Remove ambient clamp hack for analytic shadows.

The hack was added to make analytic ambient shadows match the geometric
ones exactly. Removing it does produce a slight difference, but it's
only visible at full black values (and then, only slightly) and this
makes room to pass a blend parameter for falloff.

Also fixes an issue with filling out arcs in the shadow tesselator.

Bug: skia:7486
Change-Id: If78d0104df7e18f4320c1658af75576f6a4a8c73
Reviewed-on: https://skia-review.googlesource.com/122580
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>

1 files changed, 1 insertions, 6 deletions

diff --git a/src/gpu/GrRenderTargetContext.cpp b/src/gpu/GrRenderTargetContext.cpp
index cdb25fb533..6feb345ffa 100644
--- a/src/gpu/GrRenderTargetContext.cpp
+++ b/src/gpu/GrRenderTargetContext.cpp
@@ -1024,15 +1024,10 @@ bool GrRenderTargetContext::drawFastShadow(const GrClip& clip,
             // set a large inset to force a fill
             devSpaceInsetWidth = ambientRRect.width();
         }
-        // the fraction of the blur we want to apply is devSpaceInsetWidth/devSpaceAmbientBlur,
-        // which is just 1/umbraRecipAlpha.
-        SkScalar blurClamp = SkScalarInvert(umbraRecipAlpha);
-
         std::unique_ptr<GrDrawOp> op = GrShadowRRectOp::Make(ambientColor, viewMatrix,
                                                              ambientRRect,
                                                              devSpaceAmbientBlur,
-                                                             devSpaceInsetWidth,
-                                                             blurClamp);
+                                                             devSpaceInsetWidth);
         SkASSERT(op);
         this->addDrawOp(clip, std::move(op));
     }