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Revert d204175d39
Revert fat-line clipping optimization that checked for straight curves, as unfortunately it wasn't reliable in many edge cases. Relates to #1263
This commit is contained in:
Jürg Lehni
parent
867d0874dc
commit
ecc1edb6ea
3 changed files with 59 additions and 53 deletions
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@ -63,9 +63,6 @@
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- Improve reliability of `Curve#getIntersections()` (#1174).
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- Fix `getOverlaps()` to always return overlaps in correct sequence (#1223).
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- Improve handling of multiple crossings on the same curve.
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- Improve and optimize fat-line clipping algorithm by checking if subdivided
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curves are straight and falling back on line-line / line-curve approach if
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they are.
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- Improve tangent direction handling in `CurveLocation#isCrossing()`, by finding
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unambiguous vectors, taking inception points and "peaks" into account
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(#1073, #1074).
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@ -1760,30 +1760,17 @@ new function() { // Scope for bezier intersection using fat-line clipping
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}
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}
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function addCurveIntersections(v1, v2, c1, c2, tMin, tMax, uMin, uMax,
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locations, include, recursion, calls, flip) {
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function addCurveIntersections(v1, v2, c1, c2, locations, include, flip,
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recursion, calls, tMin, tMax, uMin, uMax) {
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// Avoid deeper recursion, by counting the total amount of recursions,
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// as well as the total amount of calls, to avoid massive call-trees as
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// suggested by @iconexperience in #904#issuecomment-225283430.
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// See also: #565 #899 #1074
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var abort = ++calls > 4096 || recursion > 40,
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// If we need to abort, consider both curves as straight and see if
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// their lines intersect.
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straight1 = abort || Curve.isStraight(v1),
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straight2 = abort || Curve.isStraight(v2);
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if (straight1 || straight2) {
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(straight1 && straight2
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? addLineIntersection
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: addCurveLineIntersections)(
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flip ? v2 : v1, flip ? v1 : v2,
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flip ? c2 : c1, flip ? c1 : c2,
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locations, include, recursion,
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flip ? straight2 : straight1);
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if (++calls >= 4096 || ++recursion >= 40)
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return calls;
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}
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// Use an epsilon smaller than CURVETIME_EPSILON to compare curve-time
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// parameters in fat-line clipping code.
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var epsilon = /*#=*/Numerical.EPSILON,
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var fatLineEpsilon = 1e-9,
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// Let P be the first curve and Q be the second
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q0x = v2[0], q0y = v2[1], q3x = v2[6], q3y = v2[7],
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getSignedDistance = Line.getSignedDistance,
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@ -1820,7 +1807,7 @@ new function() { // Scope for bezier intersection using fat-line clipping
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// original parameter range for v2.
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var tMinNew = tMin + (tMax - tMin) * tMinClip,
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tMaxNew = tMin + (tMax - tMin) * tMaxClip;
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if (Math.max(uMax - uMin, tMaxNew - tMinNew) < epsilon) {
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if (Math.max(uMax - uMin, tMaxNew - tMinNew) < fatLineEpsilon) {
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// We have isolated the intersection with sufficient precision
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var t = (tMinNew + tMaxNew) / 2,
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u = (uMin + uMax) / 2;
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@ -1828,7 +1815,6 @@ new function() { // Scope for bezier intersection using fat-line clipping
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flip ? c2 : c1, flip ? u : t, null,
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flip ? c1 : c2, flip ? t : u, null);
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} else {
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recursion++;
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// Apply the result of the clipping to curve 1:
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v1 = Curve.getPart(v1, tMinClip, tMaxClip);
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if (tMaxClip - tMinClip > 0.8) {
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@ -1837,32 +1823,32 @@ new function() { // Scope for bezier intersection using fat-line clipping
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var parts = Curve.subdivide(v1, 0.5),
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t = (tMinNew + tMaxNew) / 2;
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calls = addCurveIntersections(
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v2, parts[0], c2, c1, uMin, uMax, tMinNew, t,
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locations, include, recursion, calls, !flip);
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v2, parts[0], c2, c1, locations, include, !flip,
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recursion, calls, uMin, uMax, tMinNew, t);
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calls = addCurveIntersections(
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v2, parts[1], c2, c1, uMin, uMax, t, tMaxNew,
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locations, include, recursion, calls, !flip);
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v2, parts[1], c2, c1, locations, include, !flip,
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recursion, calls, uMin, uMax, t, tMaxNew);
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} else {
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var parts = Curve.subdivide(v2, 0.5),
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u = (uMin + uMax) / 2;
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calls = addCurveIntersections(
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parts[0], v1, c2, c1, uMin, u, tMinNew, tMaxNew,
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locations, include, recursion, calls, !flip);
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parts[0], v1, c2, c1, locations, include, !flip,
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recursion, calls, uMin, u, tMinNew, tMaxNew);
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calls = addCurveIntersections(
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parts[1], v1, c2, c1, u, uMax, tMinNew, tMaxNew,
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locations, include, recursion, calls, !flip);
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parts[1], v1, c2, c1, locations, include, !flip,
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recursion, calls, u, uMax, tMinNew, tMaxNew);
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}
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} else { // Iterate
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if (uMax - uMin >= epsilon) {
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if (uMax - uMin >= fatLineEpsilon) {
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calls = addCurveIntersections(
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v2, v1, c2, c1, uMin, uMax, tMinNew, tMaxNew,
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locations, include, recursion, calls, !flip);
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v2, v1, c2, c1, locations, include, !flip,
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recursion, calls, uMin, uMax, tMinNew, tMaxNew);
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} else {
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// The interval on the other curve is already tight enough,
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// therefore we keep iterating on the same curve.
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calls = addCurveIntersections(
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v1, v2, c1, c2, tMinNew, tMaxNew, uMin, uMax,
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locations, include, recursion, calls, flip);
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v1, v2, c1, c2, locations, include, flip,
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recursion, calls, tMinNew, tMaxNew, uMin, uMax);
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}
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}
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}
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@ -1993,28 +1979,28 @@ new function() { // Scope for bezier intersection using fat-line clipping
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}
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function addCurveLineIntersections(v1, v2, c1, c2, locations, include,
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recursion, straight1) {
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var flip = straight1,
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vc = flip ? v2 : v1,
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vl = flip ? v1 : v2,
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x1 = vl[0], y1 = vl[1],
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x2 = vl[6], y2 = vl[7],
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roots = getCurveLineIntersections(vc, x1, y1, x2 - x1, y2 - y1);
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flip) {
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// addCurveLineIntersections() is called so that v1 is always the curve
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// and v2 the line. flip indicates whether the curves need to be flipped
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// in the call to addLocation().
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var x1 = v2[0], y1 = v2[1],
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x2 = v2[6], y2 = v2[7],
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roots = getCurveLineIntersections(v1, x1, y1, x2 - x1, y2 - y1);
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// NOTE: count could be -1 for infinite solutions, but that should only
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// happen with lines, in which case we should not be here.
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for (var i = 0, l = roots.length; i < l; i++) {
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// For each found solution on the rotated curve, get the point on
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// the real curve and with that the location on the line.
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var tc = roots[i],
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pc = Curve.getPoint(vc, tc),
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tl = Curve.getTimeOf(vl, pc);
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if (tl !== null) {
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var pl = Curve.getPoint(vl, tl);
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var t1 = roots[i],
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p1 = Curve.getPoint(v1, t1),
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t2 = Curve.getTimeOf(v2, p1);
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if (t2 !== null) {
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var p2 = Curve.getPoint(v2, t2);
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// Only use the time values if there was no recursion, and let
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// addLocation() figure out the actual time values otherwise.
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addLocation(locations, include,
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c1, recursion ? null : flip ? tl : tc, flip ? pl : pc,
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c2, recursion ? null : flip ? tc : tl, flip ? pc : pl);
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flip ? c2 : c1, flip ? t2 : t1, flip ? p2 : p1,
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flip ? c1 : c2, flip ? t1 : t2, flip ? p1 : p2);
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}
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}
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}
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@ -2056,9 +2042,29 @@ new function() { // Scope for bezier intersection using fat-line clipping
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c2, overlap[1], null, true);
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}
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} else {
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addCurveIntersections(
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v1, v2, c1, c2, 0, 1, 0, 1, // tMin, tMax, uMin, uMax
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locations, include, 0, 0, 0); // recursion, calls, flip
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var straight1 = Curve.isStraight(v1),
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straight2 = Curve.isStraight(v2),
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straight = straight1 && straight2,
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flip = straight1 && !straight2,
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before = locations.length;
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// Determine the correct intersection method based on whether
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// one or curves are straight lines:
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(straight
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? addLineIntersection
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: straight1 || straight2
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? addCurveLineIntersections
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: addCurveIntersections)(
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flip ? v2 : v1, flip ? v1 : v2,
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flip ? c2 : c1, flip ? c1 : c2,
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locations, include, flip,
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// Define the defaults for these parameters of
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// addCurveIntersections():
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// recursion, calls, tMin, tMax, uMin, uMax
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0, 0, 0, 1, 0, 1);
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// We're done if we handle lines and found one intersection
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// already: #805#issuecomment-148503018
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if (straight && locations.length > before)
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return locations;
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// Handle the special case where the first curve's start- / end-
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// point overlaps with the second curve's start- / end-point.
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@ -249,8 +249,11 @@ test('#1239', function() {
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testIntersections(p1.getIntersections(p2), [
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{ point: { x: 956.28999, y: 351.925 }, index: 1, time: 0.000577, crossing: true},
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{ point: { x: 956.28948, y: 352.2327 }, index: 1, time: 0.003804, crossing: true},
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{ point: { x: 939.50932, y: 415.17952 }, index: 1, time: 0.701801, crossing: true},
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{ point: { x: 922.9625, y: 437.995 }, index: 2, time: 0, crossing: false},
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{ point: { x: 911.15, y: 427.245 }, index: 3, time: 0, crossing: false}
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{ point: { x: 911.15, y: 427.245 }, index: 3, time: 0, crossing: false},
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{ point: { x: 932.08099, y: 394.02288 }, index: 3, time: 0.477224, crossing: true},
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{ point: { x: 940.28956, y: 352.18697 }, index: 3, time: 0.996218, crossing: true}
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]);
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});
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