Added comments to trisurf example.

This mesh was taken from the triplot demo. I have taken out an input
point rotation, this is in the interest of keeping the example code to a
minimum.

Author: dmcdougall

examples/mplot3d/trisurf3d_demo.py

@@ -5,15 +5,23 @@
 
 n_angles = 36
 n_radii = 8
-min_radius = 0.25
-radii = np.linspace(min_radius, 0.95, n_radii)
 
+# An array of radii
+# Does not include radius r=0, this is to eliminate duplicate points
+radii = np.linspace(0.125, 1.0, n_radii)
+
+# An array of angles
 angles = np.linspace(0, 2*np.pi, n_angles, endpoint=False)
+
+# Repeat all angles for each radius
 angles = np.repeat(angles[...,np.newaxis], n_radii, axis=1)
-angles[:,1::2] += np.pi/n_angles
 
+# Convert polar (radii, angles) coords to cartesian (x, y) coords
+# (0, 0) is added here. There are no duplicate points in the (x, y) plane
 x = np.append(0, (radii*np.cos(angles)).flatten())
 y = np.append(0, (radii*np.sin(angles)).flatten())
+
+# Pringle surface
 z = np.sin(-x*y)
 
 fig = plt.figure()