mechanism.py

#====================== BEGIN GPL LICENSE BLOCK ======================
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#  modify it under the terms of the GNU General Public License
#  as published by the Free Software Foundation; either version 2
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#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
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#  along with this program; if not, write to the Free Software Foundation,
#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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#======================= END GPL LICENSE BLOCK ========================

# <pep8 compliant>

import bpy
import re

from rna_prop_ui import rna_idprop_ui_create, rna_idprop_ui_prop_get
from rna_prop_ui import rna_idprop_quote_path as quote_property

#=============================================
# Constraint creation utilities
#=============================================

_TRACK_AXIS_MAP =  {
    'X': 'TRACK_X', '-X': 'TRACK_NEGATIVE_X',
    'Y': 'TRACK_Y', '-Y': 'TRACK_NEGATIVE_Y',
    'Z': 'TRACK_Z', '-Z': 'TRACK_NEGATIVE_Z',
}

def _set_default_attr(obj, options, attr, value):
    if hasattr(obj, attr):
        options.setdefault(attr, value)

def make_constraint(
        owner, type, target=None, subtarget=None, *, insert_index=None,
        space=None, track_axis=None, use_xyz=None, use_limit_xyz=None, invert_xyz=None,
        **options):
    """
    Creates and initializes constraint of the specified type for the owner bone.

    Specially handled keyword arguments:

      target, subtarget: if both not None, passed through to the constraint
      insert_index     : insert at the specified index in the stack, instead of at the end
      space            : assigned to both owner_space and target_space
      track_axis       : allows shorter X, Y, Z, -X, -Y, -Z notation
      use_xyz          : list of 3 items is assigned to use_x, use_y and use_z options
      use_limit_xyz    : list of 3 items is assigned to use_limit_x/y/z options
      invert_xyz       : list of 3 items is assigned to invert_x, invert_y and invert_z options
      min/max_x/y/z    : a corresponding use_(min/max/limit)_(x/y/z) option is set to True

    Other keyword arguments are directly assigned to the constraint options.
    Returns the newly created constraint.
    """
    con = owner.constraints.new(type)

    if insert_index is not None:
        owner.constraints.move(len(owner.constraints)-1, insert_index)

    if target is not None and hasattr(con, 'target'):
        con.target = target

    if subtarget is not None:
        con.subtarget = subtarget

    if space is not None:
        _set_default_attr(con, options, 'owner_space', space)
        _set_default_attr(con, options, 'target_space', space)

    if track_axis is not None:
        con.track_axis = _TRACK_AXIS_MAP.get(track_axis, track_axis)

    if use_xyz is not None:
        con.use_x, con.use_y, con.use_z = use_xyz[0:3]

    if use_limit_xyz is not None:
        con.use_limit_x, con.use_limit_y, con.use_limit_z = use_limit_xyz[0:3]

    if invert_xyz is not None:
        con.invert_x, con.invert_y, con.invert_z = invert_xyz[0:3]

    for key in ['min_x', 'max_x', 'min_y', 'max_y', 'min_z', 'max_z']:
        if key in options:
            _set_default_attr(con, options, 'use_'+key, True)
            _set_default_attr(con, options, 'use_limit_'+key[-1], True)

    for p, v in options.items():
        setattr(con, p, v)

    return con

#=============================================
# Custom property creation utilities
#=============================================

def make_property(
        owner, name, default, *, min=0.0, max=1.0, soft_min=None, soft_max=None,
        description=None, overridable=True, **options):
    """
    Creates and initializes a custom property of owner.

    The soft_min and soft_max parameters default to min and max.
    Description defaults to the property name.
    """

    # Some keyword argument defaults differ
    return rna_idprop_ui_create(
        owner, name, default = default,
        min = min, max = max, soft_min = soft_min, soft_max = soft_max,
        description = description or name,
        overridable = overridable,
        **options
    )

#=============================================
# Driver creation utilities
#=============================================

def _init_driver_target(drv_target, var_info, target_id):
    """Initialize a driver variable target from a specification."""

    # Parse the simple list format for the common case.
    if isinstance(var_info, tuple):
        # [ (target_id,) subtarget, ...path ]

        # If target_id is supplied as parameter, allow omitting it
        if target_id is None or isinstance(var_info[0], bpy.types.ID):
            target_id,subtarget,*refs = var_info
        else:
            subtarget,*refs = var_info

        # Simple path string case.
        if len(refs) == 0:
            # [ (target_id,) path_str ]
            path = subtarget
        else:
            # If subtarget is a string, look up a bone in the target
            if isinstance(subtarget, str):
                subtarget = target_id.pose.bones[subtarget]

            if subtarget == target_id:
                path = ''
            else:
                path = subtarget.path_from_id()

            # Use ".foo" type path items verbatim, otherwise quote
            for item in refs:
                if isinstance(item, str):
                    path += item if item[0] == '.' else quote_property(item)
                else:
                    path += '[%r]' % (item)

            if path[0] == '.':
                path = path[1:]

        drv_target.id = target_id
        drv_target.data_path = path

    else:
        # { 'id': ..., ... }
        target_id = var_info.get('id', target_id)

        if target_id is not None:
            drv_target.id = target_id

        for tp, tv in var_info.items():
            setattr(drv_target, tp, tv)


def _add_driver_variable(drv, var_name, var_info, target_id):
    """Add and initialize a driver variable."""

    var = drv.variables.new()
    var.name = var_name

    # Parse the simple list format for the common case.
    if isinstance(var_info, tuple):
        # [ (target_id,) subtarget, ...path ]
        var.type = "SINGLE_PROP"

        _init_driver_target(var.targets[0], var_info, target_id)

    else:
        # Variable info as generic dictionary - assign properties.
        # { 'type': 'SINGLE_PROP', 'targets':[...] }
        var.type = var_info['type']

        for p, v in var_info.items():
            if p == 'targets':
                for i, tdata in enumerate(v):
                    _init_driver_target(var.targets[i], tdata, target_id)
            elif p != 'type':
                setattr(var, p, v)

def make_driver(owner, prop, *, index=-1, type='SUM', expression=None, variables={}, polynomial=None, target_id=None):
    """
    Creates and initializes a driver for the 'prop' property of owner.

    Arguments:
      index           : item index for vector properties
      type, expression: mutually exclusive options to set core driver mode.
      variables       : either a list or dictionary of variable specifications.
      polynomial      : coefficients of the POLYNOMIAL driver modifier
      target_id       : specifies the target ID of variables implicitly

    Specification format:
        If the variables argument is a dictionary, keys specify variable names.
        Otherwise names are set to var, var1, var2, ... etc:

          variables = [ ..., ..., ... ]
          variables = { 'var': ..., 'var1': ..., 'var2': ... }

        Variable specifications are constructed as nested dictionaries and lists that
        follow the property structure of the original Blender objects, but the most
        common case can be abbreviated as a simple tuple.

        The following specifications are equivalent:

          ( target, subtarget, '.foo', 'bar' )

          { 'type': 'SINGLE_PROP', 'targets':[( target, subtarget, '.foo', 'bar' )] }

          { 'type': 'SINGLE_PROP',
            'targets':[{ 'id': target, 'data_path': subtarget.path_from_id() + '.foo["bar"]' }] }

        If subtarget is as string, it is automatically looked up within target as a bone.

        It is possible to specify path directly as a simple string without following items:

          ( target, 'path' )

          { 'type': 'SINGLE_PROP', 'targets':[{ 'id': target, 'data_path': 'path' }] }

        If the target_id parameter is not None, it is possible to omit target:

          ( subtarget, '.foo', 'bar' )

          { 'type': 'SINGLE_PROP',
            'targets':[{ 'id': target_id, 'data_path': subtarget.path_from_id() + '.foo["bar"]' }] }

    Returns the newly created driver FCurve.
    """
    fcu = owner.driver_add(prop, index)
    drv = fcu.driver

    if expression is not None:
        drv.type = 'SCRIPTED'
        drv.expression = expression
    else:
        drv.type = type

    # In case the driver already existed, remove contents
    for var in list(drv.variables):
        drv.variables.remove(var)

    for mod in list(fcu.modifiers):
        fcu.modifiers.remove(mod)

    # Fill in new data
    if isinstance(variables, list):
        # variables = [ info, ... ]
        for i, var_info in enumerate(variables):
            var_name = 'var' if i == 0 else 'var' + str(i)
            _add_driver_variable(drv, var_name, var_info, target_id)
    else:
        # variables = { 'varname': info, ... }
        for var_name, var_info in variables.items():
            _add_driver_variable(drv, var_name, var_info, target_id)

    if polynomial is not None:
        drv_modifier = fcu.modifiers.new('GENERATOR')
        drv_modifier.mode = 'POLYNOMIAL'
        drv_modifier.poly_order = len(polynomial)-1
        for i,v in enumerate(polynomial):
            drv_modifier.coefficients[i] = v

    return fcu


def driver_var_transform(target, bone=None, *, type='LOC_X', space='WORLD', rotation_mode='AUTO'):
    """
    Create a Transform Channel driver variable specification.

    Usage:
        make_driver(..., variables=[driver_var_transform(...)])
    """

    assert space in {'WORLD', 'TRANSFORM', 'LOCAL'}

    target_map = {
        'id': target,
        'transform_type': type,
        'transform_space': space + '_SPACE',
        'rotation_mode': rotation_mode,
    }

    if bone is not None:
        target_map['bone_target'] = bone

    return { 'type': 'TRANSFORMS', 'targets': [ target_map ] }


#=============================================
# Custom property management
#=============================================

def deactivate_custom_properties(obj, *, reset=True):
    """Disable drivers on custom properties and reset values to default."""

    prefix = '["'

    if obj != obj.id_data:
        prefix = obj.path_from_id() + prefix

    adt = obj.id_data.animation_data
    if adt:
        for fcu in adt.drivers:
            if fcu.data_path.startswith(prefix):
                fcu.mute = True

    if reset:
        for key, value in obj.items():
            valtype = type(value)
            if valtype in {int, float}:
                info = rna_idprop_ui_prop_get(obj, key, False) or {}
                obj[key] = valtype(info.get("default", 0))


def reactivate_custom_properties(obj):
    """Re-enable drivers on custom properties."""

    prefix = '["'

    if obj != obj.id_data:
        prefix = obj.path_from_id() + prefix

    adt = obj.id_data.animation_data
    if adt:
        for fcu in adt.drivers:
            if fcu.data_path.startswith(prefix):
                fcu.mute = False


def copy_custom_properties(src, dest, *, prefix='', dest_prefix='', link_driver=False):
    """Copy custom properties with filtering by prefix. Optionally link using drivers."""
    res = []
    exclude = {'_RNA_UI', 'rigify_parameters', 'rigify_type'}

    for key, value in src.items():
        if key.startswith(prefix) and key not in exclude:
            new_key = dest_prefix + key[len(prefix):]

            dest[new_key] = value

            info = rna_idprop_ui_prop_get(src, key, False)
            if info:
                info2 = rna_idprop_ui_prop_get(dest, new_key, True)
                for ki, vi in info.items():
                    info2[ki] = vi

            if link_driver:
                make_driver(src, quote_property(key), variables=[(dest.id_data, dest, new_key)])

            res.append((key, new_key, value, info))

    return res


def copy_custom_properties_with_ui(rig, src, dest_bone, *, ui_controls=None, **options):
    """Copy custom properties, and create rig UI for them."""
    if isinstance(src, str):
        src = rig.get_bone(src)

    bone = rig.get_bone(dest_bone)
    mapping = copy_custom_properties(src, bone, **options)

    if mapping:
        panel = rig.script.panel_with_selected_check(rig, ui_controls or rig.bones.ctrl.flatten())

        for key,new_key,value,info in mapping:
            name = re.sub(r'[_.-]', ' ', new_key).title()
            slider = type(value) is float and info and info.get("min", None) == 0 and info.get("max", None) == 1

            panel.custom_prop(dest_bone, new_key, text=name, slider=slider)

    return mapping


#=============================================
# Utility mixin
#=============================================

class MechanismUtilityMixin(object):
    """
    Provides methods for more convenient creation of constraints, properties
    and drivers within an armature (by implicitly providing context).

    Requires self.obj to be the armature object being worked on.
    """

    def make_constraint(self, bone, type, subtarget=None, **args):
        assert(self.obj.mode == 'OBJECT')
        return make_constraint(self.obj.pose.bones[bone], type, self.obj, subtarget, **args)

    def make_property(self, bone, name, default, **args):
        assert(self.obj.mode == 'OBJECT')
        return make_property(self.obj.pose.bones[bone], name, default, **args)

    def make_driver(self, owner, prop, **args):
        assert(self.obj.mode == 'OBJECT')
        if isinstance(owner, str):
            owner = self.obj.pose.bones[owner]
        return make_driver(owner, prop, target_id=self.obj, **args)