traffic.cpp

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/* traffic.cpp
 *
 * Micropolis, Unix Version.  This game was released for the Unix platform
 * in or about 1990 and has been modified for inclusion in the One Laptop
 * Per Child program.  Copyright (C) 1989 - 2007 Electronic Arts Inc.  If
 * you need assistance with this program, you may contact:
 *   http://wiki.laptop.org/go/Micropolis  or email  micropolis@laptop.org.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or (at
 * your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.  You should have received a
 * copy of the GNU General Public License along with this program.  If
 * not, see <http://www.gnu.org/licenses/>.
 *
 *             ADDITIONAL TERMS per GNU GPL Section 7
 *
 * No trademark or publicity rights are granted.  This license does NOT
 * give you any right, title or interest in the trademark SimCity or any
 * other Electronic Arts trademark.  You may not distribute any
 * modification of this program using the trademark SimCity or claim any
 * affliation or association with Electronic Arts Inc. or its employees.
 *
 * Any propagation or conveyance of this program must include this
 * copyright notice and these terms.
 *
 * If you convey this program (or any modifications of it) and assume
 * contractual liability for the program to recipients of it, you agree
 * to indemnify Electronic Arts for any liability that those contractual
 * assumptions impose on Electronic Arts.
 *
 * You may not misrepresent the origins of this program; modified
 * versions of the program must be marked as such and not identified as
 * the original program.
 *
 * This disclaimer supplements the one included in the General Public
 * License.  TO THE FULLEST EXTENT PERMISSIBLE UNDER APPLICABLE LAW, THIS
 * PROGRAM IS PROVIDED TO YOU "AS IS," WITH ALL FAULTS, WITHOUT WARRANTY
 * OF ANY KIND, AND YOUR USE IS AT YOUR SOLE RISK.  THE ENTIRE RISK OF
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 * ANY AUTHORIZED REPRESENTATIVE SHALL CREATE A WARRANTY.  SOME
 * JURISDICTIONS DO NOT ALLOW THE EXCLUSION OF OR LIMITATIONS ON IMPLIED
 * WARRANTIES OR THE LIMITATIONS ON THE APPLICABLE STATUTORY RIGHTS OF A
 * CONSUMER, SO SOME OR ALL OF THE ABOVE EXCLUSIONS AND LIMITATIONS MAY
 * NOT APPLY TO YOU.
 */
 
 
 
#include "micropolis.h"
 
 
 
 
short Micropolis::makeTrafficAt(int x, int y, ZoneType dest)
{
    Position pos;
    pos.posX = x;
    pos.posY = y;
 
    if (tryDrive(pos, dest)) { /* attempt to drive somewhere */
        addToTrafficDensityMap(); /* if sucessful, inc trafdensity */
        return 1;             /* traffic passed */
    }
 
    return 0;                 /* traffic failed */
}
 
 
short Micropolis::makeTraffic(int x, int y, ZoneType dest)
{
    Position startPos;
    startPos.posX = x;
    startPos.posY = y;
    return makeTraffic(startPos, dest);
}
 
 
short Micropolis::makeTraffic(const Position &startPos, ZoneType dest)
{
    curMapStackPointer = 0; // Clear position stack
 
    Position pos(startPos);
 
#if 0
      if ((!getRandom(2)) && findPerimeterTelecom(pos)) {
        /* printf("Telecom!\n"); */
        return 1;
      }
#endif
 
    if (findPerimeterRoad(&pos)) { /* look for road on zone perimeter */
 
        if (tryDrive(pos, dest)) { /* attempt to drive somewhere */
            addToTrafficDensityMap(); /* if sucessful, inc trafdensity */
            return 1;             /* traffic passed */
        }
 
        return 0;                 /* traffic failed */
    } else {
        return -1;                /* no road found */
    }
}
 
 
void Micropolis::addToTrafficDensityMap()
{
    /* For each saved position of the drive */
    while (curMapStackPointer > 0) {
 
        Position pos = pullPos();
        if (pos.testBounds()) {
 
            MapTile tile = map[pos.posX][pos.posY] & LOMASK;
 
            if (tile >= ROADBASE && tile < POWERBASE) {
                SimSprite *sprite;
 
                // Update traffic density.
                int traffic = trafficDensityMap.worldGet(pos.posX, pos.posY);
                traffic += 50;
                traffic = min(traffic, 240);
                trafficDensityMap.worldSet(pos.posX, pos.posY, (Byte)traffic);
 
                // Check for heavy traffic.
                if (traffic >= 240 && getRandom(5) == 0) {
 
                    trafMaxX = pos.posX;
                    trafMaxY = pos.posY;
 
                    /* Direct helicopter towards heavy traffic */
                    sprite = getSprite(SPRITE_HELICOPTER);
                    if (sprite != NULL && sprite->control == -1) {
 
                        sprite->destX = trafMaxX * 16;
                        sprite->destY = trafMaxY * 16;
 
                    }
                }
            }
        }
    }
}
 
 
void Micropolis::pushPos(const Position &pos)
{
    curMapStackPointer++;
    assert(curMapStackPointer < MAX_TRAFFIC_DISTANCE + 1);
    curMapStackXY[curMapStackPointer] = pos;
}
 
 
Position Micropolis::pullPos()
{
    assert(curMapStackPointer > 0);
    curMapStackPointer--;
    return curMapStackXY[curMapStackPointer + 1];
}
 
 
bool Micropolis::findPerimeterRoad(Position *pos)
{
    /* look for road on edges of zone */
    static const short PerimX[12] = {-1, 0, 1, 2, 2, 2, 1, 0,-1,-2,-2,-2};
    static const short PerimY[12] = {-2,-2,-2,-1, 0, 1, 2, 2, 2, 1, 0,-1};
    short tx, ty;
 
    for (short z = 0; z < 12; z++) {
 
        tx = pos->posX + PerimX[z];
        ty = pos->posY + PerimY[z];
 
        if (testBounds(tx, ty)) {
 
            if (roadTest(map[tx][ty])) {
 
                pos->posX = tx;
                pos->posY = ty;
 
                return true;
            }
        }
    }
 
    return false;
}
 
 
bool Micropolis::findPerimeterTelecom(const Position &pos)
{
    /* look for telecom on edges of zone */
    static const short PerimX[12] = {-1, 0, 1, 2, 2, 2, 1, 0,-1,-2,-2,-2};
    static const short PerimY[12] = {-2,-2,-2,-1, 0, 1, 2, 2, 2, 1, 0,-1};
    short tx, ty, tile;
 
    for (short z = 0; z < 12; z++) {
 
        tx = pos.posX + PerimX[z];
        ty = pos.posX + PerimY[z];
 
        if (testBounds(tx, ty)) {
 
            tile = map[tx][ty] & LOMASK;
            if (tile >= TELEBASE && tile <= TELELAST) {
                return true;
            }
        }
    }
 
    return false;
}
 
 
bool Micropolis::tryDrive(const Position &startPos, ZoneType destZone)
{
    Direction2 dirLast = DIR2_INVALID;
    Position drivePos(startPos);
 
    /* Maximum distance to try */
    for (short dist = 0; dist < MAX_TRAFFIC_DISTANCE; dist++) {
 
        Direction2 dir = tryGo(drivePos, dirLast);
        if (dir != DIR2_INVALID) { // we found a road
            drivePos.move(dir);
            dirLast = rotate180(dir);
 
            /* Save pos every other move.
             * This also relates to
             * Micropolis::trafficDensityMap::MAP_BLOCKSIZE
             */
            if (dist & 1) {
                pushPos(drivePos);
            }
 
            if (driveDone(drivePos, destZone)) { // if destination is reached
                return true; /* pass */
            }
 
        } else {
 
            if (curMapStackPointer > 0) { /* dead end, backup */
                curMapStackPointer--;
                dist += 3;
            } else {
                return false; /* give up at start  */
            }
 
        }
    }
 
    return false; /* gone MAX_TRAFFIC_DISTANCE */
}
 
 
Direction2 Micropolis::tryGo(const Position &pos, Direction2 dirLast)
{
    Direction2 directions[4];
 
    // Find connections from current position.
    Direction2 dir = DIR2_NORTH;
    int count = 0;
    for (int i = 0; i < 4; i++) {
        if (dir != dirLast && roadTest(getTileFromMap(pos, dir, DIRT))) {
            // found a road in an allowed direction
            directions[i] = dir;
            count++;
        } else {
            directions[i] = DIR2_INVALID;
        }
 
        dir = rotate90(dir);
    }
 
    if (count == 0) { // dead end
        return DIR2_INVALID;
    }
 
    // We have at least one way to go.
 
    if (count == 1) { // only one solution
        for (int i = 0; i < 4; i++) {
            if (directions[i] != DIR2_INVALID) {
                return directions[i];
            }
        }
    }
 
    // more than one choice, draw a random number.
    int i = getRandom16() & 3;
    while (directions[i] == DIR2_INVALID) {
        i = (i + 1) & 3;
    }
    return directions[i];
}
 
 
MapTile Micropolis::getTileFromMap(const Position &pos,
                                    Direction2 dir, MapTile defaultTile)
{
    switch (dir) {
 
        case DIR2_NORTH:
            if (pos.posY > 0) {
              return map[pos.posX][pos.posY - 1] & LOMASK;
            }
 
            return defaultTile;
 
        case DIR2_EAST:
            if (pos.posX < WORLD_W - 1) {
              return map[pos.posX + 1][pos.posY] & LOMASK;
            }
 
            return defaultTile;
 
        case DIR2_SOUTH:
            if (pos.posY < WORLD_H - 1) {
              return map[pos.posX][pos.posY + 1] & LOMASK;
            }
 
            return defaultTile;
 
        case DIR2_WEST:
            if (pos.posX > 0) {
              return map[pos.posX - 1][pos.posY] & LOMASK;
            }
 
            return defaultTile;
 
        default:
            return defaultTile;
 
    }
}
 
 
bool Micropolis::driveDone(const Position &pos, ZoneType destZone)
{
    // FIXME: Use macros to determine the zone type: residential, commercial or industrial.
    /* commercial, industrial, residential destinations */
    static const MapTile targetLow[3] = {COMBASE, LHTHR, LHTHR};
    static const MapTile targetHigh[3] = {NUCLEAR, PORT, COMBASE};
 
    assert(ZT_NUM_DESTINATIONS == LENGTH_OF(targetLow));
    assert(ZT_NUM_DESTINATIONS == LENGTH_OF(targetHigh));
 
    MapTile l = targetLow[destZone]; // Lowest acceptable tile value
    MapTile h = targetHigh[destZone]; // Highest acceptable tile value
 
    if (pos.posY > 0) {
        MapTile z = map[pos.posX][pos.posY - 1] & LOMASK;
        if (z >= l && z <= h) {
            return true;
        }
    }
 
    if (pos.posX < (WORLD_W - 1)) {
        MapTile z = map[pos.posX + 1][pos.posY] & LOMASK;
        if (z >= l && z <= h) {
            return true;
        }
    }
 
    if (pos.posY < (WORLD_H - 1)) {
        MapTile z = map[pos.posX][pos.posY + 1] & LOMASK;
        if (z >= l && z <= h) {
            return true;
        }
    }
 
    if (pos.posX > 0) {
        MapTile z = map[pos.posX - 1][pos.posY] & LOMASK;
        if (z >= l && z <= h) {
            return true;
        }
    }
 
    return false;
}
 
 
bool Micropolis::roadTest(MapValue mv)
{
    MapTile tile = mv & LOMASK;
 
    if (tile < ROADBASE || tile > LASTRAIL) {
        return false;
    }
 
    if (tile >= POWERBASE && tile < LASTPOWER) {
        return false;
    }
 
    return true;
}