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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.
#
# Imports
#
from mathutils import Vector, Quaternion, Matrix
from . import gltf2_blender_export_keys
from ...io.com.gltf2_io_debug import print_console
from ...io.com.gltf2_io_color_management import color_srgb_to_scene_linear
from io_scene_gltf2.blender.exp import gltf2_blender_gather_skins
#
# Classes
#
class Prim:
def __init__(self):
self.verts = {}
self.indices = []
class ShapeKey:
def __init__(self, shape_key, split_normals):
self.shape_key = shape_key
self.split_normals = split_normals
#
# Functions
#
def convert_swizzle_normal(loc, armature, blender_object, export_settings):
"""Convert a normal data from Blender coordinate system to glTF coordinate system."""
if (not armature) or (not blender_object):
# Classic case. Mesh is not skined, no need to apply armature transfoms on vertices / normals / tangents
if export_settings[gltf2_blender_export_keys.YUP]:
return Vector((loc[0], loc[2], -loc[1]))
else:
return Vector((loc[0], loc[1], loc[2]))
else:
# Mesh is skined, we have to apply armature transforms on data
apply_matrix = (armature.matrix_world.inverted() @ blender_object.matrix_world).to_3x3().inverted()
apply_matrix.transpose()
new_loc = ((armature.matrix_world.to_3x3() @ apply_matrix).to_4x4() @ Matrix.Translation(Vector((loc[0], loc[1], loc[2])))).to_translation()
new_loc.normalize()
if export_settings[gltf2_blender_export_keys.YUP]:
return Vector((new_loc[0], new_loc[2], -new_loc[1]))
else:
return Vector((new_loc[0], new_loc[1], new_loc[2]))
def convert_swizzle_location(loc, armature, blender_object, export_settings):
"""Convert a location from Blender coordinate system to glTF coordinate system."""
if (not armature) or (not blender_object):
# Classic case. Mesh is not skined, no need to apply armature transfoms on vertices / normals / tangents
if export_settings[gltf2_blender_export_keys.YUP]:
return Vector((loc[0], loc[2], -loc[1]))
else:
return Vector((loc[0], loc[1], loc[2]))
else:
# Mesh is skined, we have to apply armature transforms on data
apply_matrix = armature.matrix_world.inverted() @ blender_object.matrix_world
new_loc = (armature.matrix_world @ apply_matrix @ Matrix.Translation(Vector((loc[0], loc[1], loc[2])))).to_translation()
if export_settings[gltf2_blender_export_keys.YUP]:
return Vector((new_loc[0], new_loc[2], -new_loc[1]))
else:
return Vector((new_loc[0], new_loc[1], new_loc[2]))
def convert_swizzle_tangent(tan, armature, blender_object, export_settings):
"""Convert a tangent from Blender coordinate system to glTF coordinate system."""
if tan[0] == 0.0 and tan[1] == 0.0 and tan[2] == 0.0:
print_console('WARNING', 'Tangent has zero length.')
if (not armature) or (not blender_object):
# Classic case. Mesh is not skined, no need to apply armature transfoms on vertices / normals / tangents
if export_settings[gltf2_blender_export_keys.YUP]:
return Vector((tan[0], tan[2], -tan[1]))
else:
return Vector((tan[0], tan[1], tan[2]))
else:
# Mesh is skined, we have to apply armature transforms on data
apply_matrix = armature.matrix_world.inverted() @ blender_object.matrix_world
new_tan = apply_matrix.to_quaternion() @ Vector((tan[0], tan[1], tan[2]))
if export_settings[gltf2_blender_export_keys.YUP]:
return Vector((new_tan[0], new_tan[2], -new_tan[1]))
else:
return Vector((new_tan[0], new_tan[1], new_tan[2]))
def convert_swizzle_rotation(rot, export_settings):
"""
Convert a quaternion rotation from Blender coordinate system to glTF coordinate system.
'w' is still at first position.
"""
if export_settings[gltf2_blender_export_keys.YUP]:
return Quaternion((rot[0], rot[1], rot[3], -rot[2]))
else:
return Quaternion((rot[0], rot[1], rot[2], rot[3]))
def convert_swizzle_scale(scale, export_settings):
"""Convert a scale from Blender coordinate system to glTF coordinate system."""
if export_settings[gltf2_blender_export_keys.YUP]:
return Vector((scale[0], scale[2], scale[1]))
else:
return Vector((scale[0], scale[1], scale[2]))
def decompose_transition(matrix, export_settings):
translation, rotation, scale = matrix.decompose()
return translation, rotation, scale
def extract_primitives(glTF, blender_mesh, library, blender_object, blender_vertex_groups, modifiers, export_settings):
"""
Extract primitives from a mesh. Polygons are triangulated and sorted by material.
Vertices in multiple faces get split up as necessary.
"""
print_console('INFO', 'Extracting primitive: ' + blender_mesh.name)
#
# First, decide what attributes to gather (eg. how many COLOR_n, etc.)
# Also calculate normals/tangents now if necessary.
#
use_normals = export_settings[gltf2_blender_export_keys.NORMALS]
if use_normals:
if blender_mesh.has_custom_normals:
# Custom normals are all (0, 0, 0) until calling calc_normals_split() or calc_tangents().
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)
bone_max = 0 # number of JOINTS_n sets needed (1 set = 4 influences)
armature = 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
else:
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]
# Find out max number of bone influences
for blender_polygon in blender_mesh.polygons:
for loop_index in blender_polygon.loop_indices:
vertex_index = blender_mesh.loops[loop_index].vertex_index
groups_count = len(blender_mesh.vertices[vertex_index].groups)
bones_count = (groups_count + 3) // 4
bone_max = max(bone_max, bones_count)
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]
shape_keys = []
if blender_mesh.shape_keys and export_settings[gltf2_blender_export_keys.MORPH]:
for blender_shape_key in blender_mesh.shape_keys.key_blocks:
if blender_shape_key == blender_shape_key.relative_key or blender_shape_key.mute:
continue
split_normals = None
if use_morph_normals:
split_normals = blender_shape_key.normals_split_get()
shape_keys.append(ShapeKey(
blender_shape_key,
split_normals,
))
use_materials = export_settings[gltf2_blender_export_keys.MATERIALS]
#
# Gather the verts and indices for each primitive.
#
prims = {}
blender_mesh.calc_loop_triangles()
for loop_tri in blender_mesh.loop_triangles:
blender_polygon = blender_mesh.polygons[loop_tri.polygon_index]
material_idx = -1
if use_materials:
material_idx = blender_polygon.material_index
prim = prims.get(material_idx)
if not prim:
prim = Prim()
prims[material_idx] = prim
if use_normals:
face_normal = None
if not (blender_polygon.use_smooth or blender_mesh.use_auto_smooth):
# Calc face normal/tangents
face_normal = blender_polygon.normal
if use_tangents:
face_tangent = Vector((0.0, 0.0, 0.0))
face_bitangent = Vector((0.0, 0.0, 0.0))
for loop_index in blender_polygon.loop_indices:
loop = blender_mesh.loops[loop_index]
face_tangent += loop.tangent
face_bitangent += loop.bitangent
face_tangent.normalize()
face_bitangent.normalize()
for loop_index in loop_tri.loops:
vertex_index = blender_mesh.loops[loop_index].vertex_index
vertex = blender_mesh.vertices[vertex_index]
# vert will be a tuple of all the vertex attributes.
# Used as cache key in prim.verts.
vert = (vertex_index,)
v = vertex.co
vert += ((v[0], v[1], v[2]),)
if use_normals:
if face_normal is None:
if blender_mesh.has_custom_normals:
n = blender_mesh.loops[loop_index].normal
else:
n = vertex.normal
if use_tangents:
t = blender_mesh.loops[loop_index].tangent
b = blender_mesh.loops[loop_index].bitangent
else:
n = face_normal
if use_tangents:
t = face_tangent
b = face_bitangent
vert += ((n[0], n[1], n[2]),)
if use_tangents:
vert += ((t[0], t[1], t[2]),)
vert += ((b[0], b[1], b[2]),)
# TODO: store just bitangent_sign in vert, not whole bitangent?
for tex_coord_index in range(0, tex_coord_max):
uv = blender_mesh.uv_layers[tex_coord_index].data[loop_index].uv
uv = (uv.x, 1.0 - uv.y)
vert += (uv,)
for color_index in range(0, color_max):
color = blender_mesh.vertex_colors[color_index].data[loop_index].color
col = (
color_srgb_to_scene_linear(color[0]),
color_srgb_to_scene_linear(color[1]),
color_srgb_to_scene_linear(color[2]),
color[3],
)
vert += (col,)
if bone_max:
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)
bones = tuple(bones)
vert += (bones,)
for shape_key in shape_keys:
v_morph = shape_key.shape_key.data[vertex_index].co
v_morph = v_morph - v # store delta
vert += ((v_morph[0], v_morph[1], v_morph[2]),)
if use_morph_normals:
normals = shape_key.split_normals
n_morph = Vector(normals[loop_index * 3 : loop_index * 3 + 3])
n_morph = n_morph - n # store delta
vert += ((n_morph[0], n_morph[1], n_morph[2]),)
vert_idx = prim.verts.setdefault(vert, len(prim.verts))
prim.indices.append(vert_idx)
#
# Put the verts into attribute arrays.
#
result_primitives = []
for material_idx, prim in prims.items():
if not prim.indices:
continue
vs = []
ns = []
ts = []
uvs = [[] for _ in range(tex_coord_max)]
cols = [[] for _ in range(color_max)]
joints = [[] for _ in range(bone_max)]
weights = [[] for _ in range(bone_max)]
vs_morph = [[] for _ in shape_keys]
ns_morph = [[] for _ in shape_keys]
ts_morph = [[] for _ in shape_keys]
for vert in prim.verts.keys():
i = 0
i += 1 # skip over Blender mesh index
v = vert[i]
i += 1
v = convert_swizzle_location(v, armature, blender_object, export_settings)
vs.extend(v)
if use_normals:
n = vert[i]
i += 1
n = convert_swizzle_normal(n, armature, blender_object, export_settings)
ns.extend(n)
if use_tangents:
t = vert[i]
i += 1
t = convert_swizzle_tangent(t, armature, blender_object, export_settings)
ts.extend(t)
b = vert[i]
i += 1
b = convert_swizzle_tangent(b, armature, blender_object, export_settings)
b_sign = -1.0 if (Vector(n).cross(Vector(t))).dot(Vector(b)) < 0.0 else 1.0
ts.append(b_sign)
for tex_coord_index in range(0, tex_coord_max):
uv = vert[i]
i += 1
uvs[tex_coord_index].extend(uv)
for color_index in range(0, color_max):
col = vert[i]
i += 1
cols[color_index].extend(col)
if bone_max:
bones = vert[i]
i += 1
for j in range(0, 4 * bone_max):
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 shape_key_index in range(0, len(shape_keys)):
v_morph = vert[i]
i += 1
v_morph = convert_swizzle_location(v_morph, armature, blender_object, export_settings)
vs_morph[shape_key_index].extend(v_morph)
if use_morph_normals:
n_morph = vert[i]
i += 1
n_morph = convert_swizzle_normal(n_morph, armature, blender_object, export_settings)
ns_morph[shape_key_index].extend(n_morph)
if use_morph_tangents:
rotation = n_morph.rotation_difference(n)
t_morph = Vector(t)
t_morph.rotate(rotation)
ts_morph[shape_key_index].extend(t_morph)
attributes = {}
attributes['POSITION'] = vs
if ns: attributes['NORMAL'] = ns
if ts: attributes['TANGENT'] = ts
for i, uv in enumerate(uvs): attributes['TEXCOORD_%d' % i] = uv
for i, col in enumerate(cols): attributes['COLOR_%d' % i] = col
for i, js in enumerate(joints): attributes['JOINTS_%d' % i] = js
for i, ws in enumerate(weights): attributes['WEIGHTS_%d' % i] = ws
for i, vm in enumerate(vs_morph): attributes['MORPH_POSITION_%d' % i] = vm
for i, nm in enumerate(ns_morph): attributes['MORPH_NORMAL_%d' % i] = nm
for i, tm in enumerate(ts_morph): attributes['MORPH_TANGENT_%d' % i] = tm
result_primitives.append({
'attributes': attributes,
'indices': prim.indices,
'material': material_idx,
})
print_console('INFO', 'Primitives created: %d' % len(result_primitives))
return result_primitives
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