// please keep in sync with debugMergeMatches()
// Look to see if pt-t linked list contains same segment more than once
// if so, and if each pt-t is directly pointed to by spans in that segment,
// merge them
// keep the points, but remove spans so that the segment doesn't have 2 or more
// spans pointing to the same pt-t loop at different loop elements
void SkOpSpanBase::mergeMatches(SkOpSpanBase* opp) {
SkOpPtT* test = &fPtT;
SkOpPtT* testNext;
const SkOpPtT* stop = test;
do {
testNext = test->next();
if (test->deleted()) {
continue;
}
SkOpSpanBase* testBase = test->span();
SkASSERT(testBase->ptT() == test);
SkOpSegment* segment = test->segment();
if (segment->done()) {
continue;
}
SkOpPtT* inner = opp->ptT();
const SkOpPtT* innerStop = inner;
do {
if (inner->segment() != segment) {
continue;
}
if (inner->deleted()) {
continue;
}
SkOpSpanBase* innerBase = inner->span();
SkASSERT(innerBase->ptT() == inner);
// when the intersection is first detected, the span base is marked if there are
// more than one point in the intersection.
if (!zero_or_one(inner->fT)) {
innerBase->upCast()->release(test);
} else {
SkOPASSERT(inner->fT != test->fT);
if (!zero_or_one(test->fT)) {
testBase->upCast()->release(inner);
} else {
segment->markAllDone(); // mark segment as collapsed
SkDEBUGCODE(testBase->debugSetDeleted());
test->setDeleted();
SkDEBUGCODE(innerBase->debugSetDeleted());
inner->setDeleted();
}
}
#ifdef SK_DEBUG // assert if another undeleted entry points to segment
const SkOpPtT* debugInner = inner;
while ((debugInner = debugInner->next()) != innerStop) {
if (debugInner->segment() != segment) {
continue;
}
if (debugInner->deleted()) {
continue;
}
SkOPASSERT(0);
}
#endif
break;
} while ((inner = inner->next()) != innerStop);
} while ((test = testNext) != stop);
this->checkForCollapsedCoincidence();
}
// this pair of spans share a common t value or point; merge them and eliminate duplicates
// this does not compute the best t or pt value; this merely moves all data into a single list
void SkOpSpanBase::merge(SkOpSpan* span) {
SkOpPtT* spanPtT = span->ptT();
SkASSERT(this->t() != spanPtT->fT);
SkASSERT(!zero_or_one(spanPtT->fT));
span->release(this->ptT());
if (this->contains(span)) {
SkOPASSERT(0); // check to see if this ever happens -- should have been found earlier
return; // merge is already in the ptT loop
}
SkOpPtT* remainder = spanPtT->next();
this->ptT()->insert(spanPtT);
while (remainder != spanPtT) {
SkOpPtT* next = remainder->next();
SkOpPtT* compare = spanPtT->next();
while (compare != spanPtT) {
SkOpPtT* nextC = compare->next();
if (nextC->span() == remainder->span() && nextC->fT == remainder->fT) {
goto tryNextRemainder;
}
compare = nextC;
}
spanPtT->insert(remainder);
tryNextRemainder:
remainder = next;
}
fSpanAdds += span->fSpanAdds;
}
void SkIntersections::cleanUpParallelLines(bool parallel) {
while (fUsed > 2) {
removeOne(1);
}
if (fUsed == 2 && !parallel) {
bool startMatch = fT[0][0] == 0 || zero_or_one(fT[1][0]);
bool endMatch = fT[0][1] == 1 || zero_or_one(fT[1][1]);
if ((!startMatch && !endMatch) || approximately_equal(fT[0][0], fT[0][1])) {
SkASSERT(startMatch || endMatch);
if (startMatch && endMatch && (fT[0][0] != 0 || !zero_or_one(fT[1][0]))
&& fT[0][1] == 1 && zero_or_one(fT[1][1])) {
removeOne(0);
} else {
removeOne(endMatch);
}
}
}
if (fUsed == 2) {
fIsCoincident[0] = fIsCoincident[1] = 0x03;
}
}
SkDVector SkDConic::dxdyAtT(double t) const {
SkDVector result = {
conic_eval_tan(&fPts[0].fX, fWeight, t),
conic_eval_tan(&fPts[0].fY, fWeight, t)
};
if (result.fX == 0 && result.fY == 0) {
if (zero_or_one(t)) {
result = fPts[2] - fPts[0];
} else {
// incomplete
SkDebugf("!k");
}
}
return result;
}
SkDVector SkDQuad::dxdyAtT(double t) const {
double a = t - 1;
double b = 1 - 2 * t;
double c = t;
SkDVector result = { a * fPts[0].fX + b * fPts[1].fX + c * fPts[2].fX,
a * fPts[0].fY + b * fPts[1].fY + c * fPts[2].fY };
if (result.fX == 0 && result.fY == 0) {
if (zero_or_one(t)) {
result = fPts[2] - fPts[0];
} else {
// incomplete
SkDebugf("!q");
}
}
return result;
}
// OPTIMIZE? compute t^2, t(1-t), and (1-t)^2 and pass them to another version of derivative at t?
SkDVector SkDCubic::dxdyAtT(double t) const {
SkDVector result = { derivative_at_t(&fPts[0].fX, t), derivative_at_t(&fPts[0].fY, t) };
if (result.fX == 0 && result.fY == 0) {
if (t == 0) {
result = fPts[2] - fPts[0];
} else if (t == 1) {
result = fPts[3] - fPts[1];
} else {
// incomplete
SkDebugf("!c");
}
if (result.fX == 0 && result.fY == 0 && zero_or_one(t)) {
result = fPts[3] - fPts[0];
}
}
return result;
}
