CCmpUnitMotion.h

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/* Copyright (C) 2023 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. 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.
 *
 * 0 A.D. 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 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef INCLUDED_CCMPUNITMOTION
#define INCLUDED_CCMPUNITMOTION
 
#include "simulation2/system/Component.h"
#include "ICmpUnitMotion.h"
 
#include "simulation2/components/CCmpUnitMotionManager.h"
#include "simulation2/components/ICmpObstruction.h"
#include "simulation2/components/ICmpObstructionManager.h"
#include "simulation2/components/ICmpOwnership.h"
#include "simulation2/components/ICmpPosition.h"
#include "simulation2/components/ICmpPathfinder.h"
#include "simulation2/components/ICmpRangeManager.h"
#include "simulation2/components/ICmpValueModificationManager.h"
#include "simulation2/components/ICmpVisual.h"
#include "simulation2/helpers/Geometry.h"
#include "simulation2/helpers/Render.h"
#include "simulation2/MessageTypes.h"
#include "simulation2/serialization/SerializedPathfinder.h"
#include "simulation2/serialization/SerializedTypes.h"
 
#include "graphics/Overlay.h"
#include "maths/FixedVector2D.h"
#include "ps/CLogger.h"
#include "ps/Profile.h"
#include "renderer/Scene.h"
 
#include <algorithm>
 
// NB: this implementation of ICmpUnitMotion is very tightly coupled with UnitMotionManager.
// As such, both are compiled in the same TU.
 
// For debugging; units will start going straight to the target
// instead of calling the pathfinder
#define DISABLE_PATHFINDER 0
 
namespace
{
/**
 * Min/Max range to restrict short path queries to. (Larger ranges are (much) slower,
 * smaller ranges might miss some legitimate routes around large obstacles.)
 * NB: keep the max-range in sync with the vertex pathfinder "move the search space" heuristic.
 */
constexpr entity_pos_t SHORT_PATH_MIN_SEARCH_RANGE = entity_pos_t::FromInt(12 * Pathfinding::NAVCELL_SIZE_INT);
constexpr entity_pos_t SHORT_PATH_MAX_SEARCH_RANGE = entity_pos_t::FromInt(56 * Pathfinding::NAVCELL_SIZE_INT);
constexpr entity_pos_t SHORT_PATH_SEARCH_RANGE_INCREMENT = entity_pos_t::FromInt(4 * Pathfinding::NAVCELL_SIZE_INT);
constexpr u8 SHORT_PATH_SEARCH_RANGE_INCREASE_DELAY = 1;
 
/**
 * When using the short-pathfinder to rejoin a long-path waypoint, aim for a circle of this radius around the waypoint.
 */
constexpr entity_pos_t SHORT_PATH_LONG_WAYPOINT_RANGE = entity_pos_t::FromInt(4 * Pathfinding::NAVCELL_SIZE_INT);
 
/**
 * Minimum distance to goal for a long path request
 */
constexpr entity_pos_t LONG_PATH_MIN_DIST = entity_pos_t::FromInt(16 * Pathfinding::NAVCELL_SIZE_INT);
 
/**
 * If we are this close to our target entity/point, then think about heading
 * for it in a straight line instead of pathfinding.
 */
constexpr entity_pos_t DIRECT_PATH_RANGE = entity_pos_t::FromInt(24 * Pathfinding::NAVCELL_SIZE_INT);
 
/**
 * To avoid recomputing paths too often, have some leeway for target range checks
 * based on our distance to the target. Increase that incertainty by one navcell
 * for every this many tiles of distance.
 */
constexpr entity_pos_t TARGET_UNCERTAINTY_MULTIPLIER = entity_pos_t::FromInt(8 * Pathfinding::NAVCELL_SIZE_INT);
 
/**
 * When following a known imperfect path (i.e. a path that won't take us in range of our goal
 * we still recompute a new path every N turn to adapt to moving targets (for example, ships that must pickup
 * units may easily end up in this state, they still need to adjust to moving units).
 * This is rather arbitrary and mostly for simplicity & optimisation (a better recomputing algorithm
 * would not need this).
 */
constexpr u8 KNOWN_IMPERFECT_PATH_RESET_COUNTDOWN = 12;
 
/**
 * When we fail to move this many turns in a row, inform other components that the move will fail.
 * Experimentally, this number needs to be somewhat high or moving groups of units will lead to stuck units.
 * However, too high means units will look idle for a long time when they are failing to move.
 * TODO: if UnitMotion could send differentiated "unreachable" and "currently stuck" failing messages,
 * this could probably be lowered.
 */
constexpr u8 MAX_FAILED_MOVEMENTS = 35;
 
/**
 * When computing paths but failing to move, we want to occasionally alternate pathfinder systems
 * to avoid getting stuck (the short pathfinder can unstuck the long-range one and vice-versa, depending).
 */
constexpr u8 ALTERNATE_PATH_TYPE_DELAY = 3;
constexpr u8 ALTERNATE_PATH_TYPE_EVERY = 6;
 
/**
 * Units can occasionally get stuck near corners. The cause is a mismatch between CheckMovement and the short pathfinder.
 * The problem is the short pathfinder finds an impassable path when units are right on an obstruction edge.
 * Fixing this math mismatch is perhaps possible, but fixing it in UM is rather easy: just try backing up a bit
 * and that will probably un-stuck the unit. This is the 'failed movement' turn on which to try that.
 */
constexpr u8 BACKUP_HACK_DELAY = 10;
 
/**
 * After this many failed computations, start sending "VERY_OBSTRUCTED" messages instead.
 * Should probably be larger than ALTERNATE_PATH_TYPE_DELAY.
 */
constexpr u8 VERY_OBSTRUCTED_THRESHOLD = 10;
 
const CColor OVERLAY_COLOR_LONG_PATH(1, 1, 1, 1);
const CColor OVERLAY_COLOR_SHORT_PATH(1, 0, 0, 1);
} // anonymous namespace
 
class CCmpUnitMotion final : public ICmpUnitMotion
{
    friend class CCmpUnitMotionManager;
public:
    static void ClassInit(CComponentManager& componentManager)
    {
        componentManager.SubscribeToMessageType(MT_Create);
        componentManager.SubscribeToMessageType(MT_Destroy);
        componentManager.SubscribeToMessageType(MT_PathResult);
        componentManager.SubscribeToMessageType(MT_OwnershipChanged);
        componentManager.SubscribeToMessageType(MT_ValueModification);
        componentManager.SubscribeToMessageType(MT_MovementObstructionChanged);
        componentManager.SubscribeToMessageType(MT_Deserialized);
    }
 
    DEFAULT_COMPONENT_ALLOCATOR(UnitMotion)
 
    bool m_DebugOverlayEnabled;
    std::vector<SOverlayLine> m_DebugOverlayLongPathLines;
    std::vector<SOverlayLine> m_DebugOverlayShortPathLines;
 
    // Template state:
 
    bool m_IsFormationController;
 
    fixed m_TemplateWalkSpeed, m_TemplateRunMultiplier, m_TemplateAcceleration, m_TemplateWeight;
    pass_class_t m_PassClass;
    std::string m_PassClassName;
 
    // Dynamic state:
 
    entity_pos_t m_Clearance;
 
    // cached for efficiency
    fixed m_WalkSpeed, m_RunMultiplier;
 
    bool m_FacePointAfterMove;
 
    // Whether the unit participates in pushing.
    bool m_Pushing = false;
 
    // Whether the unit blocks movement (& is blocked by movement blockers)
    // Cached from ICmpObstruction.
    bool m_BlockMovement = false;
 
    // Internal counter used when recovering from obstructed movement.
    // Most notably, increases the search range of the vertex pathfinder.
    // See HandleObstructedMove() for more details.
    u8 m_FailedMovements = 0;
 
    // If > 0, PathingUpdateNeeded returns false always.
    // This exists because the goal may be unreachable to the short/long pathfinder.
    // In such cases, we would compute inacceptable paths and PathingUpdateNeeded would trigger every turn,
    // which would be quite bad for performance.
    // To avoid that, when we know the new path is imperfect, treat it as OK and follow it anyways.
    // When reaching the end, we'll go through HandleObstructedMove and reset regardless.
    // To still recompute now and then (the target may be moving), this is a countdown decremented on each frame.
    u8 m_FollowKnownImperfectPathCountdown = 0;
 
    struct Ticket {
        u32 m_Ticket = 0; // asynchronous request ID we're waiting for, or 0 if none
        enum Type {
            SHORT_PATH,
            LONG_PATH
        } m_Type = SHORT_PATH; // Pick some default value to avoid UB.
 
        void clear() { m_Ticket = 0; }
    } m_ExpectedPathTicket;
 
    struct MoveRequest {
        enum Type {
            NONE,
            POINT,
            ENTITY,
            OFFSET
        } m_Type = NONE;
        entity_id_t m_Entity = INVALID_ENTITY;
        CFixedVector2D m_Position;
        entity_pos_t m_MinRange, m_MaxRange;
 
        // For readability
        CFixedVector2D GetOffset() const { return m_Position; };
 
        MoveRequest() = default;
        MoveRequest(CFixedVector2D pos, entity_pos_t minRange, entity_pos_t maxRange) : m_Type(POINT), m_Position(pos), m_MinRange(minRange), m_MaxRange(maxRange) {};
        MoveRequest(entity_id_t target, entity_pos_t minRange, entity_pos_t maxRange) : m_Type(ENTITY), m_Entity(target), m_MinRange(minRange), m_MaxRange(maxRange) {};
        MoveRequest(entity_id_t target, CFixedVector2D offset) : m_Type(OFFSET), m_Entity(target), m_Position(offset) {};
    } m_MoveRequest;
 
    // If this is not INVALID_ENTITY, the unit is a formation member.
    entity_id_t m_FormationController = INVALID_ENTITY;
 
    // If the entity moves, it will do so at m_WalkSpeed * m_SpeedMultiplier.
    fixed m_SpeedMultiplier;
    // This caches the resulting speed from m_WalkSpeed * m_SpeedMultiplier for convenience.
    fixed m_Speed;
 
    // Mean speed over the last turn.
    fixed m_LastTurnSpeed;
 
    // The speed achieved at the end of the current turn.
    fixed m_CurrentSpeed;
 
    fixed m_InstantTurnAngle;
 
    fixed m_Acceleration;
 
    // Currently active paths (storing waypoints in reverse order).
    // The last item in each path is the point we're currently heading towards.
    WaypointPath m_LongPath;
    WaypointPath m_ShortPath;
 
    static std::string GetSchema()
    {
        return
            "<a:help>Provides the unit with the ability to move around the world by itself.</a:help>"
            "<a:example>"
                "<WalkSpeed>7.0</WalkSpeed>"
                "<PassabilityClass>default</PassabilityClass>"
            "</a:example>"
            "<element name='FormationController'>"
                "<data type='boolean'/>"
            "</element>"
            "<element name='WalkSpeed' a:help='Basic movement speed (in metres per second).'>"
                "<ref name='positiveDecimal'/>"
            "</element>"
            "<optional>"
                "<element name='RunMultiplier' a:help='How much faster the unit goes when running (as a multiple of walk speed).'>"
                    "<ref name='positiveDecimal'/>"
                "</element>"
            "</optional>"
            "<element name='InstantTurnAngle' a:help='Angle we can turn instantly. Any value greater than pi will disable turning times. Avoid zero since it stops the entity every turn.'>"
                "<ref name='positiveDecimal'/>"
            "</element>"
            "<element name='Acceleration' a:help='Acceleration (in metres per second^2).'>"
                "<ref name='positiveDecimal'/>"
            "</element>"
            "<element name='PassabilityClass' a:help='Identifies the terrain passability class (values are defined in special/pathfinder.xml).'>"
                "<text/>"
            "</element>"
            "<element name='Weight' a:help='Makes this unit both push harder and harder to push. 10 is considered the base value.'>"
                "<ref name='positiveDecimal'/>"
            "</element>"
            "<optional>"
                "<element name='DisablePushing'>"
                    "<data type='boolean'/>"
                "</element>"
            "</optional>";
    }
 
    void Init(const CParamNode& paramNode) override
    {
        m_IsFormationController = paramNode.GetChild("FormationController").ToBool();
 
        m_FacePointAfterMove = true;
 
        m_WalkSpeed = m_TemplateWalkSpeed = m_Speed = paramNode.GetChild("WalkSpeed").ToFixed();
        m_SpeedMultiplier = fixed::FromInt(1);
        m_LastTurnSpeed = m_CurrentSpeed = fixed::Zero();
 
        m_RunMultiplier = m_TemplateRunMultiplier = fixed::FromInt(1);
        if (paramNode.GetChild("RunMultiplier").IsOk())
            m_RunMultiplier = m_TemplateRunMultiplier = paramNode.GetChild("RunMultiplier").ToFixed();
 
        m_InstantTurnAngle = paramNode.GetChild("InstantTurnAngle").ToFixed();
 
        m_Acceleration = m_TemplateAcceleration = paramNode.GetChild("Acceleration").ToFixed();
 
        m_TemplateWeight = paramNode.GetChild("Weight").ToFixed();
 
        m_PassClassName = paramNode.GetChild("PassabilityClass").ToString();
        SetPassabilityData(m_PassClassName);
 
        CmpPtr<ICmpObstruction> cmpObstruction(GetEntityHandle());
        if (cmpObstruction)
            m_BlockMovement = cmpObstruction->GetBlockMovementFlag(true);
 
        SetParticipateInPushing(!paramNode.GetChild("DisablePushing").IsOk() || !paramNode.GetChild("DisablePushing").ToBool());
 
        m_DebugOverlayEnabled = false;
    }
 
    void Deinit() override
    {
    }
 
    template<typename S>
    void SerializeCommon(S& serialize)
    {
        // m_Clearance and m_PassClass are constructed from this.
        serialize.StringASCII("pass class", m_PassClassName, 0, 64);
 
        serialize.NumberU32_Unbounded("ticket", m_ExpectedPathTicket.m_Ticket);
        Serializer(serialize, "ticket type", m_ExpectedPathTicket.m_Type, Ticket::Type::LONG_PATH);
 
        serialize.NumberU8_Unbounded("failed movements", m_FailedMovements);
        serialize.NumberU8_Unbounded("followknownimperfectpath", m_FollowKnownImperfectPathCountdown);
 
        Serializer(serialize, "target type", m_MoveRequest.m_Type, MoveRequest::Type::OFFSET);
        serialize.NumberU32_Unbounded("target entity", m_MoveRequest.m_Entity);
        serialize.NumberFixed_Unbounded("target pos x", m_MoveRequest.m_Position.X);
        serialize.NumberFixed_Unbounded("target pos y", m_MoveRequest.m_Position.Y);
        serialize.NumberFixed_Unbounded("target min range", m_MoveRequest.m_MinRange);
        serialize.NumberFixed_Unbounded("target max range", m_MoveRequest.m_MaxRange);
 
        serialize.NumberU32_Unbounded("formation controller", m_FormationController);
 
        serialize.NumberFixed_Unbounded("speed multiplier", m_SpeedMultiplier);
 
        serialize.NumberFixed_Unbounded("last turn speed", m_LastTurnSpeed);
        serialize.NumberFixed_Unbounded("current speed", m_CurrentSpeed);
 
        serialize.NumberFixed_Unbounded("instant turn angle", m_InstantTurnAngle);
 
        serialize.NumberFixed_Unbounded("acceleration", m_Acceleration);
 
        serialize.Bool("facePointAfterMove", m_FacePointAfterMove);
        serialize.Bool("pushing", m_Pushing);
 
        Serializer(serialize, "long path", m_LongPath.m_Waypoints);
        Serializer(serialize, "short path", m_ShortPath.m_Waypoints);
    }
 
    void Serialize(ISerializer& serialize) override
    {
        SerializeCommon(serialize);
    }
 
    void Deserialize(const CParamNode& paramNode, IDeserializer& deserialize) override
    {
        Init(paramNode);
 
        SerializeCommon(deserialize);
 
        SetPassabilityData(m_PassClassName);
 
        CmpPtr<ICmpObstruction> cmpObstruction(GetEntityHandle());
        if (cmpObstruction)
            m_BlockMovement = cmpObstruction->GetBlockMovementFlag(false);
    }
 
    void HandleMessage(const CMessage& msg, bool UNUSED(global)) override
    {
        switch (msg.GetType())
        {
        case MT_RenderSubmit:
        {
            PROFILE("UnitMotion::RenderSubmit");
            const CMessageRenderSubmit& msgData = static_cast<const CMessageRenderSubmit&> (msg);
            RenderSubmit(msgData.collector);
            break;
        }
        case MT_PathResult:
        {
            const CMessagePathResult& msgData = static_cast<const CMessagePathResult&> (msg);
            PathResult(msgData.ticket, msgData.path);
            break;
        }
        case MT_Create:
        {
            if (!ENTITY_IS_LOCAL(GetEntityId()))
                CmpPtr<ICmpUnitMotionManager>(GetSystemEntity())->Register(this, GetEntityId(), m_IsFormationController);
            break;
        }
        case MT_Destroy:
        {
            if (!ENTITY_IS_LOCAL(GetEntityId()))
                CmpPtr<ICmpUnitMotionManager>(GetSystemEntity())->Unregister(GetEntityId());
            break;
        }
        case MT_MovementObstructionChanged:
        {
            CmpPtr<ICmpObstruction> cmpObstruction(GetEntityHandle());
            if (cmpObstruction)
                m_BlockMovement = cmpObstruction->GetBlockMovementFlag(false);
            break;
        }
        case MT_ValueModification:
        {
            const CMessageValueModification& msgData = static_cast<const CMessageValueModification&> (msg);
            if (msgData.component != L"UnitMotion")
                break;
            FALLTHROUGH;
        }
        case MT_OwnershipChanged:
        {
            OnValueModification();
            break;
        }
        case MT_Deserialized:
        {
            OnValueModification();
            break;
        }
        }
    }
 
    void UpdateMessageSubscriptions()
    {
        bool needRender = m_DebugOverlayEnabled;
        GetSimContext().GetComponentManager().DynamicSubscriptionNonsync(MT_RenderSubmit, this, needRender);
    }
 
    bool IsMoveRequested() const override
    {
        return m_MoveRequest.m_Type != MoveRequest::NONE;
    }
 
    fixed GetSpeedMultiplier() const override
    {
        return m_SpeedMultiplier;
    }
 
    void SetSpeedMultiplier(fixed multiplier) override
    {
        m_SpeedMultiplier = std::min(multiplier, m_RunMultiplier);
        m_Speed = m_SpeedMultiplier.Multiply(GetWalkSpeed());
    }
 
    fixed GetSpeed() const override
    {
        return m_Speed;
    }
 
    fixed GetWalkSpeed() const override
    {
        return m_WalkSpeed;
    }
 
    fixed GetRunMultiplier() const override
    {
        return m_RunMultiplier;
    }
 
    CFixedVector2D EstimateFuturePosition(const fixed dt) const override
    {
        CmpPtr<ICmpPosition> cmpPosition(GetEntityHandle());
        if (!cmpPosition || !cmpPosition->IsInWorld())
            return CFixedVector2D();
 
        // TODO: formation members should perhaps try to use the controller's position.
 
        CFixedVector2D pos = cmpPosition->GetPosition2D();
        entity_angle_t angle = cmpPosition->GetRotation().Y;
        fixed speed = m_CurrentSpeed;
        // Copy the path so we don't change it.
        WaypointPath shortPath = m_ShortPath;
        WaypointPath longPath = m_LongPath;
 
        PerformMove(dt, cmpPosition->GetTurnRate(), shortPath, longPath, pos, speed, angle, 0);
        return pos;
    }
 
    fixed GetAcceleration() const override
    {
        return m_Acceleration;
    }
 
    void SetAcceleration(fixed acceleration) override
    {
        m_Acceleration = acceleration;
    }
 
    virtual entity_pos_t GetWeight() const
    {
        return m_TemplateWeight;
    }
 
    pass_class_t GetPassabilityClass() const override
    {
        return m_PassClass;
    }
 
    std::string GetPassabilityClassName() const override
    {
        return m_PassClassName;
    }
 
    void SetPassabilityClassName(const std::string& passClassName) override
    {
        if (!m_IsFormationController)
        {
            LOGWARNING("Only formation controllers can change their passability class");
            return;
        }
        SetPassabilityData(passClassName);
    }
 
    fixed GetCurrentSpeed() const override
    {
        return m_CurrentSpeed;
    }
 
    void SetFacePointAfterMove(bool facePointAfterMove) override
    {
        m_FacePointAfterMove = facePointAfterMove;
    }
 
    bool GetFacePointAfterMove() const override
    {
        return m_FacePointAfterMove;
    }
 
    void SetDebugOverlay(bool enabled) override
    {
        m_DebugOverlayEnabled = enabled;
        UpdateMessageSubscriptions();
    }
 
    bool MoveToPointRange(entity_pos_t x, entity_pos_t z, entity_pos_t minRange, entity_pos_t maxRange) override
    {
        return MoveTo(MoveRequest(CFixedVector2D(x, z), minRange, maxRange));
    }
 
    bool MoveToTargetRange(entity_id_t target, entity_pos_t minRange, entity_pos_t maxRange) override
    {
        return MoveTo(MoveRequest(target, minRange, maxRange));
    }
 
    void MoveToFormationOffset(entity_id_t controller, entity_pos_t x, entity_pos_t z) override
    {
        // Pass the controller to the move request anyways.
        MoveTo(MoveRequest(controller, CFixedVector2D(x, z)));
    }
 
    void SetMemberOfFormation(entity_id_t controller) override
    {
        m_FormationController = controller;
    }
 
    bool IsTargetRangeReachable(entity_id_t target, entity_pos_t minRange, entity_pos_t maxRange) override;
 
    void FaceTowardsPoint(entity_pos_t x, entity_pos_t z) override;
 
    /**
     * Clears the current MoveRequest - the unit will stop and no longer try and move.
     * This should never be called from UnitMotion, since MoveToX orders are given
     * by other components - these components should also decide when to stop.
     */
    void StopMoving() override
    {
        if (m_FacePointAfterMove)
        {
            CmpPtr<ICmpPosition> cmpPosition(GetEntityHandle());
            if (cmpPosition && cmpPosition->IsInWorld())
            {
                CFixedVector2D targetPos;
                if (ComputeTargetPosition(targetPos))
                    FaceTowardsPointFromPos(cmpPosition->GetPosition2D(), targetPos.X, targetPos.Y);
            }
        }
 
        m_MoveRequest = MoveRequest();
        m_ExpectedPathTicket.clear();
        m_LongPath.m_Waypoints.clear();
        m_ShortPath.m_Waypoints.clear();
    }
 
    entity_pos_t GetUnitClearance() const override
    {
        return m_Clearance;
    }
 
private:
    bool IsFormationMember() const
    {
        return m_FormationController != INVALID_ENTITY;
    }
 
    bool IsMovingAsFormation() const
    {
        return IsFormationMember() && m_MoveRequest.m_Type == MoveRequest::OFFSET;
    }
 
    bool IsFormationControllerMoving() const
    {
        CmpPtr<ICmpUnitMotion> cmpControllerMotion(GetSimContext(), m_FormationController);
        return cmpControllerMotion && cmpControllerMotion->IsMoveRequested();
    }
 
    entity_id_t GetGroup() const
    {
        return IsFormationMember() ? m_FormationController : GetEntityId();
    }
 
    void SetParticipateInPushing(bool pushing)
    {
        CmpPtr<ICmpUnitMotionManager> cmpUnitMotionManager(GetSystemEntity());
        m_Pushing = pushing && cmpUnitMotionManager->IsPushingActivated();
    }
 
    void SetPassabilityData(const std::string& passClassName)
    {
        m_PassClassName = passClassName;
        CmpPtr<ICmpPathfinder> cmpPathfinder(GetSystemEntity());
        if (cmpPathfinder)
        {
            m_PassClass = cmpPathfinder->GetPassabilityClass(passClassName);
            m_Clearance = cmpPathfinder->GetClearance(m_PassClass);
 
            CmpPtr<ICmpObstruction> cmpObstruction(GetEntityHandle());
            if (cmpObstruction)
                cmpObstruction->SetUnitClearance(m_Clearance);
        }
    }
 
    /**
     * Warns other components that our current movement will likely fail (e.g. we won't be able to reach our target)
     * This should only be called before the actual movement in a given turn, or units might both move and try to do things
     * on the same turn, leading to gliding units.
     */
    void MoveFailed()
    {
        // Don't notify if we are a formation member in a moving formation - we can occasionally be stuck for a long time
        // if our current offset is unreachable, but we don't want to end up stuck.
        // (If the formation controller has stopped moving however, we can safely message).
        if (IsFormationMember() && IsFormationControllerMoving())
            return;
 
        CMessageMotionUpdate msg(CMessageMotionUpdate::LIKELY_FAILURE);
        GetSimContext().GetComponentManager().PostMessage(GetEntityId(), msg);
    }
 
    /**
     * Warns other components that our current movement is likely over (i.e. we probably reached our destination)
     * This should only be called before the actual movement in a given turn, or units might both move and try to do things
     * on the same turn, leading to gliding units.
     */
    void MoveSucceeded()
    {
        // Don't notify if we are a formation member in a moving formation - we can occasionally be stuck for a long time
        // if our current offset is unreachable, but we don't want to end up stuck.
        // (If the formation controller has stopped moving however, we can safely message).
        if (IsFormationMember() && IsFormationControllerMoving())
            return;
 
        CMessageMotionUpdate msg(CMessageMotionUpdate::LIKELY_SUCCESS);
        GetSimContext().GetComponentManager().PostMessage(GetEntityId(), msg);
    }
 
    /**
     * Warns other components that our current movement was obstructed (i.e. we failed to move this turn).
     * This should only be called before the actual movement in a given turn, or units might both move and try to do things
     * on the same turn, leading to gliding units.
     */
    void MoveObstructed()
    {
        // Don't notify if we are a formation member in a moving formation - we can occasionally be stuck for a long time
        // if our current offset is unreachable, but we don't want to end up stuck.
        // (If the formation controller has stopped moving however, we can safely message).
        if (IsFormationMember() && IsFormationControllerMoving())
            return;
 
        CMessageMotionUpdate msg(m_FailedMovements >= VERY_OBSTRUCTED_THRESHOLD ?
            CMessageMotionUpdate::VERY_OBSTRUCTED : CMessageMotionUpdate::OBSTRUCTED);
        GetSimContext().GetComponentManager().PostMessage(GetEntityId(), msg);
    }
 
    /**
     * Increment the number of failed movements and notify other components if required.
     * @returns true if the failure was notified, false otherwise.
     */
    bool IncrementFailedMovementsAndMaybeNotify()
    {
        m_FailedMovements++;
        if (m_FailedMovements >= MAX_FAILED_MOVEMENTS)
        {
            MoveFailed();
            m_FailedMovements = 0;
            return true;
        }
        return false;
    }
 
    /**
     * If path would take us farther away from the goal than pos currently is, return false, else return true.
     */
    bool RejectFartherPaths(const PathGoal& goal, const WaypointPath& path, const CFixedVector2D& pos) const;
 
    bool ShouldAlternatePathfinder() const
    {
        return (m_FailedMovements == ALTERNATE_PATH_TYPE_DELAY) || ((MAX_FAILED_MOVEMENTS - ALTERNATE_PATH_TYPE_DELAY) % ALTERNATE_PATH_TYPE_EVERY == 0);
    }
 
    bool InShortPathRange(const PathGoal& goal, const CFixedVector2D& pos) const
    {
        return goal.DistanceToPoint(pos) < LONG_PATH_MIN_DIST;
    }
 
    entity_pos_t ShortPathSearchRange() const
    {
        u8 multiple = m_FailedMovements < SHORT_PATH_SEARCH_RANGE_INCREASE_DELAY ? 0 : m_FailedMovements - SHORT_PATH_SEARCH_RANGE_INCREASE_DELAY;
        fixed searchRange = SHORT_PATH_MIN_SEARCH_RANGE + SHORT_PATH_SEARCH_RANGE_INCREMENT * multiple;
        if (searchRange > SHORT_PATH_MAX_SEARCH_RANGE)
            searchRange = SHORT_PATH_MAX_SEARCH_RANGE;
        return searchRange;
    }
 
    /**
     * Handle the result of an asynchronous path query.
     */
    void PathResult(u32 ticket, const WaypointPath& path);
 
    void OnValueModification()
    {
        CmpPtr<ICmpValueModificationManager> cmpValueModificationManager(GetSystemEntity());
        if (!cmpValueModificationManager)
            return;
 
        m_WalkSpeed = cmpValueModificationManager->ApplyModifications(L"UnitMotion/WalkSpeed", m_TemplateWalkSpeed, GetEntityId());
        m_RunMultiplier = cmpValueModificationManager->ApplyModifications(L"UnitMotion/RunMultiplier", m_TemplateRunMultiplier, GetEntityId());
 
        // For MT_Deserialize compute m_Speed from the serialized m_SpeedMultiplier.
        // For MT_ValueModification and MT_OwnershipChanged, adjust m_SpeedMultiplier if needed
        // (in case then new m_RunMultiplier value is lower than the old).
        SetSpeedMultiplier(m_SpeedMultiplier);
    }
 
    /**
     * Check if we are at destination early in the turn, this both lets units react faster
     * and ensure that distance comparisons are done while units are not being moved
     * (otherwise they won't be commutative).
     */
    void OnTurnStart();
 
    void PreMove(CCmpUnitMotionManager::MotionState& state);
    void Move(CCmpUnitMotionManager::MotionState& state, fixed dt);
    void PostMove(CCmpUnitMotionManager::MotionState& state, fixed dt);
 
    /**
     * Returns true if we are possibly at our destination.
     * Since the concept of being at destination is dependent on why the move was requested,
     * UnitMotion can only ever hint about this, hence the conditional tone.
     */
    bool PossiblyAtDestination() const;
 
    /**
     * Process the move the unit will do this turn.
     * This does not send actually change the position.
     * @returns true if the move was obstructed.
     */
    bool PerformMove(fixed dt, const fixed& turnRate, WaypointPath& shortPath, WaypointPath& longPath, CFixedVector2D& pos, fixed& speed, entity_angle_t& angle, uint8_t pushingPressure) const;
 
    /**
     * Update other components on our speed.
     * (For performance, this should try to avoid sending messages).
     */
    void UpdateMovementState(entity_pos_t speed, entity_pos_t meanSpeed);
 
    /**
     * React if our move was obstructed.
     * @param moved - true if the unit still managed to move.
     * @returns true if the obstruction required handling, false otherwise.
     */
    bool HandleObstructedMove(bool moved);
 
    /**
     * Returns true if the target position is valid. False otherwise.
     * (this may indicate that the target is e.g. out of the world/dead).
     * NB: for code-writing convenience, if we have no target, this returns true.
     */
    bool TargetHasValidPosition(const MoveRequest& moveRequest) const;
    bool TargetHasValidPosition() const
    {
        return TargetHasValidPosition(m_MoveRequest);
    }
 
    /**
     * Computes the current location of our target entity (plus offset).
     * Returns false if no target entity or no valid position.
     */
    bool ComputeTargetPosition(CFixedVector2D& out, const MoveRequest& moveRequest) const;
    bool ComputeTargetPosition(CFixedVector2D& out) const
    {
        return ComputeTargetPosition(out, m_MoveRequest);
    }
 
    /**
     * Attempts to replace the current path with a straight line to the target,
     * if it's close enough and the route is not obstructed.
     */
    bool TryGoingStraightToTarget(const CFixedVector2D& from, bool updatePaths);
 
    /**
     * Returns whether our we need to recompute a path to reach our target.
     */
    bool PathingUpdateNeeded(const CFixedVector2D& from) const;
 
    /**
     * Rotate to face towards the target point, given the current pos
     */
    void FaceTowardsPointFromPos(const CFixedVector2D& pos, entity_pos_t x, entity_pos_t z);
 
    /**
     * Units in 'pushing' mode are marked as 'moving' in the obstruction manager.
     * Units in 'pushing' mode should skip them in checkMovement (to enable pushing).
     * However, units for which pushing is deactivated should collide against everyone.
     * Units that don't block movement never participate in pushing, but they also
     * shouldn't collide with pushing units.
     */
    bool ShouldCollideWithMovingUnits() const
    {
        return !m_Pushing && m_BlockMovement;
    }
 
    /**
     * Returns an appropriate obstruction filter for use with path requests.
     */
    ControlGroupMovementObstructionFilter GetObstructionFilter() const
    {
        return ControlGroupMovementObstructionFilter(ShouldCollideWithMovingUnits(), GetGroup());
    }
    /**
     * Filter a specific tag on top of the existing control groups.
     */
    SkipTagAndControlGroupObstructionFilter GetObstructionFilter(const ICmpObstructionManager::tag_t& tag) const
    {
        return SkipTagAndControlGroupObstructionFilter(tag, ShouldCollideWithMovingUnits(), GetGroup());
    }
 
    /**
     * Decide whether to approximate the given range from a square target as a circle,
     * rather than as a square.
     */
    bool ShouldTreatTargetAsCircle(entity_pos_t range, entity_pos_t circleRadius) const;
 
    /**
     * Create a PathGoal from a move request.
     * @returns true if the goal was successfully created.
     */
    bool ComputeGoal(PathGoal& out, const MoveRequest& moveRequest) const;
 
    /**
     * Compute a path to the given goal from the given position.
     * Might go in a straight line immediately, or might start an asynchronous path request.
     */
    void ComputePathToGoal(const CFixedVector2D& from, const PathGoal& goal);
 
    /**
     * Start an asynchronous long path query.
     */
    void RequestLongPath(const CFixedVector2D& from, const PathGoal& goal);
 
    /**
     * Start an asynchronous short path query.
     * @param extendRange - if true, extend the search range to at least the distance to the goal.
     */
    void RequestShortPath(const CFixedVector2D& from, const PathGoal& goal, bool extendRange);
 
    /**
     * General handler for MoveTo interface functions.
     */
    bool MoveTo(MoveRequest request);
 
    /**
     * Convert a path into a renderable list of lines
     */
    void RenderPath(const WaypointPath& path, std::vector<SOverlayLine>& lines, CColor color);
 
    void RenderSubmit(SceneCollector& collector);
};
 
REGISTER_COMPONENT_TYPE(UnitMotion)
 
bool CCmpUnitMotion::RejectFartherPaths(const PathGoal& goal, const WaypointPath& path, const CFixedVector2D& pos) const
{
    if (path.m_Waypoints.empty())
        return false;
 
    // Reject the new path if it does not lead us closer to the target's position.
    if (goal.DistanceToPoint(pos) <= goal.DistanceToPoint(CFixedVector2D(path.m_Waypoints.front().x, path.m_Waypoints.front().z)))
        return true;
 
    return false;
}
 
void CCmpUnitMotion::PathResult(u32 ticket, const WaypointPath& path)
{
    // Ignore obsolete path requests
    if (ticket != m_ExpectedPathTicket.m_Ticket || m_MoveRequest.m_Type == MoveRequest::NONE)
        return;
 
    Ticket::Type ticketType = m_ExpectedPathTicket.m_Type;
    m_ExpectedPathTicket.clear();
 
    // If we not longer have a position, we won't be able to do much.
    // Fail in the next Move() call.
    CmpPtr<ICmpPosition> cmpPosition(GetEntityHandle());
    if (!cmpPosition || !cmpPosition->IsInWorld())
        return;
    CFixedVector2D pos = cmpPosition->GetPosition2D();
 
    // Assume all long paths were towards the goal, and assume short paths were if there are no long waypoints.
    bool pathedTowardsGoal = ticketType == Ticket::LONG_PATH || m_LongPath.m_Waypoints.empty();
 
    // Check if we need to run the short-path hack (warning: tricky control flow).
    bool shortPathHack = false;
    if (path.m_Waypoints.empty())
    {
        // No waypoints means pathing failed. If this was a long-path, try the short-path hack.
        if (!pathedTowardsGoal)
            return;
        shortPathHack = ticketType == Ticket::LONG_PATH;
    }
    else if (PathGoal goal; pathedTowardsGoal && ComputeGoal(goal, m_MoveRequest) && RejectFartherPaths(goal, path, pos))
    {
        // Reject paths that would take the unit further away from the goal.
        // This assumes that we prefer being closer 'as the crow flies' to unreachable goals.
        // This is a hack of sorts around units 'dancing' between two positions (see e.g. #3144),
        // but never actually failing to move, ergo never actually informing unitAI that it succeeds/fails.
        // (for short paths, only do so if aiming directly for the goal
        // as sub-goals may be farther than we are).
 
        // If this was a long-path and we no longer have waypoints, try the short-path hack.
        if (!m_LongPath.m_Waypoints.empty())
            return;
        shortPathHack = ticketType == Ticket::LONG_PATH;
    }
 
    // Short-path hack: if the long-range pathfinder doesn't find an acceptable path, push a fake waypoint at the goal.
    // This means HandleObstructedMove will use the short-pathfinder to try and reach it,
    // and that may find a path as the vertex pathfinder is more precise.
    if (shortPathHack)
    {
        // If we're resorting to the short-path hack, the situation is dire. Most likely, the goal is unreachable.
        // We want to find a path or fail fast. Bump failed movements so the short pathfinder will run at max-range
        // right away. This is safe from a performance PoV because it can only happen if the target is unreachable to
        // the long-range pathfinder, which is rare, and since the entity will fail to move if the goal is actually unreachable,
        // the failed movements will be increased to MAX anyways, so just shortcut.
        m_FailedMovements = MAX_FAILED_MOVEMENTS - 2;
 
        CFixedVector2D targetPos;
        if (ComputeTargetPosition(targetPos))
            m_LongPath.m_Waypoints.emplace_back(Waypoint{ targetPos.X, targetPos.Y });
        return;
    }
 
    if (ticketType == Ticket::LONG_PATH)
    {
        m_LongPath = path;
        // Long paths don't properly follow diagonals because of JPS/the grid. Since units now take time turning,
        // they can actually slow down substantially if they have to do a one navcell diagonal movement,
        // which is somewhat common at the beginning of a new path.
        // For that reason, if the first waypoint is really close, check if we can't go directly to the second.
        if (m_LongPath.m_Waypoints.size() >= 2)
        {
            const Waypoint& firstWpt = m_LongPath.m_Waypoints.back();
            if (CFixedVector2D(firstWpt.x - pos.X, firstWpt.z - pos.Y).CompareLength(Pathfinding::NAVCELL_SIZE * 4) <= 0)
            {
                CmpPtr<ICmpPathfinder> cmpPathfinder(GetSystemEntity());
                ENSURE(cmpPathfinder);
                const Waypoint& secondWpt = m_LongPath.m_Waypoints[m_LongPath.m_Waypoints.size() - 2];
                if (cmpPathfinder->CheckMovement(GetObstructionFilter(), pos.X, pos.Y, secondWpt.x, secondWpt.z, m_Clearance, m_PassClass))
                    m_LongPath.m_Waypoints.pop_back();
            }
 
        }
    }
    else
        m_ShortPath = path;
 
    m_FollowKnownImperfectPathCountdown = 0;
 
    if (!pathedTowardsGoal)
        return;
 
    // Performance hack: If we were pathing towards the goal and this new path won't put us in range,
    // it's highly likely that we are going somewhere unreachable.
    // However, Move() will try to recompute the path every turn, which can be quite slow.
    // To avoid this, act as if our current path leads us to the correct destination.
    // NB: for short-paths, the problem might be that the search space is too small
    // but we'll still follow this path until the en and try again then.
    // Because we reject farther paths, it works out.
    if (PathingUpdateNeeded(pos))
    {
        // Inform other components early, as they might have better behaviour than waiting for the path to carry out.
        // Send OBSTRUCTED at first - moveFailed is likely to trigger path recomputation and we might end up
        // recomputing too often for nothing.
        if (!IncrementFailedMovementsAndMaybeNotify())
            MoveObstructed();
        // We'll automatically recompute a path when this reaches 0, as a way to improve behaviour.
        // (See D665 - this is needed because the target may be moving, and we should adjust to that).
        m_FollowKnownImperfectPathCountdown = KNOWN_IMPERFECT_PATH_RESET_COUNTDOWN;
    }
}
 
void CCmpUnitMotion::OnTurnStart()
{
    if (PossiblyAtDestination())
        MoveSucceeded();
    else if (!TargetHasValidPosition())
    {
        // Scrap waypoints - we don't know where to go.
        // If the move request remains unchanged and the target again has a valid position later on,
        // moving will be resumed.
        // Units may want to move to move to the target's last known position,
        // but that should be decided by UnitAI (handling MoveFailed), not UnitMotion.
        m_LongPath.m_Waypoints.clear();
        m_ShortPath.m_Waypoints.clear();
 
        MoveFailed();
    }
}
 
void CCmpUnitMotion::PreMove(CCmpUnitMotionManager::MotionState& state)
{
    state.ignore = !m_Pushing || !m_BlockMovement;
 
    state.wasObstructed = false;
    state.wentStraight = false;
 
    // If we were idle and will still be, no need for an update.
    state.needUpdate = state.cmpPosition->IsInWorld() &&
        (m_CurrentSpeed != fixed::Zero() || m_LastTurnSpeed != fixed::Zero() || m_MoveRequest.m_Type != MoveRequest::NONE);
 
    if (!m_BlockMovement)
        return;
 
    state.controlGroup = IsFormationMember() ? m_FormationController : INVALID_ENTITY;
 
    // Update moving flag, this is an internal construct used for pushing,
    // so it does not really reflect whether the unit is actually moving or not.
    state.isMoving = m_Pushing && m_MoveRequest.m_Type != MoveRequest::NONE;
    CmpPtr<ICmpObstruction> cmpObstruction(GetEntityHandle());
    if (cmpObstruction)
        cmpObstruction->SetMovingFlag(state.isMoving);
}
 
void CCmpUnitMotion::Move(CCmpUnitMotionManager::MotionState& state, fixed dt)
{
    PROFILE("Move");
 
    // If we're chasing a potentially-moving unit and are currently close
    // enough to its current position, and we can head in a straight line
    // to it, then throw away our current path and go straight to it.
    state.wentStraight = TryGoingStraightToTarget(state.initialPos, true);
 
    state.wasObstructed = PerformMove(dt, state.cmpPosition->GetTurnRate(), m_ShortPath, m_LongPath, state.pos, state.speed, state.angle, state.pushingPressure);
}
 
void CCmpUnitMotion::PostMove(CCmpUnitMotionManager::MotionState& state, fixed dt)
{
    // Update our speed over this turn so that the visual actor shows the correct animation.
    if (state.pos == state.initialPos)
    {
        if (state.angle != state.initialAngle)
            state.cmpPosition->TurnTo(state.angle);
        UpdateMovementState(fixed::Zero(), fixed::Zero());
    }
    else
    {
        // Update the Position component after our movement (if we actually moved anywhere)
        CFixedVector2D offset = state.pos - state.initialPos;
        state.cmpPosition->MoveAndTurnTo(state.pos.X, state.pos.Y, state.angle);
 
        // Calculate the mean speed over this past turn.
        UpdateMovementState(state.speed, offset.Length() / dt);
    }
 
    if (state.wasObstructed && HandleObstructedMove(state.pos != state.initialPos))
        return;
    else if (!state.wasObstructed && state.pos != state.initialPos)
        m_FailedMovements = 0;
 
    // If we moved straight, and didn't quite finish the path, reset - we'll update it next turn if still OK.
    if (state.wentStraight && !state.wasObstructed)
        m_ShortPath.m_Waypoints.clear();
 
    // We may need to recompute our path sometimes (e.g. if our target moves).
    // Since we request paths asynchronously anyways, this does not need to be done before moving.
    if (!state.wentStraight && PathingUpdateNeeded(state.pos))
    {
        PathGoal goal;
        if (ComputeGoal(goal, m_MoveRequest))
            ComputePathToGoal(state.pos, goal);
    }
    else if (m_FollowKnownImperfectPathCountdown > 0)
        --m_FollowKnownImperfectPathCountdown;
}
 
bool CCmpUnitMotion::PossiblyAtDestination() const
{
    if (m_MoveRequest.m_Type == MoveRequest::NONE)
        return false;
 
    CmpPtr<ICmpObstructionManager> cmpObstructionManager(GetSystemEntity());
    ENSURE(cmpObstructionManager);
 
    if (m_MoveRequest.m_Type == MoveRequest::POINT)
        return cmpObstructionManager->IsInPointRange(GetEntityId(), m_MoveRequest.m_Position.X, m_MoveRequest.m_Position.Y, m_MoveRequest.m_MinRange, m_MoveRequest.m_MaxRange, false);
    if (m_MoveRequest.m_Type == MoveRequest::ENTITY)
        return cmpObstructionManager->IsInTargetRange(GetEntityId(), m_MoveRequest.m_Entity, m_MoveRequest.m_MinRange, m_MoveRequest.m_MaxRange, false);
    if (m_MoveRequest.m_Type == MoveRequest::OFFSET)
    {
        CmpPtr<ICmpUnitMotion> cmpControllerMotion(GetSimContext(), m_MoveRequest.m_Entity);
        if (cmpControllerMotion && cmpControllerMotion->IsMoveRequested())
            return false;
 
        // In formation, return a match only if we are exactly at the target position.
        // Otherwise, units can go in an infinite "walzting" loop when the Idle formation timer
        // reforms them.
        CFixedVector2D targetPos;
        ComputeTargetPosition(targetPos);
        CmpPtr<ICmpPosition> cmpPosition(GetEntityHandle());
        return (targetPos-cmpPosition->GetPosition2D()).CompareLength(fixed::Zero()) <= 0;
    }
    return false;
}
 
bool CCmpUnitMotion::PerformMove(fixed dt, const fixed& turnRate, WaypointPath& shortPath, WaypointPath& longPath, CFixedVector2D& pos, fixed& speed, entity_angle_t& angle, uint8_t pushingPressure) const
{
    // If there are no waypoint, behave as though we were obstructed and let HandleObstructedMove handle it.
    if (shortPath.m_Waypoints.empty() && longPath.m_Waypoints.empty())
        return true;
 
    // Wrap the angle to (-Pi, Pi].
    while (angle > entity_angle_t::Pi())
        angle -= entity_angle_t::Pi() * 2;
    while (angle < -entity_angle_t::Pi())
        angle += entity_angle_t::Pi() * 2;
 
    CmpPtr<ICmpPathfinder> cmpPathfinder(GetSystemEntity());
    ENSURE(cmpPathfinder);
 
    fixed basicSpeed = m_Speed;
    // If in formation, run to keep up; otherwise just walk.
    if (IsMovingAsFormation())
        basicSpeed = m_Speed.Multiply(m_RunMultiplier);
 
    // If pushing pressure is applied, slow the unit down.
    if (pushingPressure)
    {
        // Values below this pressure don't slow the unit down (avoids slowing groups down).
        constexpr int pressureMinThreshold = 10;
 
        // Lower speed up to a floor to prevent units from getting stopped.
        // This helped pushing particularly for fast units, since they'll end up slowing down.
        constexpr int maxPressure = CCmpUnitMotionManager::MAX_PRESSURE - pressureMinThreshold - 80;
        constexpr entity_pos_t floorSpeed = entity_pos_t::FromFraction(3, 2);
        static_assert(maxPressure > 0);
 
        uint8_t slowdown = maxPressure - std::min(maxPressure, std::max(0, pushingPressure - pressureMinThreshold));
        basicSpeed = basicSpeed.Multiply(fixed::FromInt(slowdown) / maxPressure);
        // NB: lowering this too much will make the units behave a lot like viscous fluid
        // when the density becomes extreme. While perhaps realistic (and kind of neat),
        // it's not very helpful for gameplay. Empirically, a value of 1.5 avoids most of the effect
        // while still slowing down movement significantly, and seems like a good balance.
        // Min with the template speed to allow units that are explicitly absurdly slow.
        basicSpeed = std::max(std::min(m_TemplateWalkSpeed, floorSpeed), basicSpeed);
    }
 
    // TODO: would be nice to support terrain-dependent speed again.
    fixed maxSpeed = basicSpeed;
 
    fixed timeLeft = dt;
    fixed zero = fixed::Zero();
 
    ICmpObstructionManager::tag_t specificIgnore;
    if (m_MoveRequest.m_Type == MoveRequest::ENTITY)
    {
        CmpPtr<ICmpObstruction> cmpTargetObstruction(GetSimContext(), m_MoveRequest.m_Entity);
        if (cmpTargetObstruction)
            specificIgnore = cmpTargetObstruction->GetObstruction();
    }
 
    while (timeLeft > zero)
    {
        // If we ran out of path, we have to stop.
        if (shortPath.m_Waypoints.empty() && longPath.m_Waypoints.empty())
            break;
 
        CFixedVector2D target;
        if (shortPath.m_Waypoints.empty())
            target = CFixedVector2D(longPath.m_Waypoints.back().x, longPath.m_Waypoints.back().z);
        else
            target = CFixedVector2D(shortPath.m_Waypoints.back().x, shortPath.m_Waypoints.back().z);
 
        CFixedVector2D offset = target - pos;
 
        if (turnRate > zero && !offset.IsZero())
        {
            fixed angleDiff = angle - atan2_approx(offset.X, offset.Y);
            fixed absoluteAngleDiff = angleDiff.Absolute();
            if (absoluteAngleDiff > entity_angle_t::Pi())
                absoluteAngleDiff = entity_angle_t::Pi() * 2 - absoluteAngleDiff;
 
            // We only rotate to the instantTurnAngle angle. The rest we rotate during movement.
            if (absoluteAngleDiff > m_InstantTurnAngle)
            {
                // Stop moving when rotating this far.
                speed = zero;
 
                fixed maxRotation = turnRate.Multiply(timeLeft);
 
                // Figure out whether rotating will increase or decrease the angle, and how far we need to rotate in that direction.
                int direction = (entity_angle_t::Zero() < angleDiff && angleDiff <= entity_angle_t::Pi()) || angleDiff < -entity_angle_t::Pi() ? -1 : 1;
 
                // Can't rotate far enough, just rotate in the correct direction.
                if (absoluteAngleDiff - m_InstantTurnAngle > maxRotation)
                {
                    angle += maxRotation * direction;
                    if (angle * direction > entity_angle_t::Pi())
                        angle -= entity_angle_t::Pi() * 2 * direction;
                    break;
                }
                // Rotate towards the next waypoint and continue moving.
                angle = atan2_approx(offset.X, offset.Y);
                timeLeft = std::min(maxRotation, maxRotation - absoluteAngleDiff + m_InstantTurnAngle) / turnRate;
            }
            else
            {
                // Modify the speed depending on the angle difference.
                fixed sin, cos;
                sincos_approx(angleDiff, sin, cos);
                speed = speed.Multiply(cos);
                angle = atan2_approx(offset.X, offset.Y);
            }
        }
 
        // Work out how far we can travel in timeLeft.
        fixed accelTime = std::min(timeLeft, (maxSpeed - speed) / m_Acceleration);
        fixed accelDist = speed.Multiply(accelTime) + accelTime.Square().Multiply(m_Acceleration) / 2;
        fixed maxdist = accelDist + maxSpeed.Multiply(timeLeft - accelTime);
 
        // If the target is close, we can move there directly.
        fixed offsetLength = offset.Length();
        if (offsetLength <= maxdist)
        {
            if (cmpPathfinder->CheckMovement(GetObstructionFilter(specificIgnore), pos.X, pos.Y, target.X, target.Y, m_Clearance, m_PassClass))
            {
                pos = target;
 
                // Spend the rest of the time heading towards the next waypoint.
                // Either we still need to accelerate after, or we have reached maxSpeed.
                // The former is much less likely than the latter: usually we can reach
                // maxSpeed within one waypoint. So the Sqrt is not too bad.
                if (offsetLength <= accelDist)
                {
                    fixed requiredTime = (-speed + (speed.Square() + offsetLength.Multiply(m_Acceleration).Multiply(fixed::FromInt(2))).Sqrt()) / m_Acceleration;
                    timeLeft -= requiredTime;
                    speed += m_Acceleration.Multiply(requiredTime);
                }
                else
                {
                    timeLeft -= accelTime + (offsetLength - accelDist) / maxSpeed;
                    speed = maxSpeed;
                }
 
                if (shortPath.m_Waypoints.empty())
                    longPath.m_Waypoints.pop_back();
                else
                    shortPath.m_Waypoints.pop_back();
 
                continue;
            }
            else
            {
                // Error - path was obstructed.
                return true;
            }
        }
        else
        {
            // Not close enough, so just move in the right direction.
            offset.Normalize(maxdist);
            target = pos + offset;
 
            speed = std::min(maxSpeed, speed + m_Acceleration.Multiply(timeLeft));
 
            if (cmpPathfinder->CheckMovement(GetObstructionFilter(specificIgnore), pos.X, pos.Y, target.X, target.Y, m_Clearance, m_PassClass))
                pos = target;
            else
                return true;
 
            break;
        }
    }
    return false;
}
 
void CCmpUnitMotion::UpdateMovementState(entity_pos_t speed, entity_pos_t meanSpeed)
{
    CmpPtr<ICmpVisual> cmpVisual(GetEntityHandle());
    if (cmpVisual)
    {
        if (meanSpeed == fixed::Zero())
            cmpVisual->SelectMovementAnimation("idle", fixed::FromInt(1));
        else
            cmpVisual->SelectMovementAnimation(meanSpeed > (m_WalkSpeed / 2).Multiply(m_RunMultiplier + fixed::FromInt(1)) ? "run" : "walk", meanSpeed);
    }
 
    m_LastTurnSpeed = meanSpeed;
    m_CurrentSpeed = speed;
}
 
bool CCmpUnitMotion::HandleObstructedMove(bool moved)
{
    CmpPtr<ICmpPosition> cmpPosition(GetEntityHandle());
    if (!cmpPosition || !cmpPosition->IsInWorld())
        return false;
 
    // We failed to move, inform other components as they might handle it.
    // (don't send messages on the first failure, as that would be too noisy).
    // Also don't increment above the initial MoveObstructed message if we actually manage to move a little.
    if (!moved || m_FailedMovements < 2)
    {
        if (!IncrementFailedMovementsAndMaybeNotify() && m_FailedMovements >= 2)
            MoveObstructed();
    }
 
    PathGoal goal;
    if (!ComputeGoal(goal, m_MoveRequest))
        return false;
 
    // At this point we have a position in the world since ComputeGoal checked for that.
    CFixedVector2D pos = cmpPosition->GetPosition2D();
 
    // Assume that we are merely obstructed and the long path is salvageable, so try going around the obstruction.
    // This could be a separate function, but it doesn't really make sense to call it outside of here, and I can't find a name.
    // I use an IIFE to have nice 'return' semantics still.
    if ([&]() -> bool {
        // If the goal is close enough, we should ignore any remaining long waypoint and just
        // short path there directly, as that improves behaviour in general - see D2095).
        if (InShortPathRange(goal, pos))
            return false;
 
        // On rare occasions, when following a short path, we can end up in a position where
        // the short pathfinder thinks we are inside an obstruction (and can leave)
        // but the CheckMovement logic doesn't. I believe the cause is a small numerical difference
        // in their calculation, but haven't been able to pinpoint it precisely.
        // In those cases, the solution is to back away to prevent the short-pathfinder from being confused.
        // TODO: this should only be done if we're obstructed by a static entity.
        if (!m_ShortPath.m_Waypoints.empty() && m_FailedMovements == BACKUP_HACK_DELAY)
        {
            Waypoint next = m_ShortPath.m_Waypoints.back();
            CFixedVector2D backUp(pos.X - next.x, pos.Y - next.z);
            backUp.Normalize();
            next.x = pos.X + backUp.X;
            next.z = pos.Y + backUp.Y;
            m_ShortPath.m_Waypoints.push_back(next);
            return true;
        }
        // Delete the next waypoint if it's reasonably close,
        // because it might be blocked by units and thus unreachable.
        // NB: this number is tricky. Make it too high, and units start going down dead ends, which looks odd (#5795)
        // Make it too low, and they might get stuck behind other obstructed entities.
        // It also has performance implications because it calls the short-pathfinder.
        fixed skipbeyond = std::max(ShortPathSearchRange() / 3, Pathfinding::NAVCELL_SIZE * 8);
        if (m_LongPath.m_Waypoints.size() > 1 &&
            (pos - CFixedVector2D(m_LongPath.m_Waypoints.back().x, m_LongPath.m_Waypoints.back().z)).CompareLength(skipbeyond) < 0)
        {
            m_LongPath.m_Waypoints.pop_back();
        }
        else if (ShouldAlternatePathfinder())
        {
            // Recompute the whole thing occasionally, in case we got stuck in a dead end from removing long waypoints.
            RequestLongPath(pos, goal);
            return true;
        }
 
        if (m_LongPath.m_Waypoints.empty())
            return false;
 
        // Compute a short path in the general vicinity of the next waypoint, to help pathfinding in crowds.
        // The goal here is to manage to move in the general direction of our target, not to be super accurate.
        fixed radius = Clamp(skipbeyond/3, Pathfinding::NAVCELL_SIZE * 4, Pathfinding::NAVCELL_SIZE * 12);
        PathGoal subgoal = { PathGoal::CIRCLE, m_LongPath.m_Waypoints.back().x, m_LongPath.m_Waypoints.back().z, radius };
        RequestShortPath(pos, subgoal, false);
        return true;
    }()) return true;
 
    // If we couldn't use a workaround, try recomputing the entire path.
    ComputePathToGoal(pos, goal);
 
    return true;
}
 
bool CCmpUnitMotion::TargetHasValidPosition(const MoveRequest& moveRequest) const
{
    if (moveRequest.m_Type != MoveRequest::ENTITY)
        return true;
 
    CmpPtr<ICmpPosition> cmpPosition(GetSimContext(), moveRequest.m_Entity);
    return cmpPosition && cmpPosition->IsInWorld();
}
 
bool CCmpUnitMotion::ComputeTargetPosition(CFixedVector2D& out, const MoveRequest& moveRequest) const
{
    if (moveRequest.m_Type == MoveRequest::POINT)
    {
        out = moveRequest.m_Position;
        return true;
    }
 
    CmpPtr<ICmpPosition> cmpTargetPosition(GetSimContext(), moveRequest.m_Entity);
    if (!cmpTargetPosition || !cmpTargetPosition->IsInWorld())
        return false;
 
    if (moveRequest.m_Type == MoveRequest::OFFSET)
    {
        // There is an offset, so compute it relative to orientation
        entity_angle_t angle = cmpTargetPosition->GetRotation().Y;
        CFixedVector2D offset = moveRequest.GetOffset().Rotate(angle);
        out = cmpTargetPosition->GetPosition2D() + offset;
    }
    else
    {
        out = cmpTargetPosition->GetPosition2D();
        // Position is only updated after all units have moved & pushed.
        // Therefore, we may need to interpolate the target position, depending on when this call takes place during the turn:
        //  - On "Turn Start", we'll check positions directly without interpolation.
        //  - During movement, we'll call this for direct-pathing & we need to interpolate
        //    (this way, we move where the unit will end up at the end of _this_ turn, making it match on next turn start).
        //  - After movement, we'll call this to request paths & we need to interpolate
        //    (this way, we'll move where the unit ends up in the end of _next_ turn, making it a match in 2 turns).
        // TODO: This does not really aim many turns in advance, with orthogonal trajectories it probably should.
        CmpPtr<ICmpUnitMotion> cmpUnitMotion(GetSimContext(), moveRequest.m_Entity);
        CmpPtr<ICmpUnitMotionManager> cmpUnitMotionManager(GetSystemEntity());
        bool needInterpolation = cmpUnitMotion && cmpUnitMotion->IsMoveRequested() && cmpUnitMotionManager->ComputingMotion();
        if (needInterpolation)
        {
            // Add predicted movement.
            CFixedVector2D tempPos = out + (out - cmpTargetPosition->GetPreviousPosition2D());
            out = tempPos;
        }
    }
    return true;
}
 
bool CCmpUnitMotion::TryGoingStraightToTarget(const CFixedVector2D& from, bool updatePaths)
{
    // Assume if we have short paths we want to follow them.
    // Exception: offset movement (formations) generally have very short deltas
    // and to look good we need them to walk-straight most of the time.
    if (!IsFormationMember() && !m_ShortPath.m_Waypoints.empty())
        return false;
 
    CFixedVector2D targetPos;
    if (!ComputeTargetPosition(targetPos))
        return false;
 
    CmpPtr<ICmpPathfinder> cmpPathfinder(GetSystemEntity());
    if (!cmpPathfinder)
        return false;
 
    // Move the goal to match the target entity's new position
    PathGoal goal;
    if (!ComputeGoal(goal, m_MoveRequest))
        return false;
    goal.x = targetPos.X;
    goal.z = targetPos.Y;
    // (we ignore changes to the target's rotation, since only buildings are
    // square and buildings don't move)
 
    // Find the point on the goal shape that we should head towards
    CFixedVector2D goalPos = goal.NearestPointOnGoal(from);
 
    // Fail if the target is too far away
    if ((goalPos - from).CompareLength(DIRECT_PATH_RANGE) > 0)
        return false;
 
    // Check if there's any collisions on that route.
    // For entity goals, skip only the specific obstruction tag or with e.g. walls we might ignore too many entities.
    ICmpObstructionManager::tag_t specificIgnore;
    if (m_MoveRequest.m_Type == MoveRequest::ENTITY)
    {
        CmpPtr<ICmpObstruction> cmpTargetObstruction(GetSimContext(), m_MoveRequest.m_Entity);
        if (cmpTargetObstruction)
            specificIgnore = cmpTargetObstruction->GetObstruction();
    }
 
    // Check movement against units - we want to use the short pathfinder to walk around those if needed.
    if (specificIgnore.valid())
    {
        if (!cmpPathfinder->CheckMovement(GetObstructionFilter(specificIgnore), from.X, from.Y, goalPos.X, goalPos.Y, m_Clearance, m_PassClass))
            return false;
    }
    else if (!cmpPathfinder->CheckMovement(GetObstructionFilter(), from.X, from.Y, goalPos.X, goalPos.Y, m_Clearance, m_PassClass))
        return false;
 
    if (!updatePaths)
        return true;
 
    // That route is okay, so update our path
    m_LongPath.m_Waypoints.clear();
    m_ShortPath.m_Waypoints.clear();
    m_ShortPath.m_Waypoints.emplace_back(Waypoint{ goalPos.X, goalPos.Y });
    return true;
}
 
bool CCmpUnitMotion::PathingUpdateNeeded(const CFixedVector2D& from) const
{
    if (m_MoveRequest.m_Type == MoveRequest::NONE)
        return false;
 
    CFixedVector2D targetPos;
    if (!ComputeTargetPosition(targetPos))
        return false;
 
    if (m_FollowKnownImperfectPathCountdown > 0 && (!m_LongPath.m_Waypoints.empty() || !m_ShortPath.m_Waypoints.empty()))
        return false;
 
    if (PossiblyAtDestination())
        return false;
 
    // Get the obstruction shape and translate it where we estimate the target to be.
    ICmpObstructionManager::ObstructionSquare estimatedTargetShape;
    if (m_MoveRequest.m_Type == MoveRequest::ENTITY)
    {
        CmpPtr<ICmpObstruction> cmpTargetObstruction(GetSimContext(), m_MoveRequest.m_Entity);
        if (cmpTargetObstruction)
            cmpTargetObstruction->GetObstructionSquare(estimatedTargetShape);
    }
 
    estimatedTargetShape.x = targetPos.X;
    estimatedTargetShape.z = targetPos.Y;
 
    CmpPtr<ICmpObstruction> cmpObstruction(GetEntityHandle());
    ICmpObstructionManager::ObstructionSquare shape;
    if (cmpObstruction)
        cmpObstruction->GetObstructionSquare(shape);
 
    // Translate our own obstruction shape to our last waypoint or our current position, lacking that.
    if (m_LongPath.m_Waypoints.empty() && m_ShortPath.m_Waypoints.empty())
    {
        shape.x = from.X;
        shape.z = from.Y;
    }
    else
    {
        const Waypoint& lastWaypoint = m_LongPath.m_Waypoints.empty() ? m_ShortPath.m_Waypoints.front() : m_LongPath.m_Waypoints.front();
        shape.x = lastWaypoint.x;
        shape.z = lastWaypoint.z;
    }
 
    CmpPtr<ICmpObstructionManager> cmpObstructionManager(GetSystemEntity());
    ENSURE(cmpObstructionManager);
 
    // Increase the ranges with distance, to avoid recomputing every turn against units that are moving and far-away for example.
    entity_pos_t distance = (from - CFixedVector2D(estimatedTargetShape.x, estimatedTargetShape.z)).Length();
 
    // TODO: it could be worth computing this based on time to collision instead of linear distance.
    entity_pos_t minRange = std::max(m_MoveRequest.m_MinRange - distance / TARGET_UNCERTAINTY_MULTIPLIER, entity_pos_t::Zero());
    entity_pos_t maxRange = m_MoveRequest.m_MaxRange < entity_pos_t::Zero() ? m_MoveRequest.m_MaxRange :
        m_MoveRequest.m_MaxRange + distance / TARGET_UNCERTAINTY_MULTIPLIER;
 
    if (cmpObstructionManager->AreShapesInRange(shape, estimatedTargetShape, minRange, maxRange, false))
        return false;
 
    return true;
}
 
void CCmpUnitMotion::FaceTowardsPoint(entity_pos_t x, entity_pos_t z)
{
    CmpPtr<ICmpPosition> cmpPosition(GetEntityHandle());
    if (!cmpPosition || !cmpPosition->IsInWorld())
        return;
 
    CFixedVector2D pos = cmpPosition->GetPosition2D();
    FaceTowardsPointFromPos(pos, x, z);
}
 
void CCmpUnitMotion::FaceTowardsPointFromPos(const CFixedVector2D& pos, entity_pos_t x, entity_pos_t z)
{
    CFixedVector2D target(x, z);
    CFixedVector2D offset = target - pos;
    if (!offset.IsZero())
    {
        entity_angle_t angle = atan2_approx(offset.X, offset.Y);
 
        CmpPtr<ICmpPosition> cmpPosition(GetEntityHandle());
        if (!cmpPosition)
            return;
        cmpPosition->TurnTo(angle);
    }
}
 
// The pathfinder cannot go to "rounded rectangles" goals, which are what happens with square targets and a non-null range.
// Depending on what the best approximation is, we either pretend the target is a circle or a square.
// One needs to be careful that the approximated geometry will be in the range.
bool CCmpUnitMotion::ShouldTreatTargetAsCircle(entity_pos_t range, entity_pos_t circleRadius) const
{
    // Given a square, plus a target range we should reach, the shape at that distance
    // is a round-cornered square which we can approximate as either a circle or as a square.
    // Previously, we used the shape that minimized the worst-case error.
    // However that is unsage in some situations. So let's be less clever and
    // just check if our range is at least three times bigger than the circleradius
    return (range > circleRadius*3);
}
 
bool CCmpUnitMotion::ComputeGoal(PathGoal& out, const MoveRequest& moveRequest) const
{
    if (moveRequest.m_Type == MoveRequest::NONE)
        return false;
 
    CmpPtr<ICmpPosition> cmpPosition(GetEntityHandle());
    if (!cmpPosition || !cmpPosition->IsInWorld())
        return false;
 
    CFixedVector2D pos = cmpPosition->GetPosition2D();
 
    CFixedVector2D targetPosition;
    if (!ComputeTargetPosition(targetPosition, moveRequest))
        return false;
 
    ICmpObstructionManager::ObstructionSquare targetObstruction;
    if (moveRequest.m_Type == MoveRequest::ENTITY)
    {
        CmpPtr<ICmpObstruction> cmpTargetObstruction(GetSimContext(), moveRequest.m_Entity);
        if (cmpTargetObstruction)
            cmpTargetObstruction->GetObstructionSquare(targetObstruction);
    }
    targetObstruction.x = targetPosition.X;
    targetObstruction.z = targetPosition.Y;
 
    ICmpObstructionManager::ObstructionSquare obstruction;
    CmpPtr<ICmpObstruction> cmpObstruction(GetEntityHandle());
    if (cmpObstruction)
        cmpObstruction->GetObstructionSquare(obstruction);
    else
    {
        obstruction.x = pos.X;
        obstruction.z = pos.Y;
    }
 
    CmpPtr<ICmpObstructionManager> cmpObstructionManager(GetSystemEntity());
    ENSURE(cmpObstructionManager);
 
    out.x = targetObstruction.x;
    out.z = targetObstruction.z;
    out.hw = targetObstruction.hw;
    out.hh = targetObstruction.hh;
    out.u = targetObstruction.u;
    out.v = targetObstruction.v;
 
    if (moveRequest.m_MinRange > fixed::Zero() || moveRequest.m_MaxRange > fixed::Zero() ||
         targetObstruction.hw > fixed::Zero())
        out.type = PathGoal::SQUARE;
    else
    {
        out.type = PathGoal::POINT;
        return true;
    }
 
    entity_pos_t distance = cmpObstructionManager->DistanceBetweenShapes(obstruction, targetObstruction);
 
    entity_pos_t circleRadius = CFixedVector2D(targetObstruction.hw, targetObstruction.hh).Length();
 
    // TODO: because we cannot move to rounded rectangles, we have to make conservative approximations.
    // This means we might end up in a situation where cons(max-range) < min range < max range < cons(min-range)
    // When going outside of the min-range or inside the max-range, the unit will still go through the correct range
    // but if it moves fast enough, this might not be picked up by PossiblyAtDestination().
    // Fixing this involves moving to rounded rectangles, or checking more often in PerformMove().
    // In the meantime, one should avoid that 'Speed over a turn' > MaxRange - MinRange, in case where
    // min-range is not 0 and max-range is not infinity.
    if (distance < moveRequest.m_MinRange)
    {
        // Distance checks are nearest edge to nearest edge, so we need to account for our clearance
        // and we must make sure diagonals also fit so multiply by slightly more than sqrt(2)
        entity_pos_t goalDistance = moveRequest.m_MinRange + m_Clearance * 3 / 2;
 
        if (ShouldTreatTargetAsCircle(moveRequest.m_MinRange, circleRadius))
        {
            // We are safely away from the obstruction itself if we are away from the circumscribing circle
            out.type = PathGoal::INVERTED_CIRCLE;
            out.hw = circleRadius + goalDistance;
        }
        else
        {
            out.type = PathGoal::INVERTED_SQUARE;
            out.hw = targetObstruction.hw + goalDistance;
            out.hh = targetObstruction.hh + goalDistance;
        }
    }
    else if (moveRequest.m_MaxRange >= fixed::Zero() && distance > moveRequest.m_MaxRange)
    {
        if (ShouldTreatTargetAsCircle(moveRequest.m_MaxRange, circleRadius))
        {
            entity_pos_t goalDistance = moveRequest.m_MaxRange;
            // We must go in-range of the inscribed circle, not the circumscribing circle.
            circleRadius = std::min(targetObstruction.hw, targetObstruction.hh);
 
            out.type = PathGoal::CIRCLE;
            out.hw = circleRadius + goalDistance;
        }
        else
        {
            // The target is large relative to our range, so treat it as a square and
            // get close enough that the diagonals come within range
 
            entity_pos_t goalDistance = moveRequest.m_MaxRange * 2 / 3; // multiply by slightly less than 1/sqrt(2)
 
            out.type = PathGoal::SQUARE;
            entity_pos_t delta = std::max(goalDistance, m_Clearance + entity_pos_t::FromInt(4)/16); // ensure it's far enough to not intersect the building itself
            out.hw = targetObstruction.hw + delta;
            out.hh = targetObstruction.hh + delta;
        }
    }
    // Do nothing in particular in case we are already in range.
    return true;
}
 
void CCmpUnitMotion::ComputePathToGoal(const CFixedVector2D& from, const PathGoal& goal)
{
#if DISABLE_PATHFINDER
    {
        CmpPtr<ICmpPathfinder> cmpPathfinder (GetSimContext(), SYSTEM_ENTITY);
        CFixedVector2D goalPos = m_FinalGoal.NearestPointOnGoal(from);
        m_LongPath.m_Waypoints.clear();
        m_ShortPath.m_Waypoints.clear();
        m_ShortPath.m_Waypoints.emplace_back(Waypoint{ goalPos.X, goalPos.Y });
        return;
    }
#endif
 
    // If the target is close enough, hope that we'll be able to go straight next turn.
    if (!ShouldAlternatePathfinder() && TryGoingStraightToTarget(from, false))
    {
        // NB: since we may fail to move straight next turn, we should edge our bets.
        // Since the 'go straight' logic currently fires only if there's no short path,
        // we'll compute a long path regardless to make sure _that_ stays up to date.
        // (it's also extremely likely to be very fast to compute, so no big deal).
        m_ShortPath.m_Waypoints.clear();
        RequestLongPath(from, goal);
        return;
    }
 
    // Otherwise we need to compute a path.
 
    // If it's close then just do a short path, not a long path
    // TODO: If it's close on the opposite side of a river then we really
    // need a long path, so we shouldn't simply check linear distance
    // the check is arbitrary but should be a reasonably small distance.
    // We want to occasionally compute a long path if we're computing short-paths, because the short path domain
    // is bounded and thus it can't around very large static obstacles.
    // Likewise, we want to compile a short-path occasionally when the target is far because we might be stuck
    // on a navcell surrounded by impassable navcells, but the short-pathfinder could move us out of there.
    bool shortPath = InShortPathRange(goal, from);
    if (ShouldAlternatePathfinder())
        shortPath = !shortPath;
    if (shortPath)
    {
        m_LongPath.m_Waypoints.clear();
        // Extend the range so that our first path is probably valid.
        RequestShortPath(from, goal, true);
    }
    else
    {
        m_ShortPath.m_Waypoints.clear();
        RequestLongPath(from, goal);
    }
}
 
void CCmpUnitMotion::RequestLongPath(const CFixedVector2D& from, const PathGoal& goal)
{
    CmpPtr<ICmpPathfinder> cmpPathfinder(GetSystemEntity());
    if (!cmpPathfinder)
        return;
 
    // this is by how much our waypoints will be apart at most.
    // this value here seems sensible enough.
    PathGoal improvedGoal = goal;
    improvedGoal.maxdist = SHORT_PATH_MIN_SEARCH_RANGE - entity_pos_t::FromInt(1);
 
    cmpPathfinder->SetDebugPath(from.X, from.Y, improvedGoal, m_PassClass);
 
    m_ExpectedPathTicket.m_Type = Ticket::LONG_PATH;
    m_ExpectedPathTicket.m_Ticket = cmpPathfinder->ComputePathAsync(from.X, from.Y, improvedGoal, m_PassClass, GetEntityId());
}
 
void CCmpUnitMotion::RequestShortPath(const CFixedVector2D &from, const PathGoal& goal, bool extendRange)
{
    CmpPtr<ICmpPathfinder> cmpPathfinder(GetSystemEntity());
    if (!cmpPathfinder)
        return;
 
    entity_pos_t searchRange = ShortPathSearchRange();
    if (extendRange)
    {
        CFixedVector2D dist(from.X - goal.x, from.Y - goal.z);
        if (dist.CompareLength(searchRange - entity_pos_t::FromInt(1)) >= 0)
        {
            searchRange = dist.Length() + fixed::FromInt(1);
            if (searchRange > SHORT_PATH_MAX_SEARCH_RANGE)
                searchRange = SHORT_PATH_MAX_SEARCH_RANGE;
        }
    }
 
    m_ExpectedPathTicket.m_Type = Ticket::SHORT_PATH;
    m_ExpectedPathTicket.m_Ticket = cmpPathfinder->ComputeShortPathAsync(from.X, from.Y, m_Clearance, searchRange, goal, m_PassClass, ShouldCollideWithMovingUnits(), GetGroup(), GetEntityId());
}
 
bool CCmpUnitMotion::MoveTo(MoveRequest request)
{
    PROFILE("MoveTo");
 
    if (request.m_MinRange == request.m_MaxRange && !request.m_MinRange.IsZero())
        LOGWARNING("MaxRange must be larger than MinRange; See CCmpUnitMotion.cpp for more information");
 
    CmpPtr<ICmpPosition> cmpPosition(GetEntityHandle());
    if (!cmpPosition || !cmpPosition->IsInWorld())
        return false;
 
    PathGoal goal;
    if (!ComputeGoal(goal, request))
        return false;
 
    m_MoveRequest = request;
    m_FailedMovements = 0;
    m_FollowKnownImperfectPathCountdown = 0;
 
    ComputePathToGoal(cmpPosition->GetPosition2D(), goal);
    return true;
}
 
bool CCmpUnitMotion::IsTargetRangeReachable(entity_id_t target, entity_pos_t minRange, entity_pos_t maxRange)
{
    CmpPtr<ICmpPosition> cmpPosition(GetEntityHandle());
    if (!cmpPosition || !cmpPosition->IsInWorld())
        return false;
 
    MoveRequest request(target, minRange, maxRange);
    PathGoal goal;
    if (!ComputeGoal(goal, request))
        return false;
 
    CmpPtr<ICmpPathfinder> cmpPathfinder(GetSimContext(), SYSTEM_ENTITY);
    CFixedVector2D pos = cmpPosition->GetPosition2D();
    return cmpPathfinder->IsGoalReachable(pos.X, pos.Y, goal, m_PassClass);
}
 
 
void CCmpUnitMotion::RenderPath(const WaypointPath& path, std::vector<SOverlayLine>& lines, CColor color)
{
    bool floating = false;
    CmpPtr<ICmpPosition> cmpPosition(GetEntityHandle());
    if (cmpPosition)
        floating = cmpPosition->CanFloat();
 
    lines.clear();
    std::vector<float> waypointCoords;
    for (size_t i = 0; i < path.m_Waypoints.size(); ++i)
    {
        float x = path.m_Waypoints[i].x.ToFloat();
        float z = path.m_Waypoints[i].z.ToFloat();
        waypointCoords.push_back(x);
        waypointCoords.push_back(z);
        lines.push_back(SOverlayLine());
        lines.back().m_Color = color;
        SimRender::ConstructSquareOnGround(GetSimContext(), x, z, 1.0f, 1.0f, 0.0f, lines.back(), floating);
    }
    float x = cmpPosition->GetPosition2D().X.ToFloat();
    float z = cmpPosition->GetPosition2D().Y.ToFloat();
    waypointCoords.push_back(x);
    waypointCoords.push_back(z);
    lines.push_back(SOverlayLine());
    lines.back().m_Color = color;
    SimRender::ConstructLineOnGround(GetSimContext(), waypointCoords, lines.back(), floating);
 
}
 
void CCmpUnitMotion::RenderSubmit(SceneCollector& collector)
{
    if (!m_DebugOverlayEnabled)
        return;
 
    RenderPath(m_LongPath, m_DebugOverlayLongPathLines, OVERLAY_COLOR_LONG_PATH);
    RenderPath(m_ShortPath, m_DebugOverlayShortPathLines, OVERLAY_COLOR_SHORT_PATH);
 
    for (size_t i = 0; i < m_DebugOverlayLongPathLines.size(); ++i)
        collector.Submit(&m_DebugOverlayLongPathLines[i]);
 
    for (size_t i = 0; i < m_DebugOverlayShortPathLines.size(); ++i)
        collector.Submit(&m_DebugOverlayShortPathLines[i]);
}
 
#endif // INCLUDED_CCMPUNITMOTION