Behaviors, states and events

(copied from lucera blog) 


MindShake incorporates an easy way for defining event driven application logic. In this way the user defines a series of small objects to solve specific and concrete tasks, splitting the application logic into simpler parts to be implemented in response to certain events as 'enter new frame' or 'mouse click'. We will call these objects behaviors.

Whenever an event takes place, MindShake will be who calls to our objects, which avoid the user to worry about details beyond the logic of his application.

Furthermore, MindShake incorporates a state machine, which simplifies the creation of different stages in the application like: load, boot sequence, menu, game, credits, etc.. Allowing the user should not be complicated with these details.

The user then simply define the behaviors that should be executed in each state, and it will receive the events at the appropriate moment.

Behaviors
Unlike other kinds of MindShake’s classes, which are always created using factories, such as sprites, layers, images, etc, the user must define, instantiate, and destroy, their own kinds of behaviors. For it your behaviors must inherit from one of two basic kinds of behaviors that MindShake defines:

• CBehavior: Usually associated with logic.
• CSpriteBehavior: Associated with a sprite.

CMyBehavior class: public MindShake: CBehavior

CMySptBehavior class: public MindShake: CSpriteBehavior

 Once instantiated a behavior, this should be added to the system with CBehaviorManager class, if the class inherits CBehavior, or through CSprite class, if the class inherits CSpriteBehavior.

pBehaviorManager->AddBehavior(pMyBehavior);

pMySprite->AddBehavior(pSptBehavior);

Additionally, we can walk away from our behaviors, forgetting that we must destroy them, passing a second parameter to BehaviorManager when registering the class:

pBehaviorManager->AddBehavior(pMyBehavior, true);

pMySprite->AddBehavior(pSptBehavior, true);

Thus will be MindShake who will destroy the behaviors when we get out of the application.

CBehaviors 
These behaviors are usually associated with logic. They can be used to create new behaviors, control groups of sprites, states or parties to manage the program, and so on.

CSpriteBehaviors
These behaviors usually control a single character, or the sprites generated by this, such as bullets, aides, etc..

A sprite can have as many attached behaviors as the programmer wants, so the developer can simplify and distribute the logic associated with a sprite distributing its programming between different behaviors. For example, the user can define how the player can move through the world on one behavior, and use another behavior to handle the input.

States
As already mentioned, MindShake incorporates a simple state machine that allows users to define different stages in their implementation.

To do this the user simply has to create behaviors in a given state. Subsequently the user can jump between different states using the method GotoState(state) of the BehaviorManager class.

Once inside the behavior, the user can know both the current and previous state invoking the methods GetState  and GetLastState also of the BehaviorManager class.

Events
Each behavior may receive the following events:
• InitApp
• Begin
• EnterState
• EnterFrame
• ExitState
• End
• BeginPause
• Paused
• EndPause
• MouseEnter
• MouseWithin
• MouseLeave
• MouseDown
• MouseUp
• MouseMove

InitApp
This event is called only for the behaviors that are defined when the application runs initially, or for behaviors that are created just at this moment, in the event InitApp of a behavior that is already created at the beginning.
In any case, MindShake just calls the behaviors that are not associated with any state.

Begin
This event is called only once for each behavior.
All kinds of behaviors.
For the behaviors associated with a state, shall be called the first time you enter that state.

EnterState
This event is called when entering a state.
Behaviors associated with current state.
It’s called for all behaviors associated with the state that becomes active (current state).

EnterFrame
This event is called before rendering each frame.
All kinds of behaviors.
It’s called for the behaviors that are not associated with any state and for the behaviors associated with the current state.

ExitState
This event is called when leaving a state.
Behaviors associated with current state.
It’s called for the behaviors that are associated with the state that become inactive (previous state).
This event is called in reverse order of creation.

End
This event is called when the application exits or when calling RemoveBehavior or RemoveSpriteBehavior.
All kinds of behaviors.
When you exit the application, this event is called in reverse order of creation for all behaviors. Starting with the last defined state. This event is called first for CSpriteBehaviors associated with a state, then for CBehaviors associated with a state, finally is called for CSpriteBehaviors without state and then for CBehaviors without state.

BeginPause
This event is called when the program enter into pause mode. (IDevice::GetInstance()->Pause())
All kinds of behaviors.
It’s called for the behaviors associated with the current state and the behaviors without state.

Paused
This event is called, every frame, while the program remains in pause mode. Note that in pause mode the system does not call EnterFrame.
All kinds of behaviors.
It’s called for the behaviors associated with the current state and the behaviors without state.

EndPause
This event is called when the program exit from pause mode. (IDevice::GetInstance()->Pause())
All kinds of behaviors.
It’s called for the behaviors associated with the current state and the behaviors without state.
This event is called in reverse order of creation.

MouseEnter
This event is called when the mouse enters over the sprite.
Only SpriteBehaviors.
It’s called for the behaviors associated with the current state and the behaviors without state.

MouseWithin
This event is called when the mouse is within the sprite.
Only SpriteBehaviors.
It’s called for the behaviors associated with the current state and the behaviors without state.

MouseLeave
This event is called when the mouse leaves the sprite.
Only SpriteBehaviors.
It’s called for the behaviors associated with the current state and the behaviors without state.

MouseDown
This event is called when a mouse button is pressed.
All kinds of behaviors.
It’s called for the behaviors associated with the current state and the behaviors without state.
For SpriteBehaviors it’s only called when the mouse is within the sprite.

MouseUp
This event is called when a mouse button is released.
All kinds of behaviors.
It’s called for the behaviors associated with the current state and the behaviors without state.
For SpriteBehaviors it’s only called when the mouse is within the sprite.

MouseUpOutside
This event is called when a mouse button is pressed inside a sprite and then is released outside the sprite bounds.
Only SpriteBehaviors.
It’s called for the behaviors associated with the current state and the behaviors without state.

MouseMove
This event is called when the mouse is pressed and moved.
All kinds of behaviors.
It’s called for the behaviors associated with the current state and the behaviors without state.
For SpriteBehaviors only it’s called while the mouse is pressed and moved inside the sprite bounds.