Godot - Simple Trail Effect
How it started
Some months ago I started playing around with Godot engine, I’ve started with a Pong clone just to learn the basics, then - when talking about it to a friend - came the idea of this game where the player reflects projectiles with some sort of magic shield. And here I am, making some good progress (considering the short amount of free time I have) thanks to how high level development Godot provides, its awesome community, great documentation and great learning references, such as GD Quest!
The dash skill and its trail effect
The problem:
I have this modular character composed by head and body sprites, it doesn’t have multiple animation frames, its animations are just position and scale tweens.
My solution:
I’ve created a script and attached it to a child node of my character. This dash script has a owner_path that should point to the character. It
assumes the character has some methods:
# Character.gd
func get_speed():
return _speed
func set_speed(value):
_speed = value
func set_input_enabled(enabled):
_input_enabled = enabled
func get_current_sprites():
var head = get_node("YSort/Node2D/Head")
var body = get_node("YSort/Node2D/Body")
return [head, body] Then it uses those methods to achieve the dash with trail effect:
# Dash.gd
extends Node
# The owner of this Dash node needs to have the following methods:
# func set_input_enabled(enabled:bool)
# func get_speed()
# func set_speed(speed_scalar)
# func get_current_sprites() -> List[Sprite]
export (NodePath) var owner_path
var owner_body
var owner_speed
# list of list: each list contains all necessary sprites to represent a
# ghost copy of the original character
var ghosts = []
var tween
func _ready():
owner_body = get_node(owner_path)
var num_sprites = owner_body.get_current_sprites().size()
for i in range(5): # 5 ghost trails
var sprites = []
for j in range(num_sprites):
var s = Sprite.new()
s.set_visible(false)
add_child(s)
sprites.append(s)
ghosts.append(sprites)
tween = Tween.new()
add_child(tween)
func dash():
owner_body.set_input_enabled(false)
owner_speed = owner_body.get_speed()
owner_body.set_speed(owner_speed * 3)
var timer = Timer.new()
timer.connect("timeout", self, "_return_input_to_owner")
add_child(timer)
_start_ghost_tweens()
timer.start(0.25)
timer.set_one_shot(true)
func _start_ghost_tweens():
for i in range(ghosts.size()): # ghost trails
yield(get_tree().create_timer(0.05), "timeout")
for j in range(ghosts[i].size()): # ghost parts (head, body, etc)
var owner_sprites = owner_body.get_current_sprites()
var ghost_part = ghosts[i][j]
ghost_part.set_scale(owner_body.global_scale)
ghost_part.set_position(owner_sprites[j].global_position)
ghost_part.set_texture(owner_sprites[j].get_texture())
ghost_part.set_rotation(owner_sprites[j].global_rotation)
ghost_part.flip_h = owner_sprites[j].flip_h
ghost_part.set_visible(true)
tween.interpolate_property(
ghost_part,
"modulate",
Color(1, 1, 1, 1),
Color(1, 1, 1, 0),
0.25,
Tween.TRANS_LINEAR,
Tween.EASE_IN
)
if not tween.is_connected("tween_completed", self, "_on_complete_ghost_tween"):
tween.connect("tween_completed", self, "_on_complete_ghost_tween")
tween.start()
func _on_complete_ghost_tween(object, key):
object.set_visible(false)
func _return_input_to_owner():
owner_body.set_speed(owner_speed)
owner_body.set_input_enabled(true)Next
You can easily change this script to export the number of ghost trails and tween variables so
you can change them directly on the editor. Also, it might be a good idea to detach (by creating another script)
the trail from the dash logic, after all you might want to add the trail effect to other things that won’t have a dash skill.
Thanks for reading!