Class for performing grid based movement on an entity in a grid. More...

#include <GridMover.h>

Inheritance diagram for ime::GridMover:

Public Types
enum	Type { Type::Manual, Type::Random, Type::Target, Type::KeyboardControlled, Type::Custom }
	Types of grid movers. More...

enum	MoveRestriction { MoveRestriction::None, MoveRestriction::All, MoveRestriction::Vertical, MoveRestriction::Horizontal, MoveRestriction::Diagonal, MoveRestriction::NonDiagonal }
	Restricts the movement of the target along axes. More...

using	Ptr = std::shared_ptr< GridMover >
	Shared grid mover pointer. More...

Public Member Functions
	GridMover (TileMap &tilemap, GameObject::Ptr gameObject=nullptr)
	Create a manually controlled grid mover. More...

std::string	getClassType () const override
	Get the name of this class. More...

bool	requestDirectionChange (const Direction &newDir)
	Change the direction of the game object. More...

Direction	getDirection () const
	Get the current direction of the game object. More...

void	setTarget (GameObject::Ptr target)
	Change the controlled entity. More...

GameObject::Ptr	getTarget () const
	Get access to the controlled entity. More...

void	setMaxLinearSpeed (Vector2f speed)
	Set the maximum linear speed of the game object. More...

Vector2f	getMaxLinearSpeed () const
	Get the maximum speed of the game object. More...

void	setMovementRestriction (MoveRestriction moveRestriction)
	Restrict the movement of the game object to certain directions. More...

MoveRestriction	getMovementRestriction () const
	Get the current movement restriction of the game object. More...

virtual Index	getTargetTileIndex () const
	Get the index of the adjacent tile the target is trying to reach. More...

Type	getType () const
	Get the type of the grid mover. More...

TileMap &	getGrid ()
	Get access to the grid in which the target is moved in. More...

bool	isTargetMoving () const
	Check if target is moving or not. More...

virtual void	update (Time deltaTime)
	Update entity movement in the grid. More...

void	teleportTargetToDestination ()
	Force the target to reach it's destination. More...

int	onTargetChanged (Callback< GameObject::Ptr > callback)
	Add an event listener to a target change event. More...

int	onMoveBegin (Callback< Tile > callback)
	Add an event listener to a move begin event. More...

int	onAdjacentTileReached (Callback< Tile > callback)
	Add an event listener to an adjacent tile reached event. More...

int	onGridBorderCollision (Callback<> callback)
	Add an event listener to a tilemap border collision event. More...

int	onSolidTileCollision (Callback< Tile > callback)
	Add an event listener to a tile collision event. More...

int	onObstacleCollision (Callback< GameObject::Ptr, GameObject::Ptr > callback)
	Add an event listener to an obstacle collision. More...

int	onCollectableCollision (Callback< GameObject::Ptr, GameObject::Ptr > callback)
	Add an event listener to a collectable collision event. More...

int	onEnemyCollision (Callback< GameObject::Ptr, GameObject::Ptr > callback)
	Add an event listener to an enemy collision event. More...

int	onPlayerCollision (Callback< GameObject::Ptr, GameObject::Ptr > callback)
	Add an event listener to a player collision event. More...

bool	removeCollisionHandler (int id)
	Remove a collision handler. More...

bool	removeEventListener (const std::string &event, int id)
	Remove an event listener from an event. More...

void	resetTargetTile ()

void	onTargetTileReset (Callback< Tile > callback)

	~GridMover () override
	Destructor. More...

void	setTag (const std::string &tag)
	Assign the object an alias. More...

const std::string &	getTag () const
	Get the alias of the object. More...

unsigned int	getObjectId () const
	Get the id of the object. More...

virtual std::string	getClassName () const =0
	Get the name of the concrete class. More...

int	onPropertyChange (const std::string &property, const Callback< Property > &callback)
	Add an event listener to a specific property change event. More...

void	onPropertyChange (const Callback< Property > &callback)
	Add an event listener to a property change event. More...

int	onEvent (const std::string &event, const Callback<> &callback)
	Add an event listener to an event. More...

bool	unsubscribe (const std::string &event, int id)
	Remove an event listener from an event. More...

int	onDestruction (const Callback<> &callback)
	Add a destruction listener. More...

bool	removeDestructionListener (int id)
	Remove a destruction listener form the object. More...

bool	operator== (const Object &rhs) const
	Check if two objects are the same object or not. More...

bool	operator!= (const Object &rhs) const
	Check if two objects are not the same object. More...

Protected Member Functions
	GridMover (Type type, TileMap &tileMap, GameObject::Ptr target)
	Create a grid mover. More...

void	emitChange (const Property &property)
	Dispatch a property change event. More...

void	emit (const std::string &event)
	Dispatch an action event. More...

Detailed Description

Class for performing grid based movement on an entity in a grid.

This class monitors the movement of an entity in a grid and ensures that it always moves from one cell to the next and never between grid cells. The entities direction cannot be changed until it has completed it's current movement.

Note that the grid mover only supports orthogonal movement (left, right, up and down)

Definition at line 59 of file GridMover.h.

Member Typedef Documentation

◆ Ptr

using ime::GridMover::Ptr = std::shared_ptr<GridMover>

Shared grid mover pointer.

Definition at line 61 of file GridMover.h.

Member Enumeration Documentation

◆ MoveRestriction

enum ime::GridMover::MoveRestriction

strong

Restricts the movement of the target along axes.

Enumerator
None	Target can move in all in all 8 directions (W, NW, N, NE, E, SE, S, SW)
All	Target cannot move in any direction.
Vertical	Target can only move vertically (N or S)
Horizontal	Target can only move horizontally (W or E)
Diagonal	Target can only move diagonally (NW, NE, SE, SW)
NonDiagonal	Target can only move non-diagonally (W, N, E, S)

Definition at line 77 of file GridMover.h.

◆ Type

enum ime::GridMover::Type

strong

Types of grid movers.

Enumerator
Manual	Manually triggered grid mover.
Random	Moves a game object randomly in the grid.
Target	Moves a game object to a specific tile within the grid.
KeyboardControlled	Moves a game object within the grid using the keyboard as a trigger.
Custom	For classes that extend the grid mover outside of IME.

Definition at line 66 of file GridMover.h.

Constructor & Destructor Documentation

◆ GridMover() [1/2]

ime::GridMover::GridMover	(	TileMap &	tilemap,
		GameObject::Ptr	gameObject = `nullptr`
	)

explicit

Create a manually controlled grid mover.

Parameters

tilemap	The grid the game object is in
gameObject	The game object to be controlled by the grid mover

Warning: You may omit the game object if you want to set it later, However if the target is provided gameObject != nullptr, then it must be placed in the grid prior to instantiation of this class

See also: setTarget

◆ ~GridMover()

ime::GridMover::~GridMover ( )

override

Destructor.

◆ GridMover() [2/2]

ime::GridMover::GridMover	(	Type	type,
		TileMap &	tileMap,
		GameObject::Ptr	target
	)

protected

Create a grid mover.

Parameters

type	The type of the grid mover
tileMap	Grid to move a target entity in
target	GameObject to be moved in the grid

Note that this constructor is intended to be used by derived classes such that the user cannot change the type of the grid mover during instantiation. The public constructor sets the type to Type::Manual and it cannot be changed once set. Since derived classes must set their own type, they use this constructor to initialize the base class

Warning: if the target is not a nullptr, then it must be placed in the grid prior to instantiation of this class

Member Function Documentation

◆ emit()

void ime::Object::emit ( const std::string & event )

protectedinherited

Dispatch an action event.

Parameters

event The name of the event to be dispatched

This function will invoke all event listeners of the specified event. The function should be used for events that represent an action, rather than those that represent a property change (Use emitChange for that)

See also: emitChange

◆ emitChange()

void ime::Object::emitChange ( const Property & property )

protectedinherited

Dispatch a property change event.

Parameters

property The property that changed

This function will invoke all the event listeners of the specified property

See also: emit

◆ getClassName()

virtual std::string ime::Object::getClassName ( ) const

pure virtualinherited

Get the name of the concrete class.

Returns: The name of the objects concrete class

This function is implemented by all internal classes that inherit from this class.

See also: getClassType

Implemented in ime::Tile, ime::SpriteSheet, ime::Sprite, ime::RectangleShape, ime::ConvexShape, ime::CircleShape, ime::Camera, ime::Scene, ime::RenderLayerContainer, ime::RenderLayer, ime::TargetGridMover, ime::RandomGridMover, ime::KeyboardGridMover, ime::DistanceJoint, ime::PolygonCollider, ime::EdgeCollider, ime::CircleCollider, ime::BoxCollider, ime::Body, ime::AABB, and ime::GameObject.

◆ getClassType()

std::string ime::GridMover::getClassType ( ) const

overridevirtual

Get the name of this class.

Returns: The name of this class

Note that this function is only implemented by child classes of Object which also serve as a base class for other classes

See also: Object::getClassType and Object::getClassName

Reimplemented from ime::Object.

◆ getDirection()

Direction ime::GridMover::getDirection ( ) const

Get the current direction of the game object.

Returns: The current direction of the game object

◆ getGrid()

TileMap& ime::GridMover::getGrid ( )

Get access to the grid in which the target is moved in.

Returns: The grid in which the target is being moved in

◆ getMaxLinearSpeed()

Vector2f ime::GridMover::getMaxLinearSpeed ( ) const

Get the maximum speed of the game object.

Returns: The maximum speed of the game object

◆ getMovementRestriction()

MoveRestriction ime::GridMover::getMovementRestriction ( ) const

Get the current movement restriction of the game object.

Returns: The current movement restriction

◆ getObjectId()

unsigned int ime::Object::getObjectId ( ) const

inherited

Get the id of the object.

Returns: The id of the object

Each object has a unique id

◆ getTag()

const std::string& ime::Object::getTag ( ) const

inherited

Get the alias of the object.

Returns: The alias of the object

See also: setTag and getObjectId

◆ getTarget()

GameObject::Ptr ime::GridMover::getTarget ( ) const

Get access to the controlled entity.

Returns: The controlled entity, or a nullptr if there is no entity to control

◆ getTargetTileIndex()

virtual Index ime::GridMover::getTargetTileIndex ( ) const

virtual

Get the index of the adjacent tile the target is trying to reach.

Returns: The index of the adjacent tile the target is trying to reach

If the target it not moving towards any tiles, this function will return the index of the tile currently occupied by the target

Reimplemented in ime::RandomGridMover.

◆ getType()

Type ime::GridMover::getType ( ) const

Get the type of the grid mover.

Returns: The type of the grid mover

◆ isTargetMoving()

bool ime::GridMover::isTargetMoving ( ) const

Check if target is moving or not.

Returns: True if target is moving otherwise false

Warning: This function will return false if the target is not moving or there is no target set. Therefore, the existence of the target should be checked first for accurate results

See also: getTarget

◆ onAdjacentTileReached()

int ime::GridMover::onAdjacentTileReached ( Callback< Tile > callback )

Add an event listener to an adjacent tile reached event.

Parameters

callback Function to execute when the target reaches its target tile

Returns: The event listeners identification number

This event is emitted when the target moves from its current tile to any of its adjacent tiles.

Note: When controlled by a grid mover, the target will always move one tile at a time, regardless of how fast the target is moving

The callback is passed the tile the target moved to

See also: onMoveBegin

◆ onCollectableCollision()

int ime::GridMover::onCollectableCollision ( Callback< GameObject::Ptr, GameObject::Ptr > callback )

Add an event listener to a collectable collision event.

Parameters

callback Function to execute when the collision takes place

Returns: The event listeners identification number

This event is emitted when the target collides with a collectable in the grid. The callback is passed the target as the first argument and the collectable it collided with as the second argument

◆ onDestruction()

int ime::Object::onDestruction ( const Callback<> & callback )

inherited

Add a destruction listener.

Parameters

callback Function to be executed when the object is destroyed

Returns: The id of the destruction listener

Note that an object may have more than one destruction listeners, however, you have to keep the returned id if you may want to remove the callback at a later time

Warning: The callback is called when the object is destroyed. Do not try to access the object in the callback. Doing so is undefined behavior

See also: removeDestructionListener

◆ onEnemyCollision()

int ime::GridMover::onEnemyCollision ( Callback< GameObject::Ptr, GameObject::Ptr > callback )

Add an event listener to an enemy collision event.

Parameters

callback Function to execute when the collision takes place

Returns: The event listeners identification number

This event is emitted when the target collides with an enemy in the grid. The callback is passed the target as the first argument and the enemy it collided with as the second argument

◆ onEvent()

int ime::Object::onEvent	(	const std::string &	event,
		const Callback<> &	callback
	)

inherited

Add an event listener to an event.

Parameters

event	The name of the event to add an an event listener to
callback	The function to be executed when the event takes place

Returns: The unique identification number of the event listener

Unlike onPropertyChange, this function registers event listeners to events that occur when something happens to the object, or when the object does something (action events). Usually the name of the event/action is the name of the function:

// Add event listeners to the object
object.onEvent("attachRigidBody", [] {
    std::cout << "Rigid body attached to object << std::endl;
});
 
object.onEvent("removeRigidBody", [] {
    std::cout << "Rigid body removed from object << std::endl;
});
 
// Invokes event listener(s)
object.attachRigidBody(body);
object.removeRigidBody();

See also: onPropertyChange and unsubscribe

◆ onGridBorderCollision()

int ime::GridMover::onGridBorderCollision ( Callback<> callback )

Add an event listener to a tilemap border collision event.

Parameters

callback Function to execute when the collision takes place

Returns: The event listeners identification number

This event is emitted when the target tries to go beyond the bounds of the grid. By default the event is handled internally before it's emitted to the outside. The internal handler prevents the target from leaving the grid. That is, the target will occupy the same tile it occupied before the collision. This behaviour is not removable, however, it may be overridden since the internal handler is called first before alerting external handlers

◆ onMoveBegin()

int ime::GridMover::onMoveBegin ( Callback< Tile > callback )

Add an event listener to a move begin event.

Parameters

callback The function to be executed when the game object starts moving

Returns: The event listeners unique identification number

This event is emitted when the game object starts moving from its current tile to one of its adjacent tile. The callback is passed the tile that the game object is currently moving to

Note: When controlled by a grid mover, the game object will always move one tile at a time, regardless of how fast it's moving

See also: onAdjacentTileReached

◆ onObstacleCollision()

int ime::GridMover::onObstacleCollision ( Callback< GameObject::Ptr, GameObject::Ptr > callback )

Add an event listener to an obstacle collision.

Parameters

callback Function to execute when the collision takes place

Returns: The event listeners identification number

This event is emitted when the target collides with an obstacle in the grid. By default the event is handled internally before its emitted to the outside. The internal handler prevents the target from occupying the same tile as the obstacle by moving it back to its previous tile after the collision

The callback is passed the target as the first argument and the obstacle it collided with as the second argument

◆ onPlayerCollision()

int ime::GridMover::onPlayerCollision ( Callback< GameObject::Ptr, GameObject::Ptr > callback )

Add an event listener to a player collision event.

Parameters

callback Function to execute when the collision takes place

Returns: The event listeners identification number

This event is emitted when the target collides with a player in the grid. The callback is passed the target as the first argument and the player it collided with as the second argument

◆ onPropertyChange() [1/2]

void ime::Object::onPropertyChange ( const Callback< Property > & callback )

inherited

Add an event listener to a property change event.

Parameters

callback The function to be executed when the property changes

Returns: The unique id of the event listener

Note that only one callback function may be registered with this function. This means that adding a new event listener overwrites the previous event listener. To remove the callback, pass a nullptr as an argument. The function may be useful if you want to write the logic for property changes in one function.

See also: onPropertyChange(std::string, Callback)

◆ onPropertyChange() [2/2]

int ime::Object::onPropertyChange	(	const std::string &	property,
		const Callback< Property > &	callback
	)

inherited

Add an event listener to a specific property change event.

Parameters

property	The name of the property to listen for
callback	The function to be executed when the property changes

Returns: The unique id of the event listener

A property change event is triggered by any function that begins with set, where the the text after set is the name of the property. For example, for the setTag function, the property that the function modifies is Tag.

Note that when adding a property change event listener, the name of the property must be in lowercase:

// Prints the tag of the player object to the console everytime it changes
player.onPropertyChange("tag", [](const Property& property) {
     cout << "New tag: " <<  property.getValue<std::string>() << endl;
});
 
...
//Sets tag = "player1" and invokes event listener(s)
player.setTag("player1");

Unlike onPropertyChange(const Callback&) you can add multiple event listeners to the same property using this function. However you must store the unique id of the event listener if you wish to remove it at a later time

See also: unsubscribe and onPropertyChange(Callback)

◆ onSolidTileCollision()

int ime::GridMover::onSolidTileCollision ( Callback< Tile > callback )

Add an event listener to a tile collision event.

Parameters

callback Function to execute when the collision takes place

Returns: The event listeners identification number

This event is emitted when the target collides with a solid tile in the grid (Solid tiles are always collidable). By default, the event is handled internally before its emitted to the outside. The internal handler prevents the target from occupying the solid tile by moving it back to its previous tile after the collision

The callback is passed the tile the target collided with

◆ onTargetChanged()

int ime::GridMover::onTargetChanged ( Callback< GameObject::Ptr > callback )

Add an event listener to a target change event.

Parameters

callback Function to execute when the target changes

Returns: The event listeners identification number

◆ operator!=()

bool ime::Object::operator!= ( const Object & rhs ) const

inherited

Check if two objects are not the same object.

Parameters

rhs	Object to compare against this object

Returns: True if rhs is NOT the same object as this object, otherwise false

Two objects are different from each other if they have different object id's

See also: getObjectId and operator==

◆ operator==()

bool ime::Object::operator== ( const Object & rhs ) const

inherited

Check if two objects are the same object or not.

Parameters

rhs	Object to compare against this object

Returns: True if rhs is the same object as this object, otherwise false

Two objects are the same object if they have the same object id. Recall that each object instance has a unique id

See also: getObjectId and operator!=

◆ removeCollisionHandler()

bool ime::GridMover::removeCollisionHandler ( int id )

Remove a collision handler.

Parameters

id	Identification number of the handler

Returns: True if the handler was removed or false if no such handler exits

The identification number is the number returned when an event listener was added to a collision event

◆ removeDestructionListener()

bool ime::Object::removeDestructionListener ( int id )

inherited

Remove a destruction listener form the object.

Parameters

The	id of the destruction listener to be removed

Returns: True if the destruction listener was removed or false if the listener with the given id does not exist

◆ removeEventListener()

bool ime::GridMover::removeEventListener	(	const std::string &	event,
		int	id
	)

Remove an event listener from an event.

Parameters

event	Name of the event to remove event listener from
id	Identification number of the event listener

Returns: True if the event listener was removed or false if the given event does not have an event listener with the given id

The identification number is the number returned when an event listener was added to an events

◆ requestDirectionChange()

bool ime::GridMover::requestDirectionChange ( const Direction & newDir )

Change the direction of the game object.

Parameters

newDir The new direction of the game object

Returns: True if the direction was changed or false if the game object is in motion or the grid mover is not in control of any game object

Note that the direction of the game object cannot be changed while it is moving to another tile. This function only works with predefined directions. In addition to returning true for successful direction change, the function will emit a "direction" property change event. Usually property change events are only emitted by setters (functions that begin with a "set" prefix)

gridMover.onPropertyChange("direction", [](const ime::Property& p) {
     auto dir = p.getValue<ime::Direction>();
    // Do something - Maybe rotate the game object in the new direction
});

See also: update

◆ setMaxLinearSpeed()

void ime::GridMover::setMaxLinearSpeed ( Vector2f speed )

Set the maximum linear speed of the game object.

Parameters

speed The new maximum speed

If the game object is currently moving, the speed will be set after it reaches its current target tile

Warning: When using a grid mover the velocity of the game object must not be set directly but rather through this function. Setting the velocity directly will transfer movement management of the game object from the grid mover to the physics engine

◆ setMovementRestriction()

void ime::GridMover::setMovementRestriction ( MoveRestriction moveRestriction )

Restrict the movement of the game object to certain directions.

Parameters

moveRestriction Permitted direction of travel

By default the movement restrictions is MovementRestriction::None

◆ setTag()

void ime::Object::setTag ( const std::string & tag )

inherited

Assign the object an alias.

Parameters

name	The alias of the object

This function is useful if you want to refer to the object by tag instead of its id. Unlike an object id, multiple objects may have the same tag.

By default, the tag is an empty string

◆ setTarget()

void ime::GridMover::setTarget ( GameObject::Ptr target )

Change the controlled entity.

Parameters

target New target

Provide nullptr as argument to remove current target

Warning: if the target is not a nullptr, then it must exist in the grid prior to function call

◆ teleportTargetToDestination()

void ime::GridMover::teleportTargetToDestination ( )

Force the target to reach it's destination.

The destination in this context is always the adjacent tile the target is headed towards. This function has no effect if the target is not moving towards any tile

◆ unsubscribe()

bool ime::Object::unsubscribe	(	const std::string &	event,
		int	id
	)

inherited

Remove an event listener from an event.

Parameters

event	The name of the event to remove event listener from
id	The unique id of the event listener to be removed

Returns: True if the event listener was removed or false if the event or the event listener is does not exist

// Display the name of the object to console every time it changes
auto nameChangeId = object.onPropertyChange("name", [](Property name) {
     std::cout << name.getValue<std::string>() << std::endl;
});
 
// Stop displaying the name of the object when it changes
object.unsubscribe("name", id);

◆ update()

virtual void ime::GridMover::update ( Time deltaTime )

virtual

Update entity movement in the grid.

Parameters

deltaTime Time passed since movement was last updated

The target can only move one tile at a time and cannot be instructed to move to another tile while it is currently moving to one of its adjacent tiles. After it reaching it's target tile it stops moving until instructed to move again. Therefore if the target is to be moved multiple tiles, the request to change direction must be made immediately after the target reaches its destination

See also: onAdjacentTileReached and requestDirectionChange

Warning: The target will never move if this function is never called

Reimplemented in ime::RandomGridMover.

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

GridMover.h

Public Types

Public Member Functions

Protected Member Functions

Detailed Description

Member Typedef Documentation

◆ Ptr

Member Enumeration Documentation

◆ MoveRestriction

◆ Type

Constructor & Destructor Documentation

◆ GridMover() [1/2]

◆ ~GridMover()

◆ GridMover() [2/2]

Member Function Documentation

◆ emit()

◆ emitChange()

◆ getClassName()

◆ getClassType()

◆ getDirection()

◆ getGrid()

◆ getMaxLinearSpeed()

◆ getMovementRestriction()

◆ getObjectId()

◆ getTag()

◆ getTarget()

◆ getTargetTileIndex()

◆ getType()

◆ isTargetMoving()

◆ onAdjacentTileReached()

◆ onCollectableCollision()

◆ onDestruction()

◆ onEnemyCollision()

◆ onEvent()

◆ onGridBorderCollision()

◆ onMoveBegin()

◆ onObstacleCollision()

◆ onPlayerCollision()

◆ onPropertyChange() [1/2]

◆ onPropertyChange() [2/2]

◆ onSolidTileCollision()

◆ onTargetChanged()

◆ operator!=()

◆ operator==()

◆ removeCollisionHandler()

◆ removeDestructionListener()

◆ removeEventListener()

◆ requestDirectionChange()

◆ setMaxLinearSpeed()

◆ setMovementRestriction()

◆ setTag()

◆ setTarget()

◆ teleportTargetToDestination()

◆ unsubscribe()

◆ update()