hit flash effect for enemies using shader

utilized shader for flash effect with a uniform variable `lerp_percent`, being controlled from component scene to lerp the value for animation

2d-survivors-course/scenes/components/hit_flash_component.gd

@@ -0,0 +1,22 @@
+extends Node
+
+@export var health_component: HealthComponent
+@export var sprite: Sprite2D
+@export var hit_flash_material : ShaderMaterial
+
+var hit_flash_tween: Tween
+
+func _ready():
+	health_component.health_changed.connect(on_health_changed)
+	sprite.material = hit_flash_material
+
+
+func on_health_changed():
+	if hit_flash_tween !=null and hit_flash_tween.is_valid():
+		hit_flash_tween.kill()
+
+	(sprite.material as ShaderMaterial).set_shader_parameter("lerp_percent", 1.0)
+
+	hit_flash_tween = create_tween()
+	hit_flash_tween.tween_property(sprite.material, "shader_parameter/lerp_percent", 0.0, .25)\
+	.set_ease(Tween.EASE_IN).set_trans(Tween.TRANS_CUBIC)

2d-survivors-course/scenes/components/hit_flash_component.gdshader

@@ -0,0 +1,19 @@
+shader_type canvas_item;
+
+//void vertex() {
+	//// Called for every vertex the material is visible on.
+//}
+
+uniform float lerp_percent: hint_range(0.0, 1.0, 0.1);
+
+void fragment() {
+	// Called for every pixel the material is visible on.
+	vec4 texture_color = texture(TEXTURE, UV);
+	vec4 final_color = mix(texture_color, vec4(1.0, 1.0, 1.0, texture_color.a), lerp_percent);
+	COLOR = final_color;
+}
+
+//void light() {
+	// Called for every pixel for every light affecting the CanvasItem.
+	// Uncomment to replace the default light processing function with this one.
+//}

2d-survivors-course/scenes/components/hit_flash_component.tscn

@@ -0,0 +1,8 @@
+[gd_scene load_steps=3 format=3 uid="uid://y7fu5m6xj717"]
+
+[ext_resource type="Script" path="res://scenes/components/hit_flash_component.gd" id="1_p1022"]
+[ext_resource type="Material" uid="uid://cp2qrgnhwj747" path="res://scenes/components/hit_flash_component_material.tres" id="2_0ccf8"]
+
+[node name="HitFlashComponent" type="Node"]
+script = ExtResource("1_p1022")
+hit_flash_material = ExtResource("2_0ccf8")

2d-survivors-course/scenes/components/hit_flash_component_material.tres

@@ -0,0 +1,8 @@
+[gd_resource type="ShaderMaterial" load_steps=2 format=3 uid="uid://cp2qrgnhwj747"]
+
+[ext_resource type="Shader" path="res://scenes/components/hit_flash_component.gdshader" id="1_wsdh0"]
+
+[resource]
+resource_local_to_scene = true
+shader = ExtResource("1_wsdh0")
+shader_parameter/lerp_percent = 0.0

2d-survivors-course/scenes/game_object/basic_enemy/basic_enemy.tscn

@@ -1,4 +1,4 @@
-[gd_scene load_steps=13 format=3 uid="uid://dlsoablcbbnbn"]
+[gd_scene load_steps=16 format=3 uid="uid://dlsoablcbbnbn"]
 
 [ext_resource type="Script" path="res://scenes/game_object/basic_enemy/basic_enemy.gd" id="1_btoq0"]
 [ext_resource type="Texture2D" uid="uid://c4wr81m8ifp8g" path="res://scenes/game_object/basic_enemy/basic_enemy.png" id="1_tp3eb"]
@@ -7,6 +7,8 @@
 [ext_resource type="PackedScene" uid="uid://cjvydmwd1w4f6" path="res://scenes/components/hurt_box_component.tscn" id="4_dclov"]
 [ext_resource type="PackedScene" uid="uid://ccr2pyjml5e3f" path="res://scenes/components/death_component.tscn" id="4_ghoxd"]
 [ext_resource type="PackedScene" uid="uid://bq1vvw48qq8jf" path="res://scenes/components/velocity_component.tscn" id="4_quu7f"]
+[ext_resource type="Shader" path="res://scenes/components/hit_flash_component.gdshader" id="6_6ykum"]
+[ext_resource type="PackedScene" uid="uid://y7fu5m6xj717" path="res://scenes/components/hit_flash_component.tscn" id="8_7vpqb"]
 
 [sub_resource type="Animation" id="Animation_u4rlb"]
 length = 0.001
@@ -70,6 +72,11 @@ _data = {
 "walk": SubResource("Animation_b3l7f")
 }
 
+[sub_resource type="ShaderMaterial" id="ShaderMaterial_q55gy"]
+resource_local_to_scene = true
+shader = ExtResource("6_6ykum")
+shader_parameter/lerp_percent = 0.0
+
 [sub_resource type="CircleShape2D" id="CircleShape2D_jomo2"]
 radius = 12.0
 
@@ -96,6 +103,11 @@ health_component = NodePath("../HealthComponent")
 
 [node name="VelocityComponent" parent="." instance=ExtResource("4_quu7f")]
 
+[node name="HitFlashComponent" parent="." node_paths=PackedStringArray("health_component", "sprite") instance=ExtResource("8_7vpqb")]
+health_component = NodePath("../HealthComponent")
+sprite = NodePath("../Visuals/Sprite2D")
+hit_flash_material = SubResource("ShaderMaterial_q55gy")
+
 [node name="DeathComponent" parent="." node_paths=PackedStringArray("health_component", "sprite") instance=ExtResource("4_ghoxd")]
 health_component = NodePath("../HealthComponent")
 sprite = NodePath("../Visuals/Sprite2D")

2d-survivors-course/scenes/game_object/wizard_enemy/wizard_enemy.tscn

@@ -1,4 +1,4 @@
-[gd_scene load_steps=13 format=3 uid="uid://kjyrfs3as7an"]
+[gd_scene load_steps=16 format=3 uid="uid://kjyrfs3as7an"]
 
 [ext_resource type="Texture2D" uid="uid://clwxylm8bs8xj" path="res://scenes/game_object/wizard_enemy/wizard_enemy.png" id="1_us2gk"]
 [ext_resource type="Script" path="res://scenes/game_object/wizard_enemy/wizard_enemy.gd" id="1_yaq25"]
@@ -7,6 +7,47 @@
 [ext_resource type="PackedScene" uid="uid://ccr2pyjml5e3f" path="res://scenes/components/death_component.tscn" id="2_xyxvg"]
 [ext_resource type="PackedScene" uid="uid://buus3vhc8c05j" path="res://scenes/components/vial_drop_component.tscn" id="4_wjm1p"]
 [ext_resource type="PackedScene" uid="uid://cjvydmwd1w4f6" path="res://scenes/components/hurt_box_component.tscn" id="4_wlk0n"]
+[ext_resource type="PackedScene" uid="uid://y7fu5m6xj717" path="res://scenes/components/hit_flash_component.tscn" id="5_loq7b"]
+[ext_resource type="Shader" path="res://scenes/components/hit_flash_component.gdshader" id="6_sy68i"]
+
+[sub_resource type="Animation" id="Animation_qfuh7"]
+length = 0.001
+tracks/0/type = "value"
+tracks/0/imported = false
+tracks/0/enabled = true
+tracks/0/path = NodePath("Visuals/Sprite2D:position")
+tracks/0/interp = 1
+tracks/0/loop_wrap = true
+tracks/0/keys = {
+"times": PackedFloat32Array(0),
+"transitions": PackedFloat32Array(1),
+"update": 0,
+"values": [Vector2(0, 0)]
+}
+tracks/1/type = "value"
+tracks/1/imported = false
+tracks/1/enabled = true
+tracks/1/path = NodePath("Visuals/Sprite2D:rotation")
+tracks/1/interp = 1
+tracks/1/loop_wrap = true
+tracks/1/keys = {
+"times": PackedFloat32Array(0),
+"transitions": PackedFloat32Array(1),
+"update": 0,
+"values": [0.0]
+}
+tracks/2/type = "value"
+tracks/2/imported = false
+tracks/2/enabled = true
+tracks/2/path = NodePath("Visuals/Sprite2D:scale")
+tracks/2/interp = 1
+tracks/2/loop_wrap = true
+tracks/2/keys = {
+"times": PackedFloat32Array(0),
+"transitions": PackedFloat32Array(1),
+"update": 0,
+"values": [Vector2(1, 1)]
+}
 
 [sub_resource type="Animation" id="Animation_u4jge"]
 resource_name = "walk"
@@ -67,51 +108,17 @@ tracks/3/keys = {
 }]
 }
 
-[sub_resource type="Animation" id="Animation_qfuh7"]
-length = 0.001
-tracks/0/type = "value"
-tracks/0/imported = false
-tracks/0/enabled = true
-tracks/0/path = NodePath("Visuals/Sprite2D:position")
-tracks/0/interp = 1
-tracks/0/loop_wrap = true
-tracks/0/keys = {
-"times": PackedFloat32Array(0),
-"transitions": PackedFloat32Array(1),
-"update": 0,
-"values": [Vector2(0, 0)]
-}
-tracks/1/type = "value"
-tracks/1/imported = false
-tracks/1/enabled = true
-tracks/1/path = NodePath("Visuals/Sprite2D:rotation")
-tracks/1/interp = 1
-tracks/1/loop_wrap = true
-tracks/1/keys = {
-"times": PackedFloat32Array(0),
-"transitions": PackedFloat32Array(1),
-"update": 0,
-"values": [0.0]
-}
-tracks/2/type = "value"
-tracks/2/imported = false
-tracks/2/enabled = true
-tracks/2/path = NodePath("Visuals/Sprite2D:scale")
-tracks/2/interp = 1
-tracks/2/loop_wrap = true
-tracks/2/keys = {
-"times": PackedFloat32Array(0),
-"transitions": PackedFloat32Array(1),
-"update": 0,
-"values": [Vector2(1, 1)]
-}
-
 [sub_resource type="AnimationLibrary" id="AnimationLibrary_p77v0"]
 _data = {
 "RESET": SubResource("Animation_qfuh7"),
 "walk": SubResource("Animation_u4jge")
 }
 
+[sub_resource type="ShaderMaterial" id="ShaderMaterial_iram6"]
+resource_local_to_scene = true
+shader = ExtResource("6_sy68i")
+shader_parameter/lerp_percent = 0.0
+
 [sub_resource type="CircleShape2D" id="CircleShape2D_kgh57"]
 radius = 8.0
 
@@ -139,6 +146,11 @@ acceleration = 20.0
 [node name="VialDropComponent" parent="." node_paths=PackedStringArray("health_component") instance=ExtResource("4_wjm1p")]
 health_component = NodePath("../HealthComponent")
 
+[node name="HitFlashComponent" parent="." node_paths=PackedStringArray("health_component", "sprite") instance=ExtResource("5_loq7b")]
+health_component = NodePath("../HealthComponent")
+sprite = NodePath("../Visuals/Sprite2D")
+hit_flash_material = SubResource("ShaderMaterial_iram6")
+
 [node name="DeathComponent" parent="." node_paths=PackedStringArray("health_component", "sprite") instance=ExtResource("2_xyxvg")]
 health_component = NodePath("../HealthComponent")
 sprite = NodePath("../Visuals/Sprite2D")