added UI in 201_Normals.py

Former-commit-id: 19733ad5ff4931b319a237dcc6829b2537482e71

python/201_Normals.py

@@ -1,21 +1,48 @@
 import igl
 
-# Load a mesh in OFF format
+
 V = igl.eigen.MatrixXd()
 F = igl.eigen.MatrixXi()
+
+N_vertices = igl.eigen.MatrixXd()
+N_faces = igl.eigen.MatrixXd()
+N_corners = igl.eigen.MatrixXd()
+
+# This function is called every time a keyboard button is pressed
+def key_pressed(viewer, key, modifier):
+    if key == ord('1'):
+      viewer.data.set_normals(N_faces)
+      return True
+    elif key == ord('2'):
+      viewer.data.set_normals(N_vertices)
+      return True
+    elif key == ord('3'):
+      viewer.data.set_normals(N_corners)
+      return True
+    return False
+
+# Load a mesh in OFF format
 igl.readOFF("../tutorial/shared/fandisk.off", V, F);
 
 # Compute per-face normals
 N_faces = igl.eigen.MatrixXd()
-igl.per_face_normals(V,F,N_faces);
-print("igl::per_face_normals: \n", N_faces, sep='')
+igl.per_face_normals(V,F,N_faces)
 
 # Compute per-vertex normals
 N_vertices = igl.eigen.MatrixXd()
-igl.per_vertex_normals(V,F,igl.PER_VERTEX_NORMALS_WEIGHTING_TYPE_AREA,N_vertices);
-print("igl::per_vertex_normals: \n", N_vertices, sep='')
+igl.per_vertex_normals(V,F,igl.PER_VERTEX_NORMALS_WEIGHTING_TYPE_AREA,N_vertices)
 
 # Compute per-corner normals, |dihedral angle| > 20 degrees --> crease
 N_corners = igl.eigen.MatrixXd()
-igl.per_corner_normals(V,F,20,N_corners);
-print("igl::per_corner_normals: \n", N_corners, sep='')
+igl.per_corner_normals(V,F,20,N_corners)
+
+# Plot the mesh
+viewer = igl.viewer.Viewer()
+viewer.callback_key_pressed = key_pressed
+viewer.core.show_lines = False
+viewer.data.set_mesh(V, F)
+viewer.data.set_normals(N_faces)
+print("Press '1' for per-face normals.")
+print("Press '2' for per-vertex normals.")
+print("Press '3' for per-corner normals.")
+viewer.launch()