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

       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_unload.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 "stratagus.h"
#include "unittype.h"
#include "player.h"
#include "unit.h"
#include "actions.h"
#include "map.h"
#include "interface.h"
#include "pathfinder.h"

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


// Flag for searching a valid tileset for unloading
#define LandUnitMask ( \
    MapFieldLandUnit | \
    MapFieldBuilding | \
    MapFieldCoastAllowed | \
    MapFieldWaterAllowed | \
    MapFieldUnpassable)

#define NavalUnitMask ( \
    MapFieldLandUnit | \
    MapFieldBuilding | \
    MapFieldCoastAllowed | \
    MapFieldLandAllowed | \
    MapFieldUnpassable)


static int FindUnloadPosition(int x, int y, int *resx, int *resy, int mask)
{
    int i;
    int n;
    int addx;
    int addy;

    addx = addy = 1;
    --x;
    for (n = 0; n < 2; ++n) {
        // Nobody: There was some code here to check for unloading units that can
        // only go on even tiles. It's useless, since we can only unload land units.
        for (i = addy; i--; ++y) {
            if (CheckedCanMoveToMask(x, y, mask)) {
                *resx = x;
                *resy = y;
                return 1;
            }
        }
        ++addx;
        for (i = addx; i--; ++x) {
            if (CheckedCanMoveToMask(x, y, mask)) {
                *resx = x;
                *resy = y;
                return 1;
            }
        }
        ++addy;
        for (i = addy; i--; --y) {
            if (CheckedCanMoveToMask(x, y, mask)) {
                *resx = x;
                *resy = y;
                return 1;
            }
        }
        ++addx;
        for (i = addx; i--; --x) {
            if (CheckedCanMoveToMask(x, y, mask)) {
                *resx = x;
                *resy = y;
                return 1;
            }
        }
        ++addy;
    }
    return 0;
}

int UnloadUnit(CUnit *unit)
{
    int x;
    int y;

    Assert(unit->Removed);
    if (!FindUnloadPosition(unit->X, unit->Y, &x, &y, unit->Type->MovementMask)) {
        return 0;
    }
    unit->Boarded = 0;
    unit->Place(x, y);
    return 1;
}

static int ClosestFreeCoast(int x, int y, int *resx, int *resy)
{
    int i;
    int addx;
    int addy;
    int nullx;
    int nully;
    int n;

    addx = addy = 1;
    if (Map.CoastOnMap(x, y) &&
            FindUnloadPosition(x, y, &nullx, &nully, LandUnitMask)) {
        *resx = x;
        *resy = y;
        return 1;
    }
    --x;
    // The maximum distance to the coast. We have to stop somewhere...
    n = 20;
    while (n--) {
        for (i = addy; i--; ++y) {
            if (x >= 0 && y >= 0 && x < Map.Info.MapWidth && y < Map.Info.MapHeight &&
                    Map.CoastOnMap(x, y) && !UnitOnMapTile(x, y) &&
                    FindUnloadPosition(x, y, &nullx, &nully, LandUnitMask)) {
                *resx = x;
                *resy = y;
                return 1;
            }
        }
        ++addx;
        for (i = addx; i--; ++x) {
            if (x >= 0 && y >= 0 && x < Map.Info.MapWidth && y < Map.Info.MapHeight &&
                    Map.CoastOnMap(x, y) && !UnitOnMapTile(x ,y) &&
                    FindUnloadPosition(x, y, &nullx, &nully, LandUnitMask)) {
                *resx = x;
                *resy = y;
                return 1;
            }
        }
        ++addy;
        for (i = addy; i--; --y) {
            if (x >= 0 && y >= 0 && x < Map.Info.MapWidth && y < Map.Info.MapHeight &&
                    Map.CoastOnMap(x, y) && !UnitOnMapTile(x, y) &&
                    FindUnloadPosition(x, y, &nullx, &nully, LandUnitMask)) {
                *resx = x;
                *resy = y;
                return 1;
            }
        }
        ++addx;
        for (i = addx; i--; --x) {
            if (x >= 0 && y >= 0 && x < Map.Info.MapWidth && y < Map.Info.MapHeight &&
                    Map.CoastOnMap(x, y) && !UnitOnMapTile(x, y) &&
                    FindUnloadPosition(x, y, &nullx, &nully, LandUnitMask)) {
                *resx = x;
                *resy = y;
                return 1;
            }
        }
        ++addy;
    }
    DebugPrint("Try clicking closer to an actual coast.\n");
    return 0;
}

static int ClosestFreeDropZone(CUnit *transporter, int x, int y, int *resx, int *resy)
{
    // Type (land/fly/naval) of the transporter
    int transporterType;
    // Type (land/fly/naval) of the units to unload
    int loadedType;

    // Check there are units onboard
    if (!transporter->UnitInside) {
        return 0;
    }

    transporterType = transporter->Type->UnitType;
    // Take the type of the onboard unit
    loadedType = transporter->UnitInside->Type->UnitType;

    // Don't move in thoses cases
    if ((transporterType == loadedType) || (loadedType == UnitTypeFly)) {
        *resx = x;
        *resy = y;
        return 1;
    }

    switch (transporterType) {
        case UnitTypeLand:
            // in this case, loadedType == UnitTypeSea
            return ClosestFreeCoast(x, y, resx, resy);
        case UnitTypeNaval:
            // Same ( but reversed... )
            return ClosestFreeCoast(x, y, resx, resy);
        case UnitTypeFly:
            // Here we have loadedType in [ UnitTypeLand,UnitTypeNaval ]
            if (loadedType == UnitTypeLand) {
                return FindUnloadPosition(x, y, resx, resy, LandUnitMask);
            } else {
                return FindUnloadPosition(x, y, resx, resy, NavalUnitMask);
            }
    }
    // Just to avoid a warning
    return 0;
}

static int MoveToDropZone(CUnit *unit)
{
    switch (DoActionMove(unit)) { // reached end-point?
        case PF_UNREACHABLE:
            return -1;
        case PF_REACHED:
            break;
        default:
            return 0;
    }

    Assert(unit->Orders[0]->Action == UnitActionUnload);
    return 1;
}

static void LeaveTransporter(CUnit *unit)
{
    int i;
    int stillonboard;
    CUnit *goal;

    stillonboard = 0;
    goal = unit->Orders[0]->Goal;
    //
    // Goal is the specific unit unit that you want to unload.
    // This can be NULL, in case you want to unload everything.
    //
    if (goal) {
        unit->Orders[0]->Goal = NoUnitP;
        if (goal->Destroyed) {
            DebugPrint("destroyed unit unloading?\n");
            goal->RefsDecrease();
            return;
        }
        goal->RefsDecrease();
        goal->X = unit->X;
        goal->Y = unit->Y;
        // Try to unload the unit. If it doesn't work there is no problem.
        if (UnloadUnit(goal)) {
            unit->BoardCount--;
        }
    } else {
        // Unload all units.
        goal = unit->UnitInside;
        for (i = unit->InsideCount; i; --i, goal = goal->NextContained) {
            if (goal->Boarded) {
                goal->X = unit->X;
                goal->Y = unit->Y;
                if (!UnloadUnit(goal)) {
                    ++stillonboard;
                } else {
                    unit->BoardCount--;
                }
            }
        }
    }
    if (IsOnlySelected(unit)) {
        SelectedUnitChanged();
    }

    // We still have some units to unload, find a piece of free coast.
    if (stillonboard) {
        // We tell it to unload at it's current position. This can't be done,
        // so it will search for a piece of free coast nearby.
        unit->Orders[0]->Action = UnitActionUnload;
        unit->Orders[0]->Goal = NoUnitP;
        unit->Orders[0]->X = unit->X;
        unit->Orders[0]->Y = unit->Y;
        unit->SubAction = 0;
    } else {
        unit->ClearAction();
    }
}

void HandleActionUnload(CUnit *unit)
{
    int i;
    int x;
    int y;

    if (!CanMove(unit)) {
        unit->SubAction = 2;
    }
    switch (unit->SubAction) {
        //
        // Move the transporter
        //
        case 0:
            if (!unit->Orders[0]->Goal) {
                if (!ClosestFreeDropZone(unit, unit->Orders[0]->X, unit->Orders[0]->Y,
                        &x, &y)) {
                    // Sorry... I give up.
                    unit->ClearAction();
                    return;
                }
                unit->Orders[0]->X = x;
                unit->Orders[0]->Y = y;
            }

            NewResetPath(unit);
            unit->SubAction = 1;
        case 1:
            // The Goal is the unit that we have to unload.
            if (!unit->Orders[0]->Goal) {
                // We have to unload everything
                if ((i = MoveToDropZone(unit))) {
                    if (i == PF_REACHED) {
                        if (++unit->SubAction == 1) {
                            unit->ClearAction();
                        }
                    } else {
                        unit->SubAction = 2;
                    }
                }
                break;
            }
        //
        // Leave the transporter
        //
        case 2:
            // FIXME: show still animations ?
            LeaveTransporter(unit);
            if (CanMove(unit) && unit->Orders[0]->Action != UnitActionStill) {
                HandleActionUnload(unit);
            }
            break;
    }
}

---