SkOpSegment* FindSortableTop(const SkTArray<SkOpContour*, true>& contourList,
        SkOpAngle::IncludeType angleIncludeType, bool* firstContour, int* indexPtr,
        int* endIndexPtr, SkPoint* topLeft, bool* unsortable, bool* done, bool* onlyVertical,
        bool firstPass) {
    SkOpSegment* current = findTopSegment(contourList, indexPtr, endIndexPtr, topLeft, unsortable,
            done, firstPass);
    if (!current) {
        return NULL;
    }
    const int startIndex = *indexPtr;
    const int endIndex = *endIndexPtr;
    if (*firstContour) {
        current->initWinding(startIndex, endIndex, angleIncludeType);
        *firstContour = false;
        return current;
    }
    int minIndex = SkMin32(startIndex, endIndex);
    int sumWinding = current->windSum(minIndex);
    if (sumWinding == SK_MinS32) {
        int index = endIndex;
        int oIndex = startIndex;
        do { 
            const SkOpSpan& span = current->span(index);
            if ((oIndex < index ? span.fFromAngle : span.fToAngle) == NULL) {
                current->addSimpleAngle(index);
            }
            sumWinding = current->computeSum(oIndex, index, angleIncludeType);
            SkTSwap(index, oIndex);
        } while (sumWinding == SK_MinS32 && index == startIndex);
    }
    if (sumWinding != SK_MinS32 && sumWinding != SK_NaN32) {
        return current;
    }
    int contourWinding;
    int oppContourWinding = 0;
    // the simple upward projection of the unresolved points hit unsortable angles
    // shoot rays at right angles to the segment to find its winding, ignoring angle cases
    bool tryAgain;
    double tHit;
    SkScalar hitDx = 0;
    SkScalar hitOppDx = 0;
    do {
        // if current is vertical, find another candidate which is not
        // if only remaining candidates are vertical, then they can be marked done
        SkASSERT(*indexPtr != *endIndexPtr && *indexPtr >= 0 && *endIndexPtr >= 0);
        skipVertical(contourList, &current, indexPtr, endIndexPtr);
        SkASSERT(current);  // FIXME: if null, all remaining are vertical
        SkASSERT(*indexPtr != *endIndexPtr && *indexPtr >= 0 && *endIndexPtr >= 0);
        tryAgain = false;
        contourWinding = rightAngleWinding(contourList, &current, indexPtr, endIndexPtr, &tHit,
                &hitDx, &tryAgain, onlyVertical, false);
        if (*onlyVertical) {
            return current;
        }
        if (tryAgain) {
            continue;
        }
        if (angleIncludeType < SkOpAngle::kBinarySingle) {
            break;
        }
        oppContourWinding = rightAngleWinding(contourList, &current, indexPtr, endIndexPtr, &tHit,
                &hitOppDx, &tryAgain, NULL, true);
    } while (tryAgain);
    current->initWinding(*indexPtr, *endIndexPtr, tHit, contourWinding, hitDx, oppContourWinding,
            hitOppDx);
    if (current->done()) {
        return NULL;
    }
    return current;
}
Exemple #2
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SkOpSegment* FindSortableTop(const SkTArray<SkOpContour*, true>& contourList,
        SkOpAngle::IncludeType angleIncludeType, bool* firstContour, int* indexPtr,
        int* endIndexPtr, SkPoint* topLeft, bool* unsortable, bool* done, bool* onlyVertical,
        bool firstPass) {
    SkOpSegment* current = findTopSegment(contourList, indexPtr, endIndexPtr, topLeft, unsortable,
            done, firstPass);
    if (!current) {
        return NULL;
    }
    const int startIndex = *indexPtr;
    const int endIndex = *endIndexPtr;
    if (*firstContour) {
        current->initWinding(startIndex, endIndex, angleIncludeType);
        *firstContour = false;
        return current;
    }
    int minIndex = SkMin32(startIndex, endIndex);
    int sumWinding = current->windSum(minIndex);
    if (sumWinding == SK_MinS32) {
        int index = endIndex;
        int oIndex = startIndex;
        do { 
            const SkOpSpan& span = current->span(index);
            if ((oIndex < index ? span.fFromAngle : span.fToAngle) == NULL) {
                current->addSimpleAngle(index);
            }
            sumWinding = current->computeSum(oIndex, index, angleIncludeType);
            SkTSwap(index, oIndex);
        } while (sumWinding == SK_MinS32 && index == startIndex);
    }
    if (sumWinding != SK_MinS32 && sumWinding != SK_NaN32) {
        return current;
    }
    int contourWinding;
    int oppContourWinding = 0;
    // the simple upward projection of the unresolved points hit unsortable angles
    // shoot rays at right angles to the segment to find its winding, ignoring angle cases
    bool tryAgain;
    double tHit;
    SkScalar hitDx = 0;
    SkScalar hitOppDx = 0;
    // keep track of subsequent returns to detect infinite loops
    SkTDArray<SortableTop> sortableTops;
    do {
        // if current is vertical, find another candidate which is not
        // if only remaining candidates are vertical, then they can be marked done
        SkASSERT(*indexPtr != *endIndexPtr && *indexPtr >= 0 && *endIndexPtr >= 0);
        skipVertical(contourList, &current, indexPtr, endIndexPtr);
        SkASSERT(current);  // FIXME: if null, all remaining are vertical
        SkASSERT(*indexPtr != *endIndexPtr && *indexPtr >= 0 && *endIndexPtr >= 0);
        tryAgain = false;
        contourWinding = rightAngleWinding(contourList, &current, indexPtr, endIndexPtr, &tHit,
                &hitDx, &tryAgain, onlyVertical, false);
        if (tryAgain) {
            bool giveUp = false;
            int count = sortableTops.count();
            for (int index = 0; index < count; ++index) {
                const SortableTop& prev = sortableTops[index];
                if (giveUp) {
                    prev.fSegment->markDoneFinal(prev.fIndex);
                } else if (prev.fSegment == current
                        && (prev.fIndex == *indexPtr || prev.fEndIndex == *endIndexPtr)) {
                    // remaining edges are non-vertical and cannot have their winding computed
                    // mark them as done and return, and hope that assembly can fill the holes
                    giveUp = true;
                    index = -1;
                }
            }
            if (giveUp) {
                *done = true;
                return NULL;
            }
        }
        SortableTop* sortableTop = sortableTops.append();
        sortableTop->fSegment = current;
        sortableTop->fIndex = *indexPtr;
        sortableTop->fEndIndex = *endIndexPtr;
#if DEBUG_SORT
        SkDebugf("%s current=%d index=%d endIndex=%d tHit=%1.9g hitDx=%1.9g try=%d vert=%d\n",
                __FUNCTION__, current->debugID(), *indexPtr, *endIndexPtr, tHit, hitDx, tryAgain,
                *onlyVertical);
#endif
        if (*onlyVertical) {
            return current;
        }
        if (tryAgain) {
            continue;
        }
        if (angleIncludeType < SkOpAngle::kBinarySingle) {
            break;
        }
        oppContourWinding = rightAngleWinding(contourList, &current, indexPtr, endIndexPtr, &tHit,
                &hitOppDx, &tryAgain, NULL, true);
    } while (tryAgain);
    bool success = current->initWinding(*indexPtr, *endIndexPtr, tHit, contourWinding, hitDx,
            oppContourWinding, hitOppDx);
    if (current->done()) {
        return NULL;
    } else if (!success) {  // check if the span has a valid winding
        int min = SkTMin(*indexPtr, *endIndexPtr);
        const SkOpSpan& span = current->span(min);
        if (span.fWindSum == SK_MinS32) {
            return NULL;
        }
    }
    return current;
}