mesh_looptools.py

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bl_info = {
    'name': "LoopTools",
    'author': "Bart Crouch",
    'version': (4, 0, 1),
    'blender': (2, 6, 3),
    'location': "View3D > Toolbar and View3D > Specials (W-key)",
    'warning': "",
    'description': "Mesh modelling toolkit. Several tools to aid modelling",
    'wiki_url': "http://wiki.blender.org/index.php/Extensions:2.6/Py/"\
        "Scripts/Modeling/LoopTools",
    'tracker_url': "http://projects.blender.org/tracker/index.php?"\
        "func=detail&aid=26189",
    'category': 'Mesh'}


import bmesh
import bpy
import collections
import mathutils
import math


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


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


# 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
            d[i] = (c[i+1]-c[i]) / (3*h[i])
        for i in range(n-1):
            result.append([a[i], b[i], c[i], d[i], x[i]])
    splines = []
    for i in range(len(knots)-1):
        splines.append([result[i], result[i+n-1], result[i+(n-1)*2]])
    if circular: # cleaning up after hack
        knots = knots[4:-4]
        tknots = tknots[4:-4]
    
    return(splines)


# calculates linear splines through all given knots
def calculate_linear_splines(bm_mod, tknots, knots):
    splines = []
    for i in range(len(knots)-1):
        a = bm_mod.verts[knots[i]].co
        b = bm_mod.verts[knots[i+1]].co
        d = b-a
        t = tknots[i]