Source code for arcade.particle

"""
Particle - Object produced by an Emitter.  Often used in large quantity to produce visual effects effects
"""

from arcade.sprite import Sprite
from arcade.draw_commands import Texture
import arcade.utils
from arcade.arcade_types import Point, Vector
from typing import Union

FilenameOrTexture = Union[str, Texture]


[docs]class Particle(Sprite): """Sprite that is emitted from an Emitter"""
[docs] def __init__( self, filename_or_texture: FilenameOrTexture, change_xy: Vector, center_xy: Point = (0.0, 0.0), angle: float = 0.0, change_angle: float = 0.0, scale: float = 1.0, alpha: int = 255, mutation_callback=None ): if isinstance(filename_or_texture, Texture): super().__init__(None, scale=scale) self.append_texture(filename_or_texture) self.set_texture(0) else: super().__init__(filename_or_texture, scale=scale) self.center_x = center_xy[0] self.center_y = center_xy[1] self.change_x = change_xy[0] self.change_y = change_xy[1] self.angle = angle self.change_angle = change_angle self.alpha = alpha self.mutation_callback = mutation_callback
[docs] def update(self): """Advance the Particle's simulation""" super().update() if self.mutation_callback: self.mutation_callback(self)
# def draw(self): # raise NotImplementedError("Particle.draw needs to be implemented")
[docs] def can_reap(self): """Determine if Particle can be deleted""" raise NotImplementedError("Particle.can_reap needs to be implemented")
[docs]class EternalParticle(Particle): """Particle that has no end to its life"""
[docs] def __init__( self, filename_or_texture: FilenameOrTexture, change_xy: Vector, center_xy: Point = (0.0, 0.0), angle: float = 0, change_angle: float = 0, scale: float = 1.0, alpha: int = 255, mutation_callback=None ): super().__init__(filename_or_texture, change_xy, center_xy, angle, change_angle, scale, alpha, mutation_callback)
[docs] def can_reap(self): """Determine if Particle can be deleted""" return False
[docs]class LifetimeParticle(Particle): """Particle that lives for a given amount of time and is then deleted"""
[docs] def __init__( self, filename_or_texture: FilenameOrTexture, change_xy: Vector, lifetime: float, center_xy: Point = (0.0, 0.0), angle: float = 0, change_angle: float = 0, scale: float = 1.0, alpha: int = 255, mutation_callback=None ): super().__init__(filename_or_texture, change_xy, center_xy, angle, change_angle, scale, alpha, mutation_callback) self.lifetime_original = lifetime self.lifetime_elapsed = 0.0
[docs] def update(self): """Advance the Particle's simulation""" super().update() self.lifetime_elapsed += 1 / 60
[docs] def can_reap(self): """Determine if Particle can be deleted""" return self.lifetime_elapsed >= self.lifetime_original
[docs]def clamp(a, low, high): if a > high: return high elif a < low: return low else: return a
[docs]class FadeParticle(LifetimeParticle): """Particle that animates its alpha between two values during its lifetime"""
[docs] def __init__( self, filename_or_texture: FilenameOrTexture, change_xy: Vector, lifetime: float, center_xy: Point = (0.0, 0.0), angle: float = 0, change_angle: float = 0, scale: float = 1.0, start_alpha: int = 255, end_alpha: int = 0, mutation_callback=None ): super().__init__(filename_or_texture, change_xy, lifetime, center_xy, angle, change_angle, scale, start_alpha, mutation_callback) self.start_alpha = start_alpha self.end_alpha = end_alpha
[docs] def update(self): """Advance the Particle's simulation""" super().update() a = arcade.utils.lerp(self.start_alpha, self.end_alpha, self.lifetime_elapsed / self.lifetime_original) self.alpha = clamp(a, 0, 255)