Mike R: please sanity check SkPostConfig.h

Mike K: please sanity check Test.cpp and skia_test.cpp

Feel free to look at the rest, but I don't expect any in depth review of path ops innards.

Path Ops first iteration used QuickSort to order segments radiating from an intersection to compute the winding rule.

This revision uses a circular sort instead. Breaking out the circular sort into its own long-lived structure (SkOpAngle) allows doing less work and provides a home for caching additional sorting data.

The circle sort is more stable than the former sort, has a robust ordering and fewer exceptions. It finds unsortable ordering less often. It is less reliant on the initial curve  tangent, using convex hulls instead whenever it can.

Additional debug validation makes sure that the computed structures are self-consistent. A new visualization tool helps verify that the angle ordering is correct.

The 70+M tests pass with this change on Windows, Mac, Linux 32 and Linux 64 in debug and release.

R=mtklein@google.com, reed@google.com

Author: caryclark@google.com

Review URL: https://codereview.chromium.org/131103009

git-svn-id: http://skia.googlecode.com/svn/trunk@14183 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 60 insertions, 19 deletions

diff --git a/src/pathops/SkPathOpsTypes.h b/src/pathops/SkPathOpsTypes.h
index 4fa86abd91..e8054ad476 100644
--- a/src/pathops/SkPathOpsTypes.h
+++ b/src/pathops/SkPathOpsTypes.h
@@ -85,6 +85,7 @@ inline int UlpsDistance(double a, double b) {
 const double FLT_EPSILON_CUBED = FLT_EPSILON * FLT_EPSILON * FLT_EPSILON;
 const double FLT_EPSILON_HALF = FLT_EPSILON / 2;
 const double FLT_EPSILON_DOUBLE = FLT_EPSILON * 2;
+const double FLT_EPSILON_ORDERABLE_ERR = FLT_EPSILON * 16;
 const double FLT_EPSILON_SQUARED = FLT_EPSILON * FLT_EPSILON;
 const double FLT_EPSILON_SQRT = sqrt(FLT_EPSILON);
 const double FLT_EPSILON_INVERSE = 1 / FLT_EPSILON;
@@ -121,6 +122,10 @@ inline bool approximately_zero_double(double x) {
     return fabs(x) < FLT_EPSILON_DOUBLE;
 }
 
+inline bool approximately_zero_orderable(double x) {
+    return fabs(x) < FLT_EPSILON_ORDERABLE_ERR;
+}
+
 inline bool approximately_zero_squared(double x) {
     return fabs(x) < FLT_EPSILON_SQUARED;
 }
@@ -139,7 +144,7 @@ inline bool approximately_zero_inverse(double x) {
 
 // OPTIMIZATION: if called multiple times with the same denom, we want to pass 1/y instead
 inline bool approximately_zero_when_compared_to(double x, double y) {
-    return x == 0 || fabs(x / y) < FLT_EPSILON;
+    return x == 0 || fabs(x) < fabs(y * FLT_EPSILON);
 }
 
 // Use this for comparing Ts in the range of 0 to 1. For general numbers (larger and smaller) use
@@ -164,6 +169,10 @@ inline bool approximately_equal_double(double x, double y) {
     return approximately_zero_double(x - y);
 }
 
+inline bool approximately_equal_orderable(double x, double y) {
+    return approximately_zero_orderable(x - y);
+}
+
 inline bool approximately_equal_squared(double x, double y) {
     return approximately_equal(x, y);
 }
@@ -172,18 +181,50 @@ inline bool approximately_greater(double x, double y) {
     return x - FLT_EPSILON >= y;
 }
 
+inline bool approximately_greater_double(double x, double y) {
+    return x - FLT_EPSILON_DOUBLE >= y;
+}
+
+inline bool approximately_greater_orderable(double x, double y) {
+    return x - FLT_EPSILON_ORDERABLE_ERR >= y;
+}
+
 inline bool approximately_greater_or_equal(double x, double y) {
     return x + FLT_EPSILON > y;
 }
 
+inline bool approximately_greater_or_equal_double(double x, double y) {
+    return x + FLT_EPSILON_DOUBLE > y;
+}
+
+inline bool approximately_greater_or_equal_orderable(double x, double y) {
+    return x + FLT_EPSILON_ORDERABLE_ERR > y;
+}
+
 inline bool approximately_lesser(double x, double y) {
     return x + FLT_EPSILON <= y;
 }
 
+inline bool approximately_lesser_double(double x, double y) {
+    return x + FLT_EPSILON_DOUBLE <= y;
+}
+
+inline bool approximately_lesser_orderable(double x, double y) {
+    return x + FLT_EPSILON_ORDERABLE_ERR <= y;
+}
+
 inline bool approximately_lesser_or_equal(double x, double y) {
     return x - FLT_EPSILON < y;
 }
 
+inline bool approximately_lesser_or_equal_double(double x, double y) {
+    return x - FLT_EPSILON_DOUBLE < y;
+}
+
+inline bool approximately_lesser_or_equal_orderable(double x, double y) {
+    return x - FLT_EPSILON_ORDERABLE_ERR < y;
+}
+
 inline bool approximately_greater_than_one(double x) {
     return x > 1 - FLT_EPSILON;
 }
@@ -204,6 +245,10 @@ inline bool approximately_negative(double x) {
     return x < FLT_EPSILON;
 }
 
+inline bool approximately_negative_orderable(double x) {
+    return x < FLT_EPSILON_ORDERABLE_ERR;
+}
+
 inline bool precisely_negative(double x) {
     return x < DBL_EPSILON_ERR;
 }
@@ -212,6 +257,10 @@ inline bool approximately_one_or_less(double x) {
     return x < 1 + FLT_EPSILON;
 }
 
+inline bool approximately_one_or_less_double(double x) {
+    return x < 1 + FLT_EPSILON_DOUBLE;
+}
+
 inline bool approximately_positive(double x) {
     return x > -FLT_EPSILON;
 }
@@ -224,6 +273,16 @@ inline bool approximately_zero_or_more(double x) {
     return x > -FLT_EPSILON;
 }
 
+inline bool approximately_zero_or_more_double(double x) {
+    return x > -FLT_EPSILON_DOUBLE;
+}
+
+inline bool approximately_between_orderable(double a, double b, double c) {
+    return a <= c
+            ? approximately_negative_orderable(a - b) && approximately_negative_orderable(b - c)
+            : approximately_negative_orderable(b - a) && approximately_negative_orderable(c - b);
+}
+
 inline bool approximately_between(double a, double b, double c) {
     return a <= c ? approximately_negative(a - b) && approximately_negative(b - c)
             : approximately_negative(b - a) && approximately_negative(c - b);
@@ -311,22 +370,4 @@ inline double SkPinT(double t) {
     return precisely_less_than_zero(t) ? 0 : precisely_greater_than_one(t) ? 1 : t;
 }
 
-#ifdef SK_DEBUG
-inline void DebugDumpDouble(double x) {
-    if (x == floor(x)) {
-        SkDebugf("%.0f", x);
-    } else {
-        SkDebugf("%1.17g", x);
-    }
-}
-
-inline void DebugDumpFloat(float x) {
-    if (x == floorf(x)) {
-        SkDebugf("%.0f", x);
-    } else {
-        SkDebugf("%1.9gf", x);
-    }
-}
-#endif
-
 #endif