mesh_looptools.py

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#
#  This program is free software; you can redistribute it and/or
#  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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bl_info = {
    "name": "LoopTools",
    "author": "Bart Crouch",
    "version": (4, 6, 7),
    "blender": (2, 80, 0),
    "location": "View3D > Toolbar and View3D > Specials (W-key)",
    "warning": "",
    "description": "Mesh modelling toolkit. Several tools to aid modelling",
    "wiki_url": "https://wiki.blender.org/index.php/Extensions:2.6/Py/"
                "Scripts/Modeling/LoopTools",
    "category": "Mesh",
}


import bmesh
import bpy
import collections
import mathutils
import math
from bpy_extras import view3d_utils
from bpy.types import (
        Operator,
        Menu,
        Panel,
        PropertyGroup,
        AddonPreferences,
        )
from bpy.props import (
        BoolProperty,
        EnumProperty,
        FloatProperty,
        IntProperty,
        PointerProperty,
        StringProperty,
        )

# ########################################
# ##### General functions ################
# ########################################

# used by all tools to improve speed on reruns Unlink
looptools_cache = {}


def get_grease_pencil(object, context):
    gp = object.grease_pencil
    if not gp:
        gp = context.scene.grease_pencil
    return gp


# force a full recalculation next time
def cache_delete(tool):
    if tool in looptools_cache:
        del looptools_cache[tool]


# check cache for stored information
def cache_read(tool, object, bm, input_method, boundaries):
    # current tool not cached yet
    if tool not in looptools_cache:
        return(False, False, False, False, False)
    # check if selected object didn't change
    if object.name != looptools_cache[tool]["object"]:
        return(False, False, False, False, False)
    # check if input didn't change
    if input_method != looptools_cache[tool]["input_method"]:
        return(False, False, False, False, False)
    if boundaries != looptools_cache[tool]["boundaries"]:
        return(False, False, False, False, False)
    modifiers = [mod.name for mod in object.modifiers if mod.show_viewport and
                 mod.type == 'MIRROR']
    if modifiers != looptools_cache[tool]["modifiers"]:
        return(False, False, False, False, False)
    input = [v.index for v in bm.verts if v.select and not v.hide]
    if input != looptools_cache[tool]["input"]:
        return(False, False, False, False, False)
    # reading values
    single_loops = looptools_cache[tool]["single_loops"]
    loops = looptools_cache[tool]["loops"]
    derived = looptools_cache[tool]["derived"]
    mapping = looptools_cache[tool]["mapping"]

    return(True, single_loops, loops, derived, mapping)


# store information in the cache
def cache_write(tool, object, bm, input_method, boundaries, single_loops,
loops, derived, mapping):
    # clear cache of current tool
    if tool in looptools_cache:
        del looptools_cache[tool]
    # prepare values to be saved to cache
    input = [v.index for v in bm.verts if v.select and not v.hide]
    modifiers = [mod.name for mod in object.modifiers if mod.show_viewport
    and mod.type == 'MIRROR']
    # update cache
    looptools_cache[tool] = {
        "input": input, "object": object.name,
        "input_method": input_method, "boundaries": boundaries,
        "single_loops": single_loops, "loops": loops,
        "derived": derived, "mapping": mapping, "modifiers": modifiers}


# calculates natural cubic splines through all given knots
def calculate_cubic_splines(bm_mod, tknots, knots):
    # hack for circular loops
    if knots[0] == knots[-1] and len(knots) > 1:
        circular = True
        k_new1 = []
        for k in range(-1, -5, -1):
            if k - 1 < -len(knots):
                k += len(knots)
            k_new1.append(knots[k - 1])
        k_new2 = []
        for k in range(4):
            if k + 1 > len(knots) - 1:
                k -= len(knots)
            k_new2.append(knots[k + 1])
        for k in k_new1:
            knots.insert(0, k)
        for k in k_new2:
            knots.append(k)
        t_new1 = []
        total1 = 0
        for t in range(-1, -5, -1):
            if t - 1 < -len(tknots):
                t += len(tknots)
            total1 += tknots[t] - tknots[t - 1]
            t_new1.append(tknots[0] - total1)
        t_new2 = []
        total2 = 0
        for t in range(4):
            if t + 1 > len(tknots) - 1:
                t -= len(tknots)
            total2 += tknots[t + 1] - tknots[t]
            t_new2.append(tknots[-1] + total2)
        for t in t_new1:
            tknots.insert(0, t)
        for t in t_new2:
            tknots.append(t)
    else:
        circular = False
    # end of hack

    n = len(knots)
    if n < 2:
        return False
    x = tknots[:]
    locs = [bm_mod.verts[k].co[:] for k in knots]
    result = []
    for j in range(3):
        a = []
        for i in locs:
            a.append(i[j])
        h = []
        for i in range(n - 1):
            if x[i + 1] - x[i] == 0:
                h.append(1e-8)
            else:
                h.append(x[i + 1] - x[i])
        q = [False]
        for i in range(1, n - 1):
            q.append(3 / h[i] * (a[i + 1] - a[i]) - 3 / h[i - 1] * (a[i] - a[i - 1]))
        l = [1.0]
        u = [0.0]
        z = [0.0]
        for i in range(1, n - 1):
            l.append(2 * (x[i + 1] - x[i - 1]) - h[i - 1] * u[i - 1])
            if l[i] == 0:
                l[i] = 1e-8
            u.append(h[i] / l[i])
            z.append((q[i] - h[i - 1] * z[i - 1]) / l[i])
        l.append(1.0)
        z.append(0.0)
        b = [False for i in range(n - 1)]
        c = [False for i in range(n)]
        d = [False for i in range(n - 1)]
        c[n - 1] = 0.0
        for i in range(n - 2, -1, -1):
            c[i] = z[i] - u[i] * c[i + 1]
            b[i] = (a[i + 1] - a[i]) / h[i] - h[i] * (c[i + 1] + 2 * c[i]) / 3