[not urgent] where is the code to create this gradient texture for a sphere as scene background?

I couldn’t find the code to create the gradient texture as background of the scene in the examples of the physics library enable3d in its github repo, such as the one shown below:


Take a look at line 71 of HTML section of this codepen: https://codepen.io/prisoner849/pen/BaNvBgw

Create a canvas, draw a gradient on it, use the canvas for THREE.CanvasTexture(), use this texture in .map parameter of material for a sphere.