Source code for entities.collisions

# ../entities/collisions.py

"""Provides entity collisions functionality."""

# =============================================================================
# >> IMPORTS
# =============================================================================
# Source.Python Imports
#   Core
from core import AutoUnload
from core import WeakAutoUnload


# =============================================================================
# >> FORWARD IMPORTS
# =============================================================================
# Source.Python Imports
#   Entities
from _entities._collisions import BaseCollisionRules
from _entities._collisions import CollisionHash
from _entities._collisions import CollisionManager
from _entities._collisions import CollisionMap
from _entities._collisions import CollisionMode
from _entities._collisions import CollisionSet
from _entities._collisions import collision_manager


# =============================================================================
# >> ALL DECLARATION
# =============================================================================
__all__ = ('BaseCollisionRules',
           'CollisionHash',
           'CollisionHook',
           'CollisionManager',
           'CollisionMap',
           'CollisionMode',
           'CollisionSet',
           'collision_manager',
           )


# =============================================================================
# >> INITIALIZATION
# =============================================================================
# Inject WeakAutoUnload into BaseCollisionRules's hierarchy.
if not issubclass(BaseCollisionRules, WeakAutoUnload):
    BaseCollisionRules.__bases__ = (
        WeakAutoUnload,) + BaseCollisionRules.__bases__


# =============================================================================
# >> CLASSES
# =============================================================================
class CollisionHook(AutoUnload):
    """Decorator used to create collision hooks that auto unload.

    Example:

    .. code:: python

        from engines.trace import ContentFlags
        from entities.collisions import CollisionHook

        @CollisionHook
        def collision_hook(entity, other, trace_filter, mask):
            # Prevent hostages from being killed by bullets
            if not mask & ContentFlags.HITBOX:
                return
            return other.classname != 'hostage_entity'
    """

    def __init__(self, callback):
        """Registers the collision hook.

        :param function callback:
            Function to register as a collision hook callback.
        """
        self.callback = callback
        collision_manager.register_hook(callback)

    def _unload_instance(self):
        """Unregisters the collision hook.

        :param function callback:
            Function to unregister as a collision hook callback.
        """
        collision_manager.unregister_hook(self.callback)