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# Copyright 2018-2019 The glTF-Blender-IO authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import numpy as np
from mathutils import Vector
from . import gltf2_blender_export_keys
from ...io.com.gltf2_io_debug import print_console
from io_scene_gltf2.blender.exp import gltf2_blender_gather_skins
def extract_primitives(glTF, blender_mesh, library, blender_object, blender_vertex_groups, modifiers, export_settings):
"""Extract primitives from a mesh."""
print_console('INFO', 'Extracting primitive: ' + blender_mesh.name)
use_normals = export_settings[gltf2_blender_export_keys.NORMALS]
if use_normals:
blender_mesh.calc_normals_split()
use_tangents = False
if use_normals and export_settings[gltf2_blender_export_keys.TANGENTS]:
if blender_mesh.uv_layers.active and len(blender_mesh.uv_layers) > 0:
try:
blender_mesh.calc_tangents()
use_tangents = True
except Exception:
print_console('WARNING', 'Could not calculate tangents. Please try to triangulate the mesh first.')
tex_coord_max = 0
if export_settings[gltf2_blender_export_keys.TEX_COORDS]:
if blender_mesh.uv_layers.active:
tex_coord_max = len(blender_mesh.uv_layers)
color_max = 0
if export_settings[gltf2_blender_export_keys.COLORS]:
color_max = len(blender_mesh.vertex_colors)
armature = None
skin = None
if blender_vertex_groups and export_settings[gltf2_blender_export_keys.SKINS]:
if modifiers is not None:
modifiers_dict = {m.type: m for m in modifiers}
if "ARMATURE" in modifiers_dict:
modifier = modifiers_dict["ARMATURE"]
armature = modifier.object
# Skin must be ignored if the object is parented to a bone of the armature
# (This creates an infinite recursive error)
# So ignoring skin in that case
is_child_of_arma = (
armature and
blender_object and
blender_object.parent_type == "BONE" and
blender_object.parent.name == armature.name
)
if is_child_of_arma:
armature = None
if armature:
skin = gltf2_blender_gather_skins.gather_skin(armature, export_settings)
if not skin:
armature = None
use_morph_normals = use_normals and export_settings[gltf2_blender_export_keys.MORPH_NORMAL]
use_morph_tangents = use_morph_normals and use_tangents and export_settings[gltf2_blender_export_keys.MORPH_TANGENT]
key_blocks = []
if blender_mesh.shape_keys and export_settings[gltf2_blender_export_keys.MORPH]:
key_blocks = [
key_block
for key_block in blender_mesh.shape_keys.key_blocks
if not (key_block == key_block.relative_key or key_block.mute)
]
use_materials = export_settings[gltf2_blender_export_keys.MATERIALS]
# Fetch vert positions and bone data (joint,weights)
locs, morph_locs = __get_positions(blender_mesh, key_blocks, armature, blender_object, export_settings)
if skin:
vert_bones, num_joint_sets = __get_bone_data(blender_mesh, skin, blender_vertex_groups)
# In Blender there is both per-vert data, like position, and also per-loop
# (loop=corner-of-poly) data, like normals or UVs. glTF only has per-vert
# data, so we need to split Blender verts up into potentially-multiple glTF
# verts.
#
# First, we'll collect a "dot" for every loop: a struct that stores all the
# attributes at that loop, namely the vertex index (which determines all
# per-vert data), and all the per-loop data like UVs, etc.
#
# Each unique dot will become one unique glTF vert.
# List all fields the dot struct needs.
dot_fields = [('vertex_index', np.uint32)]
if use_normals:
dot_fields += [('nx', np.float32), ('ny', np.float32), ('nz', np.float32)]
if use_tangents:
dot_fields += [('tx', np.float32), ('ty', np.float32), ('tz', np.float32), ('tw', np.float32)]
for uv_i in range(tex_coord_max):
dot_fields += [('uv%dx' % uv_i, np.float32), ('uv%dy' % uv_i, np.float32)]
for col_i in range(color_max):
dot_fields += [
('color%dr' % col_i, np.float32),
('color%dg' % col_i, np.float32),
('color%db' % col_i, np.float32),
('color%da' % col_i, np.float32),
]
if use_morph_normals:
for morph_i, _ in enumerate(key_blocks):
dot_fields += [
('morph%dnx' % morph_i, np.float32),
('morph%dny' % morph_i, np.float32),
('morph%dnz' % morph_i, np.float32),
]
dots = np.empty(len(blender_mesh.loops), dtype=np.dtype(dot_fields))
vidxs = np.empty(len(blender_mesh.loops))
blender_mesh.loops.foreach_get('vertex_index', vidxs)
dots['vertex_index'] = vidxs
del vidxs
if use_normals:
kbs = key_blocks if use_morph_normals else []
normals, morph_normals = __get_normals(
blender_mesh, kbs, armature, blender_object, export_settings
)
dots['nx'] = normals[:, 0]
dots['ny'] = normals[:, 1]
dots['nz'] = normals[:, 2]
del normals
for morph_i, ns in enumerate(morph_normals):
dots['morph%dnx' % morph_i] = ns[:, 0]
dots['morph%dny' % morph_i] = ns[:, 1]
dots['morph%dnz' % morph_i] = ns[:, 2]
del morph_normals
if use_tangents:
tangents = __get_tangents(blender_mesh, armature, blender_object, export_settings)
dots['tx'] = tangents[:, 0]
dots['ty'] = tangents[:, 1]
dots['tz'] = tangents[:, 2]
del tangents
signs = __get_bitangent_signs(blender_mesh, armature, blender_object, export_settings)
dots['tw'] = signs
del signs
for uv_i in range(tex_coord_max):
uvs = __get_uvs(blender_mesh, uv_i)
dots['uv%dx' % uv_i] = uvs[:, 0]
dots['uv%dy' % uv_i] = uvs[:, 1]
del uvs
for col_i in range(color_max):
colors = __get_colors(blender_mesh, col_i)
dots['color%dr' % col_i] = colors[:, 0]
dots['color%dg' % col_i] = colors[:, 1]
dots['color%db' % col_i] = colors[:, 2]
dots['color%da' % col_i] = colors[:, 3]
del colors
# Calculate triangles and sort them into primitives.
blender_mesh.calc_loop_triangles()
loop_indices = np.empty(len(blender_mesh.loop_triangles) * 3, dtype=np.uint32)
blender_mesh.loop_triangles.foreach_get('loops', loop_indices)
prim_indices = {} # maps material index to TRIANGLES-style indices into dots
if use_materials == "NONE": # Only for None. For placeholder and export, keep primitives
# Put all vertices into one primitive
prim_indices[-1] = loop_indices
else:
# Bucket by material index.
tri_material_idxs = np.empty(len(blender_mesh.loop_triangles), dtype=np.uint32)
blender_mesh.loop_triangles.foreach_get('material_index', tri_material_idxs)
loop_material_idxs = np.repeat(tri_material_idxs, 3) # material index for every loop
unique_material_idxs = np.unique(tri_material_idxs)
del tri_material_idxs
for material_idx in unique_material_idxs:
prim_indices[material_idx] = loop_indices[loop_material_idxs == material_idx]
# Create all the primitives.
primitives = []
for material_idx, dot_indices in prim_indices.items():
# Extract just dots used by this primitive, deduplicate them, and
# calculate indices into this deduplicated list.
prim_dots = dots[dot_indices]
prim_dots, indices = np.unique(prim_dots, return_inverse=True)
if len(prim_dots) == 0:
continue
# Now just move all the data for prim_dots into attribute arrays
attributes = {}
blender_idxs = prim_dots['vertex_index']
attributes['POSITION'] = locs[blender_idxs]
for morph_i, vs in enumerate(morph_locs):
attributes['MORPH_POSITION_%d' % morph_i] = vs[blender_idxs]
if use_normals:
normals = np.empty((len(prim_dots), 3), dtype=np.float32)
normals[:, 0] = prim_dots['nx']
normals[:, 1] = prim_dots['ny']
normals[:, 2] = prim_dots['nz']
attributes['NORMAL'] = normals
if use_tangents:
tangents = np.empty((len(prim_dots), 4), dtype=np.float32)
tangents[:, 0] = prim_dots['tx']
tangents[:, 1] = prim_dots['ty']
tangents[:, 2] = prim_dots['tz']
tangents[:, 3] = prim_dots['tw']
attributes['TANGENT'] = tangents
if use_morph_normals:
for morph_i, _ in enumerate(key_blocks):
ns = np.empty((len(prim_dots), 3), dtype=np.float32)
ns[:, 0] = prim_dots['morph%dnx' % morph_i]
ns[:, 1] = prim_dots['morph%dny' % morph_i]
ns[:, 2] = prim_dots['morph%dnz' % morph_i]
attributes['MORPH_NORMAL_%d' % morph_i] = ns
if use_morph_tangents:
attributes['MORPH_TANGENT_%d' % morph_i] = __calc_morph_tangents(normals, ns, tangents)
for tex_coord_i in range(tex_coord_max):
uvs = np.empty((len(prim_dots), 2), dtype=np.float32)
uvs[:, 0] = prim_dots['uv%dx' % tex_coord_i]
uvs[:, 1] = prim_dots['uv%dy' % tex_coord_i]
attributes['TEXCOORD_%d' % tex_coord_i] = uvs
for color_i in range(color_max):
colors = np.empty((len(prim_dots), 4), dtype=np.float32)
colors[:, 0] = prim_dots['color%dr' % color_i]
colors[:, 1] = prim_dots['color%dg' % color_i]
colors[:, 2] = prim_dots['color%db' % color_i]
colors[:, 3] = prim_dots['color%da' % color_i]
attributes['COLOR_%d' % color_i] = colors
if skin:
joints = [[] for _ in range(num_joint_sets)]
weights = [[] for _ in range(num_joint_sets)]
for vi in blender_idxs:
bones = vert_bones[vi]
for j in range(0, 4 * num_joint_sets):
if j < len(bones):
joint, weight = bones[j]
else:
joint, weight = 0, 0.0
joints[j//4].append(joint)
weights[j//4].append(weight)
for i, (js, ws) in enumerate(zip(joints, weights)):
attributes['JOINTS_%d' % i] = js
attributes['WEIGHTS_%d' % i] = ws
primitives.append({
'attributes': attributes,
'indices': indices,
'material': material_idx,
})
print_console('INFO', 'Primitives created: %d' % len(primitives))
return primitives
def __get_positions(blender_mesh, key_blocks, armature, blender_object, export_settings):
locs = np.empty(len(blender_mesh.vertices) * 3, dtype=np.float32)
blender_mesh.vertices.foreach_get('co', locs)
locs = locs.reshape(len(blender_mesh.vertices), 3)
morph_locs = []
for key_block in key_blocks:
vs = np.empty(len(blender_mesh.vertices) * 3, dtype=np.float32)
key_block.data.foreach_get('co', vs)
vs = vs.reshape(len(blender_mesh.vertices), 3)
morph_locs.append(vs)
# Transform for skinning
if armature and blender_object:
apply_matrix = armature.matrix_world.inverted() @ blender_object.matrix_world
loc_transform = armature.matrix_world @ apply_matrix
loc_transform = blender_object.matrix_world
locs[:] = __apply_mat_to_all(loc_transform, locs)
for vs in morph_locs:
vs[:] = __apply_mat_to_all(loc_transform, vs)
# glTF stores deltas in morph targets
for vs in morph_locs:
vs -= locs
if export_settings[gltf2_blender_export_keys.YUP]:
__zup2yup(locs)
for vs in morph_locs:
__zup2yup(vs)
return locs, morph_locs
def __get_normals(blender_mesh, key_blocks, armature, blender_object, export_settings):
"""Get normal for each loop."""
blender_mesh.calc_normals_split()
normals = np.empty(len(blender_mesh.loops) * 3, dtype=np.float32)
blender_mesh.loops.foreach_get('normal', normals)
normals = normals.reshape(len(blender_mesh.loops), 3)
morph_normals = []
for key_block in key_blocks:
ns = np.array(key_block.normals_split_get(), dtype=np.float32)
ns = ns.reshape(len(blender_mesh.loops), 3)
morph_normals.append(ns)
# Transform for skinning
if armature and blender_object:
apply_matrix = (armature.matrix_world.inverted() @ blender_object.matrix_world)
apply_matrix = apply_matrix.to_3x3().inverted().transposed()
normal_transform = armature.matrix_world.to_3x3() @ apply_matrix
normals[:] = __apply_mat_to_all(normal_transform, normals)
__normalize_vecs(normals)
for ns in morph_normals:
ns[:] = __apply_mat_to_all(normal_transform, ns)
__normalize_vecs(ns)
for ns in [normals, *morph_normals]:
# Replace zero normals with the unit UP vector.
# Seems to happen sometimes with degenerate tris?
is_zero = ~ns.any(axis=1)
ns[is_zero, 2] = 1
# glTF stores deltas in morph targets
for ns in morph_normals:
ns -= normals
if export_settings[gltf2_blender_export_keys.YUP]:
__zup2yup(normals)
for ns in morph_normals:
__zup2yup(ns)
return normals, morph_normals
def __get_tangents(blender_mesh, armature, blender_object, export_settings):
"""Get an array of the tangent for each loop."""
tangents = np.empty(len(blender_mesh.loops) * 3, dtype=np.float32)
blender_mesh.loops.foreach_get('tangent', tangents)
tangents = tangents.reshape(len(blender_mesh.loops), 3)
# Transform for skinning
if armature and blender_object:
apply_matrix = armature.matrix_world.inverted() @ blender_object.matrix_world
tangent_transform = apply_matrix.to_quaternion().to_matrix()
tangents = __apply_mat_to_all(tangent_transform, tangents)
__normalize_vecs(tangents)
if export_settings[gltf2_blender_export_keys.YUP]:
__zup2yup(tangents)
return tangents
def __get_bitangent_signs(blender_mesh, armature, blender_object, export_settings):
signs = np.empty(len(blender_mesh.loops), dtype=np.float32)
blender_mesh.loops.foreach_get('bitangent_sign', signs)
# Transform for skinning
if armature and blender_object:
# Bitangent signs should flip when handedness changes
# TODO: confirm
apply_matrix = armature.matrix_world.inverted() @ blender_object.matrix_world
tangent_transform = apply_matrix.to_quaternion().to_matrix()
flipped = tangent_transform.determinant() < 0
if flipped:
signs *= -1
# No change for Zup -> Yup
return signs
def __calc_morph_tangents(normals, morph_normal_deltas, tangents):
# TODO: check if this works
morph_tangent_deltas = np.empty((len(normals), 3), dtype=np.float32)
for i in range(len(normals)):
n = Vector(normals[i])
morph_n = n + Vector(morph_normal_deltas[i]) # convert back to non-delta
t = Vector(tangents[i, :3])
rotation = morph_n.rotation_difference(n)
t_morph = Vector(t)
t_morph.rotate(rotation)
morph_tangent_deltas[i] = t_morph - t # back to delta
return morph_tangent_deltas
def __get_uvs(blender_mesh, uv_i):
layer = blender_mesh.uv_layers[uv_i]
uvs = np.empty(len(blender_mesh.loops) * 2, dtype=np.float32)
layer.data.foreach_get('uv', uvs)
uvs = uvs.reshape(len(blender_mesh.loops), 2)
# Blender UV space -> glTF UV space
# u,v -> u,1-v
uvs[:, 1] *= -1
uvs[:, 1] += 1
return uvs
def __get_colors(blender_mesh, color_i):
layer = blender_mesh.vertex_colors[color_i]
colors = np.empty(len(blender_mesh.loops) * 4, dtype=np.float32)
layer.data.foreach_get('color', colors)
colors = colors.reshape(len(blender_mesh.loops), 4)
# sRGB -> Linear
rgb = colors[:, :-1]
not_small = rgb >= 0.04045
small_result = np.where(rgb < 0.0, 0.0, rgb * (1.0 / 12.92))
large_result = np.power((rgb + 0.055) * (1.0 / 1.055), 2.4, where=not_small)
rgb[:] = np.where(not_small, large_result, small_result)
return colors
def __get_bone_data(blender_mesh, skin, blender_vertex_groups):
joint_name_to_index = {joint.name: index for index, joint in enumerate(skin.joints)}
group_to_joint = [joint_name_to_index.get(g.name) for g in blender_vertex_groups]
# List of (joint, weight) pairs for each vert
vert_bones = []
max_num_influences = 0
for vertex in blender_mesh.vertices:
bones = []
if vertex.groups:
for group_element in vertex.groups:
weight = group_element.weight
if weight <= 0.0:
continue
try:
joint = group_to_joint[group_element.group]
except Exception:
continue
if joint is None:
continue
bones.append((joint, weight))
bones.sort(key=lambda x: x[1], reverse=True)
if not bones: bones = ((0, 1.0),) # HACK for verts with zero weight (#308)
vert_bones.append(bones)
if len(bones) > max_num_influences:
max_num_influences = len(bones)
# How many joint sets do we need? 1 set = 4 influences
num_joint_sets = (max_num_influences + 3) // 4
return vert_bones, num_joint_sets
def __zup2yup(array):
# x,y,z -> x,z,-y
array[:, [1,2]] = array[:, [2,1]] # x,z,y
array[:, 2] *= -1 # x,z,-y
def __apply_mat_to_all(matrix, vectors):
"""Given matrix m and vectors [v1,v2,...], computes [m@v1,m@v2,...]"""
# Linear part
m = matrix.to_3x3() if len(matrix) == 4 else matrix
res = np.matmul(vectors, np.array(m.transposed()))
# Translation part
if len(matrix) == 4:
res += np.array(matrix.translation)
return res
def __normalize_vecs(vectors):
norms = np.linalg.norm(vectors, axis=1, keepdims=True)
np.divide(vectors, norms, out=vectors, where=norms != 0)
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