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Further clean up clipFatLine()

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This commit is contained in:
Jürg Lehni 2013-05-24 21:31:32 -07:00
parent 696887477a
commit b1562d7594
1 changed files with 19 additions and 21 deletions
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40
fatline/Intersect.js
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@ -178,10 +178,9 @@ function getCurveIntersections(v1, v2, curve1, curve2, locations,
* ntersection
*/
function clipFatLine(v1, v2, range2) {
// first curve, P
// P = first curve, Q = second curve
var p0x = v1[0], p0y = v1[1], p1x = v1[2], p1y = v1[3],
p2x = v1[4], p2y = v1[5], p3x = v1[6], p3y = v1[7],
// second curve, Q
q0x = v2[0], q0y = v2[1], q1x = v2[2], q1y = v2[3],
q2x = v2[4], q2y = v2[5], q3x = v2[6], q3y = v2[7],
// Calculate the fat-line L for P is the baseline l and two
@ -234,16 +233,16 @@ function clipFatLine(v1, v2, range2) {
dtlx1 = tmp;
}
// We know that (dtlx2 - dtlx1) is never 0
var inv_m = (dtly2 - dtly1) / (dtlx2 - dtlx1);
var inv = (dtly2 - dtly1) / (dtlx2 - dtlx1);
if (dmin >= dtly1 && dmin <= dtly2) {
var ixdx = dtlx1 + (dmin - dtly1) / inv_m;
var ixdx = dtlx1 + (dmin - dtly1) / inv;
if (ixdx < tmin)
tmin = ixdx;
if (ixdx > tmaxdmin)
tmaxdmin = ixdx;
}
if (dmax >= dtly1 && dmax <= dtly2) {
var ixdx = dtlx1 + (dmax - dtly1) / inv_m;
var ixdx = dtlx1 + (dmax - dtly1) / inv;
if (ixdx > tmax)
tmax = ixdx;
if (ixdx < tmin)
@ -288,15 +287,15 @@ function clipFatLine(v1, v2, range2) {
* convex-hull is much easier than a set of arbitrary points.
*/
function getConvexHull(dq0, dq1, dq2, dq3) {
var distq1 = getSignedDistance(0, dq0, 1, dq3, 1 / 3, dq1);
var distq2 = getSignedDistance(0, dq0, 1, dq3, 2 / 3, dq2);
var hull;
var distq1 = getSignedDistance(0, dq0, 1, dq3, 1 / 3, dq1),
distq2 = getSignedDistance(0, dq0, 1, dq3, 2 / 3, dq2),
hull;
// Check if [1/3, dq1] and [2/3, dq2] are on the same side of line
// [0,dq0, 1,dq3]
if (distq1 * distq2 < 0) {
// dq1 and dq2 lie on different sides on [0, q0, 1, q3]
// Convexhull is a quadrilateral and line [0, q0, 1, q3] is NOT part of
// the convexhull so we are pretty much done here.
// dq1 and dq2 lie on different sides on [0, q0, 1, q3]. The hull is a
// quadrilateral and line [0, q0, 1, q3] is NOT part of the hull so we
// are pretty much done here.
hull = [
[ 0, dq0, 1 / 3, dq1 ],
[ 1 / 3, dq1, 1, dq3 ],
@ -304,18 +303,17 @@ function getConvexHull(dq0, dq1, dq2, dq3) {
[ 1, dq3, 2 / 3, dq2 ]
];
} else {
// dq1 and dq2 lie on the same sides on [0, q0, 1, q3]. c-hull can be a
// triangle or a quadrilateral and line [0, q0, 1, q3] is part of the
// c-hull. Check if the hull is a triangle or a quadrilateral
var dqmin, dqmax, dqapex1, dqapex2;
// dq1 and dq2 lie on the same sides on [0, q0, 1, q3]. The hull can be
// a triangle or a quadrilateral and line [0, q0, 1, q3] is part of the
// hull. Check if the hull is a triangle or a quadrilateral.
distq1 = Math.abs(distq1);
distq2 = Math.abs(distq2);
var vqa1a2x, vqa1a2y, vqa1Maxx, vqa1Maxy, vqa1Minx, vqa1Miny;
var dqmin, dqmax, vqa1a2x, vqa1a2y, vqa1Maxx, vqa1Maxy, vqa1Minx, vqa1Miny;
if (distq1 > distq2) {
dqmin = [ 2 / 3, dq2 ];
dqmax = [ 1 / 3, dq1 ];
// apex is dq3 and the other apex point is dq0 vector
// dqapex->dqapex2 or base vector which is already part of c-hull
// dqapex->dqapex2 or base vector which is already part of the hull.
vqa1a2x = 1;
vqa1a2y = dq3 - dq0;
// vector dqapex->dqmax
@ -328,7 +326,7 @@ function getConvexHull(dq0, dq1, dq2, dq3) {
dqmin = [ 1 / 3, dq1 ];
dqmax = [ 2 / 3, dq2 ];
// apex is dq0 in this case, and the other apex point is dq3 vector
// dqapex->dqapex2 or base vector which is already part of c-hull
// dqapex->dqapex2 or base vector which is already part of the hull.
vqa1a2x = -1;
vqa1a2y = dq0 - dq3;
// vector dqapex->dqmax
@ -343,7 +341,7 @@ function getConvexHull(dq0, dq1, dq2, dq3) {
var vcrossa1a2_a1Min = vqa1a2x * vqa1Miny - vqa1a2y * vqa1Minx;
var vcrossa1Max_a1Min = vqa1Maxx * vqa1Miny - vqa1Maxy * vqa1Minx;
if (vcrossa1Max_a1Min * vcrossa1a2_a1Min < 0) {
// Point [2/3, dq2] is inside the triangle and c-hull is a triangle
// Point [2/3, dq2] is inside the triangle, the hull is a triangle.
hull = [
[ 0, dq0, dqmax[0], dqmax[1] ],
[ dqmax[0], dqmax[1], 1, dq3 ],
@ -351,7 +349,7 @@ function getConvexHull(dq0, dq1, dq2, dq3) {
];
} else {
// Convexhull is a quadrilateral and we need all lines in the
// correct order where line [0, q0, 1, q3] is part of the c-hull
// correct order where line [0, q0, 1, q3] is part of the hull.
hull = [
[ 0, dq0, 1 / 3, dq1 ],
[ 1 / 3, dq1, 2 / 3, dq2 ],
@ -374,7 +372,7 @@ function getSignedDistance(a1x, a1y, a2x, a2y, bx, by) {
/**
* Intersections between curve and line becomes rather simple here mostly
* because of Numerical class. We can rotate the curve and line so that the line
* is on X axis, and solve the implicit equations for X axis and the curve
* is on X axis, and solve the implicit equations for X axis and the curve.
*/
function getCurveLineIntersections(v1, v2, curve1, curve2, locations, flip) {
if (flip === undefined)