sprite3d outline shader, use it for sprouts

scenes/interactivity_outline2.gdshader

@@ -0,0 +1,32 @@
+shader_type spatial;
+
+
+uniform float width : hint_range(0.0, 16.0);
+uniform vec4 outline_color : source_color;
+uniform sampler2D albedo_texture : source_color, filter_nearest;
+
+
+void vertex() {
+     MODELVIEW_MATRIX = VIEW_MATRIX * mat4(INV_VIEW_MATRIX[0], vec4(0, 1, 0, 0), INV_VIEW_MATRIX[2], MODEL_MATRIX[3]);
+}
+
+/* thanks gdquest */
+void fragment() {
+    vec2 size = vec2(width) / vec2(textureSize(albedo_texture, 0));
+   
+    vec4 sprite_color = texture(albedo_texture, UV);
+   
+    float alpha = sprite_color.a;
+    alpha += texture(albedo_texture, UV + vec2(0.0, -size.y)).a;
+    alpha += texture(albedo_texture, UV + vec2(size.x, -size.y)).a;
+    alpha += texture(albedo_texture, UV + vec2(size.x, 0.0)).a;
+    alpha += texture(albedo_texture, UV + vec2(size.x, size.y)).a;
+    alpha += texture(albedo_texture, UV + vec2(0.0, size.y)).a;
+    alpha += texture(albedo_texture, UV + vec2(-size.x, size.y)).a;
+    alpha += texture(albedo_texture, UV + vec2(-size.x, 0.0)).a;
+    alpha += texture(albedo_texture, UV + vec2(-size.x, -size.y)).a;
+   
+    vec3 final_color = mix(outline_color.rgb, sprite_color.rgb, sprite_color.a);
+    ALBEDO = final_color;
+	ALPHA = clamp(alpha, 0.0, 1.0);
+}

src/ingame/sprout.gd

@@ -2,7 +2,7 @@ extends Node3D
 
 @export var _need_water_drop: Sprite3D
 @export var _production_timer: Timer
-@export var _sprite: Sprite3D
+@export var _mesh: MeshInstance3D
 
 var needs_water := true
 var stage: int = 1
@@ -19,17 +19,12 @@ func _on_production_timer_timeout() -> void:
 	_need_water_drop.show()
 
 
-@rpc("authority", "call_local", "reliable")
-func _reflect_texture(p_stage: int) -> void:
-	_sprite.texture = load("res://assets/sprout%s.png" % p_stage)
-
-
 @rpc("authority", "call_local", "reliable")
 func _water_shared(sender_id: int) -> void:
 	if stage >= final_stage:
 		return
 	stage += 1
-	_sprite.texture = load("res://assets/sprout%s.png" % stage)
+	_mesh.material_override.set("shader_parameter/albedo_texture", load("res://assets/sprout%s.png" % stage))
 	if sender_id != 0:
 		GameState.fetch().player_data[sender_id].chain_water_combo(1)
 

src/ingame/sprout.tscn

@@ -1,7 +1,8 @@
-[gd_scene load_steps=6 format=3 uid="uid://bysgtksvovyur"]
+[gd_scene load_steps=9 format=3 uid="uid://bysgtksvovyur"]
 
 [ext_resource type="Script" path="res://src/ingame/sprout.gd" id="1_snma1"]
 [ext_resource type="Texture2D" uid="uid://d35y5ckne72qe" path="res://assets/sprout1.png" id="2_ipgad"]
+[ext_resource type="Shader" path="res://scenes/interactivity_outline2.gdshader" id="2_oa2it"]
 [ext_resource type="Texture2D" uid="uid://cwbl0r1e26eja" path="res://assets/drop.png" id="3_kghdv"]
 
 [sub_resource type="SceneReplicationConfig" id="SceneReplicationConfig_rs2qp"]
@@ -12,27 +13,35 @@ properties/1/path = NodePath("NeedWaterDrop:visible")
 properties/1/spawn = true
 properties/1/replication_mode = 2
 
+[sub_resource type="ShaderMaterial" id="ShaderMaterial_3ul7y"]
+resource_local_to_scene = true
+render_priority = 0
+shader = ExtResource("2_oa2it")
+shader_parameter/width = 1.0
+shader_parameter/outline_color = Color(0, 0, 0, 1)
+shader_parameter/albedo_texture = ExtResource("2_ipgad")
+
+[sub_resource type="QuadMesh" id="QuadMesh_0x06e"]
+size = Vector2(0.5, 1)
+
 [sub_resource type="CapsuleShape3D" id="CapsuleShape3D_cwbye"]
 radius = 0.3
 height = 0.8
 
-[node name="Sprout" type="Node3D" node_paths=PackedStringArray("_need_water_drop", "_production_timer", "_sprite")]
+[node name="Sprout" type="Node3D" node_paths=PackedStringArray("_need_water_drop", "_production_timer", "_mesh")]
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0.00401986, -0.00383317, 0.00119042)
 script = ExtResource("1_snma1")
 _need_water_drop = NodePath("NeedWaterDrop")
 _production_timer = NodePath("ProductionTimer")
-_sprite = NodePath("Sprite3D")
+_mesh = NodePath("Mesh")
 
 [node name="MultiplayerSynchronizer" type="MultiplayerSynchronizer" parent="."]
 replication_config = SubResource("SceneReplicationConfig_rs2qp")
 
-[node name="Sprite3D" type="Sprite3D" parent="."]
+[node name="Mesh" type="MeshInstance3D" parent="."]
-transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0.3, 0)
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0.25, 0)
-pixel_size = 0.02
+material_override = SubResource("ShaderMaterial_3ul7y")
-billboard = 2
+mesh = SubResource("QuadMesh_0x06e")
-shaded = true
-texture_filter = 2
-texture = ExtResource("2_ipgad")
 
 [node name="NeedWaterDrop" type="Sprite3D" parent="."]
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0.3, 0)