"clipka" <nomail@nomail> wrote:
> Peter Hokanson <pch### [at] mindspringcom> wrote:
> > from povray import *
> > MyTex = texture(pigment=(1,1,1))
> > sphere((0,0,0),5,texture=MyTex)
>
> Fine. Can we also write this as
>
>   sphere((0,0,0),5,texture(pigment=(1,1,1)))
>
> ?
>
> How about more complex scenarios, like multi-layered textures for instance?

I think this can be done with positional arguments. The constructor for a type
would have to accept variable arguments  and then determine if there is more
than one texture by if more than one argument is a texture object:

class baseobject:
  def __init__(self, *args):
    for i in *args:
      if isinstance(i, texture):
        self.textures.append(i)
        self.texture_transforms.append(transform())
      if isinstance(i, (transform, rotate, scale, translate)):
        self.transform_matrix.update(i)
        for j in self.texture_transforms:
          j.update(i)

class sphere(baseobject):
  def __init__(self, *args):
    # Extract sphere-specific arguments first and pass the rest to the base
    baseobject.__init__(self, ...)


mysphere = sphere(
  (0, 0, 0), 5,
  scale(4), # Doesn't affect any texture
  texture(
    pigment(
      checker(0.5, color(0.0, 0.0, 0.0, 0.5), color(0.5, 0.5, 0.5, 0.5))
    ),
    finish(...),
  )
  scale(x=4, y=1), # Affects the first texture only
  texture(...),
  ...
)

My question would be, how to differentiate between creating an object or just
declaring it.  Maybe a special function to add the object to the scene:

add(sphere(
  ....
))

or perhaps a special global object that if in the attributes would cause it not
to be added to the scene list

class Dummy:
  pass

nocreate = Dummy()

class baseobject:
  def __init__(self, *args):
    create = True
    for i in args:
      ...
      if i is nocreate:
        create = False
    if create:
      scene_objects.append(self)


mysphere = sphere(..., nocreate)

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