bool intersect(double minT1, double maxT1, double minT2, double maxT2) {
Cubic sub1, sub2;
// FIXME: carry last subdivide and reduceOrder result with cubic
sub_divide(cubic1, minT1, maxT1, sub1);
sub_divide(cubic2, minT2, maxT2, sub2);
Intersections i;
intersect2(sub1, sub2, i);
if (i.used() == 0) {
return false;
}
double x1, y1, x2, y2;
t1 = minT1 + i.fT[0][0] * (maxT1 - minT1);
t2 = minT2 + i.fT[1][0] * (maxT2 - minT2);
xy_at_t(cubic1, t1, x1, y1);
xy_at_t(cubic2, t2, x2, y2);
if (AlmostEqualUlps(x1, x2) && AlmostEqualUlps(y1, y2)) {
return true;
}
double half1 = (minT1 + maxT1) / 2;
double half2 = (minT2 + maxT2) / 2;
++depth;
bool result;
if (depth & 1) {
result = intersect(minT1, half1, minT2, maxT2) || intersect(half1, maxT1, minT2, maxT2)
|| intersect(minT1, maxT1, minT2, half2) || intersect(minT1, maxT1, half2, maxT2);
} else {
result = intersect(minT1, maxT1, minT2, half2) || intersect(minT1, maxT1, half2, maxT2)
|| intersect(minT1, half1, minT2, maxT2) || intersect(half1, maxT1, minT2, maxT2);
}
--depth;
return result;
}
static int quadPart(const Cubic& cubic, double tStart, double tEnd, Quadratic& simple) {
Cubic part;
sub_divide(cubic, tStart, tEnd, part);
Quadratic quad;
demote_cubic_to_quad(part, quad);
// FIXME: should reduceOrder be looser in this use case if quartic is going to blow up on an
// extremely shallow quadratic?
int order = reduceOrder(quad, simple, kReduceOrder_TreatAsFill);
#if DEBUG_QUAD_PART
SkDebugf("%s cubic=(%1.17g,%1.17g %1.17g,%1.17g %1.17g,%1.17g %1.17g,%1.17g) t=(%1.17g,%1.17g)\n",
__FUNCTION__, cubic[0].x, cubic[0].y, cubic[1].x, cubic[1].y, cubic[2].x, cubic[2].y,
cubic[3].x, cubic[3].y, tStart, tEnd);
SkDebugf("%s part=(%1.17g,%1.17g %1.17g,%1.17g %1.17g,%1.17g %1.17g,%1.17g)"
" quad=(%1.17g,%1.17g %1.17g,%1.17g %1.17g,%1.17g)\n", __FUNCTION__, part[0].x, part[0].y,
part[1].x, part[1].y, part[2].x, part[2].y, part[3].x, part[3].y, quad[0].x, quad[0].y,
quad[1].x, quad[1].y, quad[2].x, quad[2].y);
SkDebugf("%s simple=(%1.17g,%1.17g", __FUNCTION__, simple[0].x, simple[0].y);
if (order > 1) {
SkDebugf(" %1.17g,%1.17g", simple[1].x, simple[1].y);
}
if (order > 2) {
SkDebugf(" %1.17g,%1.17g", simple[2].x, simple[2].y);
}
SkDebugf(")\n");
SkASSERT(order < 4 && order > 0);
#endif
return order;
}
void CubicCoincidence_Test() {
// split large quadratic
// upscale quadratics to cubics
// compare original, parts, to see if the are coincident
for (size_t index = firstCubicCoincidenceTest; index < quadratics_count; ++index) {
const Quadratic& test = quadratics[index];
QuadraticPair split;
chop_at(test, split, 0.5);
Quadratic midThird;
sub_divide(test, 1.0/3, 2.0/3, midThird);
Cubic whole, first, second, mid;
quad_to_cubic(test, whole);
quad_to_cubic(split.first(), first);
quad_to_cubic(split.second(), second);
quad_to_cubic(midThird, mid);
if (!implicit_matches(whole, first)) {
printf("%s-1 %d\n", __FUNCTION__, (int)index);
}
if (!implicit_matches(whole, second)) {
printf("%s-2 %d\n", __FUNCTION__, (int)index);
}
if (!implicit_matches(mid, first)) {
printf("%s-3 %d\n", __FUNCTION__, (int)index);
}
if (!implicit_matches(mid, second)) {
printf("%s-4 %d\n", __FUNCTION__, (int)index);
}
if (!implicit_matches(first, second)) {
printf("%s-5 %d\n", __FUNCTION__, (int)index);
}
}
}
bool intersect(const Cubic& cubic, Intersections& i) {
SkTDArray<double> ts;
double precision = calcPrecision(cubic);
cubic_to_quadratics(cubic, precision, ts);
int tsCount = ts.count();
if (tsCount == 1) {
return false;
}
double t1Start = 0;
Cubic part;
for (int idx = 0; idx < tsCount; ++idx) {
double t1 = ts[idx];
Quadratic q1;
sub_divide(cubic, t1Start, t1, part);
demote_cubic_to_quad(part, q1);
double t2Start = t1;
for (int i2 = idx + 1; i2 <= tsCount; ++i2) {
const double t2 = i2 < tsCount ? ts[i2] : 1;
Quadratic q2;
sub_divide(cubic, t2Start, t2, part);
demote_cubic_to_quad(part, q2);
Intersections locals;
intersect2(q1, q2, locals);
for (int tIdx = 0; tIdx < locals.used(); ++tIdx) {
// discard intersections at cusp? (maximum curvature)
double t1sect = locals.fT[0][tIdx];
double t2sect = locals.fT[1][tIdx];
if (idx + 1 == i2 && t1sect == 1 && t2sect == 0) {
continue;
}
double to1 = t1Start + (t1 - t1Start) * t1sect;
double to2 = t2Start + (t2 - t2Start) * t2sect;
i.insert(to1, to2);
}
t2Start = t2;
}
t1Start = t1;
}
return i.intersected();
}
_Point top(const Quadratic& quad, double startT, double endT) {
Quadratic sub;
sub_divide(quad, startT, endT, sub);
_Point topPt = sub[0];
if (topPt.y > sub[2].y || (topPt.y == sub[2].y && topPt.x > sub[2].x)) {
topPt = sub[2];
}
if (!between(sub[0].y, sub[1].y, sub[2].y)) {
double extremeT;
if (findExtrema(sub[0].y, sub[1].y, sub[2].y, &extremeT)) {
extremeT = startT + (endT - startT) * extremeT;
_Point test;
xy_at_t(quad, extremeT, test.x, test.y);
if (topPt.y > test.y || (topPt.y == test.y && topPt.x > test.x)) {
topPt = test;
}
}
}
return topPt;
}
_Point top(const Cubic& cubic, double startT, double endT) {
Cubic sub;
sub_divide(cubic, startT, endT, sub);
_Point topPt = sub[0];
if (topPt.y > sub[3].y || (topPt.y == sub[3].y && topPt.x > sub[3].x)) {
topPt = sub[3];
}
double extremeTs[2];
if (!monotonic_in_y(sub)) {
int roots = findExtrema(sub[0].y, sub[1].y, sub[2].y, sub[3].y, extremeTs);
for (int index = 0; index < roots; ++index) {
_Point mid;
double t = startT + (endT - startT) * extremeTs[index];
xy_at_t(cubic, t, mid.x, mid.y);
if (topPt.y > mid.y || (topPt.y == mid.y && topPt.x > mid.x)) {
topPt = mid;
}
}
}
return topPt;
}
int intersect(const Cubic& cubic, const Quadratic& quad, Intersections& i) {
SkTDArray<double> ts;
double precision = calcPrecision(cubic);
cubic_to_quadratics(cubic, precision, ts);
double tStart = 0;
Cubic part;
int tsCount = ts.count();
for (int idx = 0; idx <= tsCount; ++idx) {
double t = idx < tsCount ? ts[idx] : 1;
Quadratic q1;
sub_divide(cubic, tStart, t, part);
demote_cubic_to_quad(part, q1);
Intersections locals;
intersect2(q1, quad, locals);
for (int tIdx = 0; tIdx < locals.used(); ++tIdx) {
double globalT = tStart + (t - tStart) * locals.fT[0][tIdx];
i.insertOne(globalT, 0);
globalT = locals.fT[1][tIdx];
i.insertOne(globalT, 1);
}
tStart = t;
}
return i.used();
}
bool intersect(double minT1, double maxT1, double minT2, double maxT2) {
bool t1IsLine = maxT1 - minT1 <= quad1Divisions;
bool t2IsLine = maxT2 - minT2 <= quad2Divisions;
if (t1IsLine | t2IsLine) {
return intersectAsLine(minT1, maxT1, minT2, maxT2, t1IsLine, t2IsLine);
}
Quadratic smaller, larger;
// FIXME: carry last subdivide and reduceOrder result with quad
sub_divide(quad1, minT1, maxT1, intersections.swapped() ? larger : smaller);
sub_divide(quad2, minT2, maxT2, intersections.swapped() ? smaller : larger);
double minT, maxT;
if (!bezier_clip(smaller, larger, minT, maxT)) {
if (approximately_equal(minT, maxT)) {
double smallT, largeT;
_Point q2pt, q1pt;
if (intersections.swapped()) {
largeT = interp(minT2, maxT2, minT);
xy_at_t(quad2, largeT, q2pt.x, q2pt.y);
xy_at_t(quad1, minT1, q1pt.x, q1pt.y);
if (AlmostEqualUlps(q2pt.x, q1pt.x) && AlmostEqualUlps(q2pt.y, q1pt.y)) {
smallT = minT1;
} else {
xy_at_t(quad1, maxT1, q1pt.x, q1pt.y); // FIXME: debug code
assert(AlmostEqualUlps(q2pt.x, q1pt.x) && AlmostEqualUlps(q2pt.y, q1pt.y));
smallT = maxT1;
}
} else {
smallT = interp(minT1, maxT1, minT);
xy_at_t(quad1, smallT, q1pt.x, q1pt.y);
xy_at_t(quad2, minT2, q2pt.x, q2pt.y);
if (AlmostEqualUlps(q2pt.x, q1pt.x) && AlmostEqualUlps(q2pt.y, q1pt.y)) {
largeT = minT2;
} else {
xy_at_t(quad2, maxT2, q2pt.x, q2pt.y); // FIXME: debug code
assert(AlmostEqualUlps(q2pt.x, q1pt.x) && AlmostEqualUlps(q2pt.y, q1pt.y));
largeT = maxT2;
}
}
intersections.add(smallT, largeT);
return true;
}
return false;
}
int split;
if (intersections.swapped()) {
double newMinT1 = interp(minT1, maxT1, minT);
double newMaxT1 = interp(minT1, maxT1, maxT);
split = (newMaxT1 - newMinT1 > (maxT1 - minT1) * tClipLimit) << 1;
#define VERBOSE 0
#if VERBOSE
printf("%s d=%d s=%d new1=(%g,%g) old1=(%g,%g) split=%d\n", __FUNCTION__, depth,
splits, newMinT1, newMaxT1, minT1, maxT1, split);
#endif
minT1 = newMinT1;
maxT1 = newMaxT1;
} else {
double newMinT2 = interp(minT2, maxT2, minT);
double newMaxT2 = interp(minT2, maxT2, maxT);
split = newMaxT2 - newMinT2 > (maxT2 - minT2) * tClipLimit;
#if VERBOSE
printf("%s d=%d s=%d new2=(%g,%g) old2=(%g,%g) split=%d\n", __FUNCTION__, depth,
splits, newMinT2, newMaxT2, minT2, maxT2, split);
#endif
minT2 = newMinT2;
maxT2 = newMaxT2;
}
return chop(minT1, maxT1, minT2, maxT2, split);
}
double calcPrecision(const Cubic& cubic, double t, double scale) {
Cubic part;
sub_divide(cubic, SkTMax(0., t - scale), SkTMin(1., t + scale), part);
return calcPrecision(part);
}
bool intersect(double minT1, double maxT1, double minT2, double maxT2) {
Quadratic smaller, larger;
// FIXME: carry last subdivide and reduceOrder result with quad
sub_divide(quad1, minT1, maxT1, intersections.swapped() ? larger : smaller);
sub_divide(quad2, minT2, maxT2, intersections.swapped() ? smaller : larger);
Quadratic smallResult;
if (reduceOrder(smaller, smallResult) <= 2) {
Quadratic largeResult;
if (reduceOrder(larger, largeResult) <= 2) {
double smallT[2], largeT[2];
const _Line& smallLine = (const _Line&) smallResult;
const _Line& largeLine = (const _Line&) largeResult;
// FIXME: this doesn't detect or deal with coincident lines
if (!::intersect(smallLine, largeLine, smallT, largeT)) {
return false;
}
if (intersections.swapped()) {
smallT[0] = interp(minT2, maxT2, smallT[0]);
largeT[0] = interp(minT1, maxT1, largeT[0]);
} else {
smallT[0] = interp(minT1, maxT1, smallT[0]);
largeT[0] = interp(minT2, maxT2, largeT[0]);
}
intersections.add(smallT[0], largeT[0]);
return true;
}
}
double minT, maxT;
if (!bezier_clip(smaller, larger, minT, maxT)) {
if (minT == maxT) {
if (intersections.swapped()) {
minT1 = (minT1 + maxT1) / 2;
minT2 = interp(minT2, maxT2, minT);
} else {
minT1 = interp(minT1, maxT1, minT);
minT2 = (minT2 + maxT2) / 2;
}
intersections.add(minT1, minT2);
return true;
}
return false;
}
int split;
if (intersections.swapped()) {
double newMinT1 = interp(minT1, maxT1, minT);
double newMaxT1 = interp(minT1, maxT1, maxT);
split = (newMaxT1 - newMinT1 > (maxT1 - minT1) * tClipLimit) << 1;
#define VERBOSE 0
#if VERBOSE
printf("%s d=%d s=%d new1=(%g,%g) old1=(%g,%g) split=%d\n", __FUNCTION__, depth,
splits, newMinT1, newMaxT1, minT1, maxT1, split);
#endif
minT1 = newMinT1;
maxT1 = newMaxT1;
} else {
double newMinT2 = interp(minT2, maxT2, minT);
double newMaxT2 = interp(minT2, maxT2, maxT);
split = newMaxT2 - newMinT2 > (maxT2 - minT2) * tClipLimit;
#define VERBOSE 0
#if VERBOSE
printf("%s d=%d s=%d new2=(%g,%g) old2=(%g,%g) split=%d\n", __FUNCTION__, depth,
splits, newMinT2, newMaxT2, minT2, maxT2, split);
#endif
minT2 = newMinT2;
maxT2 = newMaxT2;
}
return chop(minT1, maxT1, minT2, maxT2, split);
}
// this flavor centers potential intersections recursively. In contrast, '2' may inadvertently
// chase intersections near quadratic ends, requiring odd hacks to find them.
static bool intersect3(const Cubic& cubic1, double t1s, double t1e, const Cubic& cubic2,
double t2s, double t2e, double precisionScale, Intersections& i) {
i.upDepth();
bool result = false;
Cubic c1, c2;
sub_divide(cubic1, t1s, t1e, c1);
sub_divide(cubic2, t2s, t2e, c2);
SkTDArray<double> ts1;
// OPTIMIZE: if c1 == c2, call once (happens when detecting self-intersection)
cubic_to_quadratics(c1, calcPrecision(c1) * precisionScale, ts1);
SkTDArray<double> ts2;
cubic_to_quadratics(c2, calcPrecision(c2) * precisionScale, ts2);
double t1Start = t1s;
int ts1Count = ts1.count();
for (int i1 = 0; i1 <= ts1Count; ++i1) {
const double tEnd1 = i1 < ts1Count ? ts1[i1] : 1;
const double t1 = t1s + (t1e - t1s) * tEnd1;
Quadratic s1;
int o1 = quadPart(cubic1, t1Start, t1, s1);
double t2Start = t2s;
int ts2Count = ts2.count();
for (int i2 = 0; i2 <= ts2Count; ++i2) {
const double tEnd2 = i2 < ts2Count ? ts2[i2] : 1;
const double t2 = t2s + (t2e - t2s) * tEnd2;
if (cubic1 == cubic2 && t1Start >= t2Start) {
t2Start = t2;
continue;
}
Quadratic s2;
int o2 = quadPart(cubic2, t2Start, t2, s2);
#if ONE_OFF_DEBUG
char tab[] = " ";
if (tLimits1[0][0] >= t1Start && tLimits1[0][1] <= t1
&& tLimits1[1][0] >= t2Start && tLimits1[1][1] <= t2) {
Cubic cSub1, cSub2;
sub_divide(cubic1, t1Start, t1, cSub1);
sub_divide(cubic2, t2Start, t2, cSub2);
SkDebugf("%.*s %s t1=(%1.9g,%1.9g) t2=(%1.9g,%1.9g)", i.depth()*2, tab, __FUNCTION__,
t1Start, t1, t2Start, t2);
Intersections xlocals;
intersectWithOrder(s1, o1, s2, o2, xlocals);
SkDebugf(" xlocals.fUsed=%d\n", xlocals.used());
}
#endif
Intersections locals;
intersectWithOrder(s1, o1, s2, o2, locals);
double coStart[2] = { -1 };
_Point coPoint;
int tCount = locals.used();
for (int tIdx = 0; tIdx < tCount; ++tIdx) {
double to1 = t1Start + (t1 - t1Start) * locals.fT[0][tIdx];
double to2 = t2Start + (t2 - t2Start) * locals.fT[1][tIdx];
// if the computed t is not sufficiently precise, iterate
_Point p1 = xy_at_t(cubic1, to1);
_Point p2 = xy_at_t(cubic2, to2);
if (p1.approximatelyEqual(p2)) {
if (locals.fIsCoincident[0] & 1 << tIdx) {
if (coStart[0] < 0) {
coStart[0] = to1;
coStart[1] = to2;
coPoint = p1;
} else {
i.insertCoincidentPair(coStart[0], to1, coStart[1], to2, coPoint, p1);
coStart[0] = -1;
}
result = true;
} else if (cubic1 != cubic2 || !approximately_equal(to1, to2)) {
if (i.swapped()) { // FIXME: insert should respect swap
i.insert(to2, to1, p1);
} else {
i.insert(to1, to2, p1);
}
result = true;
}
} else {
double offset = precisionScale / 16; // FIME: const is arbitrary -- test & refine
#if 1
double c1Bottom = tIdx == 0 ? 0 :
(t1Start + (t1 - t1Start) * locals.fT[0][tIdx - 1] + to1) / 2;
double c1Min = SkTMax(c1Bottom, to1 - offset);
double c1Top = tIdx == tCount - 1 ? 1 :
(t1Start + (t1 - t1Start) * locals.fT[0][tIdx + 1] + to1) / 2;
double c1Max = SkTMin(c1Top, to1 + offset);
double c2Min = SkTMax(0., to2 - offset);
double c2Max = SkTMin(1., to2 + offset);
#if ONE_OFF_DEBUG
SkDebugf("%.*s %s 1 contains1=%d/%d contains2=%d/%d\n", i.depth()*2, tab, __FUNCTION__,
c1Min <= tLimits1[0][1] && tLimits1[0][0] <= c1Max
&& c2Min <= tLimits1[1][1] && tLimits1[1][0] <= c2Max,
to1 - offset <= tLimits1[0][1] && tLimits1[0][0] <= to1 + offset
&& to2 - offset <= tLimits1[1][1] && tLimits1[1][0] <= to2 + offset,
c1Min <= tLimits2[0][1] && tLimits2[0][0] <= c1Max
&& c2Min <= tLimits2[1][1] && tLimits2[1][0] <= c2Max,
to1 - offset <= tLimits2[0][1] && tLimits2[0][0] <= to1 + offset
&& to2 - offset <= tLimits2[1][1] && tLimits2[1][0] <= to2 + offset);
SkDebugf("%.*s %s 1 c1Bottom=%1.9g c1Top=%1.9g c2Bottom=%1.9g c2Top=%1.9g"
" 1-o=%1.9g 1+o=%1.9g 2-o=%1.9g 2+o=%1.9g offset=%1.9g\n",
i.depth()*2, tab, __FUNCTION__, c1Bottom, c1Top, 0., 1.,
to1 - offset, to1 + offset, to2 - offset, to2 + offset, offset);
SkDebugf("%.*s %s 1 to1=%1.9g to2=%1.9g c1Min=%1.9g c1Max=%1.9g c2Min=%1.9g"
" c2Max=%1.9g\n", i.depth()*2, tab, __FUNCTION__, to1, to2, c1Min, c1Max, c2Min, c2Max);
#endif
intersect3(cubic1, c1Min, c1Max, cubic2, c2Min, c2Max, offset, i);
#if ONE_OFF_DEBUG
SkDebugf("%.*s %s 1 i.used=%d t=%1.9g\n", i.depth()*2, tab, __FUNCTION__, i.used(),
i.used() > 0 ? i.fT[0][i.used() - 1] : -1);
#endif
if (tCount > 1) {
c1Min = SkTMax(0., to1 - offset);
c1Max = SkTMin(1., to1 + offset);
double c2Bottom = tIdx == 0 ? to2 :
(t2Start + (t2 - t2Start) * locals.fT[1][tIdx - 1] + to2) / 2;
double c2Top = tIdx == tCount - 1 ? to2 :
(t2Start + (t2 - t2Start) * locals.fT[1][tIdx + 1] + to2) / 2;
if (c2Bottom > c2Top) {
SkTSwap(c2Bottom, c2Top);
}
if (c2Bottom == to2) {
c2Bottom = 0;
}
if (c2Top == to2) {
c2Top = 1;
}
c2Min = SkTMax(c2Bottom, to2 - offset);
c2Max = SkTMin(c2Top, to2 + offset);
#if ONE_OFF_DEBUG
SkDebugf("%.*s %s 2 contains1=%d/%d contains2=%d/%d\n", i.depth()*2, tab, __FUNCTION__,
c1Min <= tLimits1[0][1] && tLimits1[0][0] <= c1Max
&& c2Min <= tLimits1[1][1] && tLimits1[1][0] <= c2Max,
to1 - offset <= tLimits1[0][1] && tLimits1[0][0] <= to1 + offset
&& to2 - offset <= tLimits1[1][1] && tLimits1[1][0] <= to2 + offset,
c1Min <= tLimits2[0][1] && tLimits2[0][0] <= c1Max
&& c2Min <= tLimits2[1][1] && tLimits2[1][0] <= c2Max,
to1 - offset <= tLimits2[0][1] && tLimits2[0][0] <= to1 + offset
&& to2 - offset <= tLimits2[1][1] && tLimits2[1][0] <= to2 + offset);
SkDebugf("%.*s %s 2 c1Bottom=%1.9g c1Top=%1.9g c2Bottom=%1.9g c2Top=%1.9g"
" 1-o=%1.9g 1+o=%1.9g 2-o=%1.9g 2+o=%1.9g offset=%1.9g\n",
i.depth()*2, tab, __FUNCTION__, 0., 1., c2Bottom, c2Top,
to1 - offset, to1 + offset, to2 - offset, to2 + offset, offset);
SkDebugf("%.*s %s 2 to1=%1.9g to2=%1.9g c1Min=%1.9g c1Max=%1.9g c2Min=%1.9g"
" c2Max=%1.9g\n", i.depth()*2, tab, __FUNCTION__, to1, to2, c1Min, c1Max, c2Min, c2Max);
#endif
intersect3(cubic1, c1Min, c1Max, cubic2, c2Min, c2Max, offset, i);
#if ONE_OFF_DEBUG
SkDebugf("%.*s %s 2 i.used=%d t=%1.9g\n", i.depth()*2, tab, __FUNCTION__, i.used(),
i.used() > 0 ? i.fT[0][i.used() - 1] : -1);
#endif
c1Min = SkTMax(c1Bottom, to1 - offset);
c1Max = SkTMin(c1Top, to1 + offset);
#if ONE_OFF_DEBUG
SkDebugf("%.*s %s 3 contains1=%d/%d contains2=%d/%d\n", i.depth()*2, tab, __FUNCTION__,
c1Min <= tLimits1[0][1] && tLimits1[0][0] <= c1Max
&& c2Min <= tLimits1[1][1] && tLimits1[1][0] <= c2Max,
to1 - offset <= tLimits1[0][1] && tLimits1[0][0] <= to1 + offset
&& to2 - offset <= tLimits1[1][1] && tLimits1[1][0] <= to2 + offset,
c1Min <= tLimits2[0][1] && tLimits2[0][0] <= c1Max
&& c2Min <= tLimits2[1][1] && tLimits2[1][0] <= c2Max,
to1 - offset <= tLimits2[0][1] && tLimits2[0][0] <= to1 + offset
&& to2 - offset <= tLimits2[1][1] && tLimits2[1][0] <= to2 + offset);
SkDebugf("%.*s %s 3 c1Bottom=%1.9g c1Top=%1.9g c2Bottom=%1.9g c2Top=%1.9g"
" 1-o=%1.9g 1+o=%1.9g 2-o=%1.9g 2+o=%1.9g offset=%1.9g\n",
i.depth()*2, tab, __FUNCTION__, 0., 1., c2Bottom, c2Top,
to1 - offset, to1 + offset, to2 - offset, to2 + offset, offset);
SkDebugf("%.*s %s 3 to1=%1.9g to2=%1.9g c1Min=%1.9g c1Max=%1.9g c2Min=%1.9g"
" c2Max=%1.9g\n", i.depth()*2, tab, __FUNCTION__, to1, to2, c1Min, c1Max, c2Min, c2Max);
#endif
intersect3(cubic1, c1Min, c1Max, cubic2, c2Min, c2Max, offset, i);
#if ONE_OFF_DEBUG
SkDebugf("%.*s %s 3 i.used=%d t=%1.9g\n", i.depth()*2, tab, __FUNCTION__, i.used(),
i.used() > 0 ? i.fT[0][i.used() - 1] : -1);
#endif
}
#else
double c1Bottom = tIdx == 0 ? 0 :
(t1Start + (t1 - t1Start) * locals.fT[0][tIdx - 1] + to1) / 2;
double c1Min = SkTMax(c1Bottom, to1 - offset);
double c1Top = tIdx == tCount - 1 ? 1 :
(t1Start + (t1 - t1Start) * locals.fT[0][tIdx + 1] + to1) / 2;
double c1Max = SkTMin(c1Top, to1 + offset);
double c2Bottom = tIdx == 0 ? to2 :
(t2Start + (t2 - t2Start) * locals.fT[1][tIdx - 1] + to2) / 2;
double c2Top = tIdx == tCount - 1 ? to2 :
(t2Start + (t2 - t2Start) * locals.fT[1][tIdx + 1] + to2) / 2;
if (c2Bottom > c2Top) {
SkTSwap(c2Bottom, c2Top);
}
if (c2Bottom == to2) {
c2Bottom = 0;
}
if (c2Top == to2) {
c2Top = 1;
}
double c2Min = SkTMax(c2Bottom, to2 - offset);
double c2Max = SkTMin(c2Top, to2 + offset);
#if ONE_OFF_DEBUG
SkDebugf("%s contains1=%d/%d contains2=%d/%d\n", __FUNCTION__,
c1Min <= 0.210357794 && 0.210357794 <= c1Max
&& c2Min <= 0.223476406 && 0.223476406 <= c2Max,
to1 - offset <= 0.210357794 && 0.210357794 <= to1 + offset
&& to2 - offset <= 0.223476406 && 0.223476406 <= to2 + offset,
c1Min <= 0.211324707 && 0.211324707 <= c1Max
&& c2Min <= 0.211327209 && 0.211327209 <= c2Max,
to1 - offset <= 0.211324707 && 0.211324707 <= to1 + offset
&& to2 - offset <= 0.211327209 && 0.211327209 <= to2 + offset);
SkDebugf("%s c1Bottom=%1.9g c1Top=%1.9g c2Bottom=%1.9g c2Top=%1.9g"
" 1-o=%1.9g 1+o=%1.9g 2-o=%1.9g 2+o=%1.9g offset=%1.9g\n",
__FUNCTION__, c1Bottom, c1Top, c2Bottom, c2Top,
to1 - offset, to1 + offset, to2 - offset, to2 + offset, offset);
SkDebugf("%s to1=%1.9g to2=%1.9g c1Min=%1.9g c1Max=%1.9g c2Min=%1.9g"
" c2Max=%1.9g\n", __FUNCTION__, to1, to2, c1Min, c1Max, c2Min, c2Max);
#endif
#endif
intersect3(cubic1, c1Min, c1Max, cubic2, c2Min, c2Max, offset, i);
// TODO: if no intersection is found, either quadratics intersected where
// cubics did not, or the intersection was missed. In the former case, expect
// the quadratics to be nearly parallel at the point of intersection, and check
// for that.
}
}
SkASSERT(coStart[0] == -1);
t2Start = t2;
}
t1Start = t1;
}
i.downDepth();
return result;
}
// this flavor approximates the cubics with quads to find the intersecting ts
// OPTIMIZE: if this strategy proves successful, the quad approximations, or the ts used
// to create the approximations, could be stored in the cubic segment
// FIXME: this strategy needs to intersect the convex hull on either end with the opposite to
// account for inset quadratics that cause the endpoint intersection to avoid detection
// the segments can be very short -- the length of the maximum quadratic error (precision)
// FIXME: this needs to recurse on itself, taking a range of T values and computing the new
// t range ala is linear inner. The range can be figured by taking the dx/dy and determining
// the fraction that matches the precision. That fraction is the change in t for the smaller cubic.
static bool intersect2(const Cubic& cubic1, double t1s, double t1e, const Cubic& cubic2,
double t2s, double t2e, double precisionScale, Intersections& i) {
Cubic c1, c2;
sub_divide(cubic1, t1s, t1e, c1);
sub_divide(cubic2, t2s, t2e, c2);
SkTDArray<double> ts1;
cubic_to_quadratics(c1, calcPrecision(c1) * precisionScale, ts1);
SkTDArray<double> ts2;
cubic_to_quadratics(c2, calcPrecision(c2) * precisionScale, ts2);
double t1Start = t1s;
int ts1Count = ts1.count();
for (int i1 = 0; i1 <= ts1Count; ++i1) {
const double tEnd1 = i1 < ts1Count ? ts1[i1] : 1;
const double t1 = t1s + (t1e - t1s) * tEnd1;
Cubic part1;
sub_divide(cubic1, t1Start, t1, part1);
Quadratic q1;
demote_cubic_to_quad(part1, q1);
// start here;
// should reduceOrder be looser in this use case if quartic is going to blow up on an
// extremely shallow quadratic?
Quadratic s1;
int o1 = reduceOrder(q1, s1);
double t2Start = t2s;
int ts2Count = ts2.count();
for (int i2 = 0; i2 <= ts2Count; ++i2) {
const double tEnd2 = i2 < ts2Count ? ts2[i2] : 1;
const double t2 = t2s + (t2e - t2s) * tEnd2;
Cubic part2;
sub_divide(cubic2, t2Start, t2, part2);
Quadratic q2;
demote_cubic_to_quad(part2, q2);
Quadratic s2;
double o2 = reduceOrder(q2, s2);
Intersections locals;
if (o1 == 3 && o2 == 3) {
intersect2(q1, q2, locals);
} else if (o1 <= 2 && o2 <= 2) {
locals.fUsed = intersect((const _Line&) s1, (const _Line&) s2, locals.fT[0],
locals.fT[1]);
} else if (o1 == 3 && o2 <= 2) {
intersect(q1, (const _Line&) s2, locals);
} else {
SkASSERT(o1 <= 2 && o2 == 3);
intersect(q2, (const _Line&) s1, locals);
for (int s = 0; s < locals.fUsed; ++s) {
SkTSwap(locals.fT[0][s], locals.fT[1][s]);
}
}
for (int tIdx = 0; tIdx < locals.used(); ++tIdx) {
double to1 = t1Start + (t1 - t1Start) * locals.fT[0][tIdx];
double to2 = t2Start + (t2 - t2Start) * locals.fT[1][tIdx];
// if the computed t is not sufficiently precise, iterate
_Point p1, p2;
xy_at_t(cubic1, to1, p1.x, p1.y);
xy_at_t(cubic2, to2, p2.x, p2.y);
if (p1.approximatelyEqual(p2)) {
i.insert(i.swapped() ? to2 : to1, i.swapped() ? to1 : to2);
} else {
double dt1, dt2;
computeDelta(cubic1, to1, (t1e - t1s), cubic2, to2, (t2e - t2s), dt1, dt2);
double scale = precisionScale;
if (dt1 > 0.125 || dt2 > 0.125) {
scale /= 2;
SkDebugf("%s scale=%1.9g\n", __FUNCTION__, scale);
}
#if SK_DEBUG
++debugDepth;
assert(debugDepth < 10);
#endif
i.swap();
intersect2(cubic2, SkTMax(to2 - dt2, 0.), SkTMin(to2 + dt2, 1.),
cubic1, SkTMax(to1 - dt1, 0.), SkTMin(to1 + dt1, 1.), scale, i);
i.swap();
#if SK_DEBUG
--debugDepth;
#endif
}
}
t2Start = t2;
}
t1Start = t1;
}
return i.intersected();
}
