from .render_node import RenderNode

class RenderCallbackNode( RenderNode ):

"""A RenderNode that takes an initialisation and a

render function as callbacks to perform rendering.

"""

def __init__( self, name, initialise_callback, render_callback ):

"""Initialises the node with the specified callbacks.

Args:

name: The name to give the node.

initialise_callback: The function to call when the

node is to be initialised.

The function must accept a pointer to this object.

render_callback: The function to call when the

node is to be rendered.

The function must accept a pointer to this object.

It must also accept a **kwargs parameter which will

be passed from the render() method.

Raises:

ValueError: Raised if the render callback == None.

"""

super( RenderCallbackNode, self ).__init__( name )

if render_callback == None:

raise ValueError(

"RenderNode render_callback cannot be None"

)

self.initialise_callback = initialise_callback

self.render_callback = render_callback

# initialise the mesh now

if self.initialise_callback != None:

self.initialise_callback( self )

def on_context_lost( self ):

# re-create any data for the mesh

if self.initialise_callback != None:

self.initialise_callback( self )

def render( self, **kwargs ):

self.render_callback( self, **kwargs )