(*

 * Hedgewars, a free turn based strategy game

 * Copyright (c) 2004-2010 Andrey Korotaev <unC0Rr@gmail.com>

 *

 * 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; version 2 of the License

 *

 * 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, write to the Free Software

 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA

 *)

////////////////////////////////////////////////////////////////////////////////

procedure ChangeAmmo(Gear: PGear);

var slot, i: Longword;

begin

slot:= Gear^.MsgParam;

with PHedgehog(Gear^.Hedgehog)^ do

    begin

    Gear^.Message:= Gear^.Message and not gm_Slot;

    if ((Gear^.State and (gstAttacking or gstAttacked)) <> 0)

        or (MultiShootAttacks > 0)

        or ((Gear^.State and gstHHDriven) = 0) then exit;

    Gear^.Message:= Gear^.Message and not (gm_LJump or gm_HJump);

    if CurSlot = slot then

        begin

        i:= 0;

        repeat

        inc(CurAmmo);

        if (CurAmmo > cMaxSlotAmmoIndex) then

            begin

            CurAmmo:= 0;

            inc(i);

            TryDo(i < 2, 'Engine bug: no ammo in current slot', true)

            end;

        until (Ammo^[slot, CurAmmo].Count > 0) and (Team^.Clan^.TurnNumber > Ammoz[Ammo^[slot, CurAmmo].AmmoType].SkipTurns)

        end else

        begin

        i:= 0;

        // check whether there is ammo in slot

        while (i <= cMaxSlotAmmoIndex)

          and ((Ammo^[slot, i].Count = 0)

               or (Team^.Clan^.TurnNumber <= Ammoz[Ammo^[slot, i].AmmoType].SkipTurns)) do inc(i);

        if i <= cMaxSlotAmmoIndex then

            begin

            CurSlot:= slot;

            CurAmmo:= i

            end

        end

    end

end;

procedure HHSetWeapon(Gear: PGear);

var t: LongInt;

    weap: TAmmoType;

begin

weap:= TAmmoType(Gear^.MsgParam);

if PHedgehog(Gear^.Hedgehog)^.Team^.Clan^.TurnNumber <= Ammoz[weap].SkipTurns then exit; // weapon is not activated yet

Gear^.MsgParam:= Ammoz[weap].Slot;

t:= cMaxSlotAmmoIndex;

Gear^.Message:= Gear^.Message and not gm_Weapon;

with PHedgehog(Gear^.Hedgehog)^ do

    while (Ammo^[CurSlot, CurAmmo].AmmoType <> weap) and (t >= 0) do

        begin

        ChangeAmmo(Gear);

        dec(t)

        end;

ApplyAmmoChanges(PHedgehog(Gear^.Hedgehog)^)

end;

procedure HHSetTimer(Gear: PGear);

begin

Gear^.Message:= Gear^.Message and not gm_Timer;

with PHedgehog(Gear^.Hedgehog)^ do

    if (Ammo^[CurSlot, CurAmmo].Propz and ammoprop_Timerable) <> 0 then

        begin

        Ammo^[CurSlot, CurAmmo].Timer:= 1000 * Gear^.MsgParam;

        with CurrentTeam^ do

            ApplyAmmoChanges(Hedgehogs[CurrHedgehog]);

        end;

end;

procedure Attack(Gear: PGear);

var xx, yy: hwFloat;

    tmpGear: PVisualGear;

begin

bShowFinger:= false;

with Gear^,

     PHedgehog(Gear^.Hedgehog)^ do

     begin

     if ((State and gstHHDriven) <> 0)and

        ((State and (gstAttacked or gstHHChooseTarget)) = 0) and

        (((State and gstMoving) = 0) or

            // Allow attacks while moving on ammo with AltAttack

            ((CurAmmoGear <> nil) and ((Ammoz[CurAmmoGear^.AmmoType].Ammo.Propz and ammoprop_AltAttack) <> 0)) or

            ((Ammo^[CurSlot, CurAmmo].Propz and ammoprop_AttackInMove) <> 0)) and

        ((TargetPoint.X <> NoPointX) or ((Ammo^[CurSlot, CurAmmo].Propz and ammoprop_NeedTarget) = 0)) then

        begin

        State:= State or gstAttacking;

        if Power = cMaxPower then Message:= Message and not gm_Attack

        else if (Ammo^[CurSlot, CurAmmo].Propz and ammoprop_Power) = 0 then Message:= Message and not gm_Attack

        else begin

             if Power = 0 then

                begin

                AttackBar:= CurrentTeam^.AttackBar;

                PlaySound(sndThrowPowerUp)

                end;

             inc(Power)

             end;

        if ((Message and gm_Attack) <> 0) then exit;

        if (Ammo^[CurSlot, CurAmmo].Propz and ammoprop_Power) <> 0 then

           begin

           StopSound(sndThrowPowerUp);

           PlaySound(sndThrowRelease);

           end;

        xx:= SignAs(AngleSin(Angle), dX);

        yy:= -AngleCos(Angle);

        if ((Gear^.State and gstHHHJump) <> 0) then xx:= - xx;

        if Ammo^[CurSlot, CurAmmo].AttackVoice <> sndNone then

           PlaySound(Ammo^[CurSlot, CurAmmo].AttackVoice, CurrentTeam^.voicepack);

             case Ammo^[CurSlot, CurAmmo].AmmoType of

                      amGrenade: FollowGear:= AddGear(hwRound(X), hwRound(Y), gtAmmo_Bomb,    0, xx*Power/cPowerDivisor, yy*Power/cPowerDivisor, Ammo^[CurSlot, CurAmmo].Timer);

                      amMolotov: FollowGear:= AddGear(hwRound(X), hwRound(Y), gtMolotov,      0, xx*Power/cPowerDivisor, yy*Power/cPowerDivisor, 0);

                  amClusterBomb: FollowGear:= AddGear(hwRound(X), hwRound(Y), gtClusterBomb,  0, xx*Power/cPowerDivisor, yy*Power/cPowerDivisor, Ammo^[CurSlot, CurAmmo].Timer);

                      amGasBomb: FollowGear:= AddGear(hwRound(X), hwRound(Y), gtGasBomb,    0, xx*Power/cPowerDivisor, yy*Power/cPowerDivisor, Ammo^[CurSlot, CurAmmo].Timer);

                      amBazooka: FollowGear:= AddGear(hwRound(X), hwRound(Y), gtAmmo_Grenade, 0, xx*Power/cPowerDivisor, yy*Power/cPowerDivisor, 0);

                          amBee: FollowGear:= AddGear(hwRound(X), hwRound(Y), gtBee,          0, xx*Power/cPowerDivisor, yy*Power/cPowerDivisor, 0);

                      amShotgun: begin

                                 PlaySound(sndShotgunReload);

                                 CurAmmoGear:= AddGear(hwRound(X), hwRound(Y), gtShotgunShot,  0, xx * _0_5, yy * _0_5, 0);

                                 end;

                   amPickHammer: CurAmmoGear:= AddGear(hwRound(Gear^.X), hwRound(Gear^.Y) + cHHRadius, gtPickHammer, 0, _0, _0, 0);

                         amSkip: ParseCommand('/skip', true);

                         amRope: CurAmmoGear:= AddGear(hwRound(Gear^.X), hwRound(Gear^.Y), gtRope, 0, xx, yy, 0);

                         amMine: AddGear(hwRound(X) + hwSign(dX) * 7, hwRound(Y), gtMine, gstWait, SignAs(_0_02, dX), _0, 3000);

                       amDEagle: CurAmmoGear:= AddGear(hwRound(X + xx * cHHRadius), hwRound(Y + yy * cHHRadius), gtDEagleShot, 0, xx * _0_5, yy * _0_5, 0);

                      amSineGun: CurAmmoGear:= AddGear(hwRound(X + xx * cHHRadius), hwRound(Y + yy * cHHRadius), gtSineGunShot, 0, xx * _0_5, yy * _0_5, 0);

(*

Ok. Here's where I plan to go with this.

1) Restrict portal gun to X shots.

2) If on first shot, delete all existing gtPortal

3) On any other shot, delete any existing portals of type X%2, and spawn a new portal of type X%2 oriented at angle 180° from the portal gun.  It might possibly be worth linking portals with a Gear reference, to save time on scanning through the Gear list every time we need a portal.

*)

                    amPortalGun: CurAmmoGear:= AddGear(hwRound(X + xx * cHHRadius), hwRound(Y + yy * cHHRadius), gtPortal, 0, xx * _0_3, yy * _0_3, 0);

                  amSniperRifle: begin

                                 PlaySound(sndSniperReload);

                                 CurAmmoGear:= AddGear(hwRound(X + xx * cHHRadius), hwRound(Y + yy * cHHRadius), gtSniperRifleShot, 0, xx * _0_5, yy * _0_5, 0);

                                 end;

                     amDynamite: AddGear(hwRound(X) + hwSign(dX) * 7, hwRound(Y), gtDynamite, 0, SignAs(_0_03, dX), _0, 5000);

                    amFirePunch: CurAmmoGear:= AddGear(hwRound(X) + hwSign(dX) * 10, hwRound(Y), gtFirePunch, 0, xx, _0, 0);

                         amWhip: begin

                                 CurAmmoGear:= AddGear(hwRound(X) + hwSign(dX) * 10, hwRound(Y), gtWhip, 0, SignAs(_1, dX), - _0_8, 0);

                                 PlaySound(sndWhipCrack)

                                 end;

                  amBaseballBat: begin

                                 CurAmmoGear:= AddGear(hwRound(X) + hwSign(dX) * 10, hwRound(Y), gtShover, gsttmpFlag, xx * _0_5, yy * _0_5, 0);

                                 PlaySound(sndBaseballBat) // TODO: Only play if something is hit?

                                 end;

                    amParachute: CurAmmoGear:= AddGear(hwRound(X), hwRound(Y), gtParachute, 0, _0, _0, 0);

                    // we save Ammo^[CurSlot, CurAmmo].Pos (in this case: cursor direction) by using it as (otherwise irrelevant) X value of the new gear.

                    amAirAttack: AddGear(Ammo^[CurSlot, CurAmmo].Pos, 0, gtAirAttack, 0, _0, _0, 0);

                   amMineStrike: AddGear(Ammo^[CurSlot, CurAmmo].Pos, 0, gtAirAttack, 1, _0, _0, 0);

                    amBlowTorch: CurAmmoGear:= AddGear(hwRound(X), hwRound(Y), gtBlowTorch, 0, SignAs(_0_5, dX), _0, 0);

                       amGirder: CurAmmoGear:= AddGear(0, 0, gtGirder, Ammo^[CurSlot, CurAmmo].Pos, _0, _0, 0);

                     amTeleport: CurAmmoGear:= AddGear(Ammo^[CurSlot, CurAmmo].Pos, 0, gtTeleport, 0, _0, _0, 0);

                       amSwitch: CurAmmoGear:= AddGear(hwRound(X), hwRound(Y), gtSwitcher, 0, _0, _0, 0);

                       amMortar: begin

                playSound(sndMortar);

                FollowGear:= AddGear(hwRound(X), hwRound(Y), gtMortar,  0, xx*cMaxPower/cPowerDivisor, yy*cMaxPower/cPowerDivisor, 0);

                 end;

                      amRCPlane: begin

                                 CurAmmoGear:= AddGear(hwRound(X), hwRound(Y), gtRCPlane,  0, xx * cMaxPower / cPowerDivisor / 4, yy * cMaxPower / cPowerDivisor / 4, 0);

                                 CurAmmoGear^.SoundChannel:= LoopSound(sndRCPlane, nil)

                                 end;

                       amKamikaze: CurAmmoGear:= AddGear(hwRound(X), hwRound(Y), gtKamikaze, 0, xx * _0_5, yy * _0_5, 0);

                         amCake: CurAmmoGear:= AddGear(hwRound(X) + hwSign(dX) * 3, hwRound(Y), gtCake, 0, xx, _0, 0);

                    amSeduction: CurAmmoGear:= AddGear(hwRound(X + xx * cHHRadius * 2), hwRound(Y + yy * cHHRadius * 2), gtSeduction, 0, xx * _0_4, yy * _0_4, 0);

                   amWatermelon: FollowGear:= AddGear(hwRound(X), hwRound(Y), gtWatermelon,  0, xx*Power/cPowerDivisor, yy*Power/cPowerDivisor, Ammo^[CurSlot, CurAmmo].Timer);

                  amHellishBomb: FollowGear:= AddGear(hwRound(X), hwRound(Y), gtHellishBomb,    0, xx*Power/cPowerDivisor, yy*Power/cPowerDivisor, 0);

                       amNapalm: AddGear(Ammo^[CurSlot, CurAmmo].Pos, 0, gtAirAttack, 2, _0, _0, 0);

                        amDrill: FollowGear:= AddGear(hwRound(X), hwRound(Y), gtDrill, 0, xx*Power/cPowerDivisor, yy*Power/cPowerDivisor, 0);

                      amBallgun: CurAmmoGear:= AddGear(hwRound(X), hwRound(Y), gtBallgun,  0, xx * _0_5, yy * _0_5, 0);

                    amJetpack: CurAmmoGear:= AddGear(hwRound(X), hwRound(Y), gtJetpack, 0, _0, _0, 0);

                    amBirdy: begin

                             PlaySound(sndWhistle);

                             CurAmmoGear:= AddGear(hwRound(X), hwRound(Y) - 32, gtBirdy, 0, _0, _0, 0);

                             end;

                      amLowGravity: begin

                                    PlaySound(sndLowGravity);

                                    cGravity:= cMaxWindSpeed

                                    end;

                      amExtraDamage: cDamageModifier:= _1_5;

                      amInvulnerable: Invulnerable:= true;

                      amExtraTime: TurnTimeLeft:= TurnTimeLeft + 30000;

                      amLaserSight: cLaserSighting:= true;

                      amVampiric: cVampiric:= true;

                      amPiano: begin

                               FollowGear:= AddGear(TargetPoint.X, 0, gtPiano, 0, _0, _0, 0);

                               PauseMusic

                               end;

                  end;

        uStats.AmmoUsed(Ammo^[CurSlot, CurAmmo].AmmoType);

        if not (SpeechText = '') then

            begin

            tmpGear:= AddVisualGear(0, 0, vgtSpeechBubble);

            if tmpGear <> nil then

               begin

               tmpGear^.Text:= SpeechText;

               tmpGear^.Hedgehog:= Gear^.Hedgehog;

               tmpGear^.FrameTicks:= SpeechType;

               end;

            SpeechText:= ''

            end;

        Power:= 0;

        if (CurAmmoGear <> nil)

           and (((Ammo^[CurSlot, CurAmmo].Propz) and ammoprop_AltUse) = 0){check for dropping ammo from rope} then

           begin

           CurAmmoGear^.Ammo:= @(Ammo^[CurSlot, CurAmmo]);

           CurAmmoGear^.AmmoType:= CurAmmoGear^.Ammo^.AmmoType;

           Message:= Message or gm_Attack;

           CurAmmoGear^.Message:= Message

           end else begin

           if not CurrentTeam^.ExtDriven and

             ((Ammo^[CurSlot, CurAmmo].Propz and ammoprop_Power) <> 0) then SendIPC('a');

           AfterAttack;

           end

        end else Message:= Message and not gm_Attack;

     end

end;

procedure AfterAttack;

var s: shortstring;

begin

with CurrentHedgehog^.Gear^,

        CurrentHedgehog^ do

    begin

    State:= State and not gstAttacking;

    if ((Ammo^[CurSlot, CurAmmo].Propz) and ammoprop_Effect) = 0 then

        begin

        Inc(MultiShootAttacks);

        if (Ammo^[CurSlot, CurAmmo].NumPerTurn >= MultiShootAttacks) then

            begin

            s:= inttostr(Ammo^[CurSlot, CurAmmo].NumPerTurn + 1 - MultiShootAttacks);

            AddCaption(format(trmsg[sidRemaining], s), cWhiteColor, capgrpAmmostate);

            end;

        if (Ammo^[CurSlot, CurAmmo].NumPerTurn >= MultiShootAttacks) or

            ((GameFlags and gfMultiWeapon) <> 0) then

            begin

            isInMultiShoot:= true

            end

        else

            begin

            TurnTimeLeft:= Ammoz[Ammo^[CurSlot, CurAmmo].AmmoType].TimeAfterTurn;

            State:= State or gstAttacked;

            OnUsedAmmo(CurrentHedgehog^);

            end;

        end

    else

        begin

        OnUsedAmmo(CurrentHedgehog^);

        ApplyAmmoChanges(CurrentHedgehog^);

        end;

    AttackBar:= 0;

    end

end;

////////////////////////////////////////////////////////////////////////////////

procedure doStepHedgehogDead(Gear: PGear);

const frametime = 200;

      timertime = frametime * 6;

begin

if PHedgehog(Gear^.Hedgehog)^.Unplaced then exit;

if Gear^.Timer > 1 then

    begin

    AllInactive:= false;

    dec(Gear^.Timer);

    if (Gear^.Timer mod frametime) = 0 then inc(Gear^.Pos)

    end else

if Gear^.Timer = 1 then

    begin

    Gear^.State:= Gear^.State or gstNoDamage;

    doMakeExplosion(hwRound(Gear^.X), hwRound(Gear^.Y), 30, EXPLAutoSound);

    AddGear(hwRound(Gear^.X), hwRound(Gear^.Y), gtGrave, 0, _0, _0, 0)^.Hedgehog:= Gear^.Hedgehog;

    DeleteGear(Gear);

    SetAllToActive

    end else // Gear^.Timer = 0

    begin

    AllInactive:= false;

    Gear^.Z:= cCurrHHZ;

    RemoveGearFromList(Gear);

    InsertGearToList(Gear);

    PlaySound(sndByeBye, PHedgehog(Gear^.Hedgehog)^.Team^.voicepack);

    Gear^.Pos:= 0;

    Gear^.Timer:= timertime

    end

end;

////////////////////////////////////////////////////////////////////////////////

procedure doStepHedgehogGone(Gear: PGear);

const frametime = 65;

      timertime = frametime * 11;

begin

if PHedgehog(Gear^.Hedgehog)^.Unplaced then exit;

if Gear^.Timer > 1 then

    begin

    AllInactive:= false;

    dec(Gear^.Timer);

    if (Gear^.Timer mod frametime) = 0 then inc(Gear^.Pos)

    end else

if Gear^.Timer = 1 then

    begin

    DeleteGear(Gear);

    SetAllToActive

    end else // Gear^.Timer = 0

    begin

    AllInactive:= false;

    Gear^.Z:= cCurrHHZ;

    RemoveGearFromList(Gear);

    InsertGearToList(Gear);

    PlaySound(sndByeBye, PHedgehog(Gear^.Hedgehog)^.Team^.voicepack);

    PlaySound(sndWarp);

    Gear^.Pos:= 0;

    Gear^.Timer:= timertime

    end

end;

////////////////////////////////////////////////////////////////////////////////

procedure PickUp(HH, Gear: PGear);

var s: shortstring;

    a: TAmmoType;

    i: LongInt;

    vga: PVisualGear;

begin

Gear^.Message:= gm_Destroy;

PlaySound(sndShotgunReload);

case Gear^.Pos of

       posCaseUtility,

       posCaseAmmo: begin

                    a:= TAmmoType(Gear^.State);

                    AddAmmo(PHedgehog(HH^.Hedgehog)^, a);

// Possibly needs to check shared clan ammo game flag once added.

// On the other hand, no obvious reason that clan members shouldn't know what ammo another clan member picked up

                    if (not (PHedgehog(HH^.Hedgehog)^.Team^.ExtDriven 

                      or (PHedgehog(HH^.Hedgehog)^.BotLevel > 0)))

                      or (PHedgehog(HH^.Hedgehog)^.Team^.Clan^.ClanIndex = LocalClan)

                      or (GameType = gmtDemo)  then

                        begin

                        s:= trammo[Ammoz[a].NameId] + ' (+' + IntToStr(Ammoz[a].NumberInCase) + ')';

                        AddCaption(s, PHedgehog(HH^.Hedgehog)^.Team^.Clan^.Color, capgrpAmmoinfo);

                        // show ammo icon

                        vga:= AddVisualGear(hwRound(Gear^.X), hwRound(Gear^.Y), vgtAmmo);

                        if vga <> nil then

                            vga^.Frame:= Longword(a);

                        end;

                    end;

     posCaseHealth: begin

                    inc(HH^.Health, Gear^.Health);

                    PHedgehog(HH^.Hedgehog)^.Effects[hePoisoned] := false;

                    str(Gear^.Health, s);

                    s:= '+' + s;

                    AddCaption(s, PHedgehog(HH^.Hedgehog)^.Team^.Clan^.Color, capgrpAmmoinfo);

                    RenderHealth(PHedgehog(HH^.Hedgehog)^);

                    RecountTeamHealth(PHedgehog(HH^.Hedgehog)^.Team);

                    i:= 0;

                    while i < Gear^.Health do

                        begin

                        AddVisualGear(hwRound(HH^.X), hwRound(HH^.Y), vgtHealth);

                        inc(i, 5);

                        end;

                    end;

     end

end;

const StepTicks: LongWord = 0;

procedure HedgehogStep(Gear: PGear);

var PrevdX: LongInt;

begin

if ((Gear^.State and (gstAttacking or gstMoving)) = 0) then

   begin

   if isCursorVisible then

      with PHedgehog(Gear^.Hedgehog)^ do

        with Ammo^[CurSlot, CurAmmo] do

          begin

          if (Gear^.Message and gm_Left  ) <> 0 then

             Pos:= (Pos + Ammoz[AmmoType].PosCount - 1) mod Ammoz[AmmoType].PosCount

          else

          if (Gear^.Message and gm_Right ) <> 0 then

             Pos:= (Pos + 1) mod Ammoz[AmmoType].PosCount

          else exit;

          StepTicks:= 200;

          exit

          end;

    if ((Gear^.Message and gm_Animate) <> 0) then

        begin

        Gear^.Message:= 0;

        Gear^.State:= Gear^.State or gstAnimation;

        Gear^.Tag:= Gear^.MsgParam;

        Gear^.Timer:= 0;

        Gear^.Pos:= 0

        end;

   if ((Gear^.Message and gm_LJump ) <> 0) then

      begin

      Gear^.Message:= Gear^.Message and not gm_LJump;

      DeleteCI(Gear);

      if not TestCollisionYwithGear(Gear, -1) then

         if not TestCollisionXwithXYShift(Gear, _0, -2, hwSign(Gear^.dX)) then Gear^.Y:= Gear^.Y - _2 else

         if not TestCollisionXwithXYShift(Gear, _0, -1, hwSign(Gear^.dX)) then Gear^.Y:= Gear^.Y - _1;

      if not (TestCollisionXwithGear(Gear, hwSign(Gear^.dX))

         or   TestCollisionYwithGear(Gear, -1)) then

         begin

         Gear^.dY:= -_0_15;

         if not cArtillery then Gear^.dX:= SignAs(_0_15, Gear^.dX);

         Gear^.State:= Gear^.State or gstMoving or gstHHJumping;

         PlaySound(sndJump1, PHedgehog(Gear^.Hedgehog)^.Team^.voicepack);

         exit

         end;

      end;

   if ((Gear^.Message and gm_HJump ) <> 0) then

      begin

      DeleteCI(Gear);

      Gear^.Message:= Gear^.Message and not gm_HJump;

      Gear^.dY:= -_0_2;

      SetLittle(Gear^.dX);

      Gear^.State:= Gear^.State or gstMoving or gstHHJumping;

      PlaySound(sndJump3, PHedgehog(Gear^.Hedgehog)^.Team^.voicepack);

      exit

      end;

   PrevdX:= hwSign(Gear^.dX);

   if (Gear^.Message and gm_Left  )<>0 then Gear^.dX:= -cLittle else

   if (Gear^.Message and gm_Right )<>0 then Gear^.dX:=  cLittle else exit;

   if (Gear^.Message and (gm_Left or gm_Right)) <> 0 then

      begin

      StepSoundTimer:= cHHStepTicks;

      end;

   StepTicks:= cHHStepTicks;

   if PrevdX <> hwSign(Gear^.dX) then

      begin

      FollowGear:= Gear;

      exit

      end;

   DeleteCI(Gear); // must be after exit!! (see previous line)

   PHedgehog(Gear^.Hedgehog)^.visStepPos:= (PHedgehog(Gear^.Hedgehog)^.visStepPos + 1) and 7;

   if TestCollisionXwithGear(Gear, hwSign(Gear^.dX)) then