Add an activeobject manager to hold active objects (#7939)

* Add an activeobject manager to hold active objects
* Add unittests

src/server/activeobjectmgr.cpp

@@ -0,0 +1,167 @@
+/*
+Minetest
+Copyright (C) 2010-2018 nerzhul, Loic BLOT <loic.blot@unix-experience.fr>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include <log.h>
+#include "mapblock.h"
+#include "profiler.h"
+#include "activeobjectmgr.h"
+
+namespace server
+{
+
+void ActiveObjectMgr::clear(const std::function<bool(ServerActiveObject *, u16)> &cb)
+{
+	std::vector<u16> objects_to_remove;
+	for (auto &it : m_active_objects) {
+		if (cb(it.second, it.first)) {
+			// Id to be removed from m_active_objects
+			objects_to_remove.push_back(it.first);
+		}
+	}
+
+	// Remove references from m_active_objects
+	for (u16 i : objects_to_remove) {
+		m_active_objects.erase(i);
+	}
+}
+
+void ActiveObjectMgr::step(
+		float dtime, const std::function<void(ServerActiveObject *)> &f)
+{
+	g_profiler->avg("Server::ActiveObjectMgr: num of objects",
+			m_active_objects.size());
+	for (auto &ao_it : m_active_objects) {
+		f(ao_it.second);
+	}
+}
+
+// clang-format off
+bool ActiveObjectMgr::registerObject(ServerActiveObject *obj)
+{
+	assert(obj); // Pre-condition
+	if (obj->getId() == 0) {
+		u16 new_id = getFreeId();
+		if (new_id == 0) {
+			errorstream << "Server::ActiveObjectMgr::addActiveObjectRaw(): "
+					<< "no free id available" << std::endl;
+			if (obj->environmentDeletes())
+				delete obj;
+			return false;
+		}
+		obj->setId(new_id);
+	} else {
+		verbosestream << "Server::ActiveObjectMgr::addActiveObjectRaw(): "
+				<< "supplied with id " << obj->getId() << std::endl;
+	}
+
+	if (!isFreeId(obj->getId())) {
+		errorstream << "Server::ActiveObjectMgr::addActiveObjectRaw(): "
+				<< "id is not free (" << obj->getId() << ")" << std::endl;
+		if (obj->environmentDeletes())
+			delete obj;
+		return false;
+	}
+
+	if (objectpos_over_limit(obj->getBasePosition())) {
+		v3f p = obj->getBasePosition();
+		warningstream << "Server::ActiveObjectMgr::addActiveObjectRaw(): "
+				<< "object position (" << p.X << "," << p.Y << "," << p.Z
+				<< ") outside maximum range" << std::endl;
+		if (obj->environmentDeletes())
+			delete obj;
+		return false;
+	}
+
+	m_active_objects[obj->getId()] = obj;
+
+	verbosestream << "Server::ActiveObjectMgr::addActiveObjectRaw(): "
+			<< "Added id=" << obj->getId() << "; there are now "
+			<< m_active_objects.size() << " active objects." << std::endl;
+	return true;
+}
+
+void ActiveObjectMgr::removeObject(u16 id)
+{
+	verbosestream << "Server::ActiveObjectMgr::removeObject(): "
+			<< "id=" << id << std::endl;
+	ServerActiveObject *obj = getActiveObject(id);
+	if (!obj) {
+		infostream << "Server::ActiveObjectMgr::removeObject(): "
+				<< "id=" << id << " not found" << std::endl;
+		return;
+	}
+
+	m_active_objects.erase(id);
+	delete obj;
+}
+
+// clang-format on
+void ActiveObjectMgr::getObjectsInsideRadius(
+		const v3f &pos, float radius, std::vector<u16> &result)
+{
+	for (auto &activeObject : m_active_objects) {
+		ServerActiveObject *obj = activeObject.second;
+		u16 id = activeObject.first;
+		const v3f &objectpos = obj->getBasePosition();
+		if (objectpos.getDistanceFrom(pos) > radius)
+			continue;
+		result.push_back(id);
+	}
+}
+
+void ActiveObjectMgr::getAddedActiveObjectsAroundPos(const v3f &player_pos, f32 radius,
+		f32 player_radius, std::set<u16> &current_objects,
+		std::queue<u16> &added_objects)
+{
+	/*
+		Go through the object list,
+		- discard removed/deactivated objects,
+		- discard objects that are too far away,
+		- discard objects that are found in current_objects.
+		- add remaining objects to added_objects
+	*/
+	for (auto &ao_it : m_active_objects) {
+		u16 id = ao_it.first;
+
+		// Get object
+		ServerActiveObject *object = ao_it.second;
+		if (!object)
+			continue;
+
+		if (object->isGone())
+			continue;
+
+		f32 distance_f = object->getBasePosition().getDistanceFrom(player_pos);
+		if (object->getType() == ACTIVEOBJECT_TYPE_PLAYER) {
+			// Discard if too far
+			if (distance_f > player_radius && player_radius != 0)
+				continue;
+		} else if (distance_f > radius)
+			continue;
+
+		// Discard if already on current_objects
+		auto n = current_objects.find(id);
+		if (n != current_objects.end())
+			continue;
+		// Add to added_objects
+		added_objects.push(id);
+	}
+}
+
+} // namespace server