Add DamageFlash component for visual feedback on damage; implement flash effect with customizable duration and color

Assets/Scripts/Systems/DamageFlash.cs

@@ -0,0 +1,64 @@
+using System;
+using System.Collections;
+using KBCore.Refs;
+using UnityEngine;
+
+namespace Systems
+{
+    public class DamageFlash : MonoBehaviour
+    {
+        private static readonly int MarkerFlashColor = Shader.PropertyToID("_FlashColor");
+        private static readonly int MarkerFlashAmount = Shader.PropertyToID("_FlashAmount");
+        private Material material;
+        private Coroutine damageFlashCoroutine;
+        
+        [SerializeField] private float flashDuration;
+        [ColorUsage(true, true)][SerializeField] private Color flashColor = Color.white;
+        [SerializeField, Self] private Health health;
+        [SerializeField, Child] private SpriteRenderer spriteRenderer;
+        
+        private void OnEnable()
+        {
+            health.OnTakeDamage += OnHit;
+            
+            Initialize();
+        }
+
+        private void OnDisable()
+        {
+            health.OnTakeDamage -= OnHit;
+        }
+
+        private void Initialize()
+        {
+            if (!spriteRenderer) return;
+            
+            material = spriteRenderer.material;
+        }
+
+        private void OnHit()
+        {
+            damageFlashCoroutine = StartCoroutine(Flash());
+        }
+
+        private IEnumerator Flash()
+        {
+            SetFlashColor(flashColor);
+            var elapsedTime = 0f;
+
+            while (elapsedTime < flashDuration)
+            {
+                elapsedTime += Time.deltaTime;
+                var currentFlashAmount = Mathf.Lerp(1f, 0f, elapsedTime / flashDuration);
+                material.SetFloat(MarkerFlashAmount, currentFlashAmount);
+                yield return null;
+            }
+        }
+        
+        private void SetFlashColor(Color color)
+        {
+            if (!material) return;
+            material.SetColor(MarkerFlashColor, color);
+        }
+    }
+}