TrailRenderer

TrailRenderer(size=[1, .01], segments=8, min_spacing=.05, fade_speed=0, color_gradient=[color.white, color.clear], **kwargs)

Located in ursina/prefabs/trail_renderer.py

Overview

TrailRenderer attaches to an Entity and leaves a smooth, fading ribbon in its wake. It uses a Pipe mesh with adjustable thickness, color gradient and fade speed.

Constructor Arguments

Argument	Type	Default	Description
`size`	`list[float]`	`[1, .01]`	Width and thickness of the trail cross-section.
`segments`	`int`	`8`	Number of radial segments in the pipe mesh.
`min_spacing`	`float`	`.05`	Minimum distance moved before adding a new segment.
`fade_speed`	`float`	`0`	How fast old segments disappear (units per second).
`color_gradient`	`list[Color]`	`[color.white, color.clear]`	Colors along the trail from start to end.
`**kwargs`	`any`		Other `Entity` parameters (`parent`, `position`, `scale`, etc.).

Attributes

Name	Description
`.renderer`	`Entity` holding a `Pipe` model that displays the trail.
`.segments`	Number of radial segments around the pipe.
`.update_step`	Distance threshold for adding new segments (same as `min_spacing`).
`.min_spacing`	Minimum movement before spawning the next trail segment.
`.fade_speed`	Speed at which older segments fade out and are removed.
`.on_enable`	Callback to enable the internal renderer.
`.on_disable`	Callback to disable the internal renderer.

Methods

Method	Description
`update()`	Called each frame to check movement and extend the trail.
`on_destroy()`	Cleanup the renderer and any remaining segments.

Example

from ursina import *
from ursina.prefabs.trail_renderer import TrailRenderer

app = Ursina(vsync=False)
window.color = color.black
mouse.visible = False

# A player entity that follows the mouse
player = Entity(z=1)
player.graphics = Entity(parent=player, scale=.1, model='circle')

# Attach one or more trail renderers to the player
trails = []
trails.append(
    TrailRenderer(
        size=[1, 1],
        segments=8,
        min_spacing=0.05,
        fade_speed=1,
        parent=player,
        color_gradient=[color.magenta, color.cyan.tint(-.5), color.clear]
    )
)

def update():
    # smooth follow the mouse
    player.position = lerp(player.position, mouse.position * 10, time.dt * 4)

def input(key):
    if key == 'escape':
        for t in trails:
            t.enabled = not t.enabled
    if key == 'space':
        destroy(player)

EditorCamera()
Entity(model=Grid(8,8), rotation_x=90, color=color.gray, y=-3, scale=8)

app.run()