Health, damage and hit feedback

your project so far

Assets/

Scenes/

Arena.unity

KnightDummy ×3

Scripts/

CharacterStats.csSkillCaster.csEquipment.csCharacterStats.OnDied eventHealthBar.csDamagePopup.csHitFlash.cs

Project settings

Enemy layer

you already havethis lesson adds

You have skills that deal damage, but nothing to hit and no way to see that it worked. A hit the player cannot feel does not exist.

animated diagram

Three signals sell a hit: a number that pops, a body that flashes, and a bar that drops.

Step 1 — something to hit

1
Create a Capsule, name it Dummy, give it a red material and put it 6 m in front of the Knight. Yes — it is the same kind of capsule the Knight itself was at the start of this tab.
2
Create a layer called Enemy: Inspector▸Layer▸Add Layer, then assign it to the Dummy.
3
Attach CharacterStats to it and set maxHealth to 120.
4
Set the Enemy Layers mask on the Knight's SkillCaster to Enemy only — now Q, E and R hit the dummies and never the Mage or the Archer.
5
Duplicate the dummy twice and spread the three around the player.

Step 2 — an event, not a poll

The health bar must not check the health every frame. Instead, CharacterStats announces when health changed, and whoever cares listens.

add to CharacterStats.cs

using System;
using UnityEngine;

// ... inside CharacterStats

/// current, max
public event Action<float, float> OnHealthChanged;
public event Action OnDied;

public void TakeDamage(float rawDamage)
{
    if (!IsAlive) return;

    float reduced = Mathf.Max(1f, rawDamage - finalDefense);
    currentHealth = Mathf.Max(0f, currentHealth - reduced);

    OnHealthChanged?.Invoke(currentHealth, finalMaxHp);   // tell the listeners
    DamagePopup.Spawn(transform.position + Vector3.up * 2f, reduced);

    if (!IsAlive)
    {
        OnDied?.Invoke();
        Die();
    }
}

public void Heal(float amount)
{
    if (!IsAlive) return;
    currentHealth = Mathf.Min(finalMaxHp, currentHealth + amount);
    OnHealthChanged?.Invoke(currentHealth, finalMaxHp);
}

✓ Event

Runs only on the frames where damage actually happened. Zero cost the rest of the time.

✖ Update() polling

Reads the value 60 times a second for 30 enemies to catch the two frames that mattered.

Step 3 — the health bar above the head

1
On the Dummy, add a child UI▸Canvas and set Render Mode = World Space.
2
Set the Canvas RectTransform to width 120, height 20, scale 0.01, position Y = 2.4.
3
Scale 0.01 turns 120 UI pixels into 1.2 metres — without it the bar is the size of a building.
4
Inside it put two Images: a dark background, and a red Fill with Image Type = Filled, Horizontal.

HealthBar.cs — put it on the world-space Canvas

using UnityEngine;
using UnityEngine.UI;

public class HealthBar : MonoBehaviour
{
    [SerializeField] private CharacterStats stats;
    [SerializeField] private Image fill;
    [SerializeField] private Image trailing;      // the slower amber bar
    [SerializeField] private float trailSpeed = 1.2f;

    private Camera cam;
    private float target = 1f;

    void Awake() => cam = Camera.main;

    void OnEnable()
    {
        stats.OnHealthChanged += Redraw;
        stats.OnDied += () => gameObject.SetActive(false);
    }

    void OnDisable() => stats.OnHealthChanged -= Redraw;   // always unsubscribe

    void Redraw(float current, float max)
    {
        target = max <= 0f ? 0f : current / max;
        fill.fillAmount = target;                          // snaps
    }

    void LateUpdate()
    {
        // the trailing bar eases down — this is what makes damage readable
        trailing.fillAmount = Mathf.MoveTowards(trailing.fillAmount, target, trailSpeed * Time.deltaTime);

        // always face the camera
        transform.rotation = cam.transform.rotation;
    }
}

Step 4 — floating damage numbers

DamagePopup.cs — on a small world-space Canvas prefab

using UnityEngine;
using TMPro;

public class DamagePopup : MonoBehaviour
{
    private static DamagePopup prefab;

    [SerializeField] private TextMeshProUGUI label;
    [SerializeField] private float lifeTime = 0.8f;
    [SerializeField] private float riseSpeed = 1.6f;

    private float age;

    public static void Spawn(Vector3 worldPos, float amount)
    {
        if (prefab == null)
            prefab = Resources.Load<DamagePopup>("DamagePopup");   // Assets/Resources/DamagePopup.prefab
        if (prefab == null) return;

        DamagePopup p = Instantiate(prefab, worldPos, Quaternion.identity);
        p.label.text = Mathf.RoundToInt(amount).ToString();

        // a little scatter so two hits never overlap
        p.transform.position += new Vector3(Random.Range(-0.3f, 0.3f), 0f, 0f);
    }

    void Update()
    {
        age += Time.deltaTime;

        transform.position += Vector3.up * riseSpeed * Time.deltaTime;
        transform.rotation = Camera.main.transform.rotation;

        float t = age / lifeTime;
        label.alpha = 1f - t;                                     // fade out
        transform.localScale = Vector3.one * (1f + 0.3f * (1f - t));

        if (age >= lifeTime) Destroy(gameObject);
    }
}

The white flash

HitFlash.cs — on the dummy

using System.Collections;
using UnityEngine;

public class HitFlash : MonoBehaviour
{
    [SerializeField] private CharacterStats stats;
    [SerializeField] private Renderer[] renderers;
    [SerializeField] private float duration = 0.09f;

    private Color[] original;

    void Awake()
    {
        original = new Color[renderers.Length];
        for (int i = 0; i < renderers.Length; i++)
            original[i] = renderers[i].material.color;
    }

    void OnEnable()  => stats.OnHealthChanged += (_, __) => { StopAllCoroutines(); StartCoroutine(Flash()); };

    IEnumerator Flash()
    {
        foreach (Renderer r in renderers) r.material.color = Color.white;
        yield return new WaitForSeconds(duration);
        for (int i = 0; i < renderers.Length; i++) renderers[i].material.color = original[i];
    }
}

0.09 s is the sweet spot. Shorter and nobody sees it; longer and the enemy looks like a strobe light.
Reading .material creates a per-object copy of the material. That is what lets one enemy flash without flashing all of them.
Combine the flash with the 0.05 s hit-stop from the VFX lesson and even a capsule feels good to punch.