/// <summary>
/// If a pig can not move directly towards it's food, this method examines all surrounding cells
/// and determines which direction is the best to move in. In the following order:
/// 1. Move towards an empty cell in the closest direction to the closest food.
/// 2. If no cells are empty move towards the cell with the oldest rope on it.
/// 3. Unable to move to any nearby cell. Do nothing.
/// pre: Pig is unable to move towards the food, or there is rope in the adjacent cell.
/// post: Pig will move to a valid location, or not at all. Depending on the above circumstances.
/// </summary>
private void ExamineSurroundingCells()
{
const double DEFAULT_LOWEST_DIRECTION_DIFFERENCE = 360.00;
Echo nearestPigFood = FindNearest(typeof(PigFood));
double lowestDirectionDifference = 360.00; //default value 360 is a placeholder
Direction closestDirectionToFood = Direction.NORTH; //default value (Direction.NORTH) is a placeholder
int oldestNearbyRope = -1; //default value -1 is a placeholder
Direction oldestRopeDirection = Direction.NORTH; //default value (Direction.NORTH) is a placeholder
for (int i = 0; i < Direction.NUMBER_POSSIBLE; i++)
{
Direction direction = Direction.GetAdjacentCellDirection(i);
Cell adjacentCell = Cell.GetAdjacentCell(direction);
if (adjacentCell != null && CanMove(direction))
{
RopePiece ropeInCell = GetMyRopePiece(adjacentCell);
if (ropeInCell == null)
{
double adjacentCellDirection = direction.Degrees;
double foodDirection = nearestPigFood.direction.Degrees;
double differenceInDegrees = Math.Abs(foodDirection - adjacentCellDirection);
// The two lines below solve the '359 degrees is right next to 0 degrees' issue using basic maths.
if (differenceInDegrees > 180) // 180 being 180 degrees (DO NOT change)
{
differenceInDegrees = 360 - differenceInDegrees; // 360 being 360 degrees (DO NOT change)
}
if (lowestDirectionDifference > differenceInDegrees)
{
lowestDirectionDifference = differenceInDegrees;
closestDirectionToFood = direction;
}
}
else if (ropeInCell != null)
{
Pig ropeOwner = ropeInCell.OwnerPig;
int ropeAge = ropeInCell.GetDistanceFromOwner();
if (oldestNearbyRope < ropeAge)
{
oldestNearbyRope = ropeAge;
oldestRopeDirection = direction;
}
}
}
}
if (lowestDirectionDifference != DEFAULT_LOWEST_DIRECTION_DIFFERENCE) //If it has changed from default value, a valid direction has been found.
{
DropRope();
Move(closestDirectionToFood);
}
else
{
DropRope();
Move(oldestRopeDirection);
}
}
/// <summary>
/// Tests if this and the other pig are full brothers/sisters. That is,
/// tests that both pigs have the same two parents.
/// </summary>
/// <param name="possibleSibling"> A Pig ... or perhaps a null reference </param>
/// <returns> true if this pig and the other pig have the same two parents. </returns>
protected bool IsSibling(Pig pig)
{
if ((pig.mother == null) || (pig.father == null))
{
return(false);
}
if ((this.mother == pig.mother) && (this.father == pig.father))
{
return(true);
}
return(false);
}
/// <summary>
/// Tests to see if this object is indeed a child of possibleParent.
/// </summary>
/// <param name="possibleParent"> The Pig who's past is in question, or a null
/// reference </param>
/// <returns> true if this pig is a child of possibleParent </returns>
public bool IsParent(Pig possibleParent)
{
if (this.mother == possibleParent)
{
return(true);
}
if (this.father == possibleParent)
{
return(true);
}
return(false);
}
/// <summary>
/// Constructs a new piece of rope.
/// </summary>
/// <param name="pigWorld"></param>
/// <param name="ownerPig"></param>
/// <param name="position"></param>
public RopePiece(PigWorld pigWorld, Pig ownerPig, Position position)
{
this.ownerPig = ownerPig;
// Allow more than one ropePiece in a cell. (See comments at top of Cell.cs.)
OnlyOneObjectOfThisTypePerCell = false;
AddToWorld(pigWorld, position);
if (this.PigWorld == null)
{
throw new Exception("Error: Rope could not be created!");
}
}
