Convex Hulls from Blender to Lua

hulls.py

import bpy
import bmesh
import itertools

# Usage, assign material slots to each unique coplanar plane in each convex hull of the mesh (leaving the first material slot for unassigned faces)

obj = bpy.data.objects['Model']
me = obj.data
vertices = me.vertices

# See https://docs.blender.org/api/current/bpy.types.Mesh.html#bpy.types.Mesh.polygons
faces = []
for poly in me.polygons:
    if poly.material_index == 0:
        continue
    faces.append( [poly.material_index, poly, None, None] )
    
def update_min_max(min, max, current):
    if current[0] < min[0]: min[0] = current[0]
    if current[1] < min[1]: min[1] = current[1]
    if current[2] < min[2]: min[2] = current[2]
    
    if current[0] > max[0]: max[0] = current[0]
    if current[1] > max[1]: max[1] = current[1]
    if current[2] > max[2]: max[2] = current[2]
    
gmin = [float('inf'), float('inf'), float('inf')]
gmax = [float('-inf'), float('-inf'), float('-inf')]
    
faces = sorted(faces, key=lambda x: x[0])
for key, group in itertools.groupby(faces, lambda x: x[0]):
    min = [float('inf'), float('inf'), float('inf')]
    max = [float('-inf'), float('-inf'), float('-inf')]
    for thing in group:
        poly = thing[1]
        for loop_index in range(poly.loop_start, poly.loop_start + poly.loop_total):
            vi = me.loops[loop_index].vertex_index
            print( vertices[vi] )
            update_min_max(min, max, vertices[vi].co.to_tuple())
            update_min_max(gmin, gmax, vertices[vi].co.to_tuple())
        thing[2] = min
        thing[3] = max


print("{")
print("  min = {%f, %f, %f}," % tuple(gmin))
print("  max = {%f, %f, %f}," % tuple(gmax))
for key, group in itertools.groupby(faces, lambda x: x[0]):
    print("  {")
    for thing in group:
        poly = thing[1]
        min = thing[2]
        max = thing[3]
        print("    { center={%f, %f, %f}, normal={%f, %f, %f} }," % (poly.center.to_tuple() + poly.normal.to_tuple()))
    print("    min = {%f, %f, %f}," % tuple(min))
    print("    max = {%f, %f, %f}," % tuple(max))
    print("  },")
print("}")