Add cost stamps

libopenage/pathfinding/cost_field.cpp

@@ -14,9 +14,10 @@ namespace openage::path {
 CostField::CostField(size_t size) :
 	size{size},
 	valid_until{time::TIME_MIN},
-	cells(this->size * this->size, COST_MIN) {
-	log::log(DBG << "Created cost field with size " << this->size << "x" << this->size);
-}
+	cells(this->size * this->size, COST_MIN),
+	cost_stamps(this->size * this->size, std::nullopt) {
+		log::log(DBG << "Created cost field with size " << this->size << "x" << this->size);
+	}
 
 size_t CostField::get_size() const {
 	return this->size;
@@ -56,6 +57,33 @@ void CostField::set_costs(std::vector<cost_t> &&cells, const time::time_t &valid
 	this->valid_until = valid_until;
 }
 
+bool CostField::stamp(size_t idx, cost_t cost, const time::time_t &stamped_at) {
+	if (this->cost_stamps[idx].has_value()) {
+	    return false;
+	}
+
+	cost_t original_cost = this->get_cost(idx);
+	this->cost_stamps[idx] = cost_stamp_t{
+		original_cost,
+		stamped_at,
+	};
+
+	this->set_cost(idx, cost, stamped_at);
+	return true;
+}
+
+bool CostField::unstamp(size_t idx, const time::time_t &unstamped_at) {
+	if (not this->cost_stamps[idx].has_value() or unstamped_at < this->cost_stamps[idx]->stamp_time) {
+	    return false;
+	}
+
+	cost_t original_cost = cost_stamps[idx]->original_cost;
+
+	this->set_cost(idx, original_cost, unstamped_at);
+	this->cost_stamps[idx].reset();
+	return true;
+}
+
 bool CostField::is_dirty(const time::time_t &time) const {
 	return time >= this->valid_until;
 }

libopenage/pathfinding/cost_field.h

@@ -4,6 +4,7 @@
 
 #include <cstddef>
 #include <vector>
+#include <optional>
 
 #include "pathfinding/types.h"
 #include "time/time.h"
@@ -106,6 +107,27 @@ class CostField {
 	 */
 	void set_costs(std::vector<cost_t> &&cells, const time::time_t &changed);
 
+	/**
+	 * Stamp a cost field cell at a given time.
+	 *
+	 * @param idx Index of the cell.
+	 * @param cost Cost to set.
+	 * @param stamped_at Time at which the cost cell is to be stamped.
+	 *
+	 * @return True if the cell was successfully stamped, false if the cell was already stamped.
+	 */
+	bool stamp(size_t idx, cost_t cost, const time::time_t &stamped_at);
+
+	/**
+	 * Unstamp a cost field cell at a given time.
+	 *
+	 * @param idx Index of the cell.
+	 * @param unstamped_at Time at which the cost cell is to be unstamped.
+	 *
+	 * @return True if the cell was successfully unstamped, false if the cell was already not stamped.
+	 */
+	bool unstamp(size_t idx, const time::time_t &unstamped_at);
+
 	/**
 	 * Check if the cost field is dirty at the specified time.
 	 *
@@ -135,6 +157,11 @@ class CostField {
 	 * Cost field values.
 	 */
 	std::vector<cost_t> cells;
+
+	/**
+	 * Cost stamp vector.
+	 */
+	std::vector<std::optional<cost_stamp_t>> cost_stamps;
 };
 
 } // namespace path

libopenage/pathfinding/types.h

@@ -1,4 +1,4 @@
-// Copyright 2024-2024 the openage authors. See copying.md for legal info.
+// Copyright 2024-2025 the openage authors. See copying.md for legal info.
 
 #pragma once
 
@@ -7,6 +7,7 @@
 #include <memory>
 #include <utility>
 
+#include "time/time.h"
 
 namespace openage::path {
 
@@ -124,4 +125,19 @@ using cache_key_t = std::pair<portal_id_t, sector_id_t>;
  */
 using field_cache_t = std::pair<std::shared_ptr<IntegrationField>, std::shared_ptr<FlowField>>;
 
+/**
+ * Cost stamp for a given cost field cell.
+ */
+struct cost_stamp_t {
+	/**
+	 * Original cost of the stamped cell.
+	 */
+	cost_t original_cost;
+
+	/**
+	 * Time the cost field cell was stamped.
+	 */
+	time::time_t stamp_time;
+};
+
 } // namespace openage::path