Re: [pygame] BUG: LayeredUpdate 'layer' vs '

Yeah I understand that. It's just the docs make it seem that the add function will add your sprite to whatever your sprite.layer attribute is if you don't specify a karg layer. But that's not true. If you then use change_layer you end up doing twice as much work since with 'add' and 'change_layer' it's doing a bisect search each time.

The point I'm making is that yes, '_layer' is an internal variable but 'layer' is never used. If you initialize a sprite and you want it to be added correctly then you have to set '_layer' before adding. Yes, don't change the '_layer' attribute after adding.

If we wanted to keep '_layer' strictly an internal variable then we need to add a bit that gets the 'layer' attribute as it says it will in the docs. Below it looks for a karg layer, '_layer' and then 'layer' before using the default.

if layer is None:
try:
layer = sprite._layer
except AttributeError:
      try:
      layer = sprite._layer = sprite.layer
      except AttributeError:
      layer = sprite._layer = self._default_layer
elif hasattr(sprite, '_layer'):
sprite._layer = layer

I hope that clarifies my point.

Jeffrey

On Wed, Mar 19, 2014 at 3:48 PM, DR0ID <dr0id@xxxxxxxxxx> wrote:

Am 19.03.2014 07:29, schrieb Jeffrey Kleykamp:

Hi all,

In pygame.sprite.LayeredUpdate.add documentation it says

"If the sprite(s) have an attribute layer then that is used for the layer.
If **kwargs contains 'layer' then the sprite(s) will be added to that
argument (overriding the sprite layer attribute). If neither is passed then
the sprite(s) will be added to the default layer."

This implies it relies on sprite.layer. But by looking at the source I saw
if you want to affect which layer your sprite will get added to, you have
to set sprite._layer before calling add(). So the documentation and the
code doesn't match.

Not so much a bug; more of a clarification.

Sincerely,
Jeffrey

Hi

In my version of sprites.py it looks like the code beneath (it might be outdated). The sprite._layer is an internal variable that should not be used directly (sprite._layer is read only).

If you want to change a layer of a sprite use 'change_layer(self, sprite, new_layer)'. So 'layer' will be handled correctly from the kwargs.

LayeredUpdates:

def add_internal(self, sprite, layer=None):
"""Do not use this method directly.

It is used by the group to add a sprite internally.

"""
self.spritedict[sprite] = Rect(0, 0, 0, 0) # add a old rect

if layer is None:
try:
layer = sprite._layer
except AttributeError:
layer = sprite._layer = self._default_layer
elif hasattr(sprite, '_layer'):
sprite._layer = layer

sprites = self._spritelist # speedup
sprites_layers = self._spritelayers
sprites_layers[sprite] = layer
....

Hope that helps

~DR0ID

--

Jeffrey Kleykamp

Re: [pygame] BUG: LayeredUpdate 'layer' vs '_layer'