Package model

Class Ghost

java.lang.Object

model.Actor

model.Ghost

public abstract class Ghost
extends Actor

A ghost in the game. This abstract class models the common behaviors and attributes of all ghosts including their appearance and different behavioral states:

- WAIT: The ghost is not currently present in the maze, its `delay` specifies how long before it enters.

- CHASE: The ghost is actively seeking PacMann. Catching up to PacMann will stop the round.

- FLEE: The ghost is running away to its designated location on the board. If PacMann catches up to this ghost, it will leave the board and enter its WAIT state.

Subclasses are responsible for specifying the `target()` vertices of that ghost in its CHASE and FLEE states.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	Ghost.GhostState	The three possible behavior states of ghosts

Nested classes/interfaces inherited from class model.Actor

Actor.DPair, Actor.Location

Field Summary

Fields

Modifier and Type	Field	Description
protected double	fleeTimeRemaining	When in the FLEE state, the number of milliseconds remaining before this ghost returns to its CHASE state
private final Color	ghostColor	The color of this ghost in its CHASE state
private List<MazeGraph.MazeEdge>	guidancePath	The edges comprising the most recently calculated path to this ghosts' `target()`
private final int	initialDelay	The total number of milliseconds before this ghost enters the maze in its CHASE state
protected Ghost.GhostState	state	The current behavioral state of this ghost
private double	waitTimeRemaining	When in the FLEE state, the number of milliseconds remaining before this ghost returns to its CHASE state

Fields inherited from class model.Actor

location, model

Constructor Summary

Constructors

Constructor	Description
Ghost(GameModel model, Color ghostColor, int initialDelay)	Construct a ghost associated to the given `model` with specified color and initial delay

Method Summary

Modifier and Type	Method	Description
double	baseSpeed()	Return the current base speed of this actor, before factoring in the weight of the edge they are traversing.
Color	color()	Return this ghost's color (for painting)
double	fleeTimeRemaining()	Return the amount of time remaining on this ghost's FLEE timer
Actor.DPair	getBoundingBoxUL()	In their WAIT state, the ghosts move from side to side in their box, otherwise, their bounding box location is delegated up to `Actor.getBoundingBoxUL`.
List<MazeGraph.MazeEdge>	guidancePath()	Return the list of Edges in this actor's current planned path through the maze (if any).
double	maxPropagationTime()	Return the amount of game time (in ms) that this actor is able to travel at its current speed before reaching a vertex or changing state.
MazeGraph.MazeEdge	nextEdge()	Returns the first edge along the shortest path from this ghost's `currentVertex()` to its `target()`.
void	propagate(double dt)	Calculate the new position for this actor after `ms` milliseconds of game time have elapsed.
void	reset()	Transition this ghost to its WAIT state and reset the `waitTimeRemaining` to this ghost's `INITIAL_DELAY`
void	respawn()	Transition this ghost to its WAIT state when it is caught in its FLEE state, and resets `waitTimeRemaining`.
void	startFlee()	Transition this ghost to its FLEE state and reset the `fleeTimeRemaining`.
Ghost.GhostState	state()	Return the current state of this ghost
protected abstract MazeGraph.MazeVertex	target()	Return the vertex that this ghost is targeting
void	visitVertex(MazeGraph.MazeVertex v)	Ghosts do not take any actions when visiting vertices
double	waitTimeRemaining()	Return the amount of time remaining on this ghost's WAIT timer

Methods inherited from class model.Actor

currentEdge, edgeSpeed, location, nearestVertex, traverseEdge

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

state

protected Ghost.GhostState state

The current behavioral state of this ghost

initialDelay

private final int initialDelay

The total number of milliseconds before this ghost enters the maze in its CHASE state

waitTimeRemaining

private double waitTimeRemaining

When in the FLEE state, the number of milliseconds remaining before this ghost returns to its CHASE state

fleeTimeRemaining

protected double fleeTimeRemaining

When in the FLEE state, the number of milliseconds remaining before this ghost returns to its CHASE state

ghostColor

private final Color ghostColor

The color of this ghost in its CHASE state

guidancePath

private List<MazeGraph.MazeEdge> guidancePath

The edges comprising the most recently calculated path to this ghosts' `target()`

Constructor Details

Ghost

public Ghost(GameModel model,
 Color ghostColor,
 int initialDelay)

Construct a ghost associated to the given `model` with specified color and initial delay

Method Details

target

protected abstract MazeGraph.MazeVertex target()

Return the vertex that this ghost is targeting

state

public Ghost.GhostState state()

Return the current state of this ghost

color

public Color color()

Return this ghost's color (for painting)

fleeTimeRemaining

public double fleeTimeRemaining()

Return the amount of time remaining on this ghost's FLEE timer

waitTimeRemaining

public double waitTimeRemaining()

Return the amount of time remaining on this ghost's WAIT timer

getBoundingBoxUL

public Actor.DPair getBoundingBoxUL()

In their WAIT state, the ghosts move from side to side in their box, otherwise, their bounding box location is delegated up to `Actor.getBoundingBoxUL`.

Overrides:

getBoundingBoxUL in class Actor

visitVertex

public void visitVertex(MazeGraph.MazeVertex v)

Ghosts do not take any actions when visiting vertices

Specified by:

visitVertex in class Actor

nextEdge

public MazeGraph.MazeEdge nextEdge()

Returns the first edge along the shortest path from this ghost's `currentVertex()` to its `target()`.

Specified by:

nextEdge in class Actor

guidancePath

public List<MazeGraph.MazeEdge> guidancePath()

Description copied from class: Actor

Return the list of Edges in this actor's current planned path through the maze (if any). This is intended to be used for visualizing actors' intended behavior. Sequence of edges must form a continuous path (e.g., `ans.get(i).dst().equals(ans.get(i+1).src())`).

Specified by:

guidancePath in class Actor

reset

public void reset()

Transition this ghost to its WAIT state and reset the `waitTimeRemaining` to this ghost's `INITIAL_DELAY`

Specified by:

reset in class Actor

baseSpeed

public double baseSpeed()

Description copied from class: Actor

Return the current base speed of this actor, before factoring in the weight of the edge they are traversing.

Specified by:

baseSpeed in class Actor

startFlee

public void startFlee()

Transition this ghost to its FLEE state and reset the `fleeTimeRemaining`. Has no effect if the ghost is in its WAIT state.

respawn

public void respawn()

Transition this ghost to its WAIT state when it is caught in its FLEE state, and resets `waitTimeRemaining`. Requires that this ghost is currently in the FLEE state.

propagate

public void propagate(double dt)

Calculate the new position for this actor after `ms` milliseconds of game time have elapsed. In the WAIT state, this updates its delay and spawns the ghost into the maze in its CHASE state when the delay reaches 0. In the FLEE state, the `fleeTimeRemaining` is updated and the ghost reverts to its CHASE state when this reaches 0. Otherwise, delegates to `Actor.updateLocation()`.

Overrides:

propagate in class Actor

maxPropagationTime

public double maxPropagationTime()

Description copied from class: Actor

Return the amount of game time (in ms) that this actor is able to travel at its current speed before reaching a vertex or changing state. Return POSITIVE_INFINITY if this actor is standing still and has no anticipated state changes.

Overrides:

maxPropagationTime in class Actor