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Gaurav Kumar ladhar
Gaurav Kumar ladhar

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How to create Trail Effect in Godot Engine

#ui #gamemech #godot #gdscript

A trail effect is a visual effect that creates a trail of particles, lines, or other graphical elements behind a moving object. It is commonly used in games to enhance the visual feedback of movement, create special effects like magic spells or sword slashes, or add a sense of speed and motion to objects.

The trail effect can be used in various scenarios, such as

  • Character Movement: Adding a trail effect to a character's movement can make it feel more dynamic and visually appealing.

  • Projectiles: Trails can be used to create a visual representation of the path of a projectile, such as a bullet or an arrow.

  • Special Effects: Trail effects can be used to create magical or fantastical effects, like a trail of fire or sparks.

  • UI Elements: Trails can be used to enhance the visual feedback of UI elements, such as highlighting a button when it is clicked or dragged.

Now, let's dive into how you can create a trail effect.

  1. Create a queue of position of player movement and draw line between them.
  2. If Line Exceeds maximum length of trail, delete the last position of queue while adding new position.
  3. During this keep updating the line using position to give trail effect.

Creating a Trail Effect in Godot using Line2D and GDScript

To create a trail effect in Godot, we can utilize the Line2D node and GDScript. The Line2D node allows us to draw lines and curves, making it suitable for creating a trail effect that follows the position of an object.

Here's how you can implement it:

Create a new script that extends the Node2D class. Let's call it "TrailEffect.gd".
In the script, define a variable to hold a reference to the Line2D node.

 @export var line2d: Line2D
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Add two additional variables to control the trail effect.

 @export var max_points: int = 10 @export var point_spacing: float = 1
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Add a variable to accumulate the distance between points

 var distance_accum: float = 0.0
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In the _ready function, check if the Line2D node is assigned

 func _ready(): if line2d == null: print("Error: line2d is not assigned. Please assign it in the editor.") return line2d.clear_points()
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In the _process function, get the current mouse position

 func _process(delta): if line2d == null: return var mouse_position = get_viewport().get_mouse_position()
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Calculate the distance from the last point to the current mouse position

 if line2d.get_point_count() > 0: var last_point = line2d.get_point_position(line2d.get_point_count() - 1) var distance = mouse_position.distance_to(last_point) distance_accum += distance else: distance_accum = point_spacing
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Add a new point if the accumulated distance exceeds the spacing

 if distance_accum >= point_spacing: line2d.add_point(mouse_position) distance_accum = 0.0 if line2d.get_point_count() > max_points: line2d.remove_point(0)
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Optionally, you can add a function to reset the trail

 func reset_trail(): if line2d != null: line2d.clear_points() distance_accum = 0.0
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Here is Complete Code

 extends Node2D # Reference to the Line2D node @export var line2d: Line2D # Maximum number of points in the trail @export var max_points: int = 10 # Distance between points @export var point_spacing: float = 1 # Used to control the spacing between trail points var distance_accum: float = 0.0 func _ready(): if line2d == null: print("Error: line2d is not assigned. Please assign it in the editor.") return # Ensure the Line2D node is empty at the start line2d.clear_points() func _process(delta): if line2d == null: return var mouse_position = get_viewport().get_mouse_position() # Calculate the distance from the last point to the current mouse position if line2d.get_point_count() > 0: var last_point = line2d.get_point_position(line2d.get_point_count() - 1) var distance = mouse_position.distance_to(last_point) distance_accum += distance else: distance_accum = point_spacing # Ensure the first point is added # Add a new point if the accumulated distance exceeds the spacing if distance_accum >= point_spacing: line2d.add_point(mouse_position) distance_accum = 0.0 # Remove the oldest point if we exceed the max number of points if line2d.get_point_count() > max_points: line2d.remove_point(0) # Optionally, you can reset the trail func reset_trail(): if line2d != null: line2d.clear_points() distance_accum = 0.0
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Result of above Code
Preview

Above Trail is also added with width curve for line.

By adding Color and Particle Effect trail we can get following Trial effects.

Trail Effect

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