scratchfoundation/paper.js
1
0
Fork 0
mirror of https://github.com/scratchfoundation/paper.js.git synced 2025-01-20 22:39:50 -05:00
Code Issues Projects Releases Packages Wiki Activity Actions

Simplify handling of ranges and curve parts.

Browse source
This commit is contained in:
Jürg Lehni 2013-05-24 21:01:37 -07:00
parent 1d1375915a
commit 08245f936b
1 changed files with 35 additions and 39 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

74
fatline/Intersect.js
View file

@ -64,27 +64,25 @@ function getCurveIntersections(v1, v2, curve1, curve2, locations, v1t, v2t,
// outside its bounds!
if (recursion > MAX_RECURSION)
return;
// cache the original parameter range.
// Set up the parameter ranges.
v1t = v1t || [ 0, 1 ];
v2t = v2t || [ 0, 1 ];
var _v1t = v1t.slice();
var _v2t = v2t.slice();
// Get the clipped parts from the original curve, to avoid cumulative errors
var _v1 = Curve.getPart(v1, _v1t[0], _v1t[1]);
var _v2 = Curve.getPart(v2, _v2t[0], _v2t[1]);
// markCurve(_v1, '#f0f', true);
// markCurve(_v2, '#0ff', false);
var p1 = Curve.getPart(v1, v1t[0], v1t[1]);
var p2 = Curve.getPart(v2, v2t[0], v2t[1]);
// markCurve(p1, '#f0f', true);
// markCurve(p2, '#0ff', false);
var iteration = 0;
// Loop until both parameter range converge. We have to handle the
// degenerate case seperately, where fat-line clipping can become
// numerically unstable when one of the curves has converged to a point and
// the other hasn't.
while (iteration++ < MAX_ITERATION
&& (Math.abs(_v1t[1] - _v1t[0]) > /*#=*/ Numerical.TOLERANCE
|| Math.abs(_v2t[1] - _v2t[0]) > /*#=*/ Numerical.TOLERANCE)) {
&& (Math.abs(v1t[1] - v1t[0]) > /*#=*/ Numerical.TOLERANCE
|| Math.abs(v2t[1] - v2t[0]) > /*#=*/ Numerical.TOLERANCE)) {
// First we clip v2 with v1's fat-line
var tmp = _v2t.slice();
var intersects1 = clipFatLine(_v1, _v2, tmp),
var range = v2t.slice();
var intersects1 = clipFatLine(p1, p2, range),
intersects2 = 0;
// Stop if there are no possible intersections
if (intersects1 === 0)
@ -92,22 +90,21 @@ function getCurveIntersections(v1, v2, curve1, curve2, locations, v1t, v2t,
if (intersects1 > 0) {
// Get the clipped parts from the original v2, to avoid cumulative
// errors ...and reuse some objects.
_v2t = tmp;
_v2 = Curve.getPart(v2, _v2t[0], _v2t[1]);
// markCurve(_v2, '#0ff', false);
v2t = range;
p2 = Curve.getPart(v2, v2t[0], v2t[1]);
// markCurve(p2, '#0ff', false);
// Next we clip v1 with nuv2's fat-line
tmp = _v1t.slice();
intersects2 = clipFatLine(_v2, _v1, tmp);
intersects2 = clipFatLine(p2, p1, range = v1t.slice());
// Stop if there are no possible intersections
if (intersects2 === 0)
break;
if (intersects1 > 0) {
// Get the clipped parts from the original v2, to avoid
// cumulative errors
_v1t = tmp;
_v1 = Curve.getPart(v1, _v1t[0], _v1t[1]);
v1t = range;
p1 = Curve.getPart(v1, v1t[0], v1t[1]);
}
// markCurve(_v1, '#f0f', true);
// markCurve(p1, '#f0f', true);
}
// Get the clipped parts from the original v1
// Check if there could be multiple intersections
@ -115,8 +112,8 @@ function getCurveIntersections(v1, v2, curve1, curve2, locations, v1t, v2t,
// Subdivide the curve which has converged the least from the
// original range [0,1], which would be the curve with the largest
// parameter range after clipping
if (_v1t[1] - _v1t[0] > _v2t[1] - _v2t[0]) {
// subdivide _v1 and recurse
if (v1t[1] - v1t[0] > v2t[1] - v2t[0]) {
// subdivide v1 and recurse
var t = (v1t[0] + v1t[1]) / 2;
getCurveIntersections(v1, v2, curve1, curve2, locations,
[ v1t[0], t ], v2t, recursion);
@ -124,7 +121,7 @@ function getCurveIntersections(v1, v2, curve1, curve2, locations, v1t, v2t,
[ t, v1t[1] ], v2t, recursion);
break;
} else {
// subdivide _v2 and recurse
// subdivide v2 and recurse
var t = (v2t[0] + v2t[1]) / 2;
getCurveIntersections(v1, v2, curve1, curve2, locations, v1t,
[ v2t[0], t ], recursion);
@ -144,34 +141,33 @@ function getCurveIntersections(v1, v2, curve1, curve2, locations, v1t, v2t,
// Check if one of the parameter range has converged completely to a
// point. Now things could get only worse if we iterate more for the
// other curve to converge if it hasn't yet happened so.
var v1Converged = (Math.abs(_v1t[1] - _v1t[0]) < /*#=*/ Numerical.EPSILON),
v2Converged = (Math.abs(_v2t[1] - _v2t[0]) < /*#=*/ Numerical.EPSILON);
if (v1Converged || v2Converged) {
addLocation(locations, curve1, null, v1Converged
? curve1.getPointAt(_v1t[0], true)
: curve2.getPointAt(_v2t[0], true), curve2);
var converged1 = (Math.abs(v1t[1] - v1t[0]) < /*#=*/ Numerical.EPSILON),
converged2 = (Math.abs(v2t[1] - v2t[0]) < /*#=*/ Numerical.EPSILON);
if (converged1 || converged2) {
addLocation(locations, curve1, null, converged1
? curve1.getPointAt(v1t[0], true)
: curve2.getPointAt(v2t[0], true), curve2);
break;
}
if (Math.abs(_v1t[1] - _v1t[0]) <= /*#=*/ Numerical.TOLERANCE
&& Math.abs(_v2t[1] - _v2t[0]) <= /*#=*/ Numerical.TOLERANCE) {
if (Math.abs(v1t[1] - v1t[0]) <= /*#=*/ Numerical.TOLERANCE
&& Math.abs(v2t[1] - v2t[0]) <= /*#=*/ Numerical.TOLERANCE) {
// Both parameter ranges have converged.
addLocation(locations, curve1, _v1t[0],
curve1.getPointAt(_v1t[0], true), curve2);
addLocation(locations, curve1, v1t[0],
curve1.getPointAt(v1t[0], true), curve2);
break;
}
// see if either or both of the curves are flat enough to be treated
// as lines.
var curve1Flat = Curve.isFlatEnough(_v1, /*#=*/ Numerical.TOLERANCE),
curve2Flat = Curve.isFlatEnough(_v2, /*#=*/ Numerical.TOLERANCE);
if (curve1Flat && curve2Flat) {
getLineLineIntersection(_v1, _v2, curve1, curve2, locations);
var flat1 = Curve.isFlatEnough(p1, /*#=*/ Numerical.TOLERANCE),
flat2 = Curve.isFlatEnough(p2, /*#=*/ Numerical.TOLERANCE);
if (flat1 && flat2) {
getLineLineIntersection(p1, p2, curve1, curve2, locations);
break;
}
if (curve1Flat || curve2Flat) {
if (flat1 || flat2) {
// Use curve line intersection method while specifying which
// curve to be treated as line
getCurveLineIntersections(_v1, _v2, curve1, curve2, locations,
curve1Flat);
getCurveLineIntersections(p1, p2, curve1, curve2, locations, flat1);
break;
}
}