pyvista_wasm.Light

class pyvista_wasm.Light(position: tuple[float, float, float] = (0.0, 0.0, 1.0), focal_point: tuple[float, float, float] = (0.0, 0.0, 0.0), color: tuple[float, float, float] | str = (1.0, 1.0, 1.0), intensity: float = 1.0, light_type: str = 'SceneLight', positional: bool = False, cone_angle: float = 30.0, cone_falloff: float = 5.0, attenuation_values: tuple[float, float, float] = (1.0, 0.0, 0.0))

Bases: object

Light class.

Parameters:

• position (sequence[float], optional) – The position of the light. The interpretation of the position depends on the type of the light and whether the light has a transformation matrix.

• focal_point (sequence[float], optional) – The focal point of the light. The interpretation of the focal point depends on the type of the light and whether the light has a transformation matrix.

• color (sequence[float] | str, optional) – The color of the light. The ambient, diffuse and specular colors will all be set to this color on creation.

• light_type (str, default: 'SceneLight') –

  The type of the light. One of 'Headlight', 'CameraLight' or 'SceneLight'.

  • A headlight is attached to the camera, looking at its focal point along the axis of the camera.

  • A camera light also moves with the camera, but it can occupy a general position with respect to it.

  • A scene light is stationary with respect to the scene, as it does not follow the camera. This is the default.

• intensity (float, optional) – The brightness of the light (between 0 and 1).

• positional (bool, optional) –

  Set if the light is positional.

  The default is a directional light, i.e. an infinitely distant point source. A positional light with a cone angle of at least 90 degrees acts like a spherical point source. A positional light with a cone angle that is less than 90 degrees is known as a spotlight.

• cone_angle (float, optional) – Cone angle of a positional light in degrees.

• cone_falloff (float, optional) – The exponent of the cosine used for spotlights.

• attenuation_values (sequence[float], optional) –

  Quadratic attenuation constants.

  The values are a 3-length sequence which specifies the constant, linear and quadratic constants in this order. These parameters only have an effect for positional lights.

Examples

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Headlight. For headlights the position and focal point properties are meaningless. No matter where you move the camera, the light always emanates from the view point:

>>> import pyvista_wasm as pv
>>> from pyvista_wasm import examples
>>> mesh = examples.download_bunny()
>>> plotter = pv.Plotter()
>>> _ = plotter.add_mesh(mesh, color='lightblue')
>>> light = pv.Light(light_type='Headlight')
>>> # these don't do anything for a headlight:
>>> light.position = (1, 2, 3)
>>> light.focal_point = (4, 5, 6)
>>> plotter.add_light(light)
>>> plotter.show()

Camera light. Camera lights move together with the camera, but can occupy any fixed relative position with respect to the camera:

>>> plotter = pv.Plotter()
>>> _ = plotter.add_mesh(mesh, color='lightblue')
>>> # a light that always shines from the right of the camera
>>> light = pv.Light(position=(1, 0, 0), light_type='CameraLight')
>>> plotter.add_light(light)
>>> plotter.show()

Scene light. Scene lights are attached to the scene, their position and focal point are interpreted as global coordinates:

>>> plotter = pv.Plotter()
>>> _ = plotter.add_mesh(mesh, color='lightblue')
>>> # a light that always shines on the left side of the bunny
>>> light = pv.Light(position=(0, 1, 0), light_type='SceneLight')
>>> plotter.add_light(light)
>>> plotter.show()

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__init__(position: tuple[float, float, float] = (0.0, 0.0, 1.0), focal_point: tuple[float, float, float] = (0.0, 0.0, 0.0), color: tuple[float, float, float] | str = (1.0, 1.0, 1.0), intensity: float = 1.0, light_type: str = 'SceneLight', positional: bool = False, cone_angle: float = 30.0, cone_falloff: float = 5.0, attenuation_values: tuple[float, float, float] = (1.0, 0.0, 0.0)) → None

Initialize a Light instance.

Methods

__init__([position, focal_point, color, ...])	Initialize a Light instance.
generate_vtk_js_code(idx)	Generate VTK.wasm JavaScript code for this light.
set_light_type_to_camera_light()	Set light type to CameraLight (moves with the camera).
set_light_type_to_headlight()	Set light type to Headlight (at camera position).
set_light_type_to_scene_light()	Set light type to SceneLight (fixed in world space).

generate_vtk_js_code(idx: int) → str

Generate VTK.wasm JavaScript code for this light.

Parameters:

idx (int) – Unique index used to avoid variable name collisions in JavaScript.

Returns:

JavaScript code that creates and configures the light.

Return type:

str

set_light_type_to_camera_light() → None

Set light type to CameraLight (moves with the camera).

set_light_type_to_headlight() → None

Set light type to Headlight (at camera position).

set_light_type_to_scene_light() → None

Set light type to SceneLight (fixed in world space).