sector1_end();
+}
+
+std::pair<size_t, size_t> Portal::get_exit_start(const std::shared_ptr<CostField> &entry_sector) const {
+	ENSURE(entry_sector == this->sector0 || entry_sector == this->sector1, "Invalid entry sector");
+
+	if (entry_sector == this->sector0) {
+		return this->get_sector1_start();
+	}
+
+	return this->get_sector0_start();
+}
+
+std::pair<size_t, size_t> Portal::get_exit_end(const std::shared_ptr<CostField> &entry_sector) const {
+	ENSURE(entry_sector == this->sector0 || entry_sector == this->sector1, "Invalid entry sector");
+
+	if (entry_sector == this->sector0) {
+		return this->get_sector1_end();
+	}
+
+	return this->get_sector0_end();
+}
+
+std::pair<size_t, size_t> Portal::get_sector0_start() const {
+	return {this->cell_start_x, this->cell_start_y};
+}
+
+std::pair<size_t, size_t> Portal::get_sector0_end() const {
+	return {this->cell_end_x, this->cell_end_y};
+}
+
+std::pair<size_t, size_t> Portal::get_sector1_start() const {
+	return {this->cell_end_x, this->cell_end_y};
+}
+
+std::pair<size_t, size_t> Portal::get_sector1_end() const {
+	return {this->cell_start_x, this->cell_start_y};
+}
+
+} // namespace openage::path

libopenage/pathfinding/portal.h

@@ -0,0 +1,196 @@
+// Copyright 2024-2024 the openage authors. See copying.md for legal info.
+
+#pragma once
+
+
+#include <memory>
+
+#include "pathfinding/cost_field.h"
+
+
+namespace openage::path {
+class CostField;
+
+/**
+ * Possible directions of a portal node.
+ */
+enum class PortalDirection {
+	NORTH_SOUTH,
+	EAST_WEST
+};
+
+/**
+ * Biderectional gateway for connecting two sectors in the flow field pathfinder.
+ *
+ * Portals are located at the border of two sectors (0 and 1), and allow units to move between them.
+ * For each of these sectors, the portal stores the start and end coordinates where the
+ * sectors overlap as well as the other portals that can be reached in the same
+ * sector. For simplicity, the portal is assumed to be a straight line of cells from the start
+ * to the end.
+ *
+ * The portal is bidirectional, meaning that it can be entered from either sector and
+ * exited into the other sector. The direction of the portal from one sector to the other
+ * is stored in the portal node. As a convention and to simplify computations, sector 0 must be
+ * the either the north or east sector on the grid in relation to sector 1.
+ */
+class Portal {
+public:
+	/**
+	 * Create a new portal between two sectors.
+	 *
+	 * As a convention, sector 0 must be the either the north or east sector
+	 * on the grid in relation to sector 1.
+	 *
+	 * @param sector0 First sector connected by the portal.
+	 *                Must be north or east on the grid in relation to sector 1.
+	 * @param sector1 Second sector connected by the portal.
+	 *                Must be south or west on the grid in relation to sector 0.
+	 * @param sector0_exits Portals reachable from this portal in sector 0.
+	 * @param sector1_exits Portals reachable from this portal in sector 1.
+	 * @param direction Direction of the portal from sector 0 to sector 1.
+	 * @param cell_start_x Start cell x coordinate in sector 0.
+	 * @param cell_start_y Start cell y coordinate in sector 0.
+	 * @param cell_end_x End cell x coordinate in sector 0.
+	 * @param cell_end_y End cell y coordinate in sector 0.
+	 */
+	Portal(std::shared_ptr<CostField> sector0,
+	       std::shared_ptr<CostField> sector1,
+	       std::vector<std::shared_ptr<Portal>> sector0_exits,
+	       std::vector<std::shared_ptr<Portal>> sector1_exits,
+	       PortalDirection direction,
+	       size_t cell_start_x,
+	       size_t cell_start_y,
+	       size_t cell_end_x,
+	       size_t cell_end_y);
+
+	~Portal() = default;
+
+	/**
+	 * Get the exit portals reachable via the portal when entering from a specified sector.
+	 *
+	 * @param entry_sector Sector from which the portal is entered.
+	 *
+	 * @return Exit portals reachable from the portal.
+	 */
+	const std::vector<std::shared_ptr<Portal>> &get_exits(const std::shared_ptr<CostField> &entry_sector) const;
+
+	/**
+	 * Get the cost field of the sector where the portal is exited.
+	 *
+	 * @param entry_sector Sector from which the portal is entered.
+	 *
+	 * @return Cost field of the sector where the portal is exited.
+	 */
+	const std::shared_ptr<CostField> &get_exit_sector(const std::shared_ptr<CostField> &entry_sector) const;
+
+	/**
+	 * Get the cost field of the sector from which the portal is entered.
+	 *
+	 * @param entry_sector Sector from which the portal is entered.
+	 *
+	 * @return Cost field of the sector from which the portal is entered.
+	 */
+	std::pair<size_t, size_t> get_entry_start(const std::shared_ptr<CostField> &entry_sector) const;
+
+	/**
+	 * Get the cell coordinates of the start of the portal in the entry sector.
+	 *
+	 * @param entry_sector Sector from which the portal is entered.
+	 *
+	 * @return Cell coordinates of the start of the portal in the entry sector.
+	 */
+	std::pair<size_t, size_t> get_entry_end(const std::shared_ptr<CostField> &entry_sector) const;
+
+	/**
+	 * Get the cell coordinates of the start of the portal in the exit sector.
+	 *
+	 * @param entry_sector Sector from which the portal is entered.
+	 *
+	 * @return Cell coordinates of the start of the portal in the exit sector.
+	 */
+	std::pair<size_t, size_t> get_exit_start(const std::shared_ptr<CostField> &entry_sector) const;
+
+	/**
+	 * Get the cell coordinates of the end of the portal in the exit sector.
+	 *
+	 * @param entry_sector Sector from which the portal is entered.
+	 *
+	 * @return Cell coordinates of the end of the portal in the exit sector.
+	 */
+	std::pair<size_t, size_t> get_exit_end(const std::shared_ptr<CostField> &entry_sector) const;
+
+private:
+	/**
+	 * Get the start cell coordinates of the portal.
+	 *
+	 * @return Start cell coordinates of the portal.
+	 */
+	std::pair<size_t, size_t> get_sector0_start() const;
+
+	/**
+	 * Get the end cell coordinates of the portal.
+	 *
+	 * @return End cell coordinates of the portal.
+	 */
+	std::pair<size_t, size_t> get_sector0_end() const;
+
+	/**
+	 * Get the start cell coordinates of the portal.
+	 *
+	 * @return Start cell coordinates of the portal.
+	 */
+	std::pair<size_t, size_t> get_sector1_start() const;
+
+	/**
+	 * Get the end cell coordinates of the portal.
+	 *
+	 * @return End cell coordinates of the portal.
+	 */
+	std::pair<size_t, size_t> get_sector1_end() const;
+
+	/**
+	 * Sector 0
+	 */
+	std::shared_ptr<CostField> sector0;
+
+	/**
+	 * Sector 1
+	 */
+	std::shared_ptr<CostField> sector1;
+
+	/**
+	 * Exits from sector 0
+	 */
+	std::vector<std::shared_ptr<Portal>> sector0_exits;
+
+	/**
+	 * Exits from sector 1
+	 */
+	std::vector<std::shared_ptr<Portal>> sector1_exits;
+
+	/**
+	 * Direction of the portal
+	 */
+	PortalDirection direction;
+
+	/**
+	 * Start cell x coordinate
+	 */
+	size_t cell_start_x;
+
+	/**
+	 * Start cell y coordinate
+	 */
+	size_t cell_start_y;
+
+	/**
+	 * End cell x coordinate
+	 */
+	size_t cell_end_x;
+
+	/**
+	 * End cell y coordinate
+	 */
+	size_t cell_end_y;
+};
+} // namespace openage::path