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Implement correct CurveLocation#isCrossing() check.
And improve curve caching. Still needs work.
This commit is contained in:
Jürg Lehni
parent
3ce7d88347
commit
60a725b527
1 changed files with 108 additions and 33 deletions
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@ -57,19 +57,24 @@ var CurveLocation = Base.extend(/** @lends CurveLocation# */{
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// since this is only required to be unique at runtime among other
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// CurveLocation objects.
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this._id = UID.get(CurveLocation);
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var path = curve._path;
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this._version = path ? path._version : 0;
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this._curve = curve;
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this._setCurve(curve);
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this._parameter = parameter;
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this._point = point || curve.getPointAt(parameter, true);
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this._distance = _distance;
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this._overlap = _overlap;
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this._crossing = null;
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this._intersection = _intersection;
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if (_intersection) {
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_intersection._intersection = this;
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// TODO: Remove this once debug logging is removed.
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_intersection._other = true;
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}
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},
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_setCurve: function(curve) {
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var path = curve._path;
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this._version = path ? path._version : 0;
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this._curve = curve;
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this._segment = null; // To be determined, see #getSegment()
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// Also store references to segment1 and segment2, in case path
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// splitting / dividing is going to happen, in which case the segments
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@ -84,25 +89,26 @@ var CurveLocation = Base.extend(/** @lends CurveLocation# */{
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* @type Segment
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* @bean
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*/
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getSegment: function(_preferFirst) {
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if (!this._segment) {
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var curve = this.getCurve(),
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parameter = this.getParameter();
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if (parameter === 1) {
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this._segment = curve._segment2;
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} else if (parameter === 0 || _preferFirst) {
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this._segment = curve._segment1;
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} else if (parameter == null) {
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return null;
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} else {
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getSegment: function() {
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// Request curve first, so _segment gets invalidated if it's out of sync
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var curve = this.getCurve(),
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segment = this._segment;
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if (!segment) {
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var parameter = this.getParameter();
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if (parameter === 0) {
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segment = curve._segment1;
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} else if (parameter === 1) {
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segment = curve._segment2;
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} else if (parameter != null) {
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// Determine the closest segment by comparing curve lengths
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this._segment = curve.getPartLength(0, parameter)
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segment = curve.getPartLength(0, parameter)
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< curve.getPartLength(parameter, 1)
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? curve._segment1
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: curve._segment2;
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}
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this._segment = segment;
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}
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return this._segment;
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return segment;
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},
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/**
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@ -113,29 +119,34 @@ var CurveLocation = Base.extend(/** @lends CurveLocation# */{
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*/
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getCurve: function() {
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var curve = this._curve,
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path = curve && curve._path;
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path = curve && curve._path,
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that = this;
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if (path && path._version !== this._version) {
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// If the path's segments have changed in the meantime, clear the
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// internal _parameter value and force refetching of the correct
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// curve again here.
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curve = null;
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this._parameter = null;
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curve = this._parameter = this._curve = null;
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}
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if (!curve) {
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// If we're asked to get the curve uncached, access current curve
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// objects through segment1 / segment2. Since path splitting or
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// dividing might have happened in the meantime, try segment1's
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// curve, and see if _point lies on it still, otherwise assume it's
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// the curve before segment2.
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curve = this._segment1.getCurve();
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if (curve.getParameterOf(this._point) == null)
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curve = this._segment2.getPrevious().getCurve();
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this._curve = curve;
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// Fetch path again as it could be on a new one through split()
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path = curve._path;
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this._version = path ? path._version : 0;
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// If path is out of sync, access current curve objects through segment1
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// / segment2. Since path splitting or dividing might have happened in
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// the meantime, try segment1's curve, and see if _point lies on it
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// still, otherwise assume it's the curve before segment2.
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function trySegment(segment) {
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var curve = segment && segment.getCurve();
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if (curve && (that._parameter = curve.getParameterOf(that._point))
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!= null) {
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// Fetch path again as it could be on a new one through split()
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that._setCurve(curve);
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that._segment = segment;
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return curve;
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}
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}
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return curve;
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return curve
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|| trySegment(this._segment)
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|| trySegment(this._segment1)
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|| trySegment(this._segment2.getPrevious());
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},
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/**
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@ -271,6 +282,70 @@ var CurveLocation = Base.extend(/** @lends CurveLocation# */{
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return curve && curve.split(this.getParameter(), true);
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},
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isCrossing: function(report) {
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// Implementation based on work by Andy Finnell:
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// http://losingfight.com/blog/2011/07/09/how-to-implement-boolean-operations-on-bezier-paths-part-3/
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// https://bitbucket.org/andyfinnell/vectorboolean
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var intersection = this._intersection,
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crossing = this._crossing;
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if (crossing != null || !intersection)
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return crossing || false;
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// TODO: isTangent() ?
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// TODO: isAtEndPoint() ?
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// -> Return if it's a tangent, or if not at an end point, only end
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// point intersections need more checking!
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var tMin = /*#=*/Numerical.CURVETIME_EPSILON,
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tMax = 1 - tMin,
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PI = Math.PI,
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PI_2 = PI * 2,
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// TODO: Make getCurve() sync work in boolean ops after splitting!!!
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c2 = this._curve,
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c1 = c2.getPrevious(),
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c4 = intersection._curve,
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c3 = c4.getPrevious();
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if (!c1 || !c3)
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return this._crossing = false;
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if (report) {
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new Path.Circle({
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center: this.getPoint(),
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radius: 10,
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strokeColor: 'red'
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});
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new Path({
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segments: [c1.getSegment1(), c1.getSegment2(), c2.getSegment2()],
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strokeColor: 'red'
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});
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new Path({
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segments: [c3.getSegment1(), c3.getSegment2(), c4.getSegment2()],
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strokeColor: 'orange'
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});
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console.log(c1.getValues(), c2.getValues(), c3.getValues(), c4.getValues());
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}
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function getAngle(tangent) {
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var a = tangent.getAngleInRadians();
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return a < -PI ? a + PI_2 : a >= PI ? a - PI_2 : a;
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}
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function isInRange(angle, min, max) {
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return min < max
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? angle > min && angle < max
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// The range wraps around 0:
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: angle > min && angle <= PI || angle >= -PI && angle < max;
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}
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// Calculate angles for all four tangents at the intersection point
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var a1 = getAngle(c1.getTangentAt(tMax, true).negate()),
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a2 = getAngle(c2.getTangentAt(tMin, true)),
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a3 = getAngle(c3.getTangentAt(tMax, true).negate()),
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a4 = getAngle(c4.getTangentAt(tMin, true));
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// Count how many times curve2 angles appear between the curve1 angles
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// If each pair of angles split the other two, then the edges cross.
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return (isInRange(a3, a1, a2) ^ isInRange(a4, a1, a2))
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&& (isInRange(a3, a2, a1) ^ isInRange(a4, a2, a1));
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},
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/**
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* Checks whether tow CurveLocation objects are describing the same location
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* on a path, by applying the same tolerances as elsewhere when dealing with
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