curve_assign_shapekey.py

#
#
# This Blender add-on assigns one or more Bezier Curves as shape keys to another
# Bezier Curve
#
# Supported Blender Version: 2.80 Beta
#
# Copyright (C) 2019  Shrinivas Kulkarni
#
# License: GPL-3.0 (https://github.com/Shriinivas/assignshapekey/blob/master/LICENSE)
#

import bpy, bmesh, bgl, gpu
from gpu_extras.batch import batch_for_shader
from bpy.props import BoolProperty, EnumProperty, StringProperty
from collections import OrderedDict
from mathutils import Vector
from math import sqrt, floor
from functools import cmp_to_key
from bpy.types import Panel, Operator, AddonPreferences


bl_info = {
    "name": "Assign Shape Keys",
    "author": "Shrinivas Kulkarni",
    "version": (1, 0, 0),
    "location": "View 3D > Sidebar > Create Tab",
    "description": "Assigns one or more Bezier curves as shape keys to another Bezier curve",
    "category": "Add Curve",
    "wiki_url": "https://github.com/Shriinivas/assignshapekey/blob/master/README.md",
    "blender": (2, 80, 0),
}

matchList = [('vCnt', 'Vertex Count', 'Match by vertex count'),
            ('bbArea', 'Area', 'Match by surface area of the bounding box'), \
            ('bbHeight', 'Height', 'Match by bounding box height'), \
            ('bbWidth', 'Width', 'Match by bounding box width'),
            ('bbDepth', 'Depth', 'Match by bounding box depth'),
            ('minX', 'Min X', 'Match by  bounding bon Min X'),
            ('maxX', 'Max X', 'Match by  bounding bon Max X'),
            ('minY', 'Min Y', 'Match by  bounding bon Min Y'),
            ('maxY', 'Max Y', 'Match by  bounding bon Max Y'),
            ('minZ', 'Min Z', 'Match by  bounding bon Min Z'),
            ('maxZ', 'Max Z', 'Match by  bounding bon Max Z')]

DEF_ERR_MARGIN = 0.0001

def isBezier(obj):
    return obj.type == 'CURVE' and len(obj.data.splines) > 0 \
        and obj.data.splines[0].type == 'BEZIER'

#Avoid errors due to floating point conversions/comparisons
#TODO: return -1, 0, 1
def floatCmpWithMargin(float1, float2, margin = DEF_ERR_MARGIN):
    return abs(float1 - float2) < margin

def vectCmpWithMargin(v1, v2, margin = DEF_ERR_MARGIN):
    return all(floatCmpWithMargin(v1[i], v2[i], margin) for i in range(0, len(v1)))

class Segment():

    #pts[0] - start, pts[1] - ctrl1, pts[2] - ctrl2, , pts[3] - end
    def pointAtT(pts, t):
        return pts[0] + t * (3 * (pts[1] - pts[0]) +
            t* (3 * (pts[0] + pts[2]) - 6 * pts[1] +
                t * (-pts[0] + 3 * (pts[1] - pts[2]) + pts[3])))

    def getSegLenRecurs(pts, start, end, t1 = 0, t2 = 1, error = DEF_ERR_MARGIN):
        t1_5 = (t1 + t2)/2
        mid = Segment.pointAtT(pts, t1_5)
        l = (end - start).length
        l2 = (mid - start).length + (end - mid).length
        if (l2 - l > error):
            return (Segment.getSegLenRecurs(pts, start, mid, t1, t1_5, error) +
                    Segment.getSegLenRecurs(pts, mid, end, t1_5, t2, error))
        return l2

    def __init__(self, start, ctrl1, ctrl2, end):
        self.start = start
        self.ctrl1 = ctrl1
        self.ctrl2 = ctrl2
        self.end = end
        pts = [start, ctrl1, ctrl2, end]
        self.length = Segment.getSegLenRecurs(pts, start, end)

    #see https://stackoverflow.com/questions/878862/drawing-part-of-a-b%c3%a9zier-curve-by-reusing-a-basic-b%c3%a9zier-curve-function/879213#879213
    def partialSeg(self, t0, t1):
        pts = [self.start, self.ctrl1, self.ctrl2, self.end]

        if(t0 > t1):
            tt = t1
            t1 = t0
            t0 = tt

        #Let's make at least the line segments of predictable length :)
        if(pts[0] == pts[1] and pts[2] == pts[3]):
            pt0 = Vector([(1 - t0) * pts[0][i] + t0 * pts[2][i] for i in range(0, 3)])
            pt1 = Vector([(1 - t1) * pts[0][i] + t1 * pts[2][i] for i in range(0, 3)])
            return Segment(pt0, pt0, pt1, pt1)

        u0 = 1.0 - t0
        u1 = 1.0 - t1

        qa = [pts[0][i]*u0*u0 + pts[1][i]*2*t0*u0 + pts[2][i]*t0*t0 for i in range(0, 3)]
        qb = [pts[0][i]*u1*u1 + pts[1][i]*2*t1*u1 + pts[2][i]*t1*t1 for i in range(0, 3)]
        qc = [pts[1][i]*u0*u0 + pts[2][i]*2*t0*u0 + pts[3][i]*t0*t0 for i in range(0, 3)]
        qd = [pts[1][i]*u1*u1 + pts[2][i]*2*t1*u1 + pts[3][i]*t1*t1 for i in range(0, 3)]

        pta = Vector([qa[i]*u0 + qc[i]*t0 for i in range(0, 3)])
        ptb = Vector([qa[i]*u1 + qc[i]*t1 for i in range(0, 3)])
        ptc = Vector([qb[i]*u0 + qd[i]*t0 for i in range(0, 3)])
        ptd = Vector([qb[i]*u1 + qd[i]*t1 for i in range(0, 3)])

        return Segment(pta, ptb, ptc, ptd)

    #see https://stackoverflow.com/questions/24809978/calculating-the-bounding-box-of-cubic-bezier-curve
    #(3 D - 9 C + 9 B - 3 A) t^2 + (6 A - 12 B + 6 C) t + 3 (B - A)
    #pts[0] - start, pts[1] - ctrl1, pts[2] - ctrl2, , pts[3] - end
    #TODO: Return Vectors to make world space calculations consistent
    def bbox(self, mw = None):
        def evalBez(AA, BB, CC, DD, t):
            return AA * (1 - t) * (1 - t) * (1 - t) + \
                    3 * BB * t * (1 - t) * (1 - t) + \
                        3 * CC * t * t * (1 - t) + \
                            DD * t * t * t

        A = self.start
        B = self.ctrl1
        C = self.ctrl2
        D = self.end

        if(mw != None):
            A = mw @ A
            B = mw @ B
            C = mw @ C
            D = mw @ D

        MINXYZ = [min([A[i], D[i]]) for i in range(0, 3)]
        MAXXYZ = [max([A[i], D[i]]) for i in range(0, 3)]
        leftBotBack_rgtTopFront = [MINXYZ, MAXXYZ]

        a = [3 * D[i] - 9 * C[i] + 9 * B[i] - 3 * A[i] for i in range(0, 3)]
        b = [6 * A[i] - 12 * B[i] + 6 * C[i] for i in range(0, 3)]
        c = [3 * (B[i] - A[i]) for i in range(0, 3)]

        solnsxyz = []
        for i in range(0, 3):
            solns = []
            if(a[i] == 0):
                if(b[i] == 0):
                    solns.append(0)#Independent of t so lets take the starting pt
                else:
                    solns.append(c[i] / b[i])
            else:
                rootFact = b[i] * b[i] - 4 * a[i] * c[i]
                if(rootFact >=0 ):
                    #Two solutions with + and - sqrt
                    solns.append((-b[i] + sqrt(rootFact)) / (2 * a[i]))
                    solns.append((-b[i] - sqrt(rootFact)) / (2 * a[i]))
            solnsxyz.append(solns)

        for i, soln in enumerate(solnsxyz):
            for j, t in enumerate(soln):
                if(t < 1 and t > 0):
                    co = evalBez(A[i], B[i], C[i], D[i], t)
                    if(co < leftBotBack_rgtTopFront[0][i]):
                        leftBotBack_rgtTopFront[0][i] = co
                    if(co > leftBotBack_rgtTopFront[1][i]):
                        leftBotBack_rgtTopFront[1][i] = co

        return leftBotBack_rgtTopFront


class Part():
    def __init__(self, parent, segs, isClosed):
        self.parent = parent
        self.segs = segs

        #use_cyclic_u
        self.isClosed = isClosed

        #Indicates if this should be closed based on its counterparts in other paths
        self.toClose = isClosed

        self.length = sum(seg.length for seg in self.segs)
        self.bbox = None
        self.bboxWorldSpace = None

    def getSeg(self, idx):
        return self.segs[idx]

    def getSegs(self):
        return self.segs

    def getSegsCopy(self, start, end):
        if(start == None):
            start = 0
        if(end == None):
            end = len(self.segs)
        return self.segs[start:end]