Unity PlatForm 09 Enemy Damaged
===
2020.08.14

###### tags: `platform`

## List
1. [Enermy Damaged](#ED)
2. [Knockback & Die](#KD)
3. [Particle System](#PS)

## Content
### Enemry Damaged<a id=ED/>
When player attack enermies, show animation, decrease hp, finally dead.<br>Set tags for enemry animations, and control in script.<br>Need some conditions and objects below.

// This for MoveSpeed with anim.
[SerializeField]
private float maxHealth, knockbackSpeedX, knockbackSpeedY, knockbackDuration, knockbackDeathSpeedX, knockbackDeathSpeedY, deathToque;
[SerializeField]
private bool applyKnockback;
[SerializeField]
private GameObject hitParticle;

private float currentHealth, knockbackStart;

private int playerFacingDirection;
private bool playerOnLeft, knockback;

//Player Class is for damage section and facing...
private PlayerPlatformAdvenced pc;
private GameObject aliveGO, brokenTopGO, brokenBotGO;
private Rigidbody2D rbAlive, rbBrokenTop, rbBrokenBot;
private Animator aliveAnim;

<br>

Damage function is activated in playerCombat script, `collider.transform.parent.SendMessage("Damage", attackDamage);`<br>Set all action and trigger.<br>Set animation direction with player's relative position.<br>So, `GetFacingDirection()` is written in Player Script.

private void Damage(float amout)
{
    currentHealth -= amout;
    playerFacingDirection = pc.GetFacingDirection();

    Instantiate(hitParticle, aliveGO.transform.position, Quaternion.Euler(0.0f, 0.0f, Random.Range(0.0f, 360.0f)));

    if (playerFacingDirection == 1)
        playerOnLeft = true;
    else
        playerOnLeft = false;

    aliveAnim.SetBool("playerOnLeft", playerOnLeft);
    aliveAnim.SetTrigger("damage");

    if (applyKnockback && currentHealth > 0.0f)
        Knockback();

    if (currentHealth <= 0)
        Die();
}

<br><br>

### Knockback & Die<a id=KD/>
Enemies are damaged, knockbacking or dying.<br>Knckback technic is same player's action.<br>Check Condition with time in `update()`.

private void Knockback()
{
    knockback = true;
    knockbackStart = Time.time;
    rbAlive.velocity = new Vector2(knockbackSpeedX * playerFacingDirection, knockbackSpeedY);
}

// In update()
private void Checkknockback()
{
    if (Time.time >= knockbackStart + knockbackDuration && knockback)
    {
        knockback = false;
        rbAlive.velocity = new Vector2(0, rbAlive.velocity.y);
    }
}

<br>

Last, HP reach 0, enemies die.<br>When die, broken objs actived, punishing other side and rotating.<br>Use torque for this movement.

 private void Die()
{
    aliveGO.SetActive(false);
    brokenTopGO.SetActive(true);
    brokenBotGO.SetActive(true);

    brokenTopGO.transform.position = aliveGO.transform.position;
    brokenBotGO.transform.position = aliveGO.transform.position;

    rbBrokenBot.velocity = new Vector2(knockbackSpeedX * playerFacingDirection, knockbackSpeedY);
    rbBrokenTop.velocity = new Vector2(knockbackDeathSpeedX * playerFacingDirection, knockbackDeathSpeedY);
    rbBrokenTop.AddTorque(deathToque * -playerFacingDirection, ForceMode2D.Impulse);
}

<br>

### Particle System<a id="PS"/>
When attack, show particles between player and enermies.<br>Attack particles are instatiated in `Damage()`, must be destroyed end attack animation.<br>It is not limited in attack, possible any other particle effects.

public class ParticleController : MonoBehaviour
{
    private void FinishAnim()
    {
        Destroy(gameObject);
    }
}