glTF exporter: Fix skinning space / Inverse Bind Matrix

This commit is contained in:
Julien Duroure 2019-09-13 21:59:14 +02:00
parent fb3a669c75
commit 7307a3c57d
6 changed files with 106 additions and 46 deletions

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@ -15,7 +15,7 @@
bl_info = {
'name': 'glTF 2.0 format',
'author': 'Julien Duroure, Norbert Nopper, Urs Hanselmann, Moritz Becher, Benjamin Schmithüsen, Jim Eckerlein, and many external contributors',
"version": (0, 9, 64),
"version": (0, 9, 65),
'blender': (2, 81, 6),
'location': 'File > Import-Export',
'description': 'Import-Export as glTF 2.0',

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@ -16,7 +16,7 @@
# Imports
#
from mathutils import Vector, Quaternion
from mathutils import Vector, Quaternion, Matrix
from mathutils.geometry import tessellate_polygon
from operator import attrgetter
@ -24,6 +24,7 @@ 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
import bpy
#
# Globals
@ -63,24 +64,61 @@ class ShapeKey:
# Functions
#
def convert_swizzle_location(loc, export_settings):
"""Convert a location from Blender coordinate system to glTF coordinate system."""
if export_settings[gltf2_blender_export_keys.YUP]:
return Vector((loc[0], loc[2], -loc[1]))
def convert_swizzle_normal_and_tangent(loc, armature, blender_object, export_settings):
"""Convert a normal data from Blender coordinate system to glTF coordinate system."""
if not armature:
# 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:
return Vector((loc[0], loc[1], loc[2]))
# Mesh is skined, we have to apply armature transforms on data
apply_matrix = armature.matrix_world.inverted() @ blender_object.matrix_world
new_loc = apply_matrix.to_quaternion() @ loc
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:
# 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, export_settings):
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 export_settings[gltf2_blender_export_keys.YUP]:
return Vector((tan[0], tan[2], -tan[1], 1.0))
if not armature:
# 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], 1.0))
else:
return Vector((tan[0], tan[1], tan[2], 1.0))
else:
return Vector((tan[0], tan[1], tan[2], 1.0))
# 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() @ tan
if export_settings[gltf2_blender_export_keys.YUP]:
return Vector((new_tan[0], new_tan[2], -new_tan[1], 1.0))
else:
return Vector((new_tan[0], new_tan[1], new_tan[2], 1.0))
def convert_swizzle_rotation(rot, export_settings):
"""
@ -383,7 +421,7 @@ def extract_primitive_pack(a, indices, use_tangents):
return result_primitive
def extract_primitives(glTF, blender_mesh, blender_vertex_groups, modifiers, export_settings):
def extract_primitives(glTF, blender_mesh, blender_object, blender_vertex_groups, modifiers, export_settings):
"""
Extract primitives from a mesh. Polygons are triangulated and sorted by material.
@ -508,6 +546,15 @@ def extract_primitives(glTF, blender_mesh, blender_vertex_groups, modifiers, exp
blender_shape_key.normals_vertex_get(), # calculate vertex normals for this shape key
blender_shape_key.normals_polygon_get())) # calculate polygon normals for this shape key
armature = None
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
#
# Convert polygon to primitive indices and eliminate invalid ones. Assign to material.
#
@ -587,20 +634,20 @@ def extract_primitives(glTF, blender_mesh, blender_vertex_groups, modifiers, exp
vertex = blender_mesh.vertices[vertex_index]
v = convert_swizzle_location(vertex.co, export_settings)
v = convert_swizzle_location(vertex.co, armature, blender_object, export_settings)
if blender_polygon.use_smooth or blender_mesh.use_auto_smooth:
if blender_mesh.has_custom_normals:
n = convert_swizzle_location(blender_mesh.loops[loop_index].normal, export_settings)
n = convert_swizzle_normal_and_tangent(blender_mesh.loops[loop_index].normal, armature, blender_object, export_settings)
else:
n = convert_swizzle_location(vertex.normal, export_settings)
n = convert_swizzle_normal_and_tangent(vertex.normal, armature, blender_object, export_settings)
if use_tangents:
t = convert_swizzle_tangent(blender_mesh.loops[loop_index].tangent, export_settings)
b = convert_swizzle_location(blender_mesh.loops[loop_index].bitangent, export_settings)
t = convert_swizzle_tangent(blender_mesh.loops[loop_index].tangent, armature, blender_object, export_settings)
b = convert_swizzle_location(blender_mesh.loops[loop_index].bitangent, armature, blender_object, export_settings)
else:
n = convert_swizzle_location(face_normal, export_settings)
n = convert_swizzle_normal_and_tangent(face_normal, armature, blender_object, export_settings)
if use_tangents:
t = convert_swizzle_tangent(face_tangent, export_settings)
b = convert_swizzle_location(face_bitangent, export_settings)
t = convert_swizzle_tangent(face_tangent, armature, blender_object, export_settings)
b = convert_swizzle_location(face_bitangent, armature, blender_object, export_settings)
if use_tangents:
tv = Vector((t[0], t[1], t[2]))
@ -669,17 +716,12 @@ def extract_primitives(glTF, blender_mesh, blender_vertex_groups, modifiers, exp
joint_index = None
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
if armature:
skin = gltf2_blender_gather_skins.gather_skin(armature, modifier.id_data, export_settings)
for index, j in enumerate(skin.joints):
if j.name == vertex_group_name:
joint_index = index
break
if armature:
skin = gltf2_blender_gather_skins.gather_skin(armature, export_settings)
for index, j in enumerate(skin.joints):
if j.name == vertex_group_name:
joint_index = index
break
#
if joint_index is not None:
@ -707,6 +749,7 @@ def extract_primitives(glTF, blender_mesh, blender_vertex_groups, modifiers, exp
blender_shape_key = blender_shape_keys[morph_index]
v_morph = convert_swizzle_location(blender_shape_key.shape_key.data[vertex_index].co,
armature, blender_object,
export_settings)
# Store delta.
@ -728,7 +771,7 @@ def extract_primitives(glTF, blender_mesh, blender_vertex_groups, modifiers, exp
temp_normals[blender_polygon.index * 3 + 0], temp_normals[blender_polygon.index * 3 + 1],
temp_normals[blender_polygon.index * 3 + 2])
n_morph = convert_swizzle_location(n_morph, export_settings)
n_morph = convert_swizzle_normal_and_tangent(n_morph, armature, blender_object, export_settings)
# Store delta.
n_morph -= n

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@ -24,6 +24,7 @@ from io_scene_gltf2.io.com.gltf2_io_debug import print_console
@cached
def gather_mesh(blender_mesh: bpy.types.Mesh,
blender_object: Optional[bpy.types.Object],
vertex_groups: Optional[bpy.types.VertexGroups],
modifiers: Optional[bpy.types.ObjectModifiers],
skip_filter: bool,
@ -37,7 +38,7 @@ def gather_mesh(blender_mesh: bpy.types.Mesh,
extensions=__gather_extensions(blender_mesh, vertex_groups, modifiers, export_settings),
extras=__gather_extras(blender_mesh, vertex_groups, modifiers, export_settings),
name=__gather_name(blender_mesh, vertex_groups, modifiers, export_settings),
primitives=__gather_primitives(blender_mesh, vertex_groups, modifiers, material_names, export_settings),
primitives=__gather_primitives(blender_mesh, blender_object, vertex_groups, modifiers, material_names, export_settings),
weights=__gather_weights(blender_mesh, vertex_groups, modifiers, export_settings)
)
@ -102,12 +103,14 @@ def __gather_name(blender_mesh: bpy.types.Mesh,
def __gather_primitives(blender_mesh: bpy.types.Mesh,
blender_object: Optional[bpy.types.Object],
vertex_groups: Optional[bpy.types.VertexGroups],
modifiers: Optional[bpy.types.ObjectModifiers],
material_names: Tuple[str],
export_settings
) -> List[gltf2_io.MeshPrimitive]:
return gltf2_blender_gather_primitives.gather_primitives(blender_mesh,
blender_object,
vertex_groups,
modifiers,
material_names,

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@ -68,7 +68,10 @@ def __gather_node(blender_object, blender_scene, export_settings):
translation=None,
weights=__gather_weights(blender_object, export_settings)
)
node.translation, node.rotation, node.scale = __gather_trans_rot_scale(blender_object, export_settings)
# If node mesh is skined, transforms should be ignored at import, so no need to set them here
if node.skin is None:
node.translation, node.rotation, node.scale = __gather_trans_rot_scale(blender_object, export_settings)
if export_settings[gltf2_blender_export_keys.YUP]:
if blender_object.type == 'LIGHT' and export_settings[gltf2_blender_export_keys.LIGHTS]:
@ -275,7 +278,18 @@ def __gather_mesh(blender_object, export_settings):
skip_filter = False
material_names = tuple([ms.material.name for ms in blender_object.material_slots if ms.material is not None])
# retrieve armature
# Because mesh data will be transforms to skeleton space,
# we can't instanciate multiple object at different location, skined by same armature
blender_object_for_skined_data = None
if export_settings[gltf2_blender_export_keys.SKINS]:
for idx, modifier in enumerate(blender_object.modifiers):
if modifier.type == 'ARMATURE':
blender_object_for_skined_data = blender_object
result = gltf2_blender_gather_mesh.gather_mesh(blender_mesh,
blender_object_for_skined_data,
vertex_groups,
modifiers,
skip_filter,
@ -309,13 +323,13 @@ def __gather_trans_rot_scale(blender_object, export_settings):
# Decomposing matrix_local gives less accuracy, but is needed if matrix_parent_inverse is not the identity.
trans, rot, sca = gltf2_blender_extract.decompose_transition(blender_object.matrix_local, export_settings)
trans = gltf2_blender_extract.convert_swizzle_location(trans, export_settings)
trans = gltf2_blender_extract.convert_swizzle_location(trans, None, None, export_settings)
rot = gltf2_blender_extract.convert_swizzle_rotation(rot, export_settings)
sca = gltf2_blender_extract.convert_swizzle_scale(sca, export_settings)
if blender_object.instance_type == 'COLLECTION' and blender_object.instance_collection:
trans = -gltf2_blender_extract.convert_swizzle_location(
blender_object.instance_collection.instance_offset, export_settings)
blender_object.instance_collection.instance_offset, None, None, export_settings)
translation, rotation, scale = (None, None, None)
trans[0], trans[1], trans[2] = gltf2_blender_math.round_if_near(trans[0], 0.0), gltf2_blender_math.round_if_near(trans[1], 0.0), \
gltf2_blender_math.round_if_near(trans[2], 0.0)
@ -350,7 +364,7 @@ def __gather_skin(blender_object, export_settings):
return None
# Skins and meshes must be in the same glTF node, which is different from how blender handles armatures
return gltf2_blender_gather_skins.gather_skin(modifiers["ARMATURE"].object, blender_object, export_settings)
return gltf2_blender_gather_skins.gather_skin(modifiers["ARMATURE"].object, export_settings)
def __gather_weights(blender_object, export_settings):

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@ -33,6 +33,7 @@ from io_scene_gltf2.io.com.gltf2_io_debug import print_console
@cached
def gather_primitives(
blender_mesh: bpy.types.Mesh,
blender_object: Optional[bpy.types.Object],
vertex_groups: Optional[bpy.types.VertexGroups],
modifiers: Optional[bpy.types.ObjectModifiers],
material_names: Tuple[str],
@ -45,7 +46,7 @@ def gather_primitives(
"""
primitives = []
blender_primitives = __gather_cache_primitives(blender_mesh,
blender_primitives = __gather_cache_primitives(blender_mesh, blender_object,
vertex_groups, modifiers, export_settings)
for internal_primitive in blender_primitives:
@ -79,6 +80,7 @@ def gather_primitives(
@cached
def __gather_cache_primitives(
blender_mesh: bpy.types.Mesh,
blender_object: Optional[bpy.types.Object],
vertex_groups: Optional[bpy.types.VertexGroups],
modifiers: Optional[bpy.types.ObjectModifiers],
export_settings
@ -89,7 +91,7 @@ def __gather_cache_primitives(
primitives = []
blender_primitives = gltf2_blender_extract.extract_primitives(
None, blender_mesh, vertex_groups, modifiers, export_settings)
None, blender_mesh, blender_object, vertex_groups, modifiers, export_settings)
for internal_primitive in blender_primitives:
primitive = {

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@ -24,12 +24,11 @@ from io_scene_gltf2.blender.com import gltf2_blender_math
@cached
def gather_skin(blender_object, mesh_object, export_settings):
def gather_skin(blender_object, export_settings):
"""
Gather armatures, bones etc into a glTF2 skin object.
:param blender_object: the object which may contain a skin
:param mesh_object: the mesh object to be deformed
:param export_settings:
:return: a glTF2 skin object
"""
@ -39,7 +38,7 @@ def gather_skin(blender_object, mesh_object, export_settings):
return gltf2_io.Skin(
extensions=__gather_extensions(blender_object, export_settings),
extras=__gather_extras(blender_object, export_settings),
inverse_bind_matrices=__gather_inverse_bind_matrices(blender_object, mesh_object, export_settings),
inverse_bind_matrices=__gather_inverse_bind_matrices(blender_object, export_settings),
joints=__gather_joints(blender_object, export_settings),
name=__gather_name(blender_object, export_settings),
skeleton=__gather_skeleton(blender_object, export_settings)
@ -62,7 +61,7 @@ def __gather_extensions(blender_object, export_settings):
def __gather_extras(blender_object, export_settings):
return None
def __gather_inverse_bind_matrices(blender_object, mesh_object, export_settings):
def __gather_inverse_bind_matrices(blender_object, export_settings):
axis_basis_change = mathutils.Matrix.Identity(4)
if export_settings[gltf2_blender_export_keys.YUP]:
axis_basis_change = mathutils.Matrix(
@ -78,11 +77,10 @@ def __gather_inverse_bind_matrices(blender_object, mesh_object, export_settings)
# traverse the matrices in the same order as the joints and compute the inverse bind matrix
def __collect_matrices(bone):
matrix_world = gltf2_blender_math.multiply(blender_object.matrix_world, mesh_object.matrix_world.inverted())
inverse_bind_matrix = gltf2_blender_math.multiply(
axis_basis_change,
gltf2_blender_math.multiply(
matrix_world,
blender_object.matrix_world,
bone.bone.matrix_local
)
).inverted()