From b42b55c5ec5b7960d66b53eab5471da427d9ce49 Mon Sep 17 00:00:00 2001
From: marcomusy <marco.musy@gmail.com>
Date: Fri, 15 Sep 2023 20:46:21 +0200
Subject: [PATCH] add examples/advanced/interpolate_scalar5.py

---
 examples/advanced/interpolate_scalar5.py | 45 ++++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 examples/advanced/interpolate_scalar5.py

diff --git a/examples/advanced/interpolate_scalar5.py b/examples/advanced/interpolate_scalar5.py
new file mode 100644
index 00000000..9d9a9189
--- /dev/null
+++ b/examples/advanced/interpolate_scalar5.py
@@ -0,0 +1,45 @@
+"""Interpolate a 2D surface through a set of points"""
+import numpy as np
+from scipy.spatial import distance_matrix
+from vedo import Grid, Points, Lines, show
+np.random.seed(1)
+
+def harmonic_shepard(pts, vals, radius):
+    dists = distance_matrix(pts, pts) + radius
+    rdists = 1.0 / dists
+    sum_vals = np.sum(rdists * vals, axis=1)
+    return sum_vals / np.sum(rdists, axis=1)
+
+# Create a grid of points
+surf = Grid(res=[25,25])
+
+# Pick n random points on the surface
+ids = np.random.randint(0, surf.npoints, 10)
+pts = surf.points(ids)
+
+# Create a set of random scalars
+scals1 = np.random.randn(10) * 0.1 
+
+ptss1 = pts.copy()
+ptss1[:,2] = scals1   # assign scalars as z-coords
+pts1 = Points(ptss1, r=15, c="red5")
+
+# Compute an interpolated (smoothed) set of scalars
+scals2 = harmonic_shepard(pts, scals1, radius=0.1)
+ptss2 = pts.copy()
+ptss2[:,2] = scals2
+pts2 = Points(ptss2, r=15, c="purple5")
+
+# Warp the surface to match the interpolated points
+ptsource, pttarget = [], []
+for pt in pts2.points():
+    pt_surf = surf.closest_point(pt)
+    ptsource.append(pt_surf)
+    pttarget.append(pt)
+warped = surf.warp(ptsource, pttarget, mode='2d')
+warped.color("b4").lc('lightblue').wireframe(False).lw(1)
+
+lines = Lines(pts1, pts2, lw=2)
+
+show(pts1, pts2, lines, warped, __doc__, axes=1, viewup="z").close()
+