Reducing Video Game Creation Effort with Eberos GML2D - Game Development Tools - page 273

and OnMessage sections of the states. As the names implies, an Actuator_Call
placed inside the OnEnter section execute when the state is entered. Any
Actuator_Call placed inside the OnUpdate sectioniscalledoneveryupdate,and
any Actuator_Call placed inside the OnExit section is called when the state is
being exited. The OnMessage section of the states is a bit different from the other
sections. Any Actuator_Call placed inside this section must have a GameMessage
specified along with it, and is only called when that GameMessage is received by
the state.
An FSM is built in Eberos GML2D by linking states together with
TransitionEvent links. Currently, a TransitionEvent link represents an edge
from one State to another State ,orone GlobalState to another GlobalState
and specifies the message that triggers the transition from such state to another.
Finally, a FSM modeled in Eberos GML2D is only valid if every state in the Eberos
GML2D game model is reachable.
19.1.4 Sprite and Animations
In Eberos GML2D, a Sprite2D represents the resource image file for a sprite or
spritesheet(see Figure19.5 ) .Thisconstructholdstheinformationspecificto
that file, such as the resource URL, the image width and height (in pixels), and
where in the screen it will be drawn by default. The screen detination is used in
particular in the case of modeling a heads-up display (HUD) or a menu. In the
case when the sprite is actually a spritesheet containing multiple animations, this
can be modeled using one of the two animation constructs, AnimationStrip2D or
CompositeAnimation2D .
Figure 19.5. Basic class diagram for entity-to-sprite relationship.