278 lines
8.8 KiB
Python
278 lines
8.8 KiB
Python
"""
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lighting.py
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--------------
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Hold basic information about lights.
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Forked from the light model in `pyrender`:
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https://github.com/mmatl/pyrender
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"""
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import numpy as np
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from .. import util
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from .. import visual
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from .. import transformations
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# default light color
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_DEFAULT_RGBA = np.array([60, 60, 60, 255], dtype=np.uint8)
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class Light(util.ABC):
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"""
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Base class for all light objects.
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Attributes
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----------
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name : str, optional
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Name of the light.
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color : (4,) uint8
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RGBA value for the light's color in linear space.
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intensity : float
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Brightness of light. The units that this is defined in depend
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on the type of light: point and spot lights use luminous intensity
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in candela (lm/sr) while directional lights use illuminance
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in lux (lm/m2).
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radius : float
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Cutoff distance at which light's intensity may be considered to
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have reached zero. Supported only for point and spot lights
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Must be > 0.0
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If None, the radius is assumed to be infinite.
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"""
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def __init__(self,
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name=None,
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color=None,
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intensity=None,
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radius=None):
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if name is None:
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# if name is not passed, make it something unique
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self.name = 'light_{}'.format(util.unique_id(6).upper())
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else:
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# otherwise assign it
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self.name = name
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self.color = color
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self.intensity = intensity
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self.radius = radius
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@property
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def color(self):
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return self._color
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@color.setter
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def color(self, value):
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if value is None:
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self._color = _DEFAULT_RGBA
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else:
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value = visual.to_rgba(value)
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if len(value.shape) == 2:
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value = value[0]
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if value.shape != (4,):
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raise ValueError("couldn't convert color to RGBA!")
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# uint8 RGB color
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self._color = value
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@property
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def intensity(self):
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return self._intensity
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@intensity.setter
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def intensity(self, value):
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if value is not None:
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self._intensity = float(value)
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else:
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self._intensity = 1.0
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@property
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def radius(self):
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return self._radius
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@radius.setter
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def radius(self, value):
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if value is None or value < 0.0:
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self._radius = value
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else:
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self._radius = float(value)
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class DirectionalLight(Light):
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"""
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Directional lights are light sources that act as though they are
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infinitely far away and emit light in the direction of the local -z axis.
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This light type inherits the orientation of the node that it belongs to;
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position and scale are ignored except for their effect on the inherited
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node orientation. Because it is at an infinite distance, the light is
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not attenuated. Its intensity is defined in lumens per metre squared,
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or lux (lm/m2).
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Attributes
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----------
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name : str, optional
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Name of the light.
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color : (4,) unit8
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RGBA value for the light's color in linear space.
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intensity : float
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Brightness of light. The units that this is defined in depend
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on the type of light.
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point and spot lights use luminous intensity in candela (lm/sr),
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while directional lights use illuminance in lux (lm/m2).
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radius : float
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Cutoff distance at which light's intensity may be considered to
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have reached zero. Supported only for point and spot lights, must be > 0.
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If None, the radius is assumed to be infinite.
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"""
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def __init__(self,
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name=None,
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color=None,
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intensity=None,
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radius=None):
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super(DirectionalLight, self).__init__(
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name=name,
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color=color,
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intensity=intensity,
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radius=radius
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)
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class PointLight(Light):
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"""
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Point lights emit light in all directions from their position in space;
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rotation and scale are ignored except for their effect on the inherited
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node position. The brightness of the light attenuates in a physically
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correct manner as distance increases from the light's position (i.e.
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brightness goes like the inverse square of the distance). Point light
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intensity is defined in candela, which is lumens per square radian (lm/sr).
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Attributes
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----------
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name : str, optional
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Name of the light.
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color : (4,) uint8
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RGBA value for the light's color in linear space.
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intensity : float
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Brightness of light. The units that this is defined in depend
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on the type of light.
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point and spot lights use luminous intensity in candela (lm/sr),
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while directional lights use illuminance in lux (lm/m2).
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radius : float
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Cutoff distance at which light's intensity may be considered to
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have reached zero. Supported only for point and spot lights, must be > 0.
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If None, the radius is assumed to be infinite.
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"""
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def __init__(self,
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name=None,
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color=None,
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intensity=None,
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radius=None):
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super(PointLight, self).__init__(
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name=name,
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color=color,
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intensity=intensity,
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radius=radius
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)
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class SpotLight(Light):
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"""
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Spot lights emit light in a cone in the direction of the local -z axis.
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The angle and falloff of the cone is defined using two numbers, the
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`innerConeAngle` and `outerConeAngle`. As with point lights, the brightness
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also attenuates in a physically correct manner as distance increases from
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the light's position (i.e. brightness goes like the inverse square of the
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distance). Spot light intensity refers to the brightness inside the
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`innerConeAngle` (and at the location of the light) and is defined in
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candela, which is lumens per square radian (lm/sr). A spot light's position
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and orientation are inherited from its node transform. Inherited scale does
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not affect cone shape, and is ignored except for its effect on position
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and orientation.
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Attributes
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----------
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name : str, optional
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Name of the light.
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color : (4,) uint8
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RGBA value for the light's color in linear space.
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intensity : float
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Brightness of light. The units that this is defined in depend
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on the type of light.
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point and spot lights use luminous intensity in candela (lm/sr),
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while directional lights use illuminance in lux (lm/m2).
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radius : float
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Cutoff distance at which light's intensity may be considered to
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have reached zero. Supported only for point and spot lights, must be > 0.
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If None, the radius is assumed to be infinite.
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innerConeAngle : float
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Angle, in radians, from centre of spotlight where falloff begins.
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Must be greater than or equal to `0` and less than `outerConeAngle`.
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outerConeAngle : float
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Angle, in radians, from centre of spotlight where falloff ends.
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Must be greater than `innerConeAngle` and less than or equal to `PI / 2.0`.
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"""
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def __init__(self,
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name=None,
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color=None,
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intensity=None,
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radius=None,
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innerConeAngle=0.0,
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outerConeAngle=np.pi / 4.0):
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super(SpotLight, self).__init__(
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name=name,
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color=color,
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intensity=intensity,
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radius=radius
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)
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self.outerConeAngle = outerConeAngle
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self.innerConeAngle = innerConeAngle
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@property
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def innerConeAngle(self):
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return self._innerConeAngle
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@innerConeAngle.setter
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def innerConeAngle(self, value):
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if value < 0.0 or value > self.outerConeAngle:
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raise ValueError('Invalid value for inner cone angle')
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self._innerConeAngle = float(value)
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@property
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def outerConeAngle(self):
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return self._outerConeAngle
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@outerConeAngle.setter
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def outerConeAngle(self, value):
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if value < 0.0 or value > np.pi / 2.0 + 1e-9:
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raise ValueError('Invalid value for outer cone angle')
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self._outerConeAngle = float(value)
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def autolight(scene):
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"""
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Generate a list of lights for a scene that looks decent.
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Parameters
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--------------
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scene : trimesh.Scene
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Scene with geometry
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Returns
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--------------
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lights : [Light]
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List of light objects
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transforms : (len(lights), 4, 4) float
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Transformation matrices for light positions.
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"""
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# create two default point lights
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lights = [PointLight(), PointLight()]
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# create two translation matrices for bounds corners
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transforms = [transformations.translation_matrix(b)
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for b in scene.bounds]
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return lights, transforms
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