Merge pull request #20471 from ibvfteh:pointcloudio

GSoC module to save and load point cloud

* Add functionality to read point cloud data from files

* address issues found on review, add tests for mesh, refactor

* enable fail-safe execution and empty arrays as output

* Some improvements for point cloud io module

Co-authored-by: Julie Bareeva <julia.bareeva@xperience.ai>

samples/python/point_cloud.py

@@ -0,0 +1,23 @@
+import numpy as np
+import cv2 as cv
+
+vertices, _ = cv.loadPointCloud("../data/teapot.obj")
+vertices = np.squeeze(vertices, axis=1)
+print(vertices)
+
+color = [1.0, 1.0, 0.0]
+colors = np.tile(color, (vertices.shape[0], 1))
+obj_pts = np.concatenate((vertices, colors), axis=1)
+obj_pts= np.float32(obj_pts)
+
+cv.viz3d.showPoints("window", "points", obj_pts)
+cv.viz3d.setGridVisible("window", True)
+
+cv.waitKey(0)
+
+vertices, _, indices = cv.loadMesh("../data/teapot.obj")
+vertices = np.squeeze(vertices, axis=1)
+
+cv.viz3d.showMesh("window", "mesh", vertices, indices)
+
+cv.waitKey(0)