from __future__ import annotations
from pathlib import Path
import attrs
import drjit as dr
import mitsuba as mi
import numpy as np
import pint
import pinttr
from ._core import Illumination
from ..core import NodeSceneElement
from ..spectra import Spectrum, spectrum_factory
from ... import validators
from ...attrs import define, documented
from ...units import unit_context_config as ucc
from ...units import unit_context_kernel as uck
from ...units import unit_registry as ureg
from ...validators import has_quantity
[docs]
@define(eq=False, slots=False)
class SpotIllumination(Illumination):
"""
Spot illumination scene element [``spot``].
Eradiate ships a beam texture that implements a gaussian beam profile with
three standard deviations included in the total beam width. This texture is
named ``gaussian_3sigma.bmp`` and can be used by retrieving the path to the
file using `eradiate.data.data_store.fetch()`.
"""
origin: pint.Quantity = documented(
pinttr.field(
factory=lambda: [1, 1, 1] * ureg.m,
validator=[validators.has_len(3), pinttr.validators.has_compatible_units],
units=ucc.deferred("length"),
),
doc="A 3-vector specifying the position of the spot.\n"
"\n"
"Unit-enabled field (default: ucc['length']).",
type="quantity",
init_type="array-like",
default="[1, 1, 1] m",
)
target: pint.Quantity = documented(
pinttr.field(
factory=lambda: [0, 0, 0] * ureg.m,
validator=[validators.has_len(3), pinttr.validators.has_compatible_units],
units=ucc.deferred("length"),
),
doc="Point location targeted by the spot.\n"
"\n"
"Unit-enabled field (default: ucc['length']).",
type="quantity",
init_type="array-like",
default="[0, 0, 0] m",
)
@target.validator
@origin.validator
def _target_origin_validator(self, attribute, value):
if np.allclose(self.target, self.origin):
raise ValueError(
f"While initializing {attribute}: "
f"Origin and target must not be equal, "
f"got target = {self.target}, origin = {self.origin}"
)
up: np.ndarray = documented(
attrs.field(
converter=np.array,
validator=validators.has_len(3),
),
doc="A 3-vector specifying the up direction of the spot.\n"
"This vector must be different from the spots's pointing direction,\n"
"which is given by ``target - origin``.",
type="array",
init_type="array-like",
default="[0, 0, 1]",
)
@up.default
def _up_factory(self):
direction = dr.normalize(
mi.ScalarVector3f(
self.origin.m_as(ucc.get("length"))
- self.target.m_as(ucc.get("length"))
)
)
return mi.coordinate_system(direction)[0]
@up.validator
def _up_validator(self, attribute, value):
direction = self.target - self.origin
if np.allclose(np.cross(direction, value), 0):
raise ValueError(
f"While initializing '{attribute.name}': "
f"up direction must not be colinear with viewing direction, "
f"got up = {self.up}, direction = {direction}"
)
beam_width: pint.Quantity = documented(
pinttr.field(default=10.0 * ureg.deg, units=ucc.deferred("angle")),
doc="Spot light beam width.\n\nUnit-enabled field (default: degree).",
type="quantity",
init_type="quantity or float",
default="10°",
)
intensity: Spectrum = documented(
attrs.field(
default=1.0,
converter=spectrum_factory.converter("intensity"),
validator=[
attrs.validators.instance_of(Spectrum),
has_quantity("intensity"),
],
),
doc="Emitted power in the plane orthogonal to the illumination direction. "
"Must be an intensity spectrum (in W/sr/nm or compatible unit). "
"Can be initialized with a dictionary processed by "
":meth:`.SpectrumFactory.convert`.",
type=":class:`~eradiate.scenes.spectra.Spectrum`",
init_type=":class:`~eradiate.scenes.spectra.Spectrum` or dict or float",
default="1.0 ucc[intensity]",
)
beam_profile: Path | None = documented(
attrs.field(
default=None,
converter=attrs.converters.optional(Path),
),
type="Path",
init_type="path-like",
default=None,
doc="Path to the file describing the beam profile. Must be a valid bitmap "
"image file.",
)
[docs]
@classmethod
def from_size_at_target(
cls,
target: np.typing.ArrayLike,
direction: np.typing.ArrayLike,
spot_radius: pint.Quantity,
beam_width: pint.Quantity,
**kwargs,
) -> SpotIllumination:
"""
Create a :class:`.SpotIllumination` which illuminates a region of a
specified size around the target point.
The illuminated area is a circle defined by the spot radius around the
target point in the plane orthogonal to the spot direction. The spot
origin is inferred from the spot radius and a beam width value
(in angle units): the spot origin will be positioned closer to the
target point as the beam width increases and further from the target
point as the beam width decreases.
Parameters
----------
target : array-like
Target point for the spot.
Unitless values are converted to ``ucc['length']``.
direction : array-like
Pointing direction for the spot, towards target.
spot_radius : float or quantity
Radius of the desired spot at the target position.
Unitless values are converted to ``ucc['length']``.
beam_width : float or quantity
Divergence angle of the spot.
Unitless values are converted to ``ucc['angle']``.
**kwargs
Remaining keyword arguments are forwarded to the
:class:`.SpotIllumination` constructor.
Returns
-------
SpotIllumination
"""
if "origin" in kwargs:
raise TypeError(
"The from_size_at_target constructor computes the origin position."
)
target = pinttr.util.ensure_units(target, default_units=ucc.get("length"))
half_angle = (
pinttr.util.ensure_units(beam_width, default_units=ureg.radian) / 2.0
)
tan_divergence = np.tan(half_angle)
distance = spot_radius / tan_divergence
origin = target - (direction * distance)
return cls(origin=origin, target=target, beam_width=beam_width, **kwargs)
@property
def _to_world(self) -> mi.ScalarTransform4f:
target = self.target.m_as(uck.get("length"))
origin = self.origin.m_as(uck.get("length"))
return mi.ScalarTransform4f.look_at(origin=origin, target=target, up=self.up)
@property
def template(self) -> dict:
retdict = {
"type": "spot",
"beam_width": self.beam_width.m_as(uck.get("angle")),
"cutoff_angle": self.beam_width.m_as(uck.get("angle")),
"to_world": self._to_world,
}
if self.beam_profile is not None:
retdict["texture"] = {
"type": "bitmap",
"filename": str(self.beam_profile),
}
return retdict
@property
def objects(self) -> dict[str, NodeSceneElement]:
return {"intensity": self.intensity}
