Resolve "(LearnerND) add iso-surface plot feature"

Closes #112 (closed)

adaptive/learner/learnerND.py

@@ -665,13 +665,15 @@ class LearnerND(BaseLearner):
         fig = plotly.figure_factory.create_trisurf(
             x=x, y=y, z=z, plot_edges=False,
             simplices=faces, title="Isosurface")
+        isosurface = fig.data[0]
+        isosurface.update(lighting=dict(ambient=1, diffuse=1, roughness=1, specular=0, fresnel=0))
 
         if hull_opacity < 1e-3:
             # Do not compute the hull_mesh.
             return plotly.offline.iplot(fig)
 
         hull_mesh = self._get_hull_mesh(opacity=hull_opacity)
-        return plotly.offline.iplot([fig.data[0], hull_mesh])
+        return plotly.offline.iplot([isosurface, hull_mesh])
 
     def _get_hull_mesh(self, opacity=0.2):
         plotly = ensure_plotly()
@@ -700,5 +702,7 @@ class LearnerND(BaseLearner):
 
         x, y, z = zip(*self._bounds_points)
         i, j, k = hull.simplices.T
+        lighting = dict(ambient=1, diffuse=1, roughness=1, specular=0, fresnel=0)
         return plotly.graph_objs.Mesh3d(x=x, y=y, z=z, i=i, j=j, k=k,
-                                        facecolor=colors, opacity=opacity)
+                                        facecolor=colors, opacity=opacity,
+                                        lighting=lighting)