Revert 6587 - Optimize entity-entity collision (#7539)

11 files changed, 78 insertions, 632 deletions

diff --git a/src/content_sao.cpp b/src/content_sao.cpp
index 6ed78beb0..b67a63e3b 100644
--- a/src/content_sao.cpp
+++ b/src/content_sao.cpp
@@ -287,7 +287,6 @@ ObjectProperties* UnitSAO::accessObjectProperties()
 
 void UnitSAO::notifyObjectPropertiesModified()
 {
-	m_env->updateActiveObject(this);
 	m_properties_sent = false;
 }
 
@@ -334,8 +333,6 @@ void LuaEntitySAO::addedToEnvironment(u32 dtime_s)
 		// Get properties
 		m_env->getScriptIface()->
 			luaentity_GetProperties(m_id, &m_prop);
-		// Notify the environment of the new properties
-		m_env->updateActiveObject(this);
 		// Initialize HP from properties
 		m_hp = m_prop.hp_max;
 		// Activate entity, supplying serialized state
@@ -669,7 +666,6 @@ void LuaEntitySAO::setPos(const v3f &pos)
 	if(isAttached())
 		return;
 	m_base_position = pos;
-	m_env->updateActiveObject(this);
 	sendPosition(false, true);
 }
 
@@ -678,7 +674,6 @@ void LuaEntitySAO::moveTo(v3f pos, bool continuous)
 	if(isAttached())
 		return;
 	m_base_position = pos;
-	m_env->updateActiveObject(this);
 	if(!continuous)
 		sendPosition(true, true);
 }
@@ -1169,7 +1164,6 @@ void PlayerSAO::setBasePosition(const v3f &position)
 
 	// Updating is not wanted/required for player migration
 	if (m_env) {
-		m_env->updateActiveObject(this);
 		m_position_not_sent = true;
 	}
 }
diff --git a/src/irr_aabb3d.h b/src/irr_aabb3d.h
index 1e2784036..73bb2db7a 100644
--- a/src/irr_aabb3d.h
+++ b/src/irr_aabb3d.h
@@ -24,5 +24,3 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <aabbox3d.h>
 
 typedef core::aabbox3d<f32> aabb3f;
-typedef core::aabbox3d<s16> aabb3s16;
-typedef core::aabbox3d<s32> aabb3s32;
diff --git a/src/irr_v3d.h b/src/irr_v3d.h
index 49c2e60ce..3e95c7913 100644
--- a/src/irr_v3d.h
+++ b/src/irr_v3d.h
@@ -18,29 +18,13 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 */
 
 #pragma once
+
 #include "irrlichttypes.h"
+
 #include <vector3d.h>
-#include <functional>
 
 typedef core::vector3df v3f;
 typedef core::vector3d<double> v3d;
 typedef core::vector3d<s16> v3s16;
 typedef core::vector3d<u16> v3u16;
 typedef core::vector3d<s32> v3s32;
-
-namespace std
-{
-template <> struct hash<v3s16>
-{
-	typedef v3s16 argument_type;
-	typedef std::size_t result_type;
-	result_type operator()(const argument_type &s) const noexcept
-	{
-		// clang-format off
-		return static_cast<size_t>((static_cast<u64>(s.X) << 20) ^
-		                           (static_cast<u64>(s.Y) << 10) ^
-		                           (static_cast<u64>(s.Z)));
-		// clang-format on
-	}
-};
-}
diff --git a/src/server/CMakeLists.txt b/src/server/CMakeLists.txt
index 98b4730b1..b892e83b3 100644
--- a/src/server/CMakeLists.txt
+++ b/src/server/CMakeLists.txt
@@ -1,4 +1,3 @@
 set(server_SRCS
 	${CMAKE_CURRENT_SOURCE_DIR}/mods.cpp
-	${CMAKE_CURRENT_SOURCE_DIR}/serveractiveobjectmap.cpp
 	PARENT_SCOPE)
diff --git a/src/server/serveractiveobjectmap.cpp b/src/server/serveractiveobjectmap.cpp
deleted file mode 100644
index 7c5c1c1ea..000000000
--- a/src/server/serveractiveobjectmap.cpp
+++ /dev/null
@@ -1,215 +0,0 @@
-/*
-Minetest
-Copyright (C) 2018 numZero, Lobachevsky Vitaly <numzer0@yandex.com>
-
-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 "serveractiveobjectmap.h"
-#include <cmath>
-#include "constants.h"
-#include "log.h"
-#include "serverobject.h"
-
-static constexpr float granularity = 16.0 * BS;
-
-static v3s16 getChunkPos(const v3f &pos)
-{
-	return v3s16(
-			std::floor(pos.X / granularity),
-			std::floor(pos.Y / granularity),
-			std::floor(pos.Z / granularity));
-}
-
-static aabb3s16 calcBox(const aabb3f &cb)
-{
-	return { getChunkPos(cb.MinEdge), getChunkPos(cb.MaxEdge) };
-}
-
-void ServerActiveObjectMap::addObject(ServerActiveObject *object)
-{
-	aabb3f cb;
-	Wrapper w;
-	u16 id = object->getId();
-	if (!isFreeId(id))
-		throw std::logic_error("ServerActiveObjectMap::addObject: "
-			"object ID in use: " + std::to_string(id));
-	w.object = object;
-	w.has_box = w.object->getCollisionBox(&cb);
-	w.pos = getChunkPos(w.object->getBasePosition());
-	if (w.has_box) {
-		w.box = calcBox(cb);
-		addObjectRefs(id, w.box);
-	}
-	addObjectRef(id, w.pos);
-	objects.emplace(id, w);
-}
-
-ServerActiveObject *ServerActiveObjectMap::removeObject(u16 id)
-{
-	auto pw = objects.find(id);
-	if (pw == objects.end())
-		return nullptr; // silently ignore non-existent object
-	Wrapper w = pw->second;
-	if (w.has_box)
-		removeObjectRefs(id, w.box);
-	removeObjectRef(id, w.pos);
-	objects.erase(pw);
-	return w.object;
-}
-
-void ServerActiveObjectMap::removeObject(ServerActiveObject *object)
-{
-	removeObject(object->getId());
-}
-
-void ServerActiveObjectMap::updateObject(u16 id)
-{
-	auto pw = objects.find(id);
-	if (pw == objects.end()) {
-		warningstream << "Trying to update non-existent object: " << id
-				<< std::endl;
-		return;
-	}
-	Wrapper &w = pw->second;
-	v3s16 pos = getChunkPos(w.object->getBasePosition());
-	aabb3f cb;
-	aabb3s16 box;
-	bool has_box = w.object->getCollisionBox(&cb);
-	if (has_box)
-		box = calcBox(cb);
-	if (w.has_box && has_box && w.box == box && pos == w.pos)
-		return;
-	if (w.has_box)
-		removeObjectRefs(id, w.box);
-	removeObjectRef(id, w.pos);
-	w.box = box;
-	w.has_box = has_box;
-	if (w.has_box)
-		addObjectRefs(id, w.box);
-	addObjectRef(id, w.pos);
-}
-
-void ServerActiveObjectMap::updateObject(ServerActiveObject *object)
-{
-	updateObject(object->getId());
-}
-
-ServerActiveObject *ServerActiveObjectMap::getObject(u16 id) const
-{
-	auto pw = objects.find(id);
-	if (pw == objects.end())
-		return nullptr;
-	return pw->second.object;
-}
-
-std::vector<u16> ServerActiveObjectMap::getObjectsInsideRadius(v3f pos, float radius)
-{
-	std::vector<u16> result;
-	auto nearby = getObjectsNearBox(calcBox({pos - radius, pos + radius}));
-	for (auto &id : nearby) {
-		ServerActiveObject *obj = getObject(id);
-		v3f objectpos = obj->getBasePosition();
-		if (objectpos.getDistanceFrom(pos) > radius)
-			continue;
-		result.push_back(id);
-	}
-	return result;
-}
-
-std::vector<u16> ServerActiveObjectMap::getObjectsTouchingBox(const aabb3f &box)
-{
-	std::vector<u16> result;
-	auto nearby = getObjectsNearBox(calcBox(box));
-	for (auto &id : nearby) {
-		ServerActiveObject *obj = getObject(id);
-		aabb3f cb;
-		if (!obj->getCollisionBox(&cb))
-			continue;
-		if (!box.intersectsWithBox(cb))
-			continue;
-		result.push_back(id);
-	}
-	return result;
-}
-
-std::unordered_set<u16> ServerActiveObjectMap::getObjectsNearBox(const aabb3s16 &box)
-{
-	std::unordered_set<u16> result;
-	v3s16 p;
-	for (p.Z = box.MinEdge.Z; p.Z <= box.MaxEdge.Z; p.Z++)
-	for (p.Y = box.MinEdge.Y; p.Y <= box.MaxEdge.Y; p.Y++)
-	for (p.X = box.MinEdge.X; p.X <= box.MaxEdge.X; p.X++) {
-		auto bounds = refmap.equal_range(p);
-		for (auto iter = bounds.first; iter != bounds.second; ++iter)
-			result.insert(iter->second);
-	}
-	return result;
-}
-
-void ServerActiveObjectMap::addObjectRef(u16 id, v3s16 pos)
-{
-	refmap.emplace(pos, id);
-}
-
-void ServerActiveObjectMap::removeObjectRef(u16 id, v3s16 pos)
-{
-	auto bounds = refmap.equal_range(pos);
-	for (auto iter = bounds.first; iter != bounds.second;) {
-		if (iter->second == id)
-			iter = refmap.erase(iter);
-		else
-			++iter;
-	}
-}
-
-void ServerActiveObjectMap::addObjectRefs(u16 id, const aabb3s16 &box)
-{
-	v3s16 p;
-	for (p.Z = box.MinEdge.Z; p.Z <= box.MaxEdge.Z; p.Z++)
-	for (p.Y = box.MinEdge.Y; p.Y <= box.MaxEdge.Y; p.Y++)
-	for (p.X = box.MinEdge.X; p.X <= box.MaxEdge.X; p.X++)
-		addObjectRef(id, p);
-}
-
-void ServerActiveObjectMap::removeObjectRefs(u16 id, const aabb3s16 &box)
-{
-	v3s16 p;
-	for (p.Z = box.MinEdge.Z; p.Z <= box.MaxEdge.Z; p.Z++)
-	for (p.Y = box.MinEdge.Y; p.Y <= box.MaxEdge.Y; p.Y++)
-	for (p.X = box.MinEdge.X; p.X <= box.MaxEdge.X; p.X++)
-		removeObjectRef(id, p);
-}
-
-bool ServerActiveObjectMap::isFreeId(u16 id)
-{
-	if (id == 0)
-		return false;
-	return objects.find(id) == objects.end();
-}
-
-u16 ServerActiveObjectMap::getFreeId()
-{
-	// try to reuse id's as late as possible
-	static u16 last_used_id = 0;
-	u16 startid = last_used_id;
-	for (;;) {
-		last_used_id++;
-		if (isFreeId(last_used_id))
-			return last_used_id;
-		if (last_used_id == startid) // wrapped around
-			return 0;
-	}
-}
diff --git a/src/server/serveractiveobjectmap.h b/src/server/serveractiveobjectmap.h
deleted file mode 100644
index 60f6890bd..000000000
--- a/src/server/serveractiveobjectmap.h
+++ /dev/null
@@ -1,143 +0,0 @@
-/*
-Minetest
-Copyright (C) 2018 numZero, Lobachevsky Vitaly <numzer0@yandex.com>
-
-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.
-*/
-
-#pragma once
-#include <unordered_set>
-#include <unordered_map>
-#include <vector>
-#include "irr_v3d.h"
-#include "irr_aabb3d.h"
-
-class ServerActiveObject;
-
-/*!
- * The class to speed up collision tests.
- *
- * @note It stores any objects but only those that has valid collision box
- * (`physical` Lua entities) are actually processed.
- * @note It uses world coordinate units, i.e. node size is always BS.
- */
-struct ServerActiveObjectMap
-{
-	struct Wrapper
-	{
-		ServerActiveObject *object;
-		aabb3s16 box;
-		v3s16 pos;
-		bool has_box;
-	};
-
-	/*!
-	 * Adds object to the map. It must have valid ID.
-	 *
-	 * If an object with the same ID already exists in the map,
-	 * std::logic_error is thrown.
-	 */
-	void addObject(ServerActiveObject *object);
-
-	/*!
-	 * Removes object from the map. The pointer must be valid.
-	 * See `removeObject(u16)` for details.
-	 */
-	void removeObject(ServerActiveObject *object);
-
-	/*!
-	 * Removes object from the map.
-	 *
-	 * If the object is not found, the call is ignored.
-	 * The function never throws, unless the underlying container throws.
-	 */
-	ServerActiveObject *removeObject(u16 id);
-
-	/*!
-	 * Updates object metadata stored in the map.
-	 * See `updateObject(u16)` for details.
-	 */
-	void updateObject(ServerActiveObject *object);
-
-	/*!
-	 * Updates object metadata stored in the map.
-	 *
-	 * The metadata includes (approximate) absolute collision box and
-	 * its existence (`physical` property for Lua entities).
-	 * This function must be called after each change of these properties,
-	 * including each object movement.
-	 */
-	void updateObject(u16 id);
-
-	/*!
-	 * Returns the object with given ID, if any.
-	 * Returns NULL otherwise.
-	 */
-	ServerActiveObject *getObject(u16 id) const;
-
-	/*!
-	 * Checks if the given ID is free and valid (i.e. non-zero).
-	 */
-	bool isFreeId(u16 id);
-
-	/*!
-	 * Returns a free ID, if any. Returns 0 in the case of failure.
-	 *
-	 * @note This function doesn't reserve the ID; it remains free until
-	 * an object with that ID is added.
-	 * @note This function tries to reclaim freed IDs as late as possible.
-	 * However, there is no guarantee.
-	 */
-	u16 getFreeId();
-
-	/*!
-	 * Returns a list of objects whose base position is at distance less
-	 * than @p radius from @p pos.
-	 *
-	 * @note Due to inexact nature of floating-point computations, it is
-	 * undefined whether an object lying exactly at the boundary is included
-	 * in the list or not.
-	 */
-	std::vector<u16> getObjectsInsideRadius(v3f pos, float radius);
-
-	/*!
-	 * Returns a list of objects whose collision box intersects with @p box
-	 *
-	 * @note Due to inexact nature of floating-point computations, it is
-	 * undefined whether an object lying exactly at the boundary is included
-	 * in the list or not.
-	 */
-	std::vector<u16> getObjectsTouchingBox(const aabb3f &box);
-
-	/*!
-	 * Returns count of objects in the map.
-	 */
-	std::size_t size() const { return objects.size(); }
-
-	/*!
-	 * Returns reference to the underlying container.
-	 */
-	const std::unordered_map<u16, Wrapper> &getObjects() const { return objects; }
-
-private:
-	void addObjectRef(u16 id, v3s16 pos);
-	void removeObjectRef(u16 id, v3s16 pos);
-	void addObjectRefs(u16 id, const aabb3s16 &box);
-	void removeObjectRefs(u16 id, const aabb3s16 &box);
-	std::unordered_set<u16> getObjectsNearBox(const aabb3s16 &box);
-
-	std::unordered_map<u16, Wrapper> objects;
-	std::unordered_multimap<v3s16, u16> refmap;
-};
diff --git a/src/serverenvironment.cpp b/src/serverenvironment.cpp
index 9835522b1..79caa24ee 100644
--- a/src/serverenvironment.cpp
+++ b/src/serverenvironment.cpp
@@ -1005,7 +1005,14 @@ bool ServerEnvironment::swapNode(v3s16 p, const MapNode &n)
 void ServerEnvironment::getObjectsInsideRadius(std::vector<u16> &objects, v3f pos,
 	float radius)
 {
-	objects = m_active_objects.getObjectsInsideRadius(pos, radius);
+	for (auto &activeObject : m_active_objects) {
+		ServerActiveObject* obj = activeObject.second;
+		u16 id = activeObject.first;
+		v3f objectpos = obj->getBasePosition();
+		if (objectpos.getDistanceFrom(pos) > radius)
+			continue;
+		objects.push_back(id);
+	}
 }
 
 void ServerEnvironment::clearObjects(ClearObjectsMode mode)
@@ -1013,9 +1020,9 @@ void ServerEnvironment::clearObjects(ClearObjectsMode mode)
 	infostream << "ServerEnvironment::clearObjects(): "
 		<< "Removing all active objects" << std::endl;
 	std::vector<u16> objects_to_remove;
-	for (auto &it : m_active_objects.getObjects()) {
+	for (auto &it : m_active_objects) {
 		u16 id = it.first;
-		ServerActiveObject* obj = it.second.object;
+		ServerActiveObject* obj = it.second;
 		if (obj->getType() == ACTIVEOBJECT_TYPE_PLAYER)
 			continue;
 
@@ -1042,7 +1049,7 @@ void ServerEnvironment::clearObjects(ClearObjectsMode mode)
 
 	// Remove references from m_active_objects
 	for (u16 i : objects_to_remove) {
-		m_active_objects.removeObject(i);
+		m_active_objects.erase(i);
 	}
 
 	// Get list of loaded blocks
@@ -1340,8 +1347,8 @@ void ServerEnvironment::step(float dtime)
 			send_recommended = true;
 		}
 
-		for (auto &ao_it : m_active_objects.getObjects()) {
-			ServerActiveObject* obj = ao_it.second.object;
+		for (auto &ao_it : m_active_objects) {
+			ServerActiveObject* obj = ao_it.second;
 			if (obj->isGone())
 				continue;
 
@@ -1427,7 +1434,40 @@ void ServerEnvironment::deleteParticleSpawner(u32 id, bool remove_from_object)
 
 ServerActiveObject* ServerEnvironment::getActiveObject(u16 id)
 {
-	return m_active_objects.getObject(id);
+	ServerActiveObjectMap::const_iterator n = m_active_objects.find(id);
+	return (n != m_active_objects.end() ? n->second : NULL);
+}
+
+/**
+ * Verify if id is a free active object id
+ * @param id
+ * @return true if slot is free
+ */
+bool ServerEnvironment::isFreeServerActiveObjectId(u16 id) const
+{
+	if (id == 0)
+		return false;
+
+	return m_active_objects.find(id) == m_active_objects.end();
+}
+
+/**
+ * Retrieve the first free ActiveObject ID
+ * @return free activeobject ID or 0 if none was found
+ */
+u16 ServerEnvironment::getFreeServerActiveObjectId()
+{
+	// try to reuse id's as late as possible
+	static u16 last_used_id = 0;
+	u16 startid = last_used_id;
+	for (;;) {
+		last_used_id++;
+		if (isFreeServerActiveObjectId(last_used_id))
+			return last_used_id;
+
+		if (last_used_id == startid)
+			return 0;
+	}
 }
 
 u16 ServerEnvironment::addActiveObject(ServerActiveObject *object)
@@ -1438,12 +1478,6 @@ u16 ServerEnvironment::addActiveObject(ServerActiveObject *object)
 	return id;
 }
 
-void ServerEnvironment::updateActiveObject(ServerActiveObject *object)
-{
-	assert(object);
-	m_active_objects.updateObject(object);
-}
-
 /*
 	Finds out what new objects have been added to
 	inside a radius around a position
@@ -1465,11 +1499,11 @@ void ServerEnvironment::getAddedActiveObjects(PlayerSAO *playersao, s16 radius,
 		- discard objects that are found in current_objects.
 		- add remaining objects to added_objects
 	*/
-	for (auto &ao_it : m_active_objects.getObjects()) {
+	for (auto &ao_it : m_active_objects) {
 		u16 id = ao_it.first;
 
 		// Get object
-		ServerActiveObject *object = ao_it.second.object;
+		ServerActiveObject *object = ao_it.second;
 		if (object == NULL)
 			continue;
 
@@ -1553,14 +1587,16 @@ void ServerEnvironment::setStaticForActiveObjectsInBlock(
 
 	for (auto &so_it : block->m_static_objects.m_active) {
 		// Get the ServerActiveObject counterpart to this StaticObject
-		ServerActiveObject *sao = m_active_objects.getObject(so_it.first);
-		if (!sao) {
+		ServerActiveObjectMap::const_iterator ao_it = m_active_objects.find(so_it.first);
+		if (ao_it == m_active_objects.end()) {
 			// If this ever happens, there must be some kind of nasty bug.
 			errorstream << "ServerEnvironment::setStaticForObjectsInBlock(): "
 				"Object from MapBlock::m_static_objects::m_active not found "
 				"in m_active_objects";
 			continue;
 		}
+
+		ServerActiveObject *sao = ao_it->second;
 		sao->m_static_exists = static_exists;
 		sao->m_static_block  = static_block;
 	}
@@ -1617,7 +1653,7 @@ u16 ServerEnvironment::addActiveObjectRaw(ServerActiveObject *object,
 {
 	assert(object); // Pre-condition
 	if(object->getId() == 0){
-		u16 new_id = m_active_objects.getFreeId();
+		u16 new_id = getFreeServerActiveObjectId();
 		if(new_id == 0)
 		{
 			errorstream<<"ServerEnvironment::addActiveObjectRaw(): "
@@ -1633,7 +1669,7 @@ u16 ServerEnvironment::addActiveObjectRaw(ServerActiveObject *object,
 			<<"supplied with id "<<object->getId()<<std::endl;
 	}
 
-	if (!m_active_objects.isFreeId(object->getId())) {
+	if(!isFreeServerActiveObjectId(object->getId())) {
 		errorstream<<"ServerEnvironment::addActiveObjectRaw(): "
 			<<"id is not free ("<<object->getId()<<")"<<std::endl;
 		if(object->environmentDeletes())
@@ -1654,7 +1690,7 @@ u16 ServerEnvironment::addActiveObjectRaw(ServerActiveObject *object,
 	/*infostream<<"ServerEnvironment::addActiveObjectRaw(): "
 			<<"added (id="<<object->getId()<<")"<<std::endl;*/
 
-	m_active_objects.addObject(object);
+	m_active_objects[object->getId()] = object;
 
 	verbosestream<<"ServerEnvironment::addActiveObjectRaw(): "
 		<<"Added id="<<object->getId()<<"; there are now "
@@ -1700,9 +1736,9 @@ u16 ServerEnvironment::addActiveObjectRaw(ServerActiveObject *object,
 void ServerEnvironment::removeRemovedObjects()
 {
 	std::vector<u16> objects_to_remove;
-	for (auto &ao_it : m_active_objects.getObjects()) {
+	for (auto &ao_it : m_active_objects) {
 		u16 id = ao_it.first;
-		ServerActiveObject* obj = ao_it.second.object;
+		ServerActiveObject* obj = ao_it.second;
 
 		// This shouldn't happen but check it
 		if (!obj) {
@@ -1767,7 +1803,7 @@ void ServerEnvironment::removeRemovedObjects()
 	}
 	// Remove references from m_active_objects
 	for (u16 i : objects_to_remove) {
-		m_active_objects.removeObject(i);
+		m_active_objects.erase(i);
 	}
 }
 
@@ -1889,11 +1925,11 @@ void ServerEnvironment::activateObjects(MapBlock *block, u32 dtime_s)
 void ServerEnvironment::deactivateFarObjects(bool _force_delete)
 {
 	std::vector<u16> objects_to_remove;
-	for (auto &ao_it : m_active_objects.getObjects()) {
+	for (auto &ao_it : m_active_objects) {
 		// force_delete might be overriden per object
 		bool force_delete = _force_delete;
 
-		ServerActiveObject* obj = ao_it.second.object;
+		ServerActiveObject* obj = ao_it.second;
 		assert(obj);
 
 		// Do not deactivate if static data creation not allowed
@@ -2024,7 +2060,7 @@ void ServerEnvironment::deactivateFarObjects(bool _force_delete)
 
 	// Remove references from m_active_objects
 	for (u16 i : objects_to_remove) {
-		m_active_objects.removeObject(i);
+		m_active_objects.erase(i);
 	}
 }
 
diff --git a/src/serverenvironment.h b/src/serverenvironment.h
index 05a68cb30..225f788d9 100644
--- a/src/serverenvironment.h
+++ b/src/serverenvironment.h
@@ -22,7 +22,6 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "activeobject.h"
 #include "environment.h"
 #include "mapnode.h"
-#include "server/serveractiveobjectmap.h"
 #include "settings.h"
 #include "util/numeric.h"
 #include <set>
@@ -194,6 +193,8 @@ enum ClearObjectsMode {
 	This is not thread-safe. Server uses an environment mutex.
 */
 
+typedef std::unordered_map<u16, ServerActiveObject *> ServerActiveObjectMap;
+
 class ServerEnvironment : public Environment
 {
 public:
@@ -253,7 +254,18 @@ public:
 	*/
 	u16 addActiveObject(ServerActiveObject *object);
 
-	void updateActiveObject(ServerActiveObject *object);
+	/**
+	 * Verify if id is a free active object id
+	 * @param id
+	 * @return true if slot is free
+	 */
+	bool isFreeServerActiveObjectId(u16 id) const;
+
+	/**
+	 * Retrieve the first free ActiveObject ID
+	 * @return free activeobject ID or 0 if none was found
+	 */
+	u16 getFreeServerActiveObjectId();
 
 	/*
 		Add an active object as a static object to the corresponding
diff --git a/src/unittest/CMakeLists.txt b/src/unittest/CMakeLists.txt
index 5d306ee75..311204e32 100644
--- a/src/unittest/CMakeLists.txt
+++ b/src/unittest/CMakeLists.txt
@@ -23,7 +23,6 @@ set (UNITTEST_SRCS
 	${CMAKE_CURRENT_SOURCE_DIR}/test_server_shutdown_state.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/test_settings.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/test_socket.cpp
-	${CMAKE_CURRENT_SOURCE_DIR}/test_serveractiveobjectmap.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/test_servermodmanager.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/test_threading.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/test_utilities.cpp
diff --git a/src/unittest/test.h b/src/unittest/test.h
index a6cd03ed2..1102f6d33 100644
--- a/src/unittest/test.h
+++ b/src/unittest/test.h
@@ -99,10 +99,6 @@ class TestFailedException : public std::exception {
 	UASSERT(exception_thrown);            \
 }
 
-#define CONCAT_IMPL(x,y) x##y
-#define CONCAT(x,y) CONCAT_IMPL(x, y)
-#define NEWNAME(prefix) CONCAT(prefix, __COUNTER__)
-
 class IGameDef;
 
 class TestBase {
diff --git a/src/unittest/test_serveractiveobjectmap.cpp b/src/unittest/test_serveractiveobjectmap.cpp
deleted file mode 100644
index 42c879229..000000000
--- a/src/unittest/test_serveractiveobjectmap.cpp
+++ /dev/null
@@ -1,214 +0,0 @@
-/*
-Minetest
-Copyright (C) 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 "test.h"
-
-#include "server/serveractiveobjectmap.h"
-#include "content_sao.h"
-
-class TestServerActiveObjectMap : public TestBase
-{
-public:
-	TestServerActiveObjectMap() { TestManager::registerTestModule(this); }
-	const char *getName() { return "TestServerActiveObjectMap"; }
-
-	void runTests(IGameDef *gamedef);
-
-	void testAddObject();
-	void testRemoveObject();
-	void testUpdateObject();
-	void testGetObject();
-	void testIsFreeID();
-	void testGetFreeID();
-	void testGetObjectsInsideRadius();
-	void testGetObjectsTouchingBox();
-};
-
-static TestServerActiveObjectMap g_test_instance;
-
-void TestServerActiveObjectMap::runTests(IGameDef *gamedef)
-{
-	TEST(testAddObject);
-	TEST(testRemoveObject);
-	TEST(testUpdateObject);
-	TEST(testGetObject);
-	TEST(testIsFreeID);
-	TEST(testGetFreeID);
-	TEST(testGetObjectsInsideRadius);
-	TEST(testGetObjectsTouchingBox);
-}
-
-void TestServerActiveObjectMap::testAddObject()
-{
-	ServerActiveObjectMap saom;
-	UASSERT(saom.getObjects().empty());
-
-	LuaEntitySAO ob1(nullptr, v3f(0, 0, 0), "", "");
-	ob1.setId(saom.getFreeId());
-	saom.addObject(&ob1);
-
-	UASSERT(saom.getObjects().size() == 1);
-	bool found = false;
-	for (const auto &pair : saom.getObjects()) {
-		UASSERT(pair.second.object == &ob1);
-		found = true;
-	}
-	UASSERT(found);
-}
-
-void TestServerActiveObjectMap::testRemoveObject()
-{
-	ServerActiveObjectMap saom;
-	UASSERT(saom.getObjects().empty());
-
-	LuaEntitySAO ob1(nullptr, v3f(0, 0, 0), "", "");
-	ob1.setId(saom.getFreeId());
-	saom.addObject(&ob1);
-
-	UASSERT(saom.getObjects().size() == 1);
-	bool found = false;
-	for (const auto &pair : saom.getObjects()) {
-		UASSERT(pair.second.object == &ob1);
-		found = true;
-	}
-	UASSERT(found);
-
-	saom.removeObject(&ob1);
-}
-
-void TestServerActiveObjectMap::testUpdateObject()
-{
-	ServerActiveObjectMap saom;
-	LuaEntitySAO ob1(nullptr, v3f(1, 0, 0), "", "");
-	ob1.accessObjectProperties()->physical = true;
-	ob1.setId(saom.getFreeId());
-	saom.addObject(&ob1);
-	UASSERT(saom.getObjectsInsideRadius(v3f(0, 0, 0), 2).size() == 1);
-	UASSERT(saom.getObjectsInsideRadius(v3f(6, 0, 0), 2).size() == 0);
-	ob1.setBasePosition(v3f(5, 0, 0));
-	saom.updateObject(&ob1);
-	UASSERT(saom.getObjectsInsideRadius(v3f(0, 0, 0), 2).size() == 0);
-	UASSERT(saom.getObjectsInsideRadius(v3f(6, 0, 0), 2).size() == 1);
-}
-
-void TestServerActiveObjectMap::testGetObject()
-{
-	ServerActiveObjectMap saom;
-	LuaEntitySAO ob1(nullptr, v3f(0, 0, 0), "", "");
-	u16 id = saom.getFreeId();
-	ob1.setId(id);
-	saom.addObject(&ob1);
-	UASSERT(saom.getObject(0) == nullptr);
-	UASSERT(saom.getObject(id) == &ob1);
-	UASSERT(saom.getObject(id + 1) == nullptr);
-}
-
-void TestServerActiveObjectMap::testIsFreeID()
-{
-	ServerActiveObjectMap saom;
-	UASSERT(!saom.isFreeId(0));
-	UASSERT(saom.isFreeId(1));
-	UASSERT(saom.isFreeId(2));
-}
-
-void TestServerActiveObjectMap::testGetFreeID()
-{
-	ServerActiveObjectMap saom;
-	u16 first_id = saom.getFreeId();
-	UASSERT(first_id > 0);
-	UASSERT(saom.getFreeId() > first_id);
-}
-
-void TestServerActiveObjectMap::testGetObjectsInsideRadius()
-{
-	ServerActiveObjectMap saom;
-#define ADD_OBJECT_IMPL(name, pos)                                                       \
-	LuaEntitySAO name(nullptr, pos, "", "");                                         \
-	name.accessObjectProperties()->physical = true;                                  \
-	name.setId(saom.getFreeId());                                                    \
-	saom.addObject(&name)
-#define ADD_OBJECT(pos) ADD_OBJECT_IMPL(NEWNAME(ob), pos)
-#define OBJECT_COUNT (saom.getObjectsInsideRadius(v3f(0, 0, 0), 5).size())
-
-	UASSERT(OBJECT_COUNT == 0);
-
-	ADD_OBJECT(v3f(0, 0, 0));
-	UASSERT(OBJECT_COUNT == 1);
-
-	ADD_OBJECT(v3f(-1, -1, -1));
-	UASSERT(OBJECT_COUNT == 2);
-
-	ADD_OBJECT(v3f(4.9, 0, 0));
-	UASSERT(OBJECT_COUNT == 3);
-
-	ADD_OBJECT(v3f(5.1, 0, 0));
-	UASSERT(OBJECT_COUNT == 3);
-
-	ADD_OBJECT(v3f(3, 3, 3));
-	UASSERT(OBJECT_COUNT == 3);
-}
-
-void TestServerActiveObjectMap::testGetObjectsTouchingBox()
-{
-	ServerActiveObjectMap saom;
-
-	LuaEntitySAO ob1(nullptr, v3f(1 * BS, 0, 0), "", "");
-	ob1.accessObjectProperties()->physical = true;
-	// Collision boxes are in nodes, not in world units:
-	ob1.accessObjectProperties()->collisionbox = {-1, -1, -1, 1, 1, 1};
-	ob1.setId(saom.getFreeId());
-	saom.addObject(&ob1);
-
-	LuaEntitySAO ob2(nullptr, v3f(1.5 * BS, 2.5 * BS, 0), "", "");
-	ob2.accessObjectProperties()->physical = true;
-	ob2.accessObjectProperties()->collisionbox = {-0.5, -0.5, -1, 3.5, 2, 1};
-	ob2.setId(saom.getFreeId());
-	saom.addObject(&ob2);
-
-	std::vector<u16> list;
-
-	list = saom.getObjectsTouchingBox(
-			{2.1 * BS, -1.0 * BS, -1.0 * BS, 2.5 * BS, 1.0 * BS, 1.0 * BS});
-	UASSERT(list.size() == 0);
-
-	// intersecting ob1
-	list = saom.getObjectsTouchingBox(
-			{1.9 * BS, -1.0 * BS, -1.0 * BS, 2.5 * BS, 1.0 * BS, 1.0 * BS});
-	UASSERT(list.size() == 1 && list[0] == ob1.getId());
-
-	// intersecting ob2
-	list = saom.getObjectsTouchingBox(
-			{2.1 * BS, -1.0 * BS, -1.0 * BS, 2.5 * BS, 2.1 * BS, 1.0 * BS});
-	UASSERT(list.size() == 1 && list[0] == ob2.getId());
-
-	// contained in ob1
-	list = saom.getObjectsTouchingBox(
-			{1.5 * BS, -0.1 * BS, -0.1 * BS, 1.9 * BS, 0.1 * BS, 0.1 * BS});
-	UASSERT(list.size() == 1 && list[0] == ob1.getId());
-
-	// contains ob2
-	list = saom.getObjectsTouchingBox(
-			{0.9 * BS, 1.5 * BS, -5.0 * BS, 6.0 * BS, 20.0 * BS, 500.0 * BS});
-	UASSERT(list.size() == 1 && list[0] == ob2.getId());
-
-	// intersecting both
-	list = saom.getObjectsTouchingBox(
-			{1.9 * BS, -1.0 * BS, -1.0 * BS, 2.5 * BS, 2.1 * BS, 1.0 * BS});
-	UASSERT(list.size() == 2);
-}