FollowMovementGenerator.cpp

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/*
 * This file is part of the TrinityCore Project. See AUTHORS file for Copyright information
 *
 * 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 2 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 "FollowMovementGenerator.h"
#include "Creature.h"
#include "CreatureAI.h"
#include "MoveSpline.h"
#include "MoveSplineInit.h"
#include "Optional.h"
#include "PathGenerator.h"
#include "Pet.h"
#include "Unit.h"
#include "Util.h"
 
static void DoMovementInform(Unit* owner, Unit* target)
{
 if (owner->GetTypeId() != TYPEID_UNIT)
 return;
 
 if (CreatureAI* AI = owner->ToCreature()->AI())
 AI->MovementInform(FOLLOW_MOTION_TYPE, target->GetGUID().GetCounter());
}
 
FollowMovementGenerator::FollowMovementGenerator(Unit* target, float range, ChaseAngle angle, Optional<Milliseconds> duration)
 : AbstractFollower(ASSERT_NOTNULL(target)), _range(range), _angle(angle), _checkTimer(CHECK_INTERVAL)
{
 Mode = MOTION_MODE_DEFAULT;
 Priority = MOTION_PRIORITY_NORMAL;
 Flags = MOVEMENTGENERATOR_FLAG_INITIALIZATION_PENDING;
 BaseUnitState = UNIT_STATE_FOLLOW;
 if (duration)
 _duration.emplace(*duration);
}
FollowMovementGenerator::~FollowMovementGenerator() = default;
 
static bool PositionOkay(Unit* owner, Unit* target, float range, Optional<ChaseAngle> angle = {})
{
 if (owner->GetExactDistSq(target) > square(owner->GetCombatReach() + target->GetCombatReach() + range))
 return false;
 
 return !angle || angle->IsAngleOkay(target->GetRelativeAngle(owner));
}
 
void FollowMovementGenerator::Initialize(Unit* owner)
{
 RemoveFlag(MOVEMENTGENERATOR_FLAG_INITIALIZATION_PENDING | MOVEMENTGENERATOR_FLAG_DEACTIVATED);
 AddFlag(MOVEMENTGENERATOR_FLAG_INITIALIZED | MOVEMENTGENERATOR_FLAG_INFORM_ENABLED);
 
 owner->StopMoving();
 UpdatePetSpeed(owner);
 _path = nullptr;
 _lastTargetPosition.reset();
}
 
void FollowMovementGenerator::Reset(Unit* owner)
{
 RemoveFlag(MOVEMENTGENERATOR_FLAG_DEACTIVATED);
 
 Initialize(owner);
}
 
bool FollowMovementGenerator::Update(Unit* owner, uint32 diff)
{
 // owner might be dead or gone
 if (!owner || !owner->IsAlive())
 return false;
 
 // our target might have gone away
 Unit* const target = GetTarget();
 if (!target || !target->IsInWorld())
 return false;
 
 if (_duration)
 {
 _duration->Update(diff);
 if (_duration->Passed())
 {
 owner->StopMoving();
 DoMovementInform(owner, target);
 return false;
 }
 }
 
 if (owner->HasUnitState(UNIT_STATE_NOT_MOVE) || owner->IsMovementPreventedByCasting())
 {
 _path = nullptr;
 owner->StopMoving();
 _lastTargetPosition.reset();
 return true;
 }
 
 float range = _range;
 if (Creature* cOwner = owner->ToCreature())
 if (cOwner->IsIgnoringChaseRange())
 range = 0.0f;
 
 _checkTimer.Update(diff);
 if (_checkTimer.Passed())
 {
 _checkTimer.Reset(CHECK_INTERVAL);
 if (HasFlag(MOVEMENTGENERATOR_FLAG_INFORM_ENABLED) && PositionOkay(owner, target, range, _angle))
 {
 RemoveFlag(MOVEMENTGENERATOR_FLAG_INFORM_ENABLED);
 _path = nullptr;
 owner->StopMoving();
 _lastTargetPosition.reset();
 DoMovementInform(owner, target);
 return true;
 }
 }
 
 if (owner->HasUnitState(UNIT_STATE_FOLLOW_MOVE) && owner->movespline->Finalized())
 {
 RemoveFlag(MOVEMENTGENERATOR_FLAG_INFORM_ENABLED);
 _path = nullptr;
 owner->ClearUnitState(UNIT_STATE_FOLLOW_MOVE);
 DoMovementInform(owner, target);
 }
 
 if (!_lastTargetPosition || _lastTargetPosition->GetExactDistSq(target->GetPosition()) > 0.0f)
 {
 _lastTargetPosition = target->GetPosition();
 if (owner->HasUnitState(UNIT_STATE_FOLLOW_MOVE) || !PositionOkay(owner, target, range + FOLLOW_RANGE_TOLERANCE))
 {
 if (!_path)
 _path = std::make_unique<PathGenerator>(owner);
 
 float x, y, z;
 
 // select angle
 float tAngle;
 float const curAngle = target->GetRelativeAngle(owner);
 if (_angle.IsAngleOkay(curAngle))
 tAngle = curAngle;
 else
 {
 float const diffUpper = Position::NormalizeOrientation(curAngle - _angle.UpperBound());
 float const diffLower = Position::NormalizeOrientation(_angle.LowerBound() - curAngle);
 if (diffUpper < diffLower)
 tAngle = _angle.UpperBound();
 else
 tAngle = _angle.LowerBound();
 }
 
 target->GetNearPoint(owner, x, y, z, range, target->ToAbsoluteAngle(tAngle));
 
 if (owner->IsHovering())
 owner->UpdateAllowedPositionZ(x, y, z);
 
 // pets are allowed to "cheat" on pathfinding when following their master
 bool allowShortcut = false;
 if (Pet* oPet = owner->ToPet())
 {
 if (target->GetGUID() == oPet->GetOwnerGUID())
 allowShortcut = true;
 }
 
 bool success = _path->CalculatePath(x, y, z, allowShortcut);
 if (!success || (_path->GetPathType() & PATHFIND_NOPATH))
 {
 owner->StopMoving();
 return true;
 }
 
 owner->AddUnitState(UNIT_STATE_FOLLOW_MOVE);
 AddFlag(MOVEMENTGENERATOR_FLAG_INFORM_ENABLED);
 
 Movement::MoveSplineInit init(owner);
 init.MovebyPath(_path->GetPath());
 init.SetWalk(target->IsWalking());
 init.SetFacing(target->GetOrientation());
 init.Launch();
 }
 }
 return true;
}
 
void FollowMovementGenerator::Deactivate(Unit* owner)
{
 AddFlag(MOVEMENTGENERATOR_FLAG_DEACTIVATED);
 RemoveFlag(MOVEMENTGENERATOR_FLAG_TRANSITORY | MOVEMENTGENERATOR_FLAG_INFORM_ENABLED);
 owner->ClearUnitState(UNIT_STATE_FOLLOW_MOVE);
}
 
void FollowMovementGenerator::Finalize(Unit* owner, bool active, bool/* movementInform*/)
{
 AddFlag(MOVEMENTGENERATOR_FLAG_FINALIZED);
 if (active)
 {
 owner->ClearUnitState(UNIT_STATE_FOLLOW_MOVE);
 UpdatePetSpeed(owner);
 }
}
 
void FollowMovementGenerator::UpdatePetSpeed(Unit* owner)
{
 if (Pet* oPet = owner->ToPet())
 {
 if (!GetTarget() || GetTarget()->GetGUID() == owner->GetOwnerGUID())
 {
 oPet->UpdateSpeed(MOVE_RUN);
 oPet->UpdateSpeed(MOVE_WALK);
 oPet->UpdateSpeed(MOVE_SWIM);
 }
 }
}