--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/parpg/grease/impl/world.py	Tue Jul 12 10:16:48 2011 +0200
@@ -0,0 +1,129 @@
+#############################################################################
+#
+# Copyright (c) 2010 by Casey Duncan and contributors
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the MIT License
+# A copy of the license should accompany this distribution.
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+#
+#############################################################################
+"""Worlds are environments described by a configuration of components, systems and 
+renderers. These parts describe the data, behavioral and presentation aspects
+of the world respectively.
+
+The world environment is the context within which entities exist. A typical
+application consists of one or more worlds containing entities that evolve
+over time and react to internal and external interaction.
+
+See :ref:`an example of world configuration in the tutorial <tut-world-example>`.
+"""
+
+__version__ = '$Id$'
+
+import itertools
+import pyglet
+from pyglet import gl
+from grease.world import *
+from grease.impl import Mode
+
+class World(Mode, BaseWorld):
+	"""A coordinated collection of components, systems and entities
+	
+	A world is also a mode that may be pushed onto a 
+	:class:`grease.mode.Manager`
+
+	:param step_rate: The rate of :meth:`step()` calls per second. 
+
+	:param master_clock: The :class:`pyglet.clock.Clock` interface used
+		as the master clock that ticks the world's clock. This 
+		defaults to the main pyglet clock.
+	"""
+
+	clock = None
+	""":class:`pyglet.clock` interface for use by constituents
+	of the world for scheduling
+	"""
+
+	time = None
+	"""Current clock time of the world, starts at 0 when the world
+	is instantiated
+	"""
+
+	running = True
+	"""Flag to indicate that the world clock is running, advancing time
+	and stepping the world. Set running to False to pause the world.
+	"""
+
+	def __init__(self, step_rate=60, master_clock=pyglet.clock,
+				 clock_factory=pyglet.clock.Clock):
+		Mode.__init__(self, step_rate, master_clock, clock_factory)
+		BaseWorld.__init__(self)
+	
+	def activate(self, manager):
+		"""Activate the world/mode for the given manager, if the world is already active, 
+		do nothing. This method is typically not used directly, it is called
+		automatically by the mode manager when the world becomes active.
+
+		The systems of the world are pushed onto `manager.event_dispatcher`
+		so they can receive system events.
+
+		:param manager: :class:`mode.BaseManager` instance
+		"""
+		if not self.active:
+			for system in self.systems:
+				manager.event_dispatcher.push_handlers(system)
+		super(World, self).activate(manager)
+	
+	def deactivate(self, manager):
+		"""Deactivate the world/mode, if the world is not active, do nothing.
+		This method is typically not used directly, it is called
+		automatically by the mode manager when the world becomes active.
+
+		Removes the system handlers from the `manager.event_dispatcher`
+
+		:param manager: :class:`mode.BaseManager` instance
+		"""
+		for system in self.systems:
+			manager.event_dispatcher.remove_handlers(system)
+		super(World, self).deactivate(manager)
+
+	def tick(self, dt):
+		"""Tick the mode's clock, but only if the world is currently running
+		
+		:param dt: The time delta since the last tick
+		:type dt: float
+		"""
+		if self.running:
+			super(World, self).tick(dt)
+	
+	def step(self, dt):
+		"""Execute a time step for the world. Updates the world `time`
+		and invokes the world's systems.
+		
+		Note that the specified time delta will be pinned to 10x the
+		configured step rate. For example if the step rate is 60,
+		then dt will be pinned at a maximum of 0.1666. This avoids 
+		pathological behavior when the time between steps goes
+		much longer than expected.
+
+		:param dt: The time delta since the last time step
+		:type dt: float
+		"""
+		dt = min(dt, 10.0 / self.step_rate)
+		for component in self.components:
+			if hasattr(component, "step"):
+				component.step(dt)
+		for system in self.systems:
+			if hasattr(system, "step"):
+				system.step(dt)
+
+	def on_draw(self, gl=pyglet.gl):
+		"""Clear the current OpenGL context, reset the model/view matrix and
+		invoke the `draw()` methods of the renderers in order
+		"""
+		gl.glClear(gl.GL_COLOR_BUFFER_BIT | gl.GL_DEPTH_BUFFER_BIT)
+		gl.glLoadIdentity()
+		BaseWorld.draw_renderers(self)
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