Rotate and scale

Alarms and Tweens is only a way to change your entity behaviour: you can change position (and many other properties), but MarteEngine help you in manipulating angle of your Entity and Scale.

Rotate

Rotate an entity is just a matter of change in angle so MarteEngine can rotate Image or Animation associated to Entity. We do this defining an alarm on entity, to change angle of Entity:

public class RotateEntity extends Entity {

	private static final String ROTATE_ME = "rotate_me";

	public RotateEntity(float x, float y, Image image) {
		super(x, y, image);

		// we set that image or animation must be rotate with Entity
		setCentered(true);
		// we define and alarm so we can rotate entity every 2 seconds
		setAlarm(ROTATE_ME, 2, false, true);
	}

	@Override
	public void alarmTriggered(String name) {
		if (name.equalsIgnoreCase(ROTATE_ME)) {
			// let's rotate a bit
			int angle = this.getAngle();
			angle += 2;
			if (angle >= 360)
				angle -= 360;
			this.setAngle(angle);
		}
	}

}

We can mark on setCentered(true) in entity constructor: you must let know to MarteEngine that image or animation associated to entity rotate with it.. in some cases you simply don't want this behaviour.

Scale

Scale entity image or animation is not so different: just change scale properties on Entity:

public class ScaleEntity extends Entity {

	private static final String SCALE_ME = "scale_me";
	private float scaleDir = -0.1f;

	public ScaleEntity(float x, float y, Image image) {
		super(x, y, image);

		// we define and alarm so we can scale entity every 2 seconds
		setAlarm(SCALE_ME, 2, false, true);
	}

	@Override
	public void alarmTriggered(String name) {
		if (name.equalsIgnoreCase(SCALE_ME)) {
			// let's scale entity
			this.scale += scaleDir;
			if (this.scale <= 0.1f || this.scale >= 2.0f){
				scaleDir *= -1;
			}
		}
	}
}

In this example we are scaling entity image from a minimum of 0.1 to 2.0 of his original width and height!

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MarteEngine version 0.2