public class TankHealth : MonoBehaviour
public float m_StartingHealth = 100f; // The amount of health each tank starts with.
public Slider m_Slider; // The slider to represent how much health the tank currently has.
public Image m_FillImage; // The image component of the slider.
public Color m_FullHealthColor = Color.green; // The color the health bar will be when on full health.
public Color m_ZeroHealthColor = Color.red; // The color the health bar will be when on no health.
public GameObject m_ExplosionPrefab; // A prefab that will be instantiated in Awake, then used whenever the tank dies.
private AudioSource m_ExplosionAudio; // The audio source to play when the tank explodes.
private ParticleSystem m_ExplosionParticles; // The particle system the will play when the tank is destroyed.
private float m_CurrentHealth; // How much health the tank currently has.
private bool m_Dead; // Has the tank been reduced beyond zero health yet?
private void Awake ()
// Instantiate the explosion prefab and get a reference to the particle system on it.
m_ExplosionParticles = Instantiate (m_ExplosionPrefab).GetComponent<ParticleSystem> ();
// Get a reference to the audio source on the instantiated prefab.
m_ExplosionAudio = m_ExplosionParticles.GetComponent<AudioSource> ();
// Disable the prefab so it can be activated when it's required.
private void OnEnable()
// When the tank is enabled, reset the tank's health and whether or not it's dead.
m_CurrentHealth = m_StartingHealth;
m_Dead = false;
// Update the health slider's value and color.
public void TakeDamage (float amount)
// Reduce current health by the amount of damage done.
m_CurrentHealth -= amount;
// Change the UI elements appropriately.
// If the current health is at or below zero and it has not yet been registered, call OnDeath.
if (m_CurrentHealth <= 0f && !m_Dead)
private void SetHealthUI ()
// Set the slider's value appropriately.
m_Slider.value = m_CurrentHealth;
// Interpolate the color of the bar between the choosen colours based on the current percentage of the starting health.
m_FillImage.color = Color.Lerp (m_ZeroHealthColor, m_FullHealthColor, m_CurrentHealth / m_StartingHealth);
private void OnDeath ()
// Set the flag so that this function is only called once.
m_Dead = true;
// Move the instantiated explosion prefab to the tank's position and turn it on.
m_ExplosionParticles.transform.position = transform.position;
// Play the particle system of the tank exploding.
// Play the tank explosion sound effect.
// Turn the tank off.