"""Radiance Glass Material.
http://radsite.lbl.gov/radiance/refer/ray.html#Glass
"""
import math
from materialbase import RadianceMaterial
from ..datatype import RadianceNumber
[docs]class Glass(RadianceMaterial):
"""Radiance glass material."""
r_transmittance = \
RadianceNumber('r_transmittance', num_type=float, valid_range=(0, 1))
g_transmittance = \
RadianceNumber('g_transmittance', num_type=float, valid_range=(0, 1))
b_transmittance = \
RadianceNumber('b_transmittance', num_type=float, valid_range=(0, 1))
refraction_index = \
RadianceNumber('refraction_index', num_type=float, check_positive=True)
def __init__(self, name, r_transmittance=0.0, g_transmittance=0.0,
b_transmittance=0.0, refraction_index=1.52, modifier="void"):
"""Create glass material.
Attributes:
name: Material name as a string. Do not use white space and special character
r_transmittance: Transmittance for red. The value should be between 0 and 1
(Default: 0).
g_transmittance: Transmittance for green. The value should be between 0 and 1
(Default: 0).
b_transmittance: Transmittance for blue. The value should be between 0 and 1
(Default: 0).
refraction: Index of refraction. 1.52 for glass and 1.4 for ETFE
(Default: 1.52).
modifier: Material modifier (Default: "void").
Usage:
glassMaterial = Glass("generic glass", .65, .65, .65)
print(glassMaterial)
"""
RadianceMaterial.__init__(self, name, modifier=modifier)
self.r_transmittance = float(r_transmittance)
"""Transmittance for red. The value should be between 0 and 1 (Default: 0)."""
self.g_transmittance = float(g_transmittance)
"""Transmittance for green. The value should be between 0 and 1 (Default: 0)."""
self.b_transmittance = float(b_transmittance)
"""Transmittance for blue. The value should be between 0 and 1 (Default: 0)."""
self.refraction_index = float(refraction_index)
"""Index of refraction. 1.52 for glass and 1.4 for ETFE (Default: 1.52)."""
self._update_values()
[docs] @classmethod
def from_json(cls, rec_json):
"""Make radiance material from json
{
"name": "", // Material Name
"r_transmittance": float, // Transmittance for red
"g_transmittance": float, // Transmittance for green
"b_transmittance": float, // Transmittance for blue
"refraction": float, // Index of refraction
"modifier": "" // material modifier (Default: "void")
}
"""
modifier = cls._analyze_json_input(cls.__name__.lower(), rec_json)
return cls(name=rec_json["name"],
r_transmittance=rec_json["r_transmittance"],
g_transmittance=rec_json["g_transmittance"],
b_transmittance=rec_json["b_transmittance"],
refraction_index=rec_json["refraction_index"],
modifier=modifier)
[docs] @classmethod
def by_single_trans_value(cls, name, rgb_transmittance=0,
refraction_index=1.52, modifier="void"):
"""Create glass material with single transmittance value.
Attributes:
name: Material name as a string. Do not use white space and special
character.
rgb_transmittance: Transmittance for red, green and blue. The value should be
between 0 and 1 (Default: 0).
refraction: Index of refraction. 1.52 for glass and 1.4 for ETFE
(Default: 1.52).
modifier: Material modifier (Default: "void").
Usage:
glassMaterial = Glass.by_single_trans_value("generic glass", .65)
print(glassMaterial)
"""
return cls(
name, r_transmittance=rgb_transmittance, g_transmittance=rgb_transmittance,
b_transmittance=rgb_transmittance, refraction_index=refraction_index,
modifier=modifier)
[docs] @classmethod
def from_string(cls, material_string, modifier=None):
"""Create a Radiance material from a string.
If the material has a modifier the modifier material should also be part of the
string or should be provided using modifier argument.
"""
modifier, name, base_material_data = cls._analyze_string_input(
cls.__name__.lower(), material_string, modifier)
if len(base_material_data) == 6:
r_transmittance, g_transmittance, b_transmittance = base_material_data[3:]
refraction = 1.52
else:
r_transmittance, g_transmittance, b_transmittance, refraction = \
base_material_data[3:]
return cls(name, r_transmittance, g_transmittance, b_transmittance, refraction,
modifier)
@property
def average_transmittance(self):
"""Calculate average transmittance."""
return 0.265 * self.r_transmittance + \
0.670 * self.g_transmittance + 0.065 * self.b_transmittance
[docs] @staticmethod
def get_transmissivity(transmittance):
"""Calculate transmissivity based on transmittance value.
"Transmissivity is the amount of light not absorbed in one traversal of
the material. Transmittance -- the value usually measured - is the total
light transmitted through the pane including multiple reflections."
"""
if transmittance == 0:
return 0
return (math.sqrt(0.8402528435 + 0.0072522239 * (transmittance ** 2)) -
0.9166530661) / 0.0036261119 / transmittance
def _update_values(self):
"""update value dictionaries."""
self._values[2] = [
self.get_transmissivity(self.r_transmittance),
self.get_transmissivity(self.g_transmittance),
self.get_transmissivity(self.b_transmittance),
self.refraction_index
]
[docs] def to_json(self):
"""Translate radiance material to json
{
"type": "glass", // Material type
"name": "", // Material Name
"r_transmittance": float, // Transmittance for red
"g_transmittance": float, // Transmittance for green
"b_transmittance": float, // Transmittance for blue
"refraction_index": float, // Index of refraction
"modifier": "" // material modifier (Default: "void")
}
"""
return {
"modifier": self.modifier.to_json(),
"type": "glass",
"name": self.name,
"r_transmittance": self.r_transmittance,
"g_transmittance": self.g_transmittance,
"b_transmittance": self.b_transmittance,
"refraction_index": self.refraction_index
}
if __name__ == "__main__":
# some test code
glassMaterial = Glass.by_single_trans_value("generic glass", .65)
print(glassMaterial)
print(glassMaterial.to_rad_string(minimal=True))
