From 4ade54d81ba2cde9cc14c85a25ef710bdc236c39 Mon Sep 17 00:00:00 2001 From: Mike Reed Date: Thu, 24 May 2018 12:30:23 -0400 Subject: allow div-by-zero in shadow utils Bug: oss-fuzz:6665 Change-Id: I5cbe02bf574d849340c85c0964d92ece45daac1f Reviewed-on: https://skia-review.googlesource.com/129932 Commit-Queue: Mike Reed Commit-Queue: Jim Van Verth Auto-Submit: Mike Reed Reviewed-by: Jim Van Verth --- src/core/SkDrawShadowInfo.h | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/src/core/SkDrawShadowInfo.h b/src/core/SkDrawShadowInfo.h index da63a08104..d5820919ea 100644 --- a/src/core/SkDrawShadowInfo.h +++ b/src/core/SkDrawShadowInfo.h @@ -30,6 +30,13 @@ namespace SkDrawShadowMetrics { static constexpr auto kAmbientHeightFactor = 1.0f / 128.0f; static constexpr auto kAmbientGeomFactor = 64.0f; +static inline float divide_and_pin(float numer, float denom, float min, float max) { + float result = SkTPin(sk_ieee_float_divide(numer, denom), min, max); + // ensure that SkTPin handled non-finites correctly + SkASSERT(result >= min && result <= max); + return result; +} + inline SkScalar AmbientBlurRadius(SkScalar height) { return height*kAmbientHeightFactor*kAmbientGeomFactor; } @@ -39,15 +46,15 @@ inline SkScalar AmbientRecipAlpha(SkScalar height) { } inline SkScalar SpotBlurRadius(SkScalar occluderZ, SkScalar lightZ, SkScalar lightRadius) { - return lightRadius*SkTPin(occluderZ / (lightZ - occluderZ), 0.0f, 0.95f); + return lightRadius*divide_and_pin(occluderZ, lightZ - occluderZ, 0.0f, 0.95f); } inline void GetSpotParams(SkScalar occluderZ, SkScalar lightX, SkScalar lightY, SkScalar lightZ, SkScalar lightRadius, SkScalar* blurRadius, SkScalar* scale, SkVector* translate) { - SkScalar zRatio = SkTPin(occluderZ / (lightZ - occluderZ), 0.0f, 0.95f); + SkScalar zRatio = divide_and_pin(occluderZ, lightZ - occluderZ, 0.0f, 0.95f); *blurRadius = lightRadius*zRatio; - *scale = SkTPin(lightZ / (lightZ - occluderZ), 1.0f, 1.95f); + *scale = divide_and_pin(lightZ, lightZ - occluderZ, 1.0f, 1.95f); *translate = SkVector::Make(-zRatio * lightX, -zRatio * lightY); } -- cgit v1.2.3