only call scalar finite when necessary

Mike points that the the ulps compares
rank high in path ops profiles. The
check for finite scalars is rarely
required.

Call it less by:
- specializing _pin version of compares
- checking for 0 divides up front
- handling failing cases before comparing
- casting float to double before adding

R=reed@google.com

Review URL: https://codereview.chromium.org/1522183002

1 files changed, 7 insertions, 1 deletions

diff --git a/src/pathops/SkPathOpsTSect.h b/src/pathops/SkPathOpsTSect.h
index bebdf40208..074fe37654 100644
--- a/src/pathops/SkPathOpsTSect.h
+++ b/src/pathops/SkPathOpsTSect.h
@@ -1467,11 +1467,17 @@ int SkTSect<TCurve, OppCurve>::linesIntersect(SkTSpan<TCurve, OppCurve>* span,
         workT += tStep;
         workPt = fCurve.ptAtT(workT);
         coinW.setPerp(fCurve, workT, workPt, opp->fCurve);
+        if (coinW.perpT() < 0) {
+            continue;
+        }
         SkDVector perpW = workPt - coinW.perpPt();
         if ((perpS.dot(perpW) >= 0) == (tStep < 0)) {
             tStep = -tStep;
         }
-    } while (!workPt.approximatelyEqual(coinW.perpPt()));
+        if (workPt.approximatelyEqual(coinW.perpPt())) {
+            break;
+        }
+    } while (true);
     double oppTTest = coinW.perpT();
     if (!opp->fHead->contains(oppTTest)) {
         return 0;