# ----------------------------------------------------------------------------
# - CloudViewer: www.cloudViewer.org -
# ----------------------------------------------------------------------------
# Copyright (c) 2018-2024 www.cloudViewer.org
# SPDX-License-Identifier: MIT
# ----------------------------------------------------------------------------
import cloudViewer as cv3d
def cv3d_material_to_bsdf(mat, vertex_color=False):
import mitsuba as mi
def create_bsdf_entry(mat, value, cv3d_name, per_vertex):
if per_vertex:
return {'type': 'mesh_attribute', 'name': 'vertex_color'}
elif cv3d_name in mat.texture_maps:
return {
'type':
'bitmap',
'bitmap':
mi.Bitmap(mat.texture_maps[cv3d_name].as_tensor().numpy())
}
else:
return {'type': 'rgb', 'value': value}
base_color = mat.vector_properties['base_color'][0:3]
roughness = mat.scalar_properties['roughness']
metallic = mat.scalar_properties['metallic']
reflectance = mat.scalar_properties['reflectance']
anisotropy = mat.scalar_properties['anisotropy']
bsdf_dict = {'type': 'principled'}
bsdf_dict['base_color'] = create_bsdf_entry(mat, base_color, 'albedo',
vertex_color)
bsdf_dict['roughness'] = create_bsdf_entry(mat, roughness, 'roughness',
False)
bsdf_dict['metallic'] = create_bsdf_entry(mat, metallic, 'metallic', False)
bsdf_dict['anisotropic'] = create_bsdf_entry(mat, anisotropy, 'anisotropy',
False)
bsdf_dict['specular'] = reflectance
# check for normal map
if 'normal' in mat.texture_maps:
nmap_dict = {'type': 'normalmap'}
nmap_dict['normalmap'] = {
'type': 'bitmap',
'raw': True,
'bitmap': mi.Bitmap(mat.texture_maps['normal'].as_tensor().numpy())
}
nmap_dict['bsdf'] = bsdf_dict
bsdf = mi.load_dict(nmap_dict)
else:
bsdf = mi.load_dict(bsdf_dict)
return bsdf
[docs]def to_mitsuba(self, name, bsdf=None):
"""Convert CloudViewer TriangleMesh to Mitsuba Mesh.
Converts an CloudViewer TriangleMesh to a Mitsuba Mesh which can be used directly
in a Mitsbua scene. The TriangleMesh's material will be converted to a
Mitsuba Principled BSDF and assigned to the Mitsuba Mesh. Optionally, the
user may provide a Mitsuba BSDF to be used instead of converting the CloudViewer
material.
Args:
name (str): Name for the Mitsuba Mesh. Used by Mitsuba as an identifier
bsdf (default None): If a Mitsuba BSDF is supplied it will be used as
the BSDF for the converted mesh. Otherwise, the TriangleMesh's material
will be converted to Mitsuba Principled BSDF.
Returns:
A Mitsuba Mesh (with associated BSDF) ready for use in a Mitsuba scene.
"""
import mitsuba as mi
import numpy as np
# What features does this mesh have
has_normals = 'normals' in self.vertex
has_uvs = 'texture_uvs' in self.triangle
has_colors = 'colors' in self.vertex
# Convert CloudViewer Material to Mitsuba's principled BSDF
if bsdf is None:
bsdf = cv3d_material_to_bsdf(self.material, vertex_color=has_colors)
# Mesh constructor looks for this specific property for setting BSDF
bsdf_prop = mi.Properties()
bsdf_prop['mesh_bsdf'] = bsdf
# Create Mitsuba mesh shell
mi_mesh = mi.Mesh(name,
vertex_count=self.vertex.positions.shape[0],
face_count=self.triangle.indices.shape[0],
has_vertex_normals=has_normals,
has_vertex_texcoords=has_uvs,
props=bsdf_prop)
# Vertex color is not a 'built-in' attribute. Needs to be added.
if has_colors:
mi_mesh.add_attribute('vertex_color', 3,
self.vertex.colors.numpy().flatten())
# "Traverse" the mesh to get its updateable parameters
mesh_params = mi.traverse(mi_mesh)
mesh_params['vertex_positions'] = self.vertex.positions.numpy().flatten()
mesh_params['faces'] = self.triangle.indices.numpy().flatten()
if has_normals:
mesh_params['vertex_normals'] = self.vertex.normals.numpy().flatten()
if has_uvs:
# Mitsuba wants UVs per-vertex so copy them into place
per_vtx_uvs = np.zeros((self.vertex.positions.shape[0], 2))
for idx, uvs in zip(self.triangle.indices, self.triangle.texture_uvs):
per_vtx_uvs[idx.numpy()] = uvs.numpy()
mesh_params['vertex_texcoords'] = np.subtract(1.0,
per_vtx_uvs,
out=per_vtx_uvs,
where=[False,
True]).flatten()
# Let Mitsuba know parameters have been updated
return mi_mesh
# Add to_mitsuba method to TriangleMesh
cv3d.t.geometry.TriangleMesh.to_mitsuba = to_mitsuba