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#======================= END GPL LICENSE BLOCK ========================

# <pep8 compliant>

if False:
    # This rig type is disabled due to its obscurity.
    # However, some of the code may be useful in the future, so
    # I'm leaving it here.
    from math import acos

    import bpy

    from ...utils import MetarigError
    from ...utils import copy_bone
    from ...utils import org_name, make_mechanism_name


    class Rig:
        """ A delta rig.
            Creates a setup that will place its child at its position in pose mode,
            but will not modifying its child's position in edit mode.
            This is a mechanism-only rig (no control or deformation bones).

        """
        def __init__(self, obj, bone, params):
            """ Gather and validate data about the rig.
                Store any data or references to data that will be needed later on.
                In particular, store references to bones that will be needed.
                Do NOT change any data in the scene.  This is a gathering phase only.

            """
            bb = obj.data.bones

            if bb[bone].children is None:
                raise MetarigError("RIGIFY ERROR: bone '%s': rig type requires one child" % org_name(bone.name))
            if bb[bone].use_connect is True:
                raise MetarigError("RIGIFY ERROR: bone '%s': rig type cannot be connected to parent" % org_name(bone.name))

            self.obj = obj
            self.org_bones = {"delta": bone, "child": bb[bone].children[0].name}
            self.org_names = [org_name(bone), org_name(bb[bone].children[0].name)]

        def generate(self):
            """ Generate the rig.
                Do NOT modify any of the original bones, except for adding constraints.
                The main armature should be selected and active before this is called.

            """
            bpy.ops.object.mode_set(mode='EDIT')
            eb = self.obj.data.edit_bones

            org_delta = self.org_bones["delta"]
            org_delta_e = eb[self.org_bones["delta"]]
            # org_child = self.org_bones["child"]  # UNUSED
            org_child_e = eb[self.org_bones["child"]]

            # Calculate the matrix for achieving the delta
            child_mat = org_delta_e.matrix.invert() * org_child_e.matrix
            mat = org_delta_e.matrix * child_mat.invert()

            # Create the delta bones.
            delta_e = eb[copy_bone(self.obj, self.org_bones["delta"])]
            delta_e.name = make_mechanism_name(self.org_names[0])
            delta = delta_e.name

            # Set the delta to the matrix's transforms
            set_mat(self.obj, delta, mat)

            bpy.ops.object.mode_set(mode='OBJECT')

            # Constrain org_delta to delta
            con = self.obj.pose.bones[org_delta].constraints.new('COPY_TRANSFORMS')
            con.name = "delta"
            con.target = self.obj
            con.subtarget = delta


    def create_sample(obj):
        # generated by rigify.utils.write_metarig
        bpy.ops.object.mode_set(mode='EDIT')
        arm = obj.data

        bones = {}

        bone = arm.edit_bones.new('delta')
        bone.head[:] = 0.0000, -0.1198, 0.1253
        bone.tail[:] = -0.0000, -0.2483, 0.2785
        bone.roll = -0.0000
        bone.use_connect = False
        bones['delta'] = bone.name
        bone = arm.edit_bones.new('Bone')
        bone.head[:] = -0.0000, 0.0000, 0.0000
        bone.tail[:] = -0.0000, 0.0000, 0.2000
        bone.roll = 0.0000
        bone.use_connect = False
        bone.parent = arm.edit_bones[bones['delta']]
        bones['Bone'] = bone.name

        bpy.ops.object.mode_set(mode='OBJECT')
        pbone = obj.pose.bones[bones['delta']]
        pbone.rigify_type = 'misc.delta'
        pbone.lock_location = (False, False, False)
        pbone.lock_rotation = (False, False, False)
        pbone.lock_rotation_w = False
        pbone.lock_scale = (False, False, False)
        pbone.rotation_mode = 'QUATERNION'
        pbone = obj.pose.bones[bones['Bone']]
        pbone.rigify_type = ''
        pbone.lock_location = (False, False, False)
        pbone.lock_rotation = (False, False, False)
        pbone.lock_rotation_w = False
        pbone.lock_scale = (False, False, False)
        pbone.rotation_mode = 'QUATERNION'

        bpy.ops.object.mode_set(mode='EDIT')
        for bone in arm.edit_bones:
            bone.select = False
            bone.select_head = False
            bone.select_tail = False
        for b in bones:
            bone = arm.edit_bones[bones[b]]
            bone.select = True
            bone.select_head = True
            bone.select_tail = True
            arm.edit_bones.active = bone


    def set_mat(obj, bone_name, matrix):
        """ Sets the bone to have the given transform matrix.
        """
        a = obj.data.edit_bones[bone_name]

        a.head = (0, 0, 0)
        a.tail = (0, 1, 0)

        a.transform(matrix)

        d = acos(a.matrix.to_quaternion().dot(matrix.to_quaternion())) * 2.0

        roll_1 = a.roll + d
        roll_2 = a.roll - d

        a.roll = roll_1
        d1 = a.matrix.to_quaternion().dot(matrix.to_quaternion())
        a.roll = roll_2
        d2 = a.matrix.to_quaternion().dot(matrix.to_quaternion())

        if d1 > d2:
            a.roll = roll_1
        else:
            a.roll = roll_2
