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Last Update: 24.09.2009. By azarai in game development | pyglet | python
Last time i made a small demo using prerendered particle effects. Today i’ll show another way of doing particle effects with python and pyglet. Instead of animating prerendered graphics i am going to use a particle system to create effects in realtime. The one i am using is [py-lepton] (http://code.google.com/p/py-lepton/ “link to py-lepton site”):
Lepton: A high-performance, pluggable particle engine and API for Python
Lepton is designed to make complex and beautiful particle effects possible, and even easy from Python programs.
Here is the demo of a simple explosion effect without using any premade texture. I made comments in the code that should explain everything.
The video:
Controls:
Left Mouse click : spawn new effect at center of the window
The Code:
from lepton import Particle, ParticleGroup, default_system
from lepton.renderer import BillboardRenderer, PointRenderer
from lepton.texturizer import SpriteTexturizer, create_point_texture
from lepton.emitter import StaticEmitter
from lepton.controller import Gravity, Lifetime, Movement, Fader, ColorBlender, Growth
import pyglet
from pyglet.gl import *
#create pyglet window
window = pyglet.window.Window(visible=False)
window.clear()
#enable alpha blending
glEnable(GL_BLEND)
glBlendFunc(GL_SRC_ALPHA,GL_ONE)
def get_color(r,g,b,a):
""" converts rgba values of 0 - 255 to the equivalent in 0 - 1"""
return (r/255.0,g/255.0,b/255.0, a/255.0)
# Setting up particle group for all explosion particles with some controllers
# ColorBlending is from white to yellow to red/orange
# For visuals us a Pointtexture generated by py-lepton
explosion = ParticleGroup(
controllers=[
Lifetime(4),
Movement(damping=0.93),
Growth(30),
Fader( fade_in_start=0, start_alpha=0, fade_in_end=0.5 ,max_alpha=0.4,
fade_out_start=1, fade_out_end=4.0),
ColorBlender([(0, get_color(255, 255, 255,255)),
(0.75, get_color(255,255,0,255)),
(1.5, get_color(255,0,0,255))
])
],
renderer=PointRenderer(64, SpriteTexturizer(create_point_texture(64,5))))
# The explosion emitter, the thing actually creating the particles
# each particle starts at window center and add some variation (start position, size and
# life time)
explosion_emitter = StaticEmitter(
template=Particle(
position=(window.width/2,window.height/2,0),
size=(20,20,0),
),
deviation=Particle(
position=(1,1,0),
size=(10,10,0),
velocity=(100,100,0),
age=2
),
)
#if left mouse button is clicked a new explosion will be started
@window.event
def on_mouse_press(x, y, button, modifiers):
if(pyglet.window.mouse.LEFT == button):
explosion_emitter.emit(400, explosion)
# clear screen and draw particles
@window.event
def on_draw():
window.clear()
default_system.draw()
# setup scheduler for particle updates and start pyglet
if __name__ == '__main__':
window.set_visible(True)
pyglet.clock.schedule_interval(default_system.update, (1.0/30.0))
pyglet.clock.set_fps_limit(None)
pyglet.app.run()
Now spice up the explosion without using any premade texture and share it.
Happy hacking :-)
Update 1: Fixed get_color method