Add shield shader

src/scenes/player.tscn

@@ -1,10 +1,11 @@
-[gd_scene load_steps=23 format=3 uid="uid://cvjqv326igmk0"]
+[gd_scene load_steps=29 format=3 uid="uid://cvjqv326igmk0"]
 
 [ext_resource type="Shader" path="res://shaders/hit-indicator.gdshader" id="1_4eijp"]
 [ext_resource type="Script" path="res://scripts/player.gd" id="1_8i3nd"]
 [ext_resource type="Texture2D" uid="uid://s8kxx0tvktsq" path="res://assets/player-idle.png" id="3_tmw0k"]
 [ext_resource type="PackedScene" uid="uid://c44q2u3nky1ek" path="res://scenes/player_ui.tscn" id="5_w4gtq"]
 [ext_resource type="Script" path="res://scripts/ghost_inventory.gd" id="6_4ximd"]
+[ext_resource type="Shader" path="res://shaders/shield.gdshader" id="6_lxgy7"]
 
 [sub_resource type="RectangleShape2D" id="RectangleShape2D_26xo2"]
 size = Vector2(9, 26)
@@ -135,6 +136,22 @@ _data = {
 "hit": SubResource("Animation_lpfv2")
 }
 
+[sub_resource type="FastNoiseLite" id="FastNoiseLite_uct1m"]
+
+[sub_resource type="NoiseTexture2D" id="NoiseTexture2D_eb6d2"]
+noise = SubResource("FastNoiseLite_uct1m")
+
+[sub_resource type="ShaderMaterial" id="ShaderMaterial_r2s7t"]
+shader = ExtResource("6_lxgy7")
+shader_parameter/noise = SubResource("NoiseTexture2D_eb6d2")
+
+[sub_resource type="Gradient" id="Gradient_mfw4p"]
+offsets = PackedFloat32Array(0)
+colors = PackedColorArray(0, 0, 0, 1)
+
+[sub_resource type="GradientTexture2D" id="GradientTexture2D_pnvrp"]
+gradient = SubResource("Gradient_mfw4p")
+
 [node name="Player" type="CharacterBody2D" groups=["player"]]
 z_index = 1
 collision_layer = 79
@@ -175,5 +192,11 @@ libraries = {
 }
 speed_scale = 3.0
 
+[node name="Shield" type="Sprite2D" parent="."]
+visible = false
+material = SubResource("ShaderMaterial_r2s7t")
+scale = Vector2(0.6, 0.6)
+texture = SubResource("GradientTexture2D_pnvrp")
+
 [connection signal="body_entered" from="Area2D" to="." method="_on_area_2d_body_entered"]
 [connection signal="body_exited" from="Area2D" to="." method="_on_area_2d_body_exited"]

src/scripts/player.gd

@@ -174,6 +174,14 @@ func take_damage(dmg: int):
 	get_tree().get_first_node_in_group('hp-bar').set_value(life)
 	hit_indicator.play('hit')
 
+func enable_shield(strength: float):
+	shield_multiplier = strength
+	$Shield.visible = true
+
+func disable_shield():
+	shield_multiplier = 1.0
+	$Shield.visible = false
+
 func _on_pentagram_layer_combo_done(combo: Array[int]):
 	var spell = SpellBook.find_spell(combo)
 	if spell > 0:

src/scripts/spells/shield.gd

@@ -1,8 +1,8 @@
 extends SpellBase
 
 func cast(player: Player, _enemies: Array[Node]):
-	player.shield_multiplier *= 0.5
+	player.enable_shield(0.5)
 
 func uncast(player: Player, _enemies: Array[Node]):
-	player.shield_multiplier *= 2.0
+	player.disable_shield()
 

src/shaders/shield.gdshader

@@ -0,0 +1,19 @@
+shader_type canvas_item;
+
+const float thickness = 0.02;
+const float feather = 0.005;
+
+uniform sampler2D noise;
+
+vec2 rotate(vec2 v, float angle) {
+	float s = sin(angle);
+	float c = cos(angle);
+	return mat2(vec2(c, s), vec2(-s, c)) * v;
+}
+
+void fragment() {
+	float alpha = COLOR.a * (1.0 - smoothstep(0.5 - feather, 0.5, length(UV - vec2(0.5, 0.5))));
+	alpha *= smoothstep(0.5 - thickness - feather, 0.5 - thickness, length(UV - vec2(0.5, 0.5)));
+	alpha *= texture(noise, rotate(UV, TIME)).r;
+	COLOR = vec4(0.0, 0.0, 1.0, alpha);
+}