Using ParticleInterval?

Scripting Issues
1

Hi, another day another puzzle. I’m trying to use ParticleInterval’s but I don’t see the particles when I start the interval. doing a isPlaying() tells me that the interval is playing but nothing appears on the screen. Here is the code I have so far:

particleEffect = m.pEffect
pI = ParticleInterval(particleEffect, render)
pI.start()
#pI.popupControls()
print pI.isPlaying()

I tried doing the same thing with the teapot particle demo but nothing happens there either. Am I missing some args or an essential step to using ParticleIntervals? Thanks.

2

Have you called base.enableParticles()? This needs to be called once, usually at startup, in order to enable the particle system.

David

3

Yup, I’ve done that. Particles work fine when started the normal way but I want to slow down the particles like in this topic.

4

I really can’t figure out how to make this work, I don’t have any examples to see so irunno. Here’s the full code for the module:

import direct.directbase.DirectStart
from direct.showbase.DirectObject import DirectObject
from direct.task.Task import Task
from direct.actor.Actor import Actor
from pandac.PandaModules import NodePath
from pandac.PandaModules import OrthographicLens
from direct.interval.ParticleInterval import ParticleInterval
from direct.interval.IntervalGlobal import *
from pandac.PandaModules import CardMaker

from MudParticles import *

class MudSimulator(DirectObject):
	
	def __init__(self):
		"""Draws an offscreen buffer for texturing the mudflow"""
		
		mainWindow=base.win
		base.enableParticles()
		
		# Offscreen buffer stuff
		self.altBuffer=mainWindow.makeTextureBuffer("hello", 512, 512)
		self.altRender=NodePath("new render")
		self.altCam=base.makeCamera(self.altBuffer)
		self.altCam.reparentTo(self.altRender)
		self.altCam.setPos(0,-20,0)
		
		# Camera stuff
		lens = OrthographicLens()
		lens.setFilmSize(20, 15)
		self.altCam.node().setLens(lens)
		
		# Makes the full screen card
		cm = CardMaker('background')
		cm.setFrame(-10,10,-7.5,7.5)
		# Try to pull the texture from the model to save memory
		if __name__ is not "__main__":
			cardTexture = loader.loadTexture("models/mayon_map.PNG")
		else:
			cardTexture = render.find_texture("mayon_map.PNG")
		self.card = self.altRender.attachNewNode(cm.generate())
		self.card.setTexture(cardTexture)
		
		# Particles and intervals should correspond to each others index
		self.mudParticleList = []
		self.mudIntervalList = []
	
	def loadParticle(self, mudType):
		if mudType == "top":
			m = MudTop()
			self.mudParticleList.append(m)
			#print "OLO", type(m)
		particle = self.mudParticleList[-1].pEffect
		
		# These lines are giving me a problem
		pI = ParticleInterval(particle, self.card, name="Particlwhat", worldRelative="0", renderParent=self.altRender)
		self.mudIntervalList.append(pI)
		pI.start() # Not really working
		print "Is particle playing?", pI.isPlaying()
		
		# The lines below work, showing the particles
		#particle.reparentTo(self.altRender)
		#particle.start()
		#particle.setPos(-0.2,0,3)

class World(DirectObject):
	def __init__(self):
		mudSim = MudSimulator()
		
		base.bufferViewer.setPosition("llcorner")
		base.bufferViewer.setCardSize(1.4, 0.0)
		base.bufferViewer.toggleEnable()
		
		mudSim.loadParticle("top")

if __name__ == "__main__":
	w = World()
	run()

Can anyone see where I’m going wrong?

5

Note that worldRelative=“0” is really the same thing as worldRelative=1, since the string “0” evaluates True by Python. If you wanted to turn off the worldRelative feature, you should remove the quotation marks: worldRelative=0.

Not sure if this is your problem or not.

David

6

I spotted the quotation marks as not being necessary but it still wouldn’t run for me. I’ve given up on ParticleIntervals for now, I got the thing done using LerpFunc’s instead. Not quite the effect I was going for but time was short on my project.

I’ll try it out again later on the steam example though.