Added a documentation page with a pythreejs example.

docs/index.rst

@@ -100,5 +100,6 @@ Horizon 2020 European Research Infrastructure project (676541).
    config_reference
    howto/initialize_cells
    minimal_example
+   pythreejs-example
    contribute
    api

docs/pythreejs-example.rst

@@ -0,0 +1,97 @@
+=================
+PyThreeJs Example
+=================
+
+Thebe can display output from pythreejs_. The examples are taken from the
+pythreejs documentation and are licensed BSD 3 Clause.
+
+.. _pythreejs: https://github.com/jupyter-widgets/pythreejs
+
+Be sure to load require.js before any of your thebe activation code::
+
+   <script src="https://cdnjs.cloudflare.com/ajax/libs/require.js/2.3.4/require.min.js"></script>
+
+.. raw:: html
+
+   <script src="https://cdnjs.cloudflare.com/ajax/libs/require.js/2.3.4/require.min.js"></script>
+
+Press the "Activate" button below to connect to a Jupyter server:
+
+.. raw:: html
+
+   <button id="activateButton" style="width: 120px; height: 40px; font-size: 1.5em;">
+     Activate
+   </button>
+   <script>
+   var bootstrapThebe = function() {
+       thebelab.bootstrap();
+   }
+   document.querySelector("#activateButton").addEventListener('click', bootstrapThebe)
+   </script>
+
+.. raw:: html
+
+   <script type="text/x-thebe-config">
+     {
+       requestKernel: true,
+       binderOptions: {
+         repo: "jupyter-widgets/pythreejs",
+         ref: "2.2.1",
+         binderUrl: "https://binder.libretexts.org",
+         repoProvider: "github",
+       },
+     }
+   </script>
+   <script src="https://unpkg.com/thebelab@latest/lib/index.js"></script>
+
+Primitive shapes can be displayed:
+
+.. raw:: html
+
+   <pre data-executable="true" data-language="python">
+   from pythreejs import BoxGeometry
+   BoxGeometry(
+       width=5,
+       height=10,
+       depth=15,
+       widthSegments=5,
+       heightSegments=10,
+       depthSegments=15)
+   </pre>
+
+More complex shapes can be constructed and viewed:
+
+.. raw:: html
+
+   <pre data-executable="true" data-language="python">
+   from IPython.display import display
+   from pythreejs import (ParametricGeometry, Mesh, PerspectiveCamera, Scene,
+                          MeshLambertMaterial, DirectionalLight, AmbientLight,
+                          Renderer, OrbitControls, PerspectiveCamera)
+
+   f = """
+   function f(origu, origv, out) {
+       // scale u and v to the ranges I want: [0, 2*pi]
+       var u = 2*Math.PI*origu;
+       var v = 2*Math.PI*origv;
+
+       var x = Math.sin(u);
+       var y = Math.cos(v);
+       var z = Math.cos(u+v);
+
+       out.set(x,y,z)
+   }
+   """
+   surf_g = ParametricGeometry(func=f, slices=16, stacks=16);
+
+   surf = Mesh(geometry=surf_g, material=MeshLambertMaterial(color='green', side='FrontSide'))
+   surf2 = Mesh(geometry=surf_g, material=MeshLambertMaterial(color='yellow', side='BackSide'))
+   c = PerspectiveCamera(position=[5, 5, 3], up=[0, 0, 1],
+                         children=[DirectionalLight(color='white',
+                                                    position=[3, 5, 1],
+                                                    intensity=0.6)])
+   scene = Scene(children=[surf, surf2, c, AmbientLight(intensity=0.5)])
+   renderer = Renderer(camera=c, scene=scene, controls=[OrbitControls(controlling=c)], width=400, height=400)
+   #display(renderer)
+   surf
+   </pre>