Dragengine.Scenery.ECBehaviorCollider Class Reference

Behavior element behavior adding collider support. More...

Inheritance diagram for Dragengine.Scenery.ECBehaviorCollider:

Classes
class	BlockListenerFactory
	Factory creating listeners using block. More...
class	DefaultListener
	Default implementation of behavior instance listener. More...
class	Instance
	Behavior instance. More...
interface	Listener
	Listener for behavior instance events. More...
interface	ListenerFactory
	Factory creating listeners. More...

Public Member Functions
void	addListenerFactory (Block blockFactory)
	Add listener factory using block. More...
void	addListenerFactory (ListenerFactory factory)
	Add listener factory. More...
void	createListeners (Instance instance)
	Create listeners from factories adding them to behavior instance. More...
void	dispose ()
	Dispose of behavior. More...
void	forEachListenerFactory (Block ablock)
	Visit listener factories with block with argument ListenerFactory. More...
ECComposeCollider	getCollider ()
	Composeable collider for element class. More...
ECBehaviorComponent	getComponent ()
	Component behavior. More...
ECBehaviorCollider	new (BehaviorElementClass eclass, ECBehaviorComponent component)
	Create behavior element class. More...
ECBehaviorCollider	new (BehaviorElementClass eclass, ECBehaviorComponent component, String prefix)
void	setGhost ()
	Set up collider as ghost collider. More...
Public Member Functions inherited from Dragengine.Scenery.DefaultECBehavior
void	assignInstanceIndex (int instanceIndex)
	Assign instance index. More...
String	getBehaviorID ()
	Unique identifier of behavior. More...
String	getID ()
	Identifier. More...
int	getInstanceIndex ()
	Instance index. More...
void	loadSupportedData (String identifier, PersistencyEnvironment env, FileReader reader, ECBehaviorInstance instance)
	Load instance data of another behavior. More...
bool	supportsBehaviorID (String identifier)
	Behavior supports loading instance data of another behavior. More...
Public Member Functions inherited from Dragengine.Scenery.ECBehavior
ECBehaviorInstance	createInstance (BehaviorElement element)
	Create Behavior instance. More...

Static Public Member Functions
static ECBehaviorCollider	getBehaviorIn (BehaviorElementClass eclass)
	Get behavior in element class or null if absent. More...

Additional Inherited Members
Protected Member Functions inherited from Dragengine.Scenery.DefaultECBehavior
DefaultECBehavior	new (BehaviorElementClass eclass)
	Create default composeable behavior with empty identifier. More...
DefaultECBehavior	new (BehaviorElementClass eclass, String id)
	Create default composeable behavior. More...
void	setBehaviorID (String identifier)
	Set behavior identifier. More...
void	useClassNameAsBehaviorID ()
	Set behavior identifier to "<class-name>:<identifier>". More...
void	useFullyQualifiedClassNameAsBehaviorID ()
	Set behavior identifier to "<fully-qualified-class-name>:<identifier>". More...

Detailed Description

Behavior element behavior adding collider support.

Colliders provide physical presence to elements allowing them to collide with other colliders, attaching them to other colliders and moving the element through the game world.

This element behavior is often required by other element behaviors to be present to function correctly.

Since this collider repositions the element upon changing position and orientation this element behavior can be present only once in a BehaviorElement. Trying to add more than one instance results in an exception thrown.

If you need additional colliders for example to sense objects using collision detection then you need to use other ECBehavior providing the desired behavior. These allow to be added multiple times.

If the ECBehaviorComponent behavior is present in the behavior element before this behavior is added a ColliderComponent is created. The component is used for collision detection and updated automatically by the collider. This is required if you intend to use per-bone collisions matching animation state or physical simulations like rag-dolls.

If the ECBehaviorComponent behavior is added after this behavior then a ColliderVolume is created. The rig assigned to the component is only used for animation purpose. The ECBehaviorComponent will then statically attach to the collider.

Hence these two use cases are possible depending on the order the behaviors are added:

Use Case 1: Shape Collision

Component is only visual. For collision only static collision shape is used. The component is attached statically to the collider and does not collide. If collider is dynamic physics simulation will be done using collision shape only.

class MyElementClass extends BehaviorElementClass
   public func new()
      var ECBehaviorCollider collider = ECBehaviorCollider.new(this, null)
      // assign collision shape or collision rig to the collider
      ECBehaviorComponent.new(this, collider)
   end
end

Use Case 2: Component Collision

Component is used for collision detection. If collider is dynamic component bones will be updated by the collider automatically.

class MyElementClass extends BehaviorElementClass
   public func new()
      var ECBehaviorComponent component = ECBehaviorComponent.new(this, null)
      ECBehaviorCollider.new(this, component)
   end
end

Element class properties have the prefix "collider.".

Collision listening

The default collision behavior clears the linear and angular velocities. To add meaningful collision behavior add listeners. If one or more listener are present the default collision behavior is disabled and the listeners are responsible. At least one listener has to do collision handling in a way that the current collision is not happening again. This can be done by modifying the velocities of the affected colliders, changing collision filters or removing elements from the game world altogether. The ECBehaviorCollider assigns the owner BehaviorElement as owner of the collider. Hence you can retrieve the BehaviorElement represented by a collider like this:

// check if a collider has been hit (other possibilities exist like height-terrain)
if info.getCollider() != null
   // check if the owner of the collider is of type BehaviorElement
   if info.getOwner() castable BehaviorElement
       var BehaviorElement element = info.getOwner() cast BehaviorElement
       // work with the element, for example check what behaviors it has attached
   end
end

Another way is to subclass ElementVisitor. This is a more object-oriented approach and keeps the code cleaner especially if the behavior is able to work with different types of elements. This way would look roughly like this:

// check if a collider has been hit (other possibilities exist like height-terrain)
if info.getCollider() != null
   // check if the owner of the collider is of type Element
   if info.getOwner() castable Element
       // visit the element to apply the desired actions
       (info.getOwner() cast Element).visit(MyElementCollisionVisitor.new())
   end
end

This behavior does require the element class to be persistable (setPersistable) only if the physics type is set to anything else but CollisionResponse.none .

TODO: possible behaviors using this system:

• sliding collision response: slides kinematic colliders along walls like actors do
• power ups: typical example of a an element touched by the actor that vanishes when touched adding all kinds of abilities. this would be an example of behaviors on different elements interacting. requires two behaviors. one behavior is the power up itself which identifies the element as a power up that can be consumed. the second is the touch power up behavior placed on the interacting element. it uses getInstanceIn() to check if the hit element has the power up behvaior and if so removes it from the game world and applies the effects.

Member Function Documentation

addListenerFactory() [1/2]

void Dragengine.Scenery.ECBehaviorCollider.addListenerFactory

(

Block

blockFactory

)

Add listener factory using block.

Block receives as parameter Instance and returns Listener.

addListenerFactory() [2/2]

void Dragengine.Scenery.ECBehaviorCollider.addListenerFactory

(

ListenerFactory

factory

)

Add listener factory.

createListeners()

void Dragengine.Scenery.ECBehaviorCollider.createListeners

(

Instance

instance

)

Create listeners from factories adding them to behavior instance.

dispose()

void Dragengine.Scenery.ECBehaviorCollider.dispose

(

)

Dispose of behavior.

Reimplemented from Dragengine.Scenery.DefaultECBehavior.

forEachListenerFactory()

void Dragengine.Scenery.ECBehaviorCollider.forEachListenerFactory

(

Block

ablock

)

Visit listener factories with block with argument ListenerFactory.

getBehaviorIn()

static ECBehaviorCollider Dragengine.Scenery.ECBehaviorCollider.getBehaviorIn ( BehaviorElementClass  eclass )

static

Get behavior in element class or null if absent.

Use this method to check if a particular BehaviorElementClass contains a behavior of type ECBehaviorCollider.

getCollider()

ECComposeCollider Dragengine.Scenery.ECBehaviorCollider.getCollider

(

)

Composeable collider for element class.

getComponent()

ECBehaviorComponent Dragengine.Scenery.ECBehaviorCollider.getComponent

(

)

Component behavior.

new() [1/2]

ECBehaviorCollider Dragengine.Scenery.ECBehaviorCollider.new	(	BehaviorElementClass	eclass,
		ECBehaviorComponent	component
	)

Create behavior element class.

These values are optional and can be null: component.

new() [2/2]

ECBehaviorCollider Dragengine.Scenery.ECBehaviorCollider.new	(	BehaviorElementClass	eclass,
		ECBehaviorComponent	component,
		String	prefix
	)

setGhost()

void Dragengine.Scenery.ECBehaviorCollider.setGhost

(

)

Set up collider as ghost collider.

Ghost colliders have empty collision filter and a small sphere shape. They collide with nothing and are useful to attach elements composing only of resources like ECBehaviorLight.

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

• ECBehaviorCollider.ds