Fix for Ovals/RRects on N4 missing interior rectangles.
Clamp square of gradiant length to non-zero value so it can be passed to
inversesqrt().
Also adds some fixes to rrect setup to avoid crossing zero.
Skia issue #1372
R=bsalomon@google.com, robertphillips@google.com
Review URL: https://codereview.chromium.org/18375003
git-svn-id: http://skia.googlecode.com/svn/trunk@9864 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrOvalRenderer.cpp b/src/gpu/GrOvalRenderer.cpp
index 465dd2b..bcd64d7 100644
--- a/src/gpu/GrOvalRenderer.cpp
+++ b/src/gpu/GrOvalRenderer.cpp
@@ -221,7 +221,12 @@
builder->fsCodeAppendf("\tvec2 scaledOffset = %s*%s.xy;\n", fsOffsetName, fsRadiiName);
builder->fsCodeAppend("\tfloat test = dot(scaledOffset, scaledOffset) - 1.0;\n");
builder->fsCodeAppendf("\tvec2 grad = 2.0*scaledOffset*%s.xy;\n", fsRadiiName);
- builder->fsCodeAppend("\tfloat invlen = inversesqrt(dot(grad, grad));\n");
+ builder->fsCodeAppend("\tfloat grad_dot = dot(grad, grad);\n");
+ // we need to clamp the length^2 of the gradiant vector to a non-zero value, because
+ // on the Nexus 4 the undefined result of inversesqrt(0) drops out an entire tile
+ // TODO: restrict this to Adreno-only
+ builder->fsCodeAppend("\tgrad_dot = max(grad_dot, 1.0e-4);\n");
+ builder->fsCodeAppend("\tfloat invlen = inversesqrt(grad_dot);\n");
builder->fsCodeAppend("\tfloat edgeAlpha = clamp(0.5-test*invlen, 0.0, 1.0);\n");
// for inner curve
@@ -808,7 +813,7 @@
bounds.fBottom
};
SkScalar yOuterOffsets[4] = {
- -yOuterRadius,
+ yOuterRadius,
SK_ScalarNearlyZero, // we're using inversesqrt() in the shader, so can't be exactly 0
SK_ScalarNearlyZero,
yOuterRadius
@@ -816,7 +821,7 @@
for (int i = 0; i < 4; ++i) {
verts->fPos = SkPoint::Make(bounds.fLeft, yCoords[i]);
- verts->fOffset = SkPoint::Make(-xOuterRadius, yOuterOffsets[i]);
+ verts->fOffset = SkPoint::Make(xOuterRadius, yOuterOffsets[i]);
verts->fOuterRadii = SkPoint::Make(xRadRecip, yRadRecip);
verts->fInnerRadii = SkPoint::Make(xInnerRadRecip, yInnerRadRecip);
verts++;