/// <summary>
/// Try to drive one tile in a random direction.
/// </summary>
/// <param name="pos">Current position.</param>
/// <param name="dirLast">Forbidden direction for movement (to prevent reversing).</param>
/// <returns>Direction of movement, DIR2_INVALID is returned if not moved.</returns>
private Direction2 tryGo(Position pos, Direction2 dirLast)
{
Direction2[] directions = new Direction2[4];
// Find connections from current position.
Direction2 dir = Direction2.DIR2_NORTH;
int count = 0;
int i;
for (i = 0; i < 4; i++)
{
if (dir != dirLast && roadTest(getTileFromMap(pos, dir, (ushort)MapTileCharacters.DIRT)))
{
// found a road in an allowed direction
directions[i] = dir;
count++;
}
else
{
directions[i] = Direction2.DIR2_INVALID;
}
dir = DirectionUtils.rotate90(dir);
}
if (count == 0)
{
// dead end
return(Direction2.DIR2_INVALID);
}
// We have at least one way to go.
if (count == 1)
{
// only one solution
for (i = 0; i < 4; i++)
{
if (directions[i] != Direction2.DIR2_INVALID)
{
return(directions[i]);
}
}
}
// more than one choice, draw a random number.
i = getRandom16() & 3;
while (directions[i] == Direction2.DIR2_INVALID)
{
i = (i + 1) & 3;
}
return(directions[i]);
}
/// <summary>
/// Try to drive to a destination.
/// </summary>
/// <param name="startPos">Starting position.</param>
/// <param name="destZone">Zonetype to drive to.</param>
/// <returns>Was drive succesful?</returns>
bool tryDrive(Position startPos, ZoneType destZone)
{
Direction2 dirLast = Direction2.DIR2_INVALID;
Position drivePos = new Position(startPos);
/* Maximum distance to try */
for (short dist = 0; dist < MAX_TRAFFIC_DISTANCE; dist++)
{
Direction2 dir = tryGo(drivePos, dirLast);
if (dir != Direction2.DIR2_INVALID)
{
// we found a road
drivePos.move(dir);
dirLast = DirectionUtils.rotate180(dir);
/* Save pos every other move.
* This also relates to
* Micropolis::trafficDensityMap::MAP_BLOCKSIZE
*/
if ((dist & 1) != 0)
{
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 */
}