from __future__ import annotations
import attrs
import mitsuba as mi
from ._core import BSDF
from ..core import traverse
from ..spectra import Spectrum, spectrum_factory
from ... import validators
from ...attrs import documented, parse_docs
from ...kernel import TypeIdLookupStrategy, UpdateParameter
[docs]
@parse_docs
@attrs.define(eq=False, slots=False)
class CheckerboardBSDF(BSDF):
"""
Checkerboard BSDF [``checkerboard``].
This class defines a Lambertian BSDF textured with a checkerboard pattern.
"""
reflectance_a: Spectrum = documented(
attrs.field(
default=0.2,
converter=spectrum_factory.converter("reflectance"),
validator=[
attrs.validators.instance_of(Spectrum),
validators.has_quantity("reflectance"),
],
),
doc="Reflectance spectrum. Can be initialised with a dictionary "
"processed by :data:`.spectrum_factory`.",
type=".Spectrum",
init_type=".Spectrum or dict or float",
default="0.2",
)
reflectance_b: Spectrum = documented(
attrs.field(
default=0.8,
converter=spectrum_factory.converter("reflectance"),
validator=[
attrs.validators.instance_of(Spectrum),
validators.has_quantity("reflectance"),
],
),
doc="Reflectance spectrum. Can be initialised with a dictionary "
"processed by :data:`.spectrum_factory`.",
type=".Spectrum",
init_type=":class:`.Spectrum` or dict or float",
default="0.8",
)
scale_pattern: float = documented(
attrs.field(
default=None,
converter=attrs.converters.optional(float),
validator=attrs.validators.optional(attrs.validators.instance_of(float)),
),
doc="Scaling factor for the checkerboard pattern. The higher the value, "
"the more checkerboard patterns will fit on the surface to which this "
"reflection model is attached.",
type="float or None",
init_type="float, optional",
)
@property
def template(self) -> dict:
# Inherit docstring
result = {"type": "diffuse", "reflectance.type": "checkerboard"}
if self.id is not None:
result["id"] = self.id
if self.scale_pattern is not None:
result["reflectance.to_uv"] = mi.ScalarTransform4f.scale(self.scale_pattern)
for obj_key, obj_values in {
"color0": traverse(self.reflectance_a)[0],
"color1": traverse(self.reflectance_b)[0],
}.items():
for key, value in obj_values.items():
result[f"reflectance.{obj_key}.{key}"] = value
return result
@property
def params(self) -> dict[str, UpdateParameter]:
# Inherit docstring
result = {}
for obj_key, obj_params in {
"color0": traverse(self.reflectance_a)[1].data,
"color1": traverse(self.reflectance_b)[1].data,
}.items():
for key, param in obj_params.items():
result[f"reflectance.{obj_key}.{key}"] = attrs.evolve(
param,
lookup_strategy=TypeIdLookupStrategy(
node_type=mi.BSDF,
node_id=self.id,
parameter_relpath=f"reflectance.{obj_key}.{key}",
)
if self.id is not None
else None,
)
return result
