73 lines
2.2 KiB
JavaScript
73 lines
2.2 KiB
JavaScript
"use strict";
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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exports.multiplicity = exports["default"] = exports.computeInsertions = exports.checkPinned = void 0;
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var _insertKnot = _interopRequireDefault(require("./insertKnot"));
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function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { "default": obj }; }
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/**
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* For a pinned spline, the knots have to be repeated k times
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* (where k is the order), at both the beginning and the end
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*/
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var checkPinned = function checkPinned(k, knots) {
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// Pinned at the start
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for (var i = 1; i < k; ++i) {
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if (knots[i] !== knots[0]) {
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throw Error("not pinned. order: ".concat(k, " knots: ").concat(knots));
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}
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}
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// Pinned at the end
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for (var _i = knots.length - 2; _i > knots.length - k - 1; --_i) {
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if (knots[_i] !== knots[knots.length - 1]) {
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throw Error("not pinned. order: ".concat(k, " knots: ").concat(knots));
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}
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}
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};
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exports.checkPinned = checkPinned;
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var multiplicity = function multiplicity(knots, index) {
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var m = 1;
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for (var i = index + 1; i < knots.length; ++i) {
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if (knots[i] === knots[index]) {
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++m;
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} else {
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break;
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}
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}
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return m;
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};
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/**
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* https://saccade.com/writing/graphics/KnotVectors.pdf
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* A quadratic piecewise Bézier knot vector with seven control points
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* will look like this [0 0 0 1 1 2 2 3 3 3]. In general, in a
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* piecewise Bézier knot vector the first k knots are the same,
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* then each subsequent group of k-1 knots is the same,
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* until you get to the end.
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*/
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exports.multiplicity = multiplicity;
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var computeInsertions = function computeInsertions(k, knots) {
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var inserts = [];
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var i = k;
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while (i < knots.length - k) {
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var knot = knots[i];
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var m = multiplicity(knots, i);
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for (var j = 0; j < k - m - 1; ++j) {
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inserts.push(knot);
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}
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i = i + m;
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}
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return inserts;
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};
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exports.computeInsertions = computeInsertions;
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var _default = function _default(k, controlPoints, knots) {
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checkPinned(k, knots);
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var insertions = computeInsertions(k, knots);
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return insertions.reduce(function (acc, tNew) {
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return (0, _insertKnot["default"])(k, acc.controlPoints, acc.knots, tNew);
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}, {
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controlPoints: controlPoints,
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knots: knots
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});
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};
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exports["default"] = _default; |