____                _       __
    / __ )____  _____   | |     / /___ ___________
   / __  / __ \/ ___/   | | /| / / __ `/ ___/ ___/
  / /_/ / /_/ (__  )    | |/ |/ / /_/ / /  (__  )
 /_____/\____/____/     |__/|__/\__,_/_/  /____/

       A futuristic real-time strategy game.
          This file is part of Bos Wars.

(C) Copyright 2001-2007 by the Bos Wars and Stratagus Project. Distributed under the "GNU General Public License"

---

action_attack.cpp

Go to the documentation of this file.

//     ____                _       __               
//    / __ )____  _____   | |     / /___ ___________
//   / __  / __ \/ ___/   | | /| / / __ `/ ___/ ___/
//  / /_/ / /_/ (__  )    | |/ |/ / /_/ / /  (__  ) 
// /_____/\____/____/     |__/|__/\__,_/_/  /____/  
//                                              
//       A futuristic real-time strategy game.
//          This file is part of Bos Wars.
//
//
//      (c) Copyright 1998-2007 by Lutz Sammer and Jimmy Salmon
//
//      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; only 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.
//


/*----------------------------------------------------------------------------
--  Includes
----------------------------------------------------------------------------*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "stratagus.h"
#include "unittype.h"
#include "animation.h"
#include "player.h"
#include "unit.h"
#include "missile.h"
#include "actions.h"
#include "sound.h"
#include "map.h"
#include "pathfinder.h"

/*----------------------------------------------------------------------------
--  Defines
----------------------------------------------------------------------------*/

#define WEAK_TARGET      2  
#define MOVE_TO_TARGET   4  
#define ATTACK_TARGET    5  

/*----------------------------------------------------------------------------
--  Functions
----------------------------------------------------------------------------*/

void AnimateActionAttack(CUnit *unit)
{
    //  No animation.
    //  So direct fire missile.
    //  FIXME : wait a little.
    if (!unit->Type->Animations || !unit->Type->Animations->Attack) {
        FireMissile(unit);
        return;
    }
    UnitShowAnimation(unit, unit->Type->Animations->Attack);
}

static int CheckForDeadGoal(CUnit *unit)
{
    CUnit *goal; // unit->Order[0].Goal

    goal = unit->Orders[0]->Goal;
    // Position or valid target, it is ok.
    if (!goal || goal->IsVisibleAsGoal(unit->Player)) {
        return 0;
    }
    // Goal could be destroyed or unseen
    // So, cannot use type.
    unit->Orders[0]->X = goal->X;
    unit->Orders[0]->Y = goal->Y;
    unit->Orders[0]->MinRange = 0;
    unit->Orders[0]->Range = 0;

    goal->RefsDecrease();
    unit->Orders[0]->Goal = NoUnitP;

    //
    // If we have a saved order continue this saved order.
    //
    if (unit->SavedOrder.Action != UnitActionStill) {
        unit->ClearAction();
        *unit->Orders[0] = unit->SavedOrder;
        unit->SavedOrder.Action = UnitActionStill;
        unit->SavedOrder.Goal = NoUnitP;
        // Restart order state.
        unit->State = 0;
        NewResetPath(unit);
        return 1;
    }
//  NewResetPath(unit); // Should be useless.
    return 0;
}

static int CheckForTargetInRange(CUnit *unit)
{
    CUnit *goal;
    CUnit *temp;

    //
    // Target is dead?
    //
    if (CheckForDeadGoal(unit)) {
        return 1;
    }
    goal = unit->Orders[0]->Goal;

    //
    // No goal: if meeting enemy attack it.
    //
    if (!goal && unit->Orders[0]->Action != UnitActionAttackGround) {
        goal = AttackUnitsInReactRange(unit);
        if (goal) {
            if (unit->SavedOrder.Action == UnitActionStill) {
                // Save current command to continue it later.
                Assert(!unit->Orders[0]->Goal);
                unit->SavedOrder = *unit->Orders[0];
            }
            goal->RefsIncrease();
            unit->Orders[0]->Goal = goal;
            unit->Orders[0]->MinRange = unit->Type->MinAttackRange;
            unit->Orders[0]->Range = unit->Stats->Variables[ATTACKRANGE_INDEX].Max;
            unit->Orders[0]->X = unit->Orders[0]->Y = -1;
            unit->SubAction |= WEAK_TARGET; // weak target
            NewResetPath(unit);
        }

    //
    // Have a weak target, try a better target.
    //
    } else if (goal && (unit->SubAction & WEAK_TARGET)) {
        temp = AttackUnitsInReactRange(unit);
        if (temp && temp->Type->Priority > goal->Type->Priority) {
            goal->RefsDecrease();
            temp->RefsIncrease();
            if (unit->SavedOrder.Action == UnitActionStill) {
                // Save current command to come back.
                unit->SavedOrder = *unit->Orders[0];
                if ((goal = unit->SavedOrder.Goal)) {
                    unit->SavedOrder.X = goal->X + goal->Type->TileWidth / 2;
                    unit->SavedOrder.Y = goal->Y + goal->Type->TileHeight / 2;
                    unit->SavedOrder.MinRange = 0;
                    unit->SavedOrder.Range = 0;
                    unit->SavedOrder.Goal = NoUnitP;
                }
            }
            unit->Orders[0]->Goal = goal = temp;
            unit->Orders[0]->X = unit->Orders[0]->Y = -1;
            NewResetPath(unit);
        }
    }

    Assert(!unit->Type->Vanishes && !unit->Destroyed && !unit->Removed);
    Assert(unit->Orders[0]->Action == UnitActionAttack ||
        unit->Orders[0]->Action == UnitActionAttackGround);

    return 0;
}

static void MoveToTarget(CUnit *unit)
{
    CUnit *goal;
    int err;

    Assert(unit);
    Assert(!unit->Type->Vanishes && !unit->Destroyed && !unit->Removed);
    Assert(unit->Orders[0]->Action == UnitActionAttack ||
        unit->Orders[0]->Action == UnitActionAttackGround);
    Assert(CanMove(unit));
    Assert(unit->Orders[0]->Goal || (unit->Orders[0]->X != -1 && unit->Orders[0]->Y != -1));

    err = DoActionMove(unit);

    if (unit->Anim.Unbreakable) {
        return;
    }
    //
    // Look if we have reached the target.
    //
    goal = unit->Orders[0]->Goal;
    if (err == 0 && !goal) {
        // Check if we're in range when attacking a location and we are waiting
        if (MapDistanceToUnit(unit->Orders[0]->X, unit->Orders[0]->Y, unit) <
                unit->Stats->Variables[ATTACKRANGE_INDEX].Max) {
            err = PF_REACHED;
        }
    }
    if (err >= 0) {
        if (CheckForTargetInRange(unit)) {
            return;
        }
        return;
    }
    if (err == PF_REACHED) {
        //
        // Have reached target? FIXME: could use the new return code?
        //
        if (goal && MapDistanceBetweenUnits(unit, goal) <=
                unit->Stats->Variables[ATTACKRANGE_INDEX].Max) {
            // Reached another unit, now attacking it
            unit->State = 0;
            UnitHeadingFromDeltaXY(unit,
                goal->X + (goal->Type->TileWidth - 1) / 2 - unit->X,
                goal->Y + (goal->Type->TileHeight - 1) / 2 - unit->Y);
            unit->SubAction++;
            return;
        }
        //
        // Attacking ground.
        //
        if (!goal && unit->Orders[0]->Action == UnitActionAttackGround &&
                MapDistanceToUnit(unit->Orders[0]->X, unit->Orders[0]->Y, unit) <=
                    unit->Stats->Variables[ATTACKRANGE_INDEX].Max) {
            // Reached ground, now attacking it
            unit->State = 0;
            UnitHeadingFromDeltaXY(unit, unit->Orders[0]->X - unit->X,
                unit->Orders[0]->Y - unit->Y);
            unit->SubAction &= WEAK_TARGET;
            unit->SubAction |= ATTACK_TARGET;
            return;
        }
    }
    //
    // Unreachable.
    //
    if (err == PF_UNREACHABLE) {
        unit->State = 0;
        if (!goal) {
            //
            // When attack-moving we have to allow a bigger range
            //
            if (unit->Orders[0]->Range < Map.Info.MapWidth ||
                    unit->Orders[0]->Range < Map.Info.MapHeight) {
                // Try again with more range
                unit->Orders[0]->Range++;
                unit->Wait = 5;
                return;
            }
        }
    }
    //
    // Return to old task?
    //
    unit->State = unit->SubAction = 0;
    if (unit->Orders[0]->Goal) {
        unit->Orders[0]->Goal->RefsDecrease();
    }
    *unit->Orders[0] = unit->SavedOrder;
    NewResetPath(unit);

    // Must finish, if saved command finishes
    unit->SavedOrder.Action = UnitActionStill;
    unit->SavedOrder.Goal = NoUnitP;
}

static void AttackTarget(CUnit *unit)
{
    CUnit *goal; // unit->Order[0].Goal
    CUnit *temp;

    Assert(unit);
    Assert(unit->Orders[0]->Goal || (unit->Orders[0]->X != -1 && unit->Orders[0]->Y != -1));

    AnimateActionAttack(unit);
    if (unit->Anim.Unbreakable) {
        return;
    }
    //
    // Goal is "weak".
    //
    goal = unit->Orders[0]->Goal;
    if (!goal && unit->Orders[0]->Action == UnitActionAttackGround) {
        return;
    }

    //
    // Target is dead ? Change order ?
    //
    if (CheckForDeadGoal(unit)) {
        return;
    }
    goal = unit->Orders[0]->Goal;

    //
    // No target choose one.
    //
    if (!goal) {
        unit->State = 0;
        goal = AttackUnitsInReactRange(unit);
        //
        // No new goal, continue way to destination.
        //
        if (!goal) {
            // Return to old task ?
            if (unit->SavedOrder.Action != UnitActionStill) {
                unit->SubAction = 0;
                Assert(unit->Orders[0]->Goal == NoUnitP);
                *unit->Orders[0] = unit->SavedOrder;
                NewResetPath(unit);
                // Must finish, if saved command finishes
                unit->SavedOrder.Action = UnitActionStill;

                // This isn't supported
                Assert(unit->SavedOrder.Goal == NoUnitP);
                return;
            }
            unit->SubAction = MOVE_TO_TARGET;
            return;
        }

        //
        // Save current command to come back.
        //
        if (unit->SavedOrder.Action == UnitActionStill) {
            Assert(unit->Orders[0]->Goal == NULL);
            unit->SavedOrder = *unit->Orders[0];
        }

        goal->RefsIncrease();
        unit->Orders[0]->Goal = goal;
        unit->Orders[0]->X = unit->Orders[0]->Y = -1;
        unit->Orders[0]->MinRange = unit->Type->MinAttackRange;
        unit->Orders[0]->Range = unit->Stats->Variables[ATTACKRANGE_INDEX].Max;
        NewResetPath(unit);
        unit->SubAction |= WEAK_TARGET;

    //
    // Have a weak target, try a better target.
    // FIXME: if out of range also try another target quick
    //
    } else if (goal && (unit->SubAction & WEAK_TARGET)) {
        temp = AttackUnitsInReactRange(unit);
        if (temp && temp->Type->Priority > goal->Type->Priority) {
            goal->RefsDecrease();
            temp->RefsIncrease();

            if (unit->SavedOrder.Action == UnitActionStill) {
                // Save current order to come back or to continue it.
                unit->SavedOrder = *unit->Orders[0];
                if ((goal = unit->SavedOrder.Goal)) {
                    DebugPrint("Have goal to come back %d\n" _C_
                        UnitNumber(goal));
                    unit->SavedOrder.X = goal->X + goal->Type->TileWidth / 2;
                    unit->SavedOrder.Y = goal->Y + goal->Type->TileHeight / 2;
                    unit->SavedOrder.MinRange = 0;
                    unit->SavedOrder.Range = 0;
                    unit->SavedOrder.Goal = NoUnitP;
                }
            }
            unit->Orders[0]->Goal = goal = temp;
            unit->Orders[0]->X = unit->Orders[0]->Y = -1;
            unit->Orders[0]->MinRange = unit->Type->MinAttackRange;
            unit->SubAction = MOVE_TO_TARGET;
            NewResetPath(unit);
        }
    }

    //
    // Still near to target, if not goto target.
    //
    if (MapDistanceBetweenUnits(unit, goal) > unit->Stats->Variables[ATTACKRANGE_INDEX].Max) {
        if (unit->SavedOrder.Action == UnitActionStill) {
            // Save current order to come back or to continue it.
            unit->SavedOrder = *unit->Orders[0];
            if ((temp = unit->SavedOrder.Goal)) {
                DebugPrint("Have goal to come back %d\n" _C_
                    UnitNumber(temp));
                unit->SavedOrder.X = temp->X + temp->Type->TileWidth / 2;
                unit->SavedOrder.Y = temp->Y + temp->Type->TileHeight / 2;
                unit->SavedOrder.MinRange = 0;
                unit->SavedOrder.Range = 0;
                unit->SavedOrder.Goal = NoUnitP;
            }
        }
        NewResetPath(unit);
        unit->Frame = 0;
        unit->State = 0;
        unit->SubAction &= WEAK_TARGET;
        unit->SubAction |= MOVE_TO_TARGET;
    }
    if (MapDistanceBetweenUnits(unit, goal) < unit->Type->MinAttackRange) {
        unit->SubAction = MOVE_TO_TARGET;
    }

    //
    // Turn always to target
    //
    if (goal) {
        UnitHeadingFromDeltaXY(unit,
            goal->X + (goal->Type->TileWidth - 1) / 2 - unit->X,
            goal->Y + (goal->Type->TileHeight - 1) / 2 - unit->Y);
    }
}

void HandleActionAttack(CUnit *unit)
{
    int dist;          // dist between unit and unit->Orders[0]->Goal.

    Assert(unit->Orders[0]->Action == UnitActionAttackGround ||
        unit->Orders[0]->Action == UnitActionAttack);
    Assert(unit->Orders[0]->Goal || (unit->Orders[0]->X != -1 && unit->Orders[0]->Y != -1));

    if (unit->Wait) {
        unit->Wait--;
        return;
    }

    switch (unit->SubAction) {
        //
        // First entry
        //
        case 0:
            // did Order change ?
            if (CheckForTargetInRange(unit)) {
                return;
            }
            // Can we already attack ?
            if (unit->Orders[0]->Goal) {
                dist = MapDistanceBetweenUnits(unit, unit->Orders[0]->Goal);
                if (unit->Type->MinAttackRange < dist && dist <= unit->Stats->Variables[ATTACKRANGE_INDEX].Max) {
                    UnitHeadingFromDeltaXY(unit,
                        unit->Orders[0]->Goal->X + (unit->Orders[0]->Goal->Type->TileWidth - 1) / 2 - unit->X,
                        unit->Orders[0]->Goal->Y + (unit->Orders[0]->Goal->Type->TileHeight - 1) / 2 - unit->Y);
                    unit->SubAction = ATTACK_TARGET;
                    AttackTarget(unit);
                    return;
                }
            }
            unit->SubAction = MOVE_TO_TARGET;
            NewResetPath(unit);
            //
            // FIXME: should use a reachable place to reduce pathfinder time.
            //
            Assert(unit->State == 0);
            // FALL THROUGH
        //
        // Move near to the target.
        //
        case MOVE_TO_TARGET:
        case MOVE_TO_TARGET + WEAK_TARGET:
            if (!CanMove(unit)) {
                // Release order.
                if (unit->Orders[0]->Goal) {
                    unit->Orders[0]->Goal->RefsDecrease();
                }
                *unit->Orders[0] = unit->SavedOrder;
                unit->SavedOrder.Action = UnitActionStill;
                unit->SavedOrder.Goal = NoUnitP;
                unit->State = 0;
                unit->SubAction = 0;
                NewResetPath(unit);
                return;
            }
            MoveToTarget(unit);
            break;

        //
        // Attack the target.
        //
        case ATTACK_TARGET:
        case ATTACK_TARGET + WEAK_TARGET:
            AttackTarget(unit);
            break;

        case WEAK_TARGET:
            DebugPrint("FIXME: wrong entry.\n");
            break;
    }
}

---