Tessellating GPU path renderer.

src/gpu/GrPathUtils.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrPathUtils.h"
 
 #include "GrTypes.h"
@@ skipping 26 matching lines @@
 static const SkScalar gMinCurveTol = 0.0001f;
 
 uint32_t GrPathUtils::quadraticPointCount(const SkPoint points[],
                                           SkScalar tol) {
     if (tol < gMinCurveTol) {
         tol = gMinCurveTol;
     }
     SkASSERT(tol > 0);
 
     SkScalar d = points[1].distanceToLineSegmentBetween(points[0], points[2]);
-    if (d <= tol) {
+    if (d <= tol || !SkScalarIsFinite(d)) {

[jvanverth1, 2015/01/30 20:48:02]

Is this an issue? When are we getting a distance of infinity?

[Stephen White, 2015/01/30 21:36:47]

There's an assert which triggers in GrNextPow2() below with both the default
path renderer and the tessellating one when run in the Fuzzer if we don't check
for this here. Something in the distanceToLineSegmentBetween() function above
can return +Inf; I'm not sure of the cause.

         return 1;
     } else {
         // Each time we subdivide, d should be cut in 4. So we need to
         // subdivide x = log4(d/tol) times. x subdivisions creates 2^(x)
         // points.
         // 2^(log4(x)) = sqrt(x);
         int temp = SkScalarCeilToInt(SkScalarSqrt(SkScalarDiv(d, tol)));
         int pow2 = GrNextPow2(temp);
         // Because of NaNs & INFs we can wind up with a degenerate temp
         // such that pow2 comes out negative. Also, our point generator
@@ skipping 34 matching lines @@
                                            SkScalar tol) {
     if (tol < gMinCurveTol) {
         tol = gMinCurveTol;
     }
     SkASSERT(tol > 0);
 
     SkScalar d = SkTMax(
         points[1].distanceToLineSegmentBetweenSqd(points[0], points[3]),
         points[2].distanceToLineSegmentBetweenSqd(points[0], points[3]));
     d = SkScalarSqrt(d);
-    if (d <= tol) {
+    if (d <= tol || !SkScalarIsFinite(d)) {
         return 1;
     } else {
         int temp = SkScalarCeilToInt(SkScalarSqrt(SkScalarDiv(d, tol)));
         int pow2 = GrNextPow2(temp);
         // Because of NaNs & INFs we can wind up with a degenerate temp
         // such that pow2 comes out negative. Also, our point generator
         // will always output at least one pt.
         if (pow2 < 1) {
             pow2 = 1;
         }
@@ skipping 685 matching lines @@
         set_loop_klm(d, controlK, controlL, controlM);
     } else if (kCusp_SkCubicType == cType) {
         SkASSERT(0.f == d[0]);
         set_cusp_klm(d, controlK, controlL, controlM);
     } else if (kQuadratic_SkCubicType == cType) {
         set_quadratic_klm(d, controlK, controlL, controlM);
     }
 
     calc_cubic_klm(p, controlK, controlL, controlM, klm, &klm[3], &klm[6]);
 }