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State Machine
Extends: N/A
Implements: N/A
Type | Parameter | Description |
---|---|---|
Time | referenceTime | Engine's physics clock |
Boolean | launchOnStart | on startup, will play simulation (run state) if true, else will not play simulation (editor state) |
Accessibility | Type | Variable Name | Description |
---|---|---|---|
public, static | String | onSaveStateInfo | alert when a save point has been reached |
public, static | Boolean | onStateMachineStateChange | alert when the state is changed |
Accessibility | Type | Field Name | Description |
---|---|---|---|
public | State | currentState | System state object controlling response to update loop |
public | List | allObjects | objects that are added to the physics loop |
public, static | Time | timer | Reference to the simulation engine's physics timer |
Accessibility | Return Type | Method Name | Description |
---|---|---|---|
public | void | addEntityToList | adds an entity to objects to be updated in the physics loop |
public | void | removeEntityFromList | removes an entity from objects to be updated in the physics loop |
public | void | cycle | reverses the allObjects list |
public | void | selectEntityWithTag | findObjectWithTag, and set this entity as "selected" |
private | void | findObjectWithTag | Return the first entity with the tag specified. |
public | void | changeState | move to a new state, given as input to this function. |
public | void | handleSimulationToggle | manages state changes and actions when receiving input regarding simulation start/stop |
public | void | clearStateMachine | removes all objects from state machine with exception of permanent objects (Settings, Camera) |
public | void | loadModel | load a preset model to the simulation using ModelLoader. |
public | void | deactivate | Closes major events and clears all simulation objects. Only called prior to shutdown. |
A state simply manages what actions will be performed during the update loop of the state machine. This way, we can easily control the program logic without having to make a cumbersome number of conditional statements. Additionally, this pattern makes the program more scalable, allowing for additional states to be created if necessary while limiting the amount of rewriting to be done to other scripts.
In conjunction with the Entity class and methods, the simulation updates according to the fps set in the State Machine/ Engine timer. The diagram below shows the relationship between the object function calls, timing, and the update loop.
The Update Loop: As described in the Engine class, the timer "ticks" periodically as determined by the frames per second (fps) variable as set by the user when creating a "Time" timer object. When each of these "ticks" occurs, this leads to the state machine, and eventually the state, calling tick as well. From there, any function within tick will be called (specifically looped over objects in the allObjects list), thus leading to repeated, periodic actions being performed by objects in the state machine. This behavior typically only occurs in the Run State, check the documentation here for more specific descriptions on how this is managed.