Initial commit

engines/pink/objects/walk/walk_shortest_path.cpp

@@ -0,0 +1,157 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "pink/objects/walk/walk_location.h"
+#include "pink/objects/walk/walk_mgr.h"
+
+namespace Pink {
+
+WalkShortestPath::WalkShortestPath(WalkMgr *manager)
+	: _manager(manager)
+{}
+
+WalkLocation *WalkShortestPath::next(WalkLocation *start, WalkLocation *destination) {
+	if (start == destination)
+		return nullptr;
+	add(start, 0.0, nullptr);
+	while (build() != destination) {}
+	return getNearestNeighbor(destination);
+}
+
+void WalkShortestPath::add(WalkLocation *wl, double val, WalkLocation *nearest) {
+	_locations.push_back(wl);
+	_visited.push_back(wl);
+	_weight.push_back(val);
+	_nearestNeigbor.push_back(nearest);
+}
+
+WalkLocation *WalkShortestPath::build() {
+	WalkLocation *nearest = nullptr;
+	WalkLocation *location = nullptr;
+	double len = -1.0;
+	addLocationsToVisit();
+	for (uint i = 0; i < _toVisit.size(); ++i) {
+		double curLen = getLengthToNearestNeigbor(_toVisit[i]);
+		if (curLen < 0) {
+			remove(_toVisit[i]);
+			continue;
+		}
+		curLen += getWeight(_toVisit[i]);
+		if (len < 0.0 || len > curLen) {
+			len = curLen;
+			location = _toVisit[i];
+			nearest = getNearestNeighbor(_toVisit[i]);
+			if (!nearest)
+				nearest = findNearestNeighbor(_toVisit[i]);
+		}
+	}
+
+	WalkLocation *neighbor = findNearestNeighbor(location);
+	if (neighbor)
+		add(neighbor, len, nearest);
+
+	return neighbor;
+}
+
+WalkLocation *WalkShortestPath::getNearestNeighbor(WalkLocation *location) {
+	for(uint i = 0; i < _visited.size(); ++i) {
+		if (_visited[i] == location)
+			return _nearestNeigbor[i];
+	}
+
+	return nullptr;
+}
+
+void WalkShortestPath::addLocationsToVisit() {
+	_toVisit.resize(_locations.size());
+	for (uint i = 0; i < _locations.size(); ++i) {
+		_toVisit[i] = _locations[i];
+	}
+}
+
+double WalkShortestPath::getLengthToNearestNeigbor(WalkLocation *location) {
+	double minLength = -1.0;
+	Common::StringArray &neighbors = location->getNeigbors();
+	for (uint i = 0; i < neighbors.size(); ++i) {
+		WalkLocation *neighbor = _manager->findLocation(neighbors[i]);
+		if (!isLocationVisited(neighbor)) {
+			double length = _manager->getLengthBetweenLocations(location, neighbor);
+			if (minLength >= 0.0) {
+				if (length < minLength)
+					minLength = length;
+			} else
+				minLength = length;
+		}
+	}
+
+	return minLength;
+}
+
+WalkLocation *WalkShortestPath::findNearestNeighbor(WalkLocation *location) {
+	double minLength = -1.0;
+	WalkLocation *nearest = nullptr;
+	Common::StringArray &neighbors = location->getNeigbors();
+	for (uint i = 0; i < neighbors.size(); ++i) {
+		WalkLocation *neighbor = _manager->findLocation(neighbors[i]);
+		if (!isLocationVisited(neighbor)) {
+			double length = _manager->getLengthBetweenLocations(location, neighbor);
+			if (minLength >= 0.0) {
+				if (length < minLength) {
+					nearest = neighbor;
+					minLength = length;
+				}
+			} else {
+				nearest = neighbor;
+				minLength = length;
+			}
+		}
+	}
+
+	return nearest;
+}
+
+double WalkShortestPath::getWeight(WalkLocation *location) {
+	for (uint i = 0; i < _locations.size(); ++i) {
+		if (_locations[i] == location)
+			return _weight[i];
+	}
+	return 0.0;
+}
+
+bool WalkShortestPath::isLocationVisited(WalkLocation *location) {
+	for (uint i = 0; i < _visited.size(); ++i) {
+		if (_visited[i] == location)
+			return true;
+	}
+	return false;
+}
+
+void WalkShortestPath::remove(WalkLocation *location) {
+	for (uint i = 0; i < _locations.size(); ++i) {
+		if (_locations[i] == location) {
+			_locations.remove_at(i);
+			_weight.remove_at(i);
+			break;
+		}
+	}
+}
+
+} // End of namespace Pink