Classes
class	Changling

Public Member Functions
	World (int width, int height)

	World (int width, int height, double partitionSize, double partitionOverlap)

Point	world2pixel (double wx, double wy, Point pxy)

Point	world2pixel (Vector2D wxy, Point pxy)

Vector2D	pixel2world (int px, int py, Vector2D wxy)

void	scale (double scale)

double	scale ()

void	panPixelX (int px)

void	panPixelY (int py)

void	panPixelXY (int px, int py)

void	panWorldX (double wx)

void	panWorldY (double wy)

void	panWorldXY (double wx, double wy)

void	moveToWorldX (double wx)

void	moveToWorldY (double wy)

void	moveToWorldXY (double wx, double wy)

double	xOffset ()

double	yOffset ()

Domain	viewOnWorld ()

BaseEntity	getEntity (int entityID)

Set< Building >	getBuildings (MovingEntity m)

Set< MovingEntity >	getMovers (MovingEntity m)

Set< MovingEntity >	getMovers (MovingEntity m, double range)

Set< Wall >	getWalls (MovingEntity m)

Set< Wall >	getWalls (MovingEntity m, double px, double py)

Set< Obstacle >	getObstacles (MovingEntity m)

Set< Obstacle >	getObstacles (double x, double y)

Set< Obstacle >	getObstacles (MovingEntity m, double px, double py)

boolean	exists (int id)

boolean	exists (BaseEntity entity)

void	add (BaseEntity entity)

void	death (BaseEntity entity, double timeToLive)

void	death (int entityID, double timeToLive)

void	birth (BaseEntity entity, double timeToBirth)

void	cancelBirthsAndDeaths ()

void	update (double deltaTime)

void	draw ()

void	draw (double elapsedTime)

boolean	isCspOn ()

boolean	isNoOverlapOn ()

void	noOverlap (boolean noOverlap)

void	printForceData ()

Public Attributes
int	nbr_artefacts = 0

int	nbr_buildings = 0

int	nbr_obstacles = 0

int	nbr_walls = 0

int	nbr_movers = 0

double	worldUpdateTime = 0

Static Public Attributes
static HashMap< Integer, BaseEntity >	allEntities = new HashMap<Integer, BaseEntity>()

Protected Member Functions
void	makeDrawSet ()

Private Member Functions
	World ()

void	remove (BaseEntity entity)

void	add (Artefact artefact)

void	add (Building b)

void	add (Obstacle obstacle)

void	add (Wall w)

void	add (MovingEntity me)

void	remove (Artefact artefact)

void	remove (Obstacle obstacle)

void	remove (Wall wall)

void	remove (Building b)

void	remove (MovingEntity me)

void	ensureNoOverlap (double deltaTime)

void	ensureNoOvelapInPartition (double deltaTime, Set< MovingEntity > partSet)

void	ensureNoOverlap (double deltaTime, MovingEntity m0, MovingEntity m1)

void	checkPartitionMoves ()

Point	getPartition (double x, double y)

Private Attributes
Set< BaseEntity >	drawSet = new TreeSet<BaseEntity> (new BaseEntity.DepthOrder())

ArrayList< Changling >	entityChangeList = new ArrayList<Changling>()

Set< Artefact >	artefacts

Set< Building >	buildings

Set< Wall >	walls

Set< Obstacle >	obstacles

Set< MovingEntity >	movers

HashMap< Point, HashSet< Artefact > >	artefact_parts

HashMap< Point, HashSet< Building > >	building_parts

HashMap< Point, HashSet< Wall > >	wall_parts

HashMap< Point, HashSet< Obstacle > >	obstacle_parts

HashMap< Point, HashSet< MovingEntity > >	moving_parts

boolean	noOverlap = true

final boolean	cspOn

final double	partSize

final double	partOverlap

Domain	viewOnWorld

double	viewScale = 1.0

final double	displayWidth

final double	displayHeight

Static Private Attributes
static StopWatch	timer = new StopWatch()

static double	cumTime

static int	count = 0

Detailed Description

This class represents the '2D game play area' on which all the game entities are placed. Internally all world coordinates are stored as doubles (rather than floats) to minimise rounding errors, particularly when using steering behaviours.
This means the size of the world is only limited by the range of numbers that can be stored in the double data type ( i.e. +/- 1.7976931348623157e+308)

This class provides the core functionality for maintaining collections of all the game entities.

When there are a large number of game entities, cell space partitioning (CSP) can significantly reduce the CPU time needed to update all the moving entities. It will also reduce the rendering time by not attempting to draw entities that fall outside of the viewable area. This is normally at the expense of additional memory needed for the data structures.

Depending on which constructor is used when creating the 'world' object determines whether CSP is used or not. The CSP implementation is totally transparent to the user - so apart from changing the constructor used no other changes are needed in the users code.

Author: Peter Lager

Constructor & Destructor Documentation

◆ World() [1/3]

game2dai.World.World ( )

private

Make the default constructor private so it can't be used

◆ World() [2/3]

game2dai.World.World	(	int	width,
		int	height
	)

Create a world without cell space partitioning.
The height and width are the physical display area size in pixels. It maybe smaller than the width and height of the application's window.
The portion of the world to be displayed will be a initialised to a rectangle (0,0) to (width, height).

(0,0) ___________________________________ X axis
      |                          |
      |                          |
      |                          |
      |                          |
      |                          |
      |                          |
      |__________________________| (width, height)
      |
      Y axis

<br<blockquote>‍

This gives a view scale of 1. (i.e. 1 pixel = 1 world unit)
The actual part of the world to be displayed cane be changed with the

moveTo, panPixel, panWorld & setScale methods.

Parameters

width	the physical screen display width in pixels
height	the physical screen display height in pixels

◆ World() [3/3]

game2dai.World.World	(	int	width,
		int	height,
		double	partitionSize,
		double	partitionOverlap
	)

Create a world with cell space partitioning.
The height and width are the physical display area size in pixels. It maybe smaller than the width and height of the applications window.
The portion of the world to be displayed will be a initialised to a rectangle (0,0) to (width, height).

(0,0) ___________________________________ X axis
      |                          |
      |                          |
      |                          |
      |                          |
      |                          |
      |                          |
      |__________________________| (width, height)
      |
      Y axis

<br<blockquote>‍

This gives a view scale of 1. (i.e. 1 pixel = 1 world unit)
The actual part of the world to be displayed cane be changed with the

moveTo, panPixel, panWorld & setScale methods.

This constructor will cause cell-space partitioning to be used. Use the following guide when deciding on the values for the partition size and overlap parameters

partitionSize >= 5 x MCR 


partitionOverlap >= 2 x MCR 


partitionSize >= 2 x partitionOverlap 


partitionOverlap > whisker length if using steering behaviours with wall avoidance enabled

<br<blockquote>‍

where MCR is the maximum collision radius for your moving entities. The values used will have a significant effect on performance so it is worth experimenting with different values for your game.

Parameters

width	the physical screen display width in pixels
height	the physical screen display height in pixels
partitionSize	the size of the partition in world distance
partitionOverlap	the overlap between partitions

Member Function Documentation

◆ add() [1/6]

void game2dai.World.add ( Artefact artefact )

private

Add an artefact .
A artefact entity may or may not have a renderer and a state machine.

◆ add() [2/6]

void game2dai.World.add ( BaseEntity entity )

This method must only be used before the main program starts. If it is called during a world update then the program is likely to crash, in this case use the birth() method instead.

Parameters

entity the entity to add.

◆ add() [3/6]

void game2dai.World.add ( Building b )

private

Adds a building to the world.

Parameters

b	the building to add.

◆ add() [4/6]

void game2dai.World.add ( MovingEntity me )

private

Add a moving object to the world.

Parameters

me	the moving object to add

◆ add() [5/6]

void game2dai.World.add ( Obstacle obstacle )

private

Adds an obstacle to the world.

Parameters

obstacle the obstacle to add.

◆ add() [6/6]

void game2dai.World.add ( Wall w )

private

Add a wall to the world.
When looking to see whether the wall passes through any particular partition then it will consider the extended partition i.e. as if it had been extended on all sides by 'partSize'.
partSize should be greater than the whisker length used in wall direction.

Parameters

w

◆ birth()

void game2dai.World.birth	(	BaseEntity	entity,
		double	timeToBirth
	)

This is the preferred method to add an entity to the world once the game is in progress i.e. outside the

setup()

method.

Parameters

entity
timeToBirth

◆ cancelBirthsAndDeaths()

void game2dai.World.cancelBirthsAndDeaths ( )

Cancels outstanding birth and deaths scheduled with birth and death methods.

◆ checkPartitionMoves()

void game2dai.World.checkPartitionMoves ( )

private

If we are using space partitioning then check if movers have crossed a partition boundary and if so move it to the correct hash set

◆ death() [1/2]

void game2dai.World.death	(	BaseEntity	entity,
		double	timeToLive
	)

This is the preferred method to remove an entity from the world once the game is in progress i.e. outside the

setup()

method.

Parameters

entity	the entity to die
timeToLive	number of seconds of life left

◆ death() [2/2]

void game2dai.World.death	(	int	entityID,
		double	timeToLive
	)

This is the preferred method to remove an entity from the world once the game is in progress i.e. outside the

setup()

method.

Parameters

entityID	the ID number of the entity to die
timeToLive	number of seconds of life left

◆ draw() [1/2]

void game2dai.World.draw ( )

DO NOT USE THIS METHOD
This method is left to ensure backward compatibility with library versions prior to 1.0
Use the draw(elapsedTime) method instead.

◆ draw() [2/2]

void game2dai.World.draw ( double elapsedTime )

Any entity that requires to be rendered will have its own render object. This method ensures that the draw method of each render object is executed.
It will not skip entities that are completely outside the visible area of the world.

Parameters

elapsedTime the elapsed time since the last update

◆ ensureNoOvelapInPartition()

void game2dai.World.ensureNoOvelapInPartition	(	double	deltaTime,
		Set< MovingEntity >	partSet
	)

private

Ensure no overlap between moving entities within a partition. If BSP is not being used then the 'whole world' is a single partition so this method will be used for a set of all movers.
Entities that touch across partition barriers are ignored.

◆ ensureNoOverlap() [1/2]

void game2dai.World.ensureNoOverlap ( double deltaTime )

private

Ensure no overlap between moving entities when using BSP ignoring entities that touch across partition barriers.

◆ ensureNoOverlap() [2/2]

void game2dai.World.ensureNoOverlap	(	double	deltaTime,
		MovingEntity	m0,
		MovingEntity	m1
	)

private

Checks to see if there is overlap between the entities. If there is it moves both entities slightly apart along the collision plane normal. The distance an entity moves is proportional to the mass of the other entity.

Parameters

deltaTime
m0
m1

◆ exists() [1/2]

boolean game2dai.World.exists ( BaseEntity entity )

Determines whether the entity still exists in this world.

Parameters

entity

Returns: true if entity is still alive

◆ exists() [2/2]

boolean game2dai.World.exists ( int id )

Determines whether the entity still exists in this world.

Parameters

id	the entity's ID number

Returns: true if entity is still alive

◆ getBuildings()

Set< Building > game2dai.World.getBuildings ( MovingEntity m )

For a particular moving entity get all the buildings in the same partition.

Parameters

m	the moving entity

Returns: a set of nearby buildings

◆ getEntity()

BaseEntity game2dai.World.getEntity ( int entityID )

Get the entity associated with a particular ID number.
If we are not using state machines or if the id number has not been used then the entity will not be found.

Parameters

entityID unique ID number for the entity

Returns: null if the entity was not found else the entity that has the given ID number

◆ getMovers() [1/2]

Set< MovingEntity > game2dai.World.getMovers ( MovingEntity m )

For a particular moving entity get all the moving entities in the same partition. It will include itself.

Parameters

m	the moving entity

Returns: a set containing all the moving entities in its partition

◆ getMovers() [2/2]

Set< MovingEntity > game2dai.World.getMovers	(	MovingEntity	m,
		double	range
	)

Get a list of moving entities in partitions within a given range of a moving entity.

Parameters

m	the mover we are interested in getting the neighbours
range	the radius of the circle surrounding neighbours.

Returns: a set containing the neighbours

◆ getObstacles() [1/2]

Set< Obstacle > game2dai.World.getObstacles ( MovingEntity m )

Get a list of obstacles that need to be tested for obstacle avoidance.

Parameters

m	the moving entity

Returns: a set containing the obstacles (maybe empty but not null)

◆ getObstacles() [2/2]

Set< Obstacle > game2dai.World.getObstacles	(	MovingEntity	m,
		double	px,
		double	py
	)

Get a list of obstacles that are in the box made by the moving entity's position and the position px,py

Parameters

m	the moving entity
px
py

Returns: a set containing the obstacles (maybe empty but not null)

◆ getPartition()

Point game2dai.World.getPartition	(	double	x,
		double	y
	)

private

For a given point get the partition key

◆ getWalls() [1/2]

Set< Wall > game2dai.World.getWalls ( MovingEntity m )

Get a list of walls that need to be tested for wall avoidance.

Parameters

m	the moving entity

Returns: a set containing the walls (maybe empty but not null)

◆ getWalls() [2/2]

Set< Wall > game2dai.World.getWalls	(	MovingEntity	m,
		double	px,
		double	py
	)

Get a list of walls that are in the box made by the moving entity's position and the position px,py

Parameters

m	the moving entity
px
py

Returns: a set containing the walls (maybe empty but not null)

◆ isCspOn()

boolean game2dai.World.isCspOn ( )

Returns: the bspOn

◆ isNoOverlapOn()

boolean game2dai.World.isNoOverlapOn ( )

Returns: the ensureZeroOverlap

◆ makeDrawSet()

void game2dai.World.makeDrawSet ( )

protected

Make a set of entities that are to be drawn in z order

◆ moveToWorldX()

void game2dai.World.moveToWorldX ( double wx )

Move the world view so it is centred about the given world position.

Parameters

wx	centre horizontally about this value.

◆ moveToWorldXY()

void game2dai.World.moveToWorldXY	(	double	wx,
		double	wy
	)

Move the world view so it is centred about the given world position.

Parameters

wx	centre horizontally about this value.
wy	centre vertically about this value.

◆ moveToWorldY()

void game2dai.World.moveToWorldY ( double wy )

Move the world view so it is centred about the given world position.

Parameters

wy	centre vertically about this value.

◆ noOverlap()

void game2dai.World.noOverlap ( boolean noOverlap )

Parameters

noOverlap the ensureZeroOverlap to set

◆ panPixelX()

void game2dai.World.panPixelX ( int px )

Pan the world display by the given number of pixels.

Parameters

px	pixels to pan horizontally.

◆ panPixelXY()

void game2dai.World.panPixelXY	(	int	px,
		int	py
	)

Pan the world display by the given number of pixels.

Parameters

px	pixels to pan horizontally.
py	pixels to pan vertically.

◆ panPixelY()

void game2dai.World.panPixelY ( int py )

Pan the world display by the given number of pixels.

Parameters

py	pixels to pan vertically.

◆ panWorldX()

void game2dai.World.panWorldX ( double wx )

Pan the world display by the given world distance.

Parameters

wx	world distance to pan horizontally.

◆ panWorldXY()

void game2dai.World.panWorldXY	(	double	wx,
		double	wy
	)

Pan the world display by the given world distance.

Parameters

wx	world distance to pan horizontally.
wy	world distance to pan vertically.

◆ panWorldY()

void game2dai.World.panWorldY ( double wy )

Pan the world display by the given world distance.

Parameters

wy	world distance to pan vertically.

◆ pixel2world()

Vector2D game2dai.World.pixel2world	(	int	px,
		int	py,
		Vector2D	wxy
	)

Calculate the equivalent world position from a pixel position.

Parameters

px	display screen pixel x position
py	display screen pixel x position
wxy	a Vector2D object to hold the world position

Returns: the calculated world position

◆ printForceData()

void game2dai.World.printForceData ( )

Used to display all collected steering force data by Vehicle
A vehicle must have it's force logger activated with

vehicle.forceLoggerOn();

◆ remove() [1/6]

void game2dai.World.remove ( Artefact artefact )

private

Removes an artefact from the world.
The only safe way to remove this artefact is to use one of these methods -

void die(BaseEntity entity, double timeToLive)


void die(int entityID, double timeToLive)

◆ remove() [2/6]

void game2dai.World.remove ( BaseEntity entity )

private

Remove an entity from the world.

Parameters

entity the entity to use

◆ remove() [3/6]

void game2dai.World.remove ( Building b )

private

Removes a building from the world.
The only safe way to remove an entity is to use one of these methods -

void die(BaseEntity entity, double timeToLive)


void die(int entityID, double timeToLive)

◆ remove() [4/6]

void game2dai.World.remove ( MovingEntity me )

private

Removes a moving entity or vehicle from the world.
The only safe way to remove an entity is to use one of these methods -

void die(BaseEntity entity, double timeToLive)


void die(int entityID, double timeToLive)

◆ remove() [5/6]

void game2dai.World.remove ( Obstacle obstacle )

private

Removes an obstacle from the world.
The only safe way to remove an entity is to use one of these methods -

void die(BaseEntity entity, double timeToLive)


void die(int entityID, double timeToLive)

◆ remove() [6/6]

void game2dai.World.remove ( Wall wall )

private

Removes a wall from the world.
The only safe way to remove an entity is to use one of these methods -

void die(BaseEntity entity, double timeToLive)


void die(int entityID, double timeToLive)

◆ scale() [1/2]

double game2dai.World.scale ( )

Get the current viewScale (zoom factor)

Returns: view scale value

◆ scale() [2/2]

void game2dai.World.scale ( double scale )

Resize the world due to changes in magnification so that the image is centred in the display area.

Parameters

scale the level of magnification (must be > 0)

◆ update()

void game2dai.World.update ( double deltaTime )

This is the core method which will loop through entity state machines (if any) then it will update the positions and velocities of all moving entities (applying any steering behaviours used).
It also calculates and stores the average time taken to perform this update.

Parameters

deltaTime the time in seconds since the last update.

◆ viewOnWorld()

Domain game2dai.World.viewOnWorld ( )

Get the extent of the world being drawn. It returns a Domain object

Returns: Domain object with the extent of the world being drawn.

◆ world2pixel() [1/2]

Point game2dai.World.world2pixel	(	double	wx,
		double	wy,
		Point	pxy
	)

Calculate the pixel position from a given world position.

Parameters

wx	world x position
wy	world y position
pxy	object to hold the calculate pixel position

Returns: the calculated pixel position

◆ world2pixel() [2/2]

Point game2dai.World.world2pixel	(	Vector2D	wxy,
		Point	pxy
	)

Calculate the pixel position from a given world position.

Parameters

wxy	world x,y position
pxy	object to hold the calculate pixel position

Returns: the calculated pixel position

◆ xOffset()

double game2dai.World.xOffset ( )

Get the world x position equivalent to the left hand side of the display area.
This is used when rendering the world view.

Returns: the amount to translate before drawing

◆ yOffset()

double game2dai.World.yOffset ( )

Get the world x position equivalent to the left hand side of the display area.
This is used when rendering the world view.

Returns: the amount to translate before drawing

Member Data Documentation

◆ nbr_artefacts

int game2dai.World.nbr_artefacts = 0

Number of artefacts in this world

◆ nbr_buildings

int game2dai.World.nbr_buildings = 0

Number of buildings in this world

◆ nbr_movers

int game2dai.World.nbr_movers = 0

Number of moving entities in this world

◆ nbr_obstacles

int game2dai.World.nbr_obstacles = 0

Number of obstacles in this world

◆ nbr_walls

int game2dai.World.nbr_walls = 0

Number of walls in this world

◆ worldUpdateTime

double game2dai.World.worldUpdateTime = 0

The average time it takes for the world to update all the components in the world.

The documentation for this class was generated from the following file:

/Users/peter/git/ai4games-repos/AI_4_2D_Games/src/game2dai/World.java

Classes

Public Member Functions

Public Attributes

Static Public Attributes

Protected Member Functions

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ World() [1/3]

◆ World() [2/3]

◆ World() [3/3]

Member Function Documentation

◆ add() [1/6]

◆ add() [2/6]

◆ add() [3/6]

◆ add() [4/6]

◆ add() [5/6]

◆ add() [6/6]

◆ birth()

◆ cancelBirthsAndDeaths()

◆ checkPartitionMoves()

◆ death() [1/2]

◆ death() [2/2]

◆ draw() [1/2]

◆ draw() [2/2]

◆ ensureNoOvelapInPartition()

◆ ensureNoOverlap() [1/2]

◆ ensureNoOverlap() [2/2]

◆ exists() [1/2]

◆ exists() [2/2]

◆ getBuildings()

◆ getEntity()

◆ getMovers() [1/2]

◆ getMovers() [2/2]

◆ getObstacles() [1/2]

◆ getObstacles() [2/2]

◆ getPartition()

◆ getWalls() [1/2]

◆ getWalls() [2/2]

◆ isCspOn()

◆ isNoOverlapOn()

◆ makeDrawSet()

◆ moveToWorldX()

◆ moveToWorldXY()

◆ moveToWorldY()

◆ noOverlap()

◆ panPixelX()

◆ panPixelXY()

◆ panPixelY()

◆ panWorldX()

◆ panWorldXY()

◆ panWorldY()

◆ pixel2world()

◆ printForceData()

◆ remove() [1/6]

◆ remove() [2/6]

◆ remove() [3/6]

◆ remove() [4/6]

◆ remove() [5/6]

◆ remove() [6/6]

◆ scale() [1/2]

◆ scale() [2/2]

◆ update()

◆ viewOnWorld()

◆ world2pixel() [1/2]

◆ world2pixel() [2/2]

◆ xOffset()

◆ yOffset()

Member Data Documentation

◆ nbr_artefacts

◆ nbr_buildings

◆ nbr_movers

◆ nbr_obstacles

◆ nbr_walls

◆ worldUpdateTime