HOW TO: Run XAtlas in Blender.

[mifth]

Hi, I was able to run the xatlas in blender and I just want to share my experience.

Blender 4.1+.
1 Open Blender
2 Open Blender's Python Console: Shift+F4
3 Run: import pip
4 Run: pip.main(['install', 'xatlas'])
5 Open Text Editor: Shift+F11
6 Paste the code above
7 Select an object(it should have a UV map) and press Play button in the Text Editor.

Code for the Text Editor:

import bpy

import xatlas
import numpy as np


context = bpy.context
active_obj: bpy.types.Object = context.active_object

# Get Verts
mesh_verts = np.zeros(len(active_obj.data.vertices) * 3, dtype=np.float64)
active_obj.data.vertices.foreach_get('co', mesh_verts)
mesh_verts.shape = (len(active_obj.data.vertices), 3)

poly_indeces = np.zeros(len(active_obj.data.loop_triangles) * 3, dtype=np.int32)
active_obj.data.loop_triangles.foreach_get('vertices', poly_indeces)
poly_indeces.shape = (len(active_obj.data.loop_triangles), 3)

poly_loops = np.zeros(len(active_obj.data.loop_triangles) * 3, dtype=np.int32)
active_obj.data.loop_triangles.foreach_get('loops', poly_loops)
poly_loops.shape = (len(active_obj.data.loop_triangles), 3)

mesh_normals = np.zeros(len(active_obj.data.vertices) * 3, dtype=np.float64)
active_obj.data.vertices.foreach_get('normal', mesh_normals)
mesh_normals.shape = (len(active_obj.data.vertices), 3)

atlas = xatlas.Atlas()
atlas.add_mesh(mesh_verts, poly_indeces, mesh_normals)

chart_options = xatlas.ChartOptions()
#chart_options.normal_deviation_weight = 0.5
#chart_options.roundness_weight = 0.5
#chart_options.straightness_weight = 0.5
#chart_options.normal_seam_weight = 0.5
#chart_options.texture_seam_weight = 0.5
#chart_options.max_cost = 0.5
#chart_options.fix_winding = True
#chart_options.use_unput_mesh_uvs = True

pack_options = xatlas.PackOptions()
#pack_options.padding = 5
#pack_options.create_image = False

atlas.generate(chart_options, pack_options, True)

xatlas_vmapping, xatlas_indices, xatlas_uvs = atlas[0]

active_uv = active_obj.data.uv_layers.active

if active_uv:
    for i, poly_indices in enumerate(xatlas_indices):
        poly_loop_ids = poly_loops[i]

        for j in range(len(poly_loop_ids)):
            active_uv.data[poly_loop_ids[j]].uv = xatlas_uvs[poly_indices[j]]

del atlas
del chart_options
del pack_options

Pictures: