auto_walk/fn.py

import bpy
import re
import numpy as np
from mathutils import Matrix, Vector, Color

def get_addon_prefs():
    '''
    function to read current addon preferences properties
    access with : get_addon_prefs().super_special_option
    '''
    import os 
    addon_name = os.path.splitext(__name__)[0]
    preferences = bpy.context.preferences
    addon_prefs = preferences.addons[addon_name].preferences
    return (addon_prefs)

def helper(name: str = '') -> str:
    '''Return name and arguments from calling obj as str
    :name: - replace definition name by your own str
    '''
    if not get_addon_prefs().debug:
        return
    import inspect
    func = inspect.currentframe().f_back
    name = name or f'def {func.f_code.co_name}'
    args = inspect.getargvalues(func).locals
    arguments = ', '.join([f'{k}={v}' for k, v in args.items()])
    return(f'{name}({arguments})')

def convertAttr(Attr):
    '''Convert given value to a Json serializable format'''
    if type(Attr) in [type(Vector()),type(Color())]:
        if len(Attr) == 3:
            return([Attr[0],Attr[1],Attr[2]])
        elif len(Attr) == 2:
            return([Attr[0],Attr[1]])
        elif len(Attr) == 1:
            return([Attr[0]])
        elif len(Attr) == 4:
            return([Attr[0],Attr[1],Attr[2],Attr[3]])
    elif type(Attr) == type(Matrix()):
        return (np.matrix(Attr).tolist())
    else:
        return(Attr)


def get_gnd():
    for o in bpy.context.scene.objects:
        if o.type == 'MESH' and o.name.lower() in ('ground', 'gnd'):
            return o
    # nothing found
    print('ERROR', 'No "gnd" object found')


def get_follow_curve_from_armature(arm):
    """Return curve and constraint or a tuple of string ('error', 'message')
    """
    pref = get_addon_prefs()
    name = pref.tgt_bone
    
    parents = []
    # root = b.id_data.pose.bones.get(name)
    root = arm.pose.bones.get(name)
    for c in root.constraints:
        if c.type == 'FOLLOW_PATH':
            const = c
        if c.type == 'CHILD_OF':
            print(f'found child-of on {name}')
            if c.target:
                parents.append(c.target)

    if not const:
        for p in parents:
            for c in p.constraints:
                if c.type == 'FOLLOW_PATH':
                    print('INFO', f'follow_path found on "{p.name}" parent object')
                    const = c
                    break
    
    if not const:
        return ('ERROR', 'No constraints founds')
    
    curve = const.target
    if not curve:
        return ('ERROR', f'no target set for {curve.name}')

    return curve, const

# --- ACTIONS

def get_obj_action(obj):
    print(helper())
    act = obj.animation_data
    if not act:
        print('ERROR', f'no animation data on {obj.name}')
        return

    act = act.action
    if not act:
        print('ERROR', f'no action on {obj.name}')
        return
    return act

def set_generated_action(obj):
    '''Backup object action and return a new action suffixed '_autogen'
    associated with the object
    '''
    print(helper())
    act = get_obj_action(obj)
    if not act: return

    regen = re.compile(r'_autogen\.?\d{0,3}$')

    if regen.search(act.name):
        # is an autogenerated one
        org_action_name = regen.sub('', act.name)
        org_action = bpy.data.actions.get(org_action_name)
        if not org_action:
            print('ERROR', f'{org_action_name} not found')
            return

        obj.animation_data.action = org_action
        bpy.data.actions.remove(act)
        
        act = org_action
    
    # backup action before doing anything crazy
    act.use_fake_user = True
    new_act = act.copy()
    new_act.name = act.name + '_autogen'
    obj.animation_data.action = new_act
    return new_act


def set_expanded_action(obj):
    '''Backup object action and return a new action
    associated with the object
    '''
    print(helper())

    rexpand = re.compile(r'_expanded\.?\d{0,3}$')
    act = obj.animation_data.action

    if rexpand.search(act.name):
        # is an autogenerated one
        org_action_name = rexpand.sub('', act.name)
        org_action = bpy.data.actions.get(org_action_name)
        if not org_action:
            print('ERROR', f'{org_action_name} not found')
            return

        obj.animation_data.action = org_action
        bpy.data.actions.remove(act)
        
        act = org_action
    
    # backup action before doing anything crazy
    act.use_fake_user = True
    new_act = act.copy()
    new_act.name = act.name + '_expanded'
    obj.animation_data.action = new_act
    return new_act


def get_curve_length(ob):
    '''Get a curve object, return a float representing world space length'''
    dg = bpy.context.evaluated_depsgraph_get()
    obeval = ob.evaluated_get(dg)#.copy()
    baked_me = obeval.to_mesh(preserve_all_data_layers=False, depsgraph=dg)
    mat = obeval.matrix_world
    total_length = 0
    for i, _v in enumerate(baked_me.vertices):
        if i == 0:
            continue
        total_length += ((mat @ baked_me.vertices[i-1].co) - (mat @ baked_me.vertices[i].co)).length

    print("total_length", total_length)#Dbg
    return total_length


def scale_matrix_from_vector(scale):
    # recreate a neutral mat scale
    matscale_x = Matrix.Scale(scale[0], 4,(1,0,0))
    matscale_y = Matrix.Scale(scale[1], 4,(0,1,0))
    matscale_z = Matrix.Scale(scale[2], 4,(0,0,1))
    matscale = matscale_x @ matscale_y @ matscale_z
    return matscale

def compose_matrix(loc, rot, scale):
    loc_mat = Matrix.Translation(loc)
    rot_mat = rot.to_matrix().to_4x4()
    scale_mat = scale_matrix_from_vector(scale)
    return loc_mat @ rot_mat @ scale_mat