Package org.xjge.core

Class Command

java.lang.Object
org.xjge.core.Command
public abstract class Command
extends java.lang.Object
Abstraction of the Gang of Four pattern by the same name- command objects serve as a point at which a Control from an InputDevice can be coupled to various player actions and passed to a Puppet object.

More generally, whenever you want to create a new action the player can perform- such as walking, jumping, or shooting, you'll define that behavior in an object that extends this class. Objects of this type are automatically supplied with information about the current state of the players input device. This information in conjunction with several convenience methods provided by the parent class can be used to create player actions that exhibit a high level of fidelity.

The command superclass lacks constructors by design to encourage subclasses to define their own. This open-ended approach allows subclasses to capture whatever supplemental information they require to sufficiently perform the player actions they've been assigned to.

Since:
2.0.0
See Also:
axisMoved(), buttonPressed(), buttonPressedOnce(), getInputValue(), triggerPulled()

  • Constructor Summary

    Constructors
    Constructor Description
    Command()  

  • Method Summary

    Modifier and Type Method Description
    protected boolean axisMoved()
    Convenience method used to check if the input state of the Control coupled to this command is of a certain value.
    protected boolean buttonPressed()
    Convenience method used to check if the input state of the Control coupled to this command is of a certain value.
    protected boolean buttonPressedOnce()
    Convenience method used to check if the input state of the Control coupled to this command is of a certain value.
    abstract void execute()
    Organizes the input logic used to control player actions.
    protected int getDeviceID()
    Obtains the ID number of the device currently executing this command.
    protected float getDeviceSetting​(java.lang.String name)
    Provides subclasses with a value that denotes some preference of the input device currently being used to execute this command.
    protected float getInputValue()
    Provides subclasses with a value describing the current state of the Control coupled to this command.
    protected boolean triggerPulled()
    Convenience method used to check if the input state of the Control coupled to this command is of a certain value.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Command

      public Command()

  • Method Details

    • execute

      public abstract void execute()
      Organizes the input logic used to control player actions. This method is called automatically once every game tick.

    • getInputValue

      protected float getInputValue()
      Provides subclasses with a value describing the current state of the Control coupled to this command. The value provided may be between -1 to 1 or 0 to 1 depending on the input device used and the interactive component being pressed.
      Returns:
      a value denoting the current state of a single interactive component on the input device

    • getDeviceSetting

      protected float getDeviceSetting​(java.lang.String name)
      Provides subclasses with a value that denotes some preference of the input device currently being used to execute this command.

      NOTE: By default the engine provides deadzone settings for both the left and right analog sticks of each input device. These settings determine how much a stick will need to be moved before its input is recognized. The values of these settings can be queried with "leftDeadzone" and "rightDeadzone" respectively.

      Additional settings can be defined with Input.setDeviceSetting(int, String, float).

      Parameters:
      name - the name of the setting to parse a value from
      Returns:
      the value of the setting or NaN if the setting of the name specified could not be found

    • getDeviceID

      protected int getDeviceID()
      Obtains the ID number of the device currently executing this command.
      Returns:
      a value indicating which input device is being used

    • buttonPressed

      protected boolean buttonPressed()
      Convenience method used to check if the input state of the Control coupled to this command is of a certain value. This is useful when we want to check if a button on a Gamepad has is being held down.

      Generally speaking gamepad buttons include:

      CROSS CIRCLE SQUARE TRIANGLE
      DPAD_UP DPAD_DOWN DPAD_LEFT DPAD_RIGHT
      L1R1 L3R3

      If you wish to check whether a button has been pressed once use buttonPressedOnce().

      Returns:
      true if the input value of the interactive component equals 1

    • buttonPressedOnce

      protected boolean buttonPressedOnce()
      Convenience method used to check if the input state of the Control coupled to this command is of a certain value. This is useful for when we want a command to only execute once per button press.

      Generally speaking gamepad buttons include:

      CROSS CIRCLE SQUARE TRIANGLE
      DPAD_UP DPAD_DOWN DPAD_LEFT DPAD_RIGHT
      L1R1 L3R3
      Returns:
      true if the input value of the interactive component equals 1 but only upon its initial press

    • axisMoved

      protected boolean axisMoved()
      Convenience method used to check if the input state of the Control coupled to this command is of a certain value. This is especially useful when we want to determine whether an analog stick on the Gamepad has been moved.

      NOTE: It's important to remember that analog sticks are notoriously unreliable in the sense that their resting values rarely reach true zero. To mitigate this effect input devices provide what's known as a "deadzone" value to indicate how much an analog stick is allowed to move before it's recognized as a conscious decision on the players part. Therefore, the result of this check may not always yield true even if an analog stick is ostensibly moved.

      Analog sticks are grouped by their axes;

      LEFT_STICK_X LEFT_STICK_Y
      RIGHT_STICK_X RIGHT_STICK_Y
      Returns:
      true if the input value of the interactive component exhibits a greater absolute value than the deadzone value

    • triggerPulled

      protected boolean triggerPulled()
      Convenience method used to check if the input state of the Control coupled to this command is of a certain value. This is useful anytime we want to detect a change in the value of a responsive trigger.

      Triggers on Gamepad style controllers may exhibit fluid input values much in the same way analog sticks do. Their function is significantly more predictable however so no deadzone value is used when determining its pulled state.

      The interactive components used to represent triggers are L2 and R2.

      Returns:
      true if the input value of the interactive component is greater than -1 (or 0 in the instance of KeyMouseCombo)