Class cocos.cocosnode.CocosNode

Known Subclasses:
particle.ParticleSystem, layer.base_layers.Layer, batch.BatchNode, batch.BatchableNode, text.TextElement, draw.Canvas, scene.Scene, menu.BaseMenuItem, skeleton.Skin

Cocosnode is the main element. Anything thats gets drawn or contains things that get drawn is a cocosnode. The most popular cocosnodes are scenes, layers and sprites.

The main features of a cocosnode are:

Some cocosnodes provide extra functionality for them or their children.

Subclassing a cocosnode usually means (one/all) of:

Methods

  __contains__(self, child)
  __init__(self)
CocosNode instance add(self, child, z=0, name=None)
Adds a child and if it becomes part of the active scene calls its on_enter method
  are_actions_running(self)
Determine whether any actions are running.
Action instance do(self, action, target=None)
Executes an action.
  draw(self, *args, **kwargs)
This is the function you will have to override if you want your subclassed to draw something on screen.
CocosNode get(self, name)
Gets a child given its name
CocosNode or None get_ancestor(self, klass)
Walks the nodes tree upwards until it finds a node of the class klass or returns None
list of CocosNode get_children(self)
Return a list with the node's childs, order is back to front
euclid.Matrix3 get_local_inverse(self)
returns an euclid.Matrix3 with the local inverse transformation matrix
euclid.Matrix3 get_local_transform(self)
returns an euclid.Matrix3 with the local transformation matrix
euclid.Matrix3 get_world_inverse(self)
returns an euclid.Matrix3 with the world inverse transformation matrix
euclid.Matrix3 get_world_transform(self)
returns an euclid.Matrix3 with the world transformation matrix
  kill(self)
Remove this object from its parent, and thus most likely from everything.
  on_enter(self)
Called every time just before the node enters the stage.
  on_exit(self)
Called every time just before the node leaves the stage
  pause(self)
Suspends the execution of actions.
  pause_scheduler(self)
Time will stop passing for this node: scheduled callbacks will not be called, worker actions will not be called
euclid.Vector2 point_to_local(self, p)
returns an euclid.Vector2 converted to local space
euclid.Vector2 point_to_world(self, p)
returns an euclid.Vector2 converted to world space
  remove(self, obj)
Removes a child given its name or object
  remove_action(self, action)
Removes an action from the node actions container, potentially calling action.stop()
  resume(self)
Resumes the execution of actions.
  resume_scheduler(self)
Time will continue/start passing for this node and callbacks will be called, worker actions will be called
  schedule(self, callback, *args, **kwargs)
Schedule a function to be called every frame.
  schedule_interval(self, callback, interval, *args, **kwargs)
Schedule a function to be called every interval seconds.
  stop(self)
Removes all actions from the running action list
  transform(self)
Apply ModelView transformations
  unschedule(self, callback)
Remove a function from the schedule.
  visit(self)
This function visits it's children in a recursive way.
list walk(self, callback, collect=None)
Executes callback on all the subtree starting at self.

Properties

(int,int) anchor
Anchor point of the object.
(int,int) anchor_x
Anchor x value for transformations and adding children
(int,int) anchor_y
Anchor y value for transformations and adding children
object parent
The parent of this object.
(int, int) position
The (x, y) coordinates of the object.
  rotation
  scale
(int,int) transform_anchor
Transformation anchor point.
  x
The x coordinate of the object
  y
The y coordinate of the object

Instance Variables

  actions
list of Action objects that are running
  camera
eye, center and up vector for the Camera.
  children
list of (int, child-reference) where int is the z-order, sorted by ascending z (back to front order)
  children_names
dictionary that maps children names with children references
  grid
the grid object for the grid actions.
  is_running
whether of not the object is running
  scheduled_calls
list of scheduled callbacks
  scheduled_interval_calls
list of scheduled interval callbacks
  skip_frame
whether or not the next frame will be skipped
  to_remove
list of Action objects to be removed
  transform_anchor_x
offset from (x,0) from where rotation and scale will be applied.
  transform_anchor_y
offset from (0,y) from where rotation and scale will be applied.
  visible
whether of not the object is visible.

Method Details

add

add(self, child, z=0, name=None)
Adds a child and if it becomes part of the active scene calls its on_enter method
Parameters:
child : CocosNode
object to be added
z : float
the z index of self
name : str
Name of the child
Returns:
CocosNode instance: self

do

do(self, action, target=None)

Executes an action. When the action finished, it will be removed from the node's actions container.

to remove an action you must use the .do return value to call .remove_action

Parameters:
action : an Action instance
Action that will be executed.
Returns:
Action instance: A clone of action

draw

draw(self, *args, **kwargs)

This is the function you will have to override if you want your subclassed to draw something on screen.

You must respect the position, scale, rotation and anchor attributes. If you want OpenGL to do the scaling for you, you can:

def draw(self):
    glPushMatrix()
    self.transform()
    # ... draw ..
    glPopMatrix()

get

get(self, name)

Gets a child given its name

Warning: if a node is added with name, then removed not by name, the name cannot be recycled: attempting to add other node with this name will produce an Exception.

Parameters:
name : string
name of the reference to be get
Returns:
CocosNode: the child named 'name'. Will raise Exception if not present

get_children

get_children(self)
Return a list with the node's childs, order is back to front
Returns:
list of CocosNode: childs of this node, ordered back to front

on_enter

on_enter(self)

Called every time just before the node enters the stage.

scheduled calls and worker actions begins or continues to perform

Good point to do .push_handlers if you have custom ones Rule: a handler pushed there is near certain to require a .pop_handlers in the .on_exit method (else it will be called even after removed from the active scene, or, if going on stage again will be called multiple times for each event ocurrence)

on_exit

on_exit(self)

Called every time just before the node leaves the stage

scheduled calls and worker actions are suspended, that is, will not be called until an on_enter event happens.

Most of the time you will want to .pop_handlers for all explicit .push_handlers found in on_enter

Consider to release here openGL resources created by this node, like compiled vertex lists

remove

remove(self, obj)

Removes a child given its name or object

If the node was added with name, it is better to remove by name, else the name will be unavailable for further adds ( and will raise Exception if add with this same name is attempted)

If the node was part of the active scene, its on_exit method will be called.

Parameters:
obj : string or object
name of the reference to be removed or object to be removed

remove_action

remove_action(self, action)

Removes an action from the node actions container, potentially calling action.stop()

If action was running, action.stop is called Mandatory interfase to remove actions in the node actions container. When skipping this there is the posibility to double call the action.stop

Parameters:
action : Action
Action to be removed Must be the return value for a .do(...) call

schedule

schedule(self, callback, *args, **kwargs)

Schedule a function to be called every frame.

The function should have a prototype that includes dt as the first argument, which gives the elapsed time, in seconds, since the last clock tick. Any additional arguments given to this function are passed on to the callback:

def callback(dt, *args, **kwargs):
    pass

This function is a wrapper to pyglet.clock.schedule. It has the additional benefit that all calllbacks are paused and resumed when the node leaves or enters a scene.

You should not have to schedule things using pyglet by yourself.

Parameters:
callback : function
The function to call each frame.

schedule_interval

schedule_interval(self, callback, interval, *args, **kwargs)

Schedule a function to be called every interval seconds.

Specifying an interval of 0 prevents the function from being called again (see schedule to call a function as often as possible).

The callback function prototype is the same as for schedule.

This function is a wrapper to pyglet.clock.schedule_interval. It has the additional benefit that all calllbacks are paused and resumed when the node leaves or enters a scene.

You should not have to schedule things using pyglet by yourself.

Parameters:
callback : function
The function to call when the timer lapses.
interval : float
The number of seconds to wait between each call.

stop

stop(self)

Removes all actions from the running action list

For each action running the stop method will be called, and the action will be retired from the actions container.

transform

transform(self)

Apply ModelView transformations

you will most likely want to wrap calls to this function with glPushMatrix/glPopMatrix

unschedule

unschedule(self, callback)

Remove a function from the schedule.

If the function appears in the schedule more than once, all occurances are removed. If the function was not scheduled, no error is raised.

This function is a wrapper to pyglet.clock.unschedule. It has the additional benefit that all calllbacks are paused and resumed when the node leaves or enters a scene.

You should not unschedule things using pyglet that where scheduled by node.schedule/node.schedule_interface.

Parameters:
callback : function
The function to remove from the schedule.

visit

visit(self)

This function visits it's children in a recursive way.

It will first visit the children that that have a z-order value less than 0.

Then it will call the draw method to draw itself.

And finally it will visit the rest of the children (the ones with a z-value bigger or equal than 0)

Before visiting any children it will call the transform method to apply any possible transformation.

walk

walk(self, callback, collect=None)
Executes callback on all the subtree starting at self. returns a list of all return values that are not none
Parameters:
callback : function
callable, takes a cocosnode as argument
collect : list
list of visited nodes
Returns:
list: the list of not-none return values

Property Details

anchor

Anchor point of the object. Children will be added at this point and transformations like scaling and rotation will use this point as the center
Type:
(int,int)

anchor_x

Anchor x value for transformations and adding children
Type:
(int,int)

anchor_y

Anchor y value for transformations and adding children
Type:
(int,int)

parent

The parent of this object.
Type:
object

position

The (x, y) coordinates of the object.
Type:
(int, int)

rotation

scale

transform_anchor

Transformation anchor point. Transformations like scaling and rotation will use this point as it's center
Type:
(int,int)

x

The x coordinate of the object

y

The y coordinate of the object

Instance Variable Details

camera

eye, center and up vector for the Camera. gluLookAt() is used with these values. Default: FOV 60, center of the screen. IMPORTANT: The camera can perform exactly the same transformation as scale, rotation and the x, y attributes (with the exception that the camera can modify also the z-coordinate) In fact, they all transform the same matrix, so use either the camera or the other attributes, but not both since the camera will be overridden by the transformations done by the other attributes. You can change the camera manually or by using the Camera3DAction action.

grid

the grid object for the grid actions. This can be a Grid3D or a TiledGrid3D object depending on the action.

transform_anchor_x

offset from (x,0) from where rotation and scale will be applied. Default: 0

transform_anchor_y

offset from (0,y) from where rotation and scale will be applied. Default: 0

visible

whether of not the object is visible. Default: True