a-star/aStar/Pather.cpp

#include "Pather.h"
#include <iostream>




Pather::Pather(Map* map_) {
	map = map_;
}

Pather::~Pather() {
}

sf::Vector2i Pather::getEndNodePosition() {
	return end_node->getPosition();
}

node* Pather::getActiveNode() {
	return active_node;
}

std::deque<int> Pather::getPathTo(sf::Vector2i start, sf::Vector2i end) {

	// Clear the visited map of erroneous data
	for (int i = 0; i < Map::CELLS_WIDTH; i++) {
		for (int l = 0; l < Map::CELLS_HEIGHT; l++) {
			visited_map(i, l) = 0;
		}
	}
	
	// Place the start and end nodes
	start_node = new node(start, 7000, 0, nullptr, this);
	end_node = new node(end, 0, 0, nullptr, this);

	// Set the entry point, clean up any stray data from last run
	active_node = start_node;
	open_list.clear();
	closed_list.clear();

	// Seed for the loop, hueristic is intentionally high
	open_list.emplace(start_node, start_node->getHueristic());

	// Set up the early exit, and enter into the loop
	early_exit = false;
	path_list = loop();

	return path_list;
}


std::deque<int> Pather::loop() {

	while (!open_list.empty() && !early_exit) {	
		
		if (closed_list.size() > 1000) {           // Quits when the path gets to be over 1000 long, janky 
			no_path = true;						  // Signal no path was found
			early_exit = true;					  // Break
			break;
		}

		// Check to see if we're at our destination, break if we are
		if (active_node->getPosition().x == end_node->getPosition().x && active_node->getPosition().y == end_node->getPosition().y) {
			early_exit = true;
			break;
		}

		// If we didn't get held up before, do a round of a*
		else {

			// Find the pair with the lowest hueristic
			std::pair<node*, double> bestMin(start_node, 10000);   // Get a clean value for the comparison

			// Compare all the values in openList for the one with the smallest hueristic
			// O(n) complexity so it can get verrrrryyyy slow
			for (auto testMin: open_list) {
				if (bestMin.second >= testMin.second)
					bestMin = testMin;
			}

			// Set the new active node to the lowest hueristic that we found earlier 
			active_node = bestMin.first;

			// Find the neighbors for that node
			active_node->getNewNeighbors();

			// Remove the active node from the openlist as you have visited it and called its neighbors
			open_list.erase(active_node);

			// Check to see if the node has already been added to the closed list, if not, add it
			if (closed_list.count(active_node) == 0) {
				closed_list.emplace(active_node, active_node->getHueristic());
			}

			
		}
	}

	// When we're done, get the return path
	std::deque<int> return_path = returnPath();
	if (no_path || return_path.empty()) {              // If we had an error, display it
		return std::deque<int>();
		std::cout << " no return path " << std::endl;
	}

	return return_path;
}

std::deque<int> Pather::returnPath() {
	// Deque that will be returned
	std::deque<int> path;

	// Backtrack through the active_nodes, adding their cameFrom value to the deque
	while (active_node->getParent() != nullptr) {
		path.push_back(active_node->getCameFrom());

		node* parent = active_node->getParent();
		delete active_node;
		active_node = parent;
	}

	return path;
}