""" This file is part of the 'Elements' Project Elements is a 2D Physics API for Python (supporting Box2D2) Copyright (C) 2008, The Elements Team, Home: http://elements.linuxuser.at IRC: #elements on irc.freenode.org Code: http://www.assembla.com/wiki/show/elements svn co http://svn2.assembla.com/svn/elements License: GPLv3 | See LICENSE for the full text This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . """ from locals import * from elements import box2d class CallbackHandler: # List of contact callbacks and shapes to start them - sorted by type for quicker access # Callbacks are saved as callbacks[callback_type][[function, parameters], ...] callbacks = {} def __init__(self, parent): self.parent = parent # init callback dict to avoid those slow try # (especially for self.get, as it is called *often*) for i in xrange(10): self.callbacks[i] = [] def add(self, callback_type, callback_handler, *args): """ Users can add callbacks for certain (or all) collisions Parameters: callback_type ......... CALLBACK_CONTACT (nothing else for now) callback_handler ...... a callback function args (optional) ....... a list of parameters which can be used with callbacks.get Return: callback_id ... used to remove a callback later (int) """ # Create contact listener if required if callback_type in [CALLBACK_CONTACT_ADD, CALLBACK_CONTACT_PERSIST, CALLBACK_CONTACT_REMOVE]: if self.parent.klistener == None: self.parent.klistener = kContactListener(self.get) self.parent.world.SetContactListener( self.parent.klistener ) print "* kContactListener added" # Get callback dict for this callback_type c = self.callbacks[callback_type] # Append to the Callback Dictionary c.append([callback_handler, args]) self.callbacks[callback_type] = c # Return Callback ID # ID = callback_type.callback_index (1...n) return "%i.%i" % (callback_type, len(c)) def get(self, callback_type): return self.callbacks[callback_type] def start(self, callback_type, *args): callbacks = self.get(callback_type) for c in callbacks: callback, params = c callback() class kContactListener(box2d.b2ContactListener): def __init__(self, get_callbacks): # Init the Box2D b2ContactListener box2d.b2ContactListener.__init__(self) # Function to get the current callbacks self.get_callbacks = get_callbacks def check_contact(self, contact_type, point): # Checks if a callback should be started with this contact point contacts = self.get_callbacks(contact_type) # Step through all callbacks for this type (eg ADD, PERSIST, REMOVE) for c in contacts: callback, bodylist = c if len(bodylist) == 0: # Without bodylist it's a universal callback (for all bodies) callback(point) else: # This is a callback with specified bodies # See if this contact involves one of the specified b1 = str(point.shape1.GetBody()) b2 = str(point.shape2.GetBody()) for s in bodylist: s = str(s) if b1 == s or b2 == s: # Yes, that's the one :) callback(point) def Add(self, point): """Called when a contact point is created""" self.check_contact(CALLBACK_CONTACT_ADD, point) def Persist(self, point): """Called when a contact point persists for more than a time step""" self.check_contact(CALLBACK_CONTACT_PERSIST, point) def Remove(self, point): """Called when a contact point is removed""" self.check_contact(CALLBACK_CONTACT_REMOVE, point)