Revert of pathops version two (patchset #16 id:150001 of https://codereview.chromium.org/1002693002/)

Reason for revert:
ASAN investigation

Original issue's description:
> pathops version two
>
> R=reed@google.com
>
> marked 'no commit' to attempt to get trybots to run
>
> TBR=reed@google.com
>
> Committed: https://skia.googlesource.com/skia/+/ccec0f958ffc71a9986d236bc2eb335cb2111119

TBR=caryclark@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1029993002

1 files changed, 223 insertions, 10 deletions

diff --git a/tests/PathOpsCubicQuadIntersectionTest.cpp b/tests/PathOpsCubicQuadIntersectionTest.cpp
index d1ce05b638..967dfc7f4e 100644
--- a/tests/PathOpsCubicQuadIntersectionTest.cpp
+++ b/tests/PathOpsCubicQuadIntersectionTest.cpp
@@ -15,32 +15,44 @@
 static struct quadCubic {
     SkDCubic cubic;
     SkDQuad quad;
+    int answerCount;
+    SkDPoint answers[2];
 } quadCubicTests[] = {
+#if 0  // FIXME : this should not fail (root problem behind skpcarrot_is24 )
     {{{{1020.08099,672.161987}, {1020.08002,630.73999}, {986.502014,597.161987}, {945.080994,597.161987}}},
-     {{{1020,672}, {1020,640.93396}, {998.03302,618.96698}}}},
+     {{{1020,672}, {1020,640.93396}, {998.03302,618.96698}}}, 1,
+      {{1019.421, 662.449}}},
+#endif
 
     {{{{778, 14089}, {778, 14091.208984375}, {776.20916748046875, 14093}, {774, 14093}}},
-     {{{778, 14089}, {777.99957275390625, 14090.65625}, {776.82843017578125, 14091.828125}}}},
+     {{{778, 14089}, {777.99957275390625, 14090.65625}, {776.82843017578125, 14091.828125}}}, 2,
+     {{778, 14089}, {776.82855609581270,14091.828250841330}}},
 
     {{{{1110, 817}, {1110.55225f, 817}, {1111, 817.447693f}, {1111, 818}}},
-     {{{1110.70715f, 817.292908f}, {1110.41406f, 817.000122f}, {1110, 817}}}},
+     {{{1110.70715f, 817.292908f}, {1110.41406f, 817.000122f}, {1110, 817}}}, 2,
+      {{1110, 817}, {1110.70715f, 817.292908f}}},
 
     {{{{1110, 817}, {1110.55225f, 817}, {1111, 817.447693f}, {1111, 818}}},
-     {{{1111, 818}, {1110.99988f, 817.585876f}, {1110.70715f, 817.292908f}}}},
+     {{{1111, 818}, {1110.99988f, 817.585876f}, {1110.70715f, 817.292908f}}}, 2,
+      {{1110.70715f, 817.292908f}, {1111, 818}}},
 
     {{{{55, 207}, {52.238574981689453, 207}, {50, 204.76142883300781}, {50, 202}}},
      {{{55, 207}, {52.929431915283203, 206.99949645996094},
-       {51.464466094970703, 205.53553771972656}}}},
+       {51.464466094970703, 205.53553771972656}}}, 2,
+      {{55, 207}, {51.464466094970703, 205.53553771972656}}},
 
     {{{{49, 47}, {49, 74.614250183105469}, {26.614250183105469, 97}, {-1, 97}}},
      {{{-8.659739592076221e-015, 96.991401672363281}, {20.065492630004883, 96.645187377929688},
-       {34.355339050292969, 82.355339050292969}}}},
+       {34.355339050292969, 82.355339050292969}}}, 2,
+      {{34.355339050292969,82.355339050292969}, {34.28654835573549, 82.424006509351585}}},
 
     {{{{10,234}, {10,229.58172607421875}, {13.581720352172852,226}, {18,226}}},
-     {{{18,226}, {14.686291694641113,226}, {12.342399597167969,228.3424072265625}}}},
+     {{{18,226}, {14.686291694641113,226}, {12.342399597167969,228.3424072265625}}}, 1,
+      {{18,226}, {0,0}}},
 
     {{{{10,234}, {10,229.58172607421875}, {13.581720352172852,226}, {18,226}}},
-     {{{12.342399597167969,228.3424072265625}, {10,230.68629455566406}, {10,234}}}},
+     {{{12.342399597167969,228.3424072265625}, {10,230.68629455566406}, {10,234}}}, 1,
+      {{10,234}, {0,0}}},
 };
 
 static const int quadCubicTests_count = (int) SK_ARRAY_COUNT(quadCubicTests);
@@ -63,9 +75,9 @@ static void cubicQuadIntersection(skiatest::Reporter* reporter, int index) {
         SkDebugf("[%d] quad order=%d\n", iIndex, order2);
         REPORTER_ASSERT(reporter, 0);
     }
-    SkDCubic quadToCubic = quad.toCubic();
     SkIntersections i;
-    int roots = i.intersect(cubic, quadToCubic);
+    int roots = i.intersect(cubic, quad);
+    SkASSERT(roots == quadCubicTests[index].answerCount);
     for (int pt = 0; pt < roots; ++pt) {
         double tt1 = i[0][pt];
         SkDPoint xy1 = cubic.ptAtT(tt1);
@@ -76,6 +88,15 @@ static void cubicQuadIntersection(skiatest::Reporter* reporter, int index) {
                 __FUNCTION__, iIndex, pt, tt1, xy1.fX, xy1.fY, tt2, xy2.fX, xy2.fY);
         }
         REPORTER_ASSERT(reporter, xy1.approximatelyEqual(xy2));
+        bool found = false;
+        for (int idx2 = 0; idx2 < quadCubicTests[index].answerCount; ++idx2) {
+            found |= quadCubicTests[index].answers[idx2].approximatelyEqual(xy1);
+        }
+        if (!found) {
+            SkDebugf("%s [%d,%d] xy1=(%g,%g) != \n",
+                __FUNCTION__, iIndex, pt, xy1.fX, xy1.fY);
+        }
+        REPORTER_ASSERT(reporter, found);
     }
     reporter->bumpTestCount();
 }
@@ -90,3 +111,195 @@ DEF_TEST(PathOpsCubicQuadIntersection, reporter) {
 DEF_TEST(PathOpsCubicQuadIntersectionOneOff, reporter) {
     cubicQuadIntersection(reporter, 0);
 }
+
+static bool gPathOpCubicQuadSlopVerbose = false;
+static const int kCubicToQuadSubdivisionDepth = 8; // slots reserved for cubic to quads subdivision
+
+// determine that slop required after quad/quad finds a candidate intersection
+// use the cross of the tangents plus the distance from 1 or 0 as knobs
+DEF_TEST(PathOpsCubicQuadSlop, reporter) {
+    // create a random non-selfintersecting cubic
+    // break it into quadratics
+    // offset the quadratic, measuring the slop required to find the intersection
+    if (!gPathOpCubicQuadSlopVerbose) {  // takes a while to run -- so exclude it by default
+        return;
+    }
+    int results[101];
+    sk_bzero(results, sizeof(results));
+    double minCross[101];
+    sk_bzero(minCross, sizeof(minCross));
+    double maxCross[101];
+    sk_bzero(maxCross, sizeof(maxCross));
+    double sumCross[101];
+    sk_bzero(sumCross, sizeof(sumCross));
+    int foundOne = 0;
+    int slopCount = 1;
+    SkRandom ran;
+    for (int index = 0; index < 10000000; ++index) {
+        if (index % 1000 == 999) SkDebugf(".");
+        SkDCubic cubic = {{
+                {ran.nextRangeF(-1000, 1000), ran.nextRangeF(-1000, 1000)},
+                {ran.nextRangeF(-1000, 1000), ran.nextRangeF(-1000, 1000)},
+                {ran.nextRangeF(-1000, 1000), ran.nextRangeF(-1000, 1000)},
+                {ran.nextRangeF(-1000, 1000), ran.nextRangeF(-1000, 1000)}
+        }};
+        SkIntersections i;
+        if (i.intersect(cubic)) {
+            continue;
+        }
+        SkSTArray<kCubicToQuadSubdivisionDepth, double, true> ts;
+        cubic.toQuadraticTs(cubic.calcPrecision(), &ts);
+        double tStart = 0;
+        int tsCount = ts.count();
+        for (int i1 = 0; i1 <= tsCount; ++i1) {
+            const double tEnd = i1 < tsCount ? ts[i1] : 1;
+            SkDCubic part = cubic.subDivide(tStart, tEnd);
+            SkDQuad quad = part.toQuad();
+            SkReduceOrder reducer;
+            int order = reducer.reduce(quad);
+            if (order != 3) {
+                continue;
+            }
+            for (int i2 = 0; i2 < 100; ++i2) {
+                SkDPoint endDisplacement = {ran.nextRangeF(-100, 100), ran.nextRangeF(-100, 100)};
+                SkDQuad nearby = {{
+                        {quad[0].fX + endDisplacement.fX, quad[0].fY + endDisplacement.fY},
+                        {quad[1].fX + ran.nextRangeF(-100, 100), quad[1].fY + ran.nextRangeF(-100, 100)},
+                        {quad[2].fX - endDisplacement.fX, quad[2].fY - endDisplacement.fY}
+                }};
+                order = reducer.reduce(nearby);
+                if (order != 3) {
+                    continue;
+                }
+                SkIntersections locals;
+                locals.allowNear(false);
+                locals.intersect(quad, nearby);
+                if (locals.used() != 1) {
+                    continue;
+                }
+                // brute force find actual intersection
+                SkDLine cubicLine = {{ {0, 0}, {cubic[0].fX, cubic[0].fY } }};
+                SkIntersections liner;
+                int i3;
+                int found = -1;
+                int foundErr = true;
+                for (i3 = 1; i3 <= 1000; ++i3) {
+                    cubicLine[0] = cubicLine[1];
+                    cubicLine[1] = cubic.ptAtT(i3 / 1000.);
+                    liner.reset();
+                    liner.allowNear(false);
+                    liner.intersect(nearby, cubicLine);
+                    if (liner.used() == 0) {
+                        continue;
+                    }
+                    if (liner.used() > 1) {
+                        foundErr = true;
+                        break;
+                    }
+                    if (found > 0) {
+                        foundErr = true;
+                        break;
+                    }
+                    foundErr = false;
+                    found = i3;
+                }
+                if (foundErr) {
+                    continue;
+                }
+                SkDVector dist = liner.pt(0) - locals.pt(0);
+                SkDVector qV = nearby.dxdyAtT(locals[0][0]);
+                double cubicT = (found - 1 + liner[1][0]) / 1000.;
+                SkDVector cV = cubic.dxdyAtT(cubicT);
+                double qxc = qV.crossCheck(cV);
+                double qvLen = qV.length();
+                double cvLen = cV.length();
+                double maxLen = SkTMax(qvLen, cvLen);
+                qxc /= maxLen;
+                double quadT = tStart + (tEnd - tStart) * locals[0][0];
+                double diffT = fabs(cubicT - quadT);
+                int diffIdx = (int) (diffT * 100);
+                results[diffIdx]++;
+                double absQxc = fabs(qxc);
+                if (sumCross[diffIdx] == 0) {
+                    minCross[diffIdx] = maxCross[diffIdx] = sumCross[diffIdx] = absQxc;
+                } else {
+                    minCross[diffIdx] = SkTMin(minCross[diffIdx], absQxc);
+                    maxCross[diffIdx] = SkTMax(maxCross[diffIdx], absQxc);
+                    sumCross[diffIdx] +=  absQxc;
+                }
+                if (diffIdx >= 20) {
+#if 01
+                    SkDebugf("cubic={{{%1.9g,%1.9g}, {%1.9g,%1.9g}, {%1.9g,%1.9g}, {%1.9g,%1.9g}}}"
+                        " quad={{{%1.9g,%1.9g}, {%1.9g,%1.9g}, {%1.9g,%1.9g}}}"
+                        " {{{%1.9g,%1.9g}, {%1.9g,%1.9g}}}"
+                        " qT=%1.9g cT=%1.9g dist=%1.9g cross=%1.9g\n",
+                        cubic[0].fX, cubic[0].fY, cubic[1].fX, cubic[1].fY,
+                        cubic[2].fX, cubic[2].fY, cubic[3].fX, cubic[3].fY,
+                        nearby[0].fX, nearby[0].fY, nearby[1].fX, nearby[1].fY,
+                        nearby[2].fX, nearby[2].fY,
+                        liner.pt(0).fX, liner.pt(0).fY,
+                        locals.pt(0).fX, locals.pt(0).fY, quadT, cubicT, dist.length(), qxc);
+#else
+                    SkDebugf("qT=%1.9g cT=%1.9g dist=%1.9g cross=%1.9g\n",
+                        quadT, cubicT, dist.length(), qxc);
+                    SkDebugf("<div id=\"slop%d\">\n", ++slopCount);
+                    SkDebugf("{{{%1.9g,%1.9g}, {%1.9g,%1.9g}, {%1.9g,%1.9g}, {%1.9g,%1.9g}}}\n"
+                        "{{{%1.9g,%1.9g}, {%1.9g,%1.9g}, {%1.9g,%1.9g}}}\n"
+                        "{{{%1.9g,%1.9g}, {%1.9g,%1.9g}}}\n",
+                        cubic[0].fX, cubic[0].fY, cubic[1].fX, cubic[1].fY,
+                        cubic[2].fX, cubic[2].fY, cubic[3].fX, cubic[3].fY,
+                        nearby[0].fX, nearby[0].fY, nearby[1].fX, nearby[1].fY,
+                        nearby[2].fX, nearby[2].fY,
+                        liner.pt(0).fX, liner.pt(0).fY,
+                        locals.pt(0).fX, locals.pt(0).fY);
+                    SkDebugf("</div>\n\n");
+#endif
+                }
+                ++foundOne;
+            }
+            tStart = tEnd;
+        }
+        if (++foundOne >= 100000) {
+            break;
+        }
+    }
+#if 01
+    SkDebugf("slopCount=%d\n", slopCount);
+    int max = 100;
+    while (results[max] == 0) {
+        --max;
+    }
+    for (int i = 0; i <= max; ++i) {
+        if (i > 0 && i % 10 == 0) {
+            SkDebugf("\n");
+        }
+        SkDebugf("%d ", results[i]);
+    }
+    SkDebugf("min\n");
+    for (int i = 0; i <= max; ++i) {
+        if (i > 0 && i % 10 == 0) {
+            SkDebugf("\n");
+        }
+        SkDebugf("%1.9g ", minCross[i]);
+    }
+    SkDebugf("max\n");
+    for (int i = 0; i <= max; ++i) {
+        if (i > 0 && i % 10 == 0) {
+            SkDebugf("\n");
+        }
+        SkDebugf("%1.9g ", maxCross[i]);
+    }
+    SkDebugf("avg\n");
+    for (int i = 0; i <= max; ++i) {
+        if (i > 0 && i % 10 == 0) {
+            SkDebugf("\n");
+        }
+        SkDebugf("%1.9g ", sumCross[i] / results[i]);
+    }
+#else
+    for (int i = 1; i < slopCount; ++i) {
+        SkDebugf("        slop%d,\n", i);
+    }
+#endif
+    SkDebugf("\n");
+}