Basic particle system example

fire.py

# fire.py
# by Dave Pape, for DMS 423
#
# Example particle system for a simple fire-like effect
# This code is intended as a trivial introduction to particle systems and
# graphics programming; it is NOT intended to be optimal; many values are
# hard-coded for simplicity.
#
# Requires: pyglet (http://www.pyglet.org/), euclid (https://code.google.com/p/pyeuclid/),
#    and a texture image fireparticle.png

import sys, time, math
from pyglet.gl import *
from euclid import *
from random import *

window = pyglet.window.Window()

gravity = Vector3(0, -2, 0)

tex = pyglet.image.load('fireparticle.png').get_texture()

class particle:
    def __init__(self, pos):
        self.pos = pos.copy()
        self.pos[0] += gauss(0,25)
        self.pos[1] += uniform(0,40)
        self.vel = Vector3(uniform(-20,20), 300+gauss(0,50), 0)
        self.removeTime = time.time() + abs(gauss(0.0,0.25))
    def update(self, dt):
        self.pos += self.vel * dt
        self.vel += gravity * dt

class particleSystem:
    def __init__(self, num=1):
        self.particles = []
        self.addParticles(num)
    def addParticles(self, num):
        for i in range(0,num):
            p = particle(Vector3(300,100,0))
            self.particles.append(p)
    def draw(self):
        glColor3f(1,1,1)
        glEnable(tex.target)
        glBindTexture(tex.target, tex.id)
        glEnable(GL_BLEND)
        glBlendFunc(GL_ONE, GL_ONE)
        glBegin(GL_QUADS)
        for p in self.particles:
            size = 20
            glTexCoord2f(0,0)
            glVertex3f(p.pos[0]-size, p.pos[1]-size, p.pos[2])
            glTexCoord2f(1,0)
            glVertex3f(p.pos[0]+size, p.pos[1]-size, p.pos[2])
            glTexCoord2f(1,1)
            glVertex3f(p.pos[0]+size, p.pos[1]+size, p.pos[2])
            glTexCoord2f(0,1)
            glVertex3f(p.pos[0]-size, p.pos[1]+size, p.pos[2])
        glEnd()
        glDisable(GL_BLEND)
        glDisable(tex.target)
    def update(self, dt):
        for p in self.particles:
            p.update(dt)
        t = time.time()
        for i in range(len(self.particles)-1, -1, -1):
            if (self.particles[i].removeTime <= t) or (self.particles[i].pos[1] < 0):
                del self.particles[i]
                self.addParticles(1)

systems = [particleSystem(200)]


@window.event
def on_draw():
    glClear(GL_COLOR_BUFFER_BIT)
    for s in systems:
        s.draw()


def update(dt):
    for s in systems: 
        s.update(dt)
    for i in range(len(systems)-1, -1, -1):
        if len(systems[i].particles) == 0:
            del systems[i]


pyglet.clock.schedule_interval(update,1/60.0)
pyglet.app.run()