Renderer properties

In [1]:
from pythreejs import *
from IPython.display import display
import ipywidgets
In [2]:
# Reduce repo churn for examples with embedded state:
from pythreejs._example_helper import use_example_model_ids

Transparent background

To have the render view use a transparent background, there are three steps you need to do: 1. Ensure that the background property of the Scene object is set to None. 2. Ensure that alpha=True is passed to the constructor of the Renderer object. This ensures that an alpha channel is used by the renderer. 3. Ensure that the clearOpacity property of the Renderer object is set to 0. For more details about this, see below.

In [3]:
ball = Mesh(geometry=SphereGeometry(),
key_light = DirectionalLight(color='white', position=[3, 5, 1], intensity=0.5)

c = PerspectiveCamera(position=[0, 5, 5], up=[0, 1, 0], children=[key_light])

scene = Scene(children=[ball, c, AmbientLight(color='#777777')], background=None)

renderer = Renderer(camera=c,

The use of clear color/opacity is explained in more detailed in the docs of three.js, but in short: - If autoClear is true the renderer output is cleared on each rendered frame. - If autoClearColor is true the background color is cleared on each frame. - When the background color is cleared, it is reset to Renderer.clearColor, with an opacity of Renderer.clearOpacity.

In [4]:
# Let's set up some controls for the clear color/opacity:

opacity = ipywidgets.FloatSlider(min=0., max=1.)
ipywidgets.jslink((opacity, 'value'), (renderer, 'clearOpacity'))

color = ipywidgets.ColorPicker()
ipywidgets.jslink((color, 'value'), (renderer, 'clearColor'))

    ipywidgets.Label('Clear color:'), color, ipywidgets.Label('Clear opactiy:'), opacity]))

Scene background

If we set the background property of the scene, it will be filled in on top of whatever clear color is there, basically making the clear color ineffective.

In [5]:
scene_background = ipywidgets.ColorPicker()
_background_link = None

def toggle_scene_background(change):
    global _background_link
    if change['new']:
        _background_link = ipywidgets.jslink((scene_background, 'value'), (scene, 'background'))
        _background_link = None
        scene.background = None

scene_background_toggle = ipywidgets.ToggleButton(False, description='Scene Color')
scene_background_toggle.observe(toggle_scene_background, 'value')

    ipywidgets.Label('Scene background color:'), scene_background, scene_background_toggle]))
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