pygfx.objects.SpotLight

class pygfx.objects.SpotLight(color='#ffffff', intensity=3, *, cast_shadow=False, distance=0, decay=0, angle=1.0471975511965976, penumbra=0, **kwargs)

Bases: Light

Directional point light source.

A light that gets emitted from a single point in one direction, along a cone that increases in size the further from the light it gets.

Parameters:

  • color (Color) – The color of the light emitted.

  • intensity (float) – The light intensity. A value of 3 corresponds to a well lit scene.

  • cast_shadow (bool) – If True, the light can cast shadows. Otherwise it doesn’t.

  • distance (float) – The maximum distance at which objects are considered illuminated by the light. Limiting this may increase performance in large scenes. A value of 0 means that all objects are considered.

  • decay (float) – The rate at which the light dims as it travels. A value of 0 means no decay. A decay of 2 is physically correct.

  • angle (float) – The central angle (in rad) of the light’s cone.

  • penumbra (float) – Percent of the spotlight cone that is attenuated due to penumbra. Takes values between zero and 1. Default is zero.

Notes

If this light is attached to a camera it’s direction will follow the camera view direction.

There are two booleans that control the behavior of shadow: cast_shadow on a Light, and receive_shadow on the illuminated object. Shadows will only be displayed if both are set to True.

When setting decay to a non-zero value you likely probably have to increase intensity (a lot) as light decays following an inverse-square profile.

property power

The light’s power. I.e. the luminous power of the light measured in lumens (lm). Changing the power will also change the light’s intensity.

property distance

When distance is zero, light will attenuate according to inverse-square law to infinite distance. When distance is non-zero, light will attenuate the same way until near the distance cutoff, where it will then attenuate quickly and smoothly to 0. Inherently, cutoffs are not physically correct.

property angle

The maximum extent of the spotlight, in radians, from its direction. Should be no more than Math.PI/2.

property penumbra

Percent of the spotlight cone that is attenuated due to penumbra. Takes values between zero and 1.

property decay

The amount the light dims along the distance of the light. A decay of 2 leads to physically realistic light falloff. Default is 0, which means the light does not decay.