ArtifactForms/MeshLibCore

package engine.components;

import engine.scene.SceneNode;
import math.Vector3f;

/**
 * A simple rotation component that rotates the owning SceneNode around a specified axis at a
 * constant angular speed.
 *
 * <p>Properties:
 *
 * <ul>
 *   <li><b>axis:</b> The axis around which the rotation occurs.
 *   <li><b>angularSpeed:</b> The speed of rotation in radians per second.
 * </ul>
 *
 * <p>The rotation is applied incrementally to the Transform component of the owning SceneNode
 * during each frame update.
 */
public class RotationComponent extends AbstractComponent {

  /** The axis around which the node will rotate. */
  private Vector3f axis;

  /** The angular speed of the rotation in radians per second. */
  private float angularSpeed;

  /**
   * Constructs a RotationComponent with default axis (0, 1, 0) and angular speed. Default settings
   * will rotate around the Y-axis.
   */
  public RotationComponent() {
    this.axis = new Vector3f(0, 1, 0); // Default rotation axis: Y-axis
    this.angularSpeed = 1.0f; // Default angular speed: 1 radian/second
  }

  /**
   * Constructs a RotationComponent with a specified axis and angular speed.
   *
   * @param axis The axis of rotation (must not be null).
   * @param angularSpeed The angular speed in radians per second.
   */
  public RotationComponent(Vector3f axis, float angularSpeed) {
    if (axis == null || axis.length() == 0) {
      throw new IllegalArgumentException("Rotation axis cannot be null or zero-length.");
    }
    this.axis = axis.normalize(); // Normalize the axis to ensure proper
    // rotation
    this.angularSpeed = angularSpeed;
  }

  /**
   * Updates the rotation logic each frame.
   *
   * @param tpf Time per frame (in seconds since the last frame).
   */
  @Override
  public void update(float tpf) {
    SceneNode node = getOwner();
    if (node == null) return;

    // Calculate the incremental rotation angle
    float angleIncrement = angularSpeed * tpf;

    // Apply rotation to the owning SceneNode's Transform
    node.getTransform().rotate(axis.mult(angleIncrement));
  }

  /**
   * Sets a new rotation axis for the component.
   *
   * @param axis The new axis of rotation.
   */
  public void setAxis(Vector3f axis) {
    if (axis == null || axis.length() == 0) {
      throw new IllegalArgumentException("Rotation axis cannot be null or zero-length.");
    }
    this.axis = axis.normalize();
  }

  /**
   * Sets the angular speed of the rotation.
   *
   * @param angularSpeed The new angular speed in radians per second.
   */
  public void setAngularSpeed(float angularSpeed) {
    this.angularSpeed = angularSpeed;
  }

  /**
   * Gets the current rotation axis.
   *
   * @return The axis of rotation.
   */
  public Vector3f getAxis() {
    return axis;
  }

  /**
   * Gets the current angular speed.
   *
   * @return The angular speed in radians per second.
   */
  public float getAngularSpeed() {
    return angularSpeed;
  }

  @Override
  public void onAttach() {}

  @Override
  public void onDetach() {}
}