cubicline intersection binary search

tests/PathOpsCubicLineIntersectionTest.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "PathOpsTestCommon.h"
 #include "SkIntersections.h"
 #include "SkPathOpsCubic.h"
 #include "SkPathOpsLine.h"
@@ skipping 31 matching lines @@
         REPORTER_ASSERT(reporter, 0);
     }
     if (order1 == 4 && order2 == 2) {
         SkIntersections i;
         int roots = i.intersect(cubic, line);
         REPORTER_ASSERT(reporter, roots == 0);
     }
 }
 
 static lineCubic lineCubicTests[] = {
+    {{{{-634.60540771484375, -481.262939453125}, {266.2696533203125, -752.70867919921875},
+            {-751.8370361328125, -317.37921142578125}, {-969.7427978515625, 824.7255859375}}},
+            {{{-287.9506133720805678, -557.1376476615772617},
+            {-285.9506133720805678, -557.1376476615772617}}}},
+
+    {{{{36.7184372,0.888650894}, {36.7184372,0.888650894}, {35.1233864,0.554015458},
+            {34.5114098,-0.115255356}}}, {{{35.4531212,0}, {31.9375,0}}}},
 
     {{{{421, 378}, {421, 380.209137f}, {418.761414f, 382}, {416, 382}}},
             {{{320, 378}, {421, 378.000031f}}}},
 
     {{{{416, 383}, {418.761414f, 383}, {421, 380.761414f}, {421, 378}}},
             {{{320, 378}, {421, 378.000031f}}}},
 
     {{{{154,715}, {151.238571,715}, {149,712.761414}, {149,710}}},
             {{{149,675}, {149,710.001465}}}},
 
@@ skipping 14 matching lines @@
             {{{979.30487060546875,561}, {1036.695068359375,291}}}},
     {{{{259.30487060546875,561}, {242.73631286621094,561}, {232.15980529785156,547.56854248046875},
             {235.68154907226562,531}}},
             {{{286.69512939453125,291}, {229.30485534667969,561}}}},
     {{{{1, 2}, {2, 6}, {2, 0}, {1, 0}}}, {{{1, 0}, {1, 2}}}},
     {{{{0, 0}, {0, 1}, {0, 1}, {1, 1}}}, {{{0, 1}, {1, 0}}}},
 };
 
 static const size_t lineCubicTests_count = SK_ARRAY_COUNT(lineCubicTests);
 
+static int doIntersect(SkIntersections& intersections, const SkDCubic& cubic, const SkDLine& line) {
+    int result;
+    bool flipped = false;
+    if (line[0].fX == line[1].fX) {
+        double top = line[0].fY;
+        double bottom = line[1].fY;
+        flipped = top > bottom;
+        if (flipped) {
+            SkTSwap<double>(top, bottom);
+        }
+        result = intersections.vertical(cubic, top, bottom, line[0].fX, flipped);
+    } else if (line[0].fY == line[1].fY) {
+        double left = line[0].fX;
+        double right = line[1].fX;
+        flipped = left > right;
+        if (flipped) {
+            SkTSwap<double>(left, right);
+        }
+        result = intersections.horizontal(cubic, left, right, line[0].fY, flipped);
+    } else {
+        intersections.intersect(cubic, line);
+        result = intersections.used();
+    }
+    return result;
+}
+
 static void testOne(skiatest::Reporter* reporter, int iIndex) {
     const SkDCubic& cubic = lineCubicTests[iIndex].cubic;
     SkASSERT(ValidCubic(cubic));
     const SkDLine& line = lineCubicTests[iIndex].line;
     SkASSERT(ValidLine(line));
     SkReduceOrder reduce1;
     SkReduceOrder reduce2;
     int order1 = reduce1.reduce(cubic, SkReduceOrder::kNo_Quadratics);
     int order2 = reduce2.reduce(line);
     if (order1 < 4) {
         SkDebugf("[%d] cubic order=%d\n", iIndex, order1);
         REPORTER_ASSERT(reporter, 0);
     }
     if (order2 < 2) {
         SkDebugf("[%d] line order=%d\n", iIndex, order2);
         REPORTER_ASSERT(reporter, 0);
     }
     if (order1 == 4 && order2 == 2) {
         SkIntersections i;
-        int roots = i.intersect(cubic, line);
+        int roots = doIntersect(i, cubic, line);
         for (int pt = 0; pt < roots; ++pt) {
             double tt1 = i[0][pt];
             SkDPoint xy1 = cubic.ptAtT(tt1);
             double tt2 = i[1][pt];
             SkDPoint xy2 = line.ptAtT(tt2);
             if (!xy1.approximatelyEqual(xy2)) {
                 SkDebugf("%s [%d,%d] x!= t1=%g (%g,%g) t2=%g (%g,%g)\n",
                     __FUNCTION__, iIndex, pt, tt1, xy1.fX, xy1.fY, tt2, xy2.fX, xy2.fY);
             }
             REPORTER_ASSERT(reporter, xy1.approximatelyEqual(xy2));
@@ skipping 34 matching lines @@
 
 DEF_TEST(PathOpsCubicLineIntersectionOneOff, reporter) {
     int iIndex = 0;
     testOne(reporter, iIndex);
     const SkDCubic& cubic = lineCubicTests[iIndex].cubic;
     const SkDLine& line = lineCubicTests[iIndex].line;
     SkIntersections i;
     i.intersect(cubic, line);
     SkASSERT(i.used() == 1);
 }