Fix overrun in aa rect renderer
Review URL: http://codereview.appspot.com/6446146/
git-svn-id: http://skia.googlecode.com/svn/trunk@5126 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrAARectRenderer.cpp b/src/gpu/GrAARectRenderer.cpp
index 5e3a017..652adcb 100644
--- a/src/gpu/GrAARectRenderer.cpp
+++ b/src/gpu/GrAARectRenderer.cpp
@@ -153,10 +153,10 @@
}
void GrAARectRenderer::strokeAARect(GrGpu* gpu,
- GrDrawTarget* target,
- const GrRect& devRect,
- const GrVec& devStrokeSize,
- bool useVertexCoverage) {
+ GrDrawTarget* target,
+ const GrRect& devRect,
+ const GrVec& devStrokeSize,
+ bool useVertexCoverage) {
const GrScalar& dx = devStrokeSize.fX;
const GrScalar& dy = devStrokeSize.fY;
const GrScalar rx = GrMul(dx, GR_ScalarHalf);
@@ -191,6 +191,9 @@
intptr_t verts = reinterpret_cast<intptr_t>(geo.vertices());
+ // We create vertices for four nested rectangles. There are two ramps from 0 to full
+ // coverage, one on the exterior of the stroke and the other on the interior.
+ // The following pointers refer to the four rects, from outermost to innermost.
GrPoint* fan0Pos = reinterpret_cast<GrPoint*>(verts);
GrPoint* fan1Pos = reinterpret_cast<GrPoint*>(verts + 4 * vsize);
GrPoint* fan2Pos = reinterpret_cast<GrPoint*>(verts + 8 * vsize);
@@ -205,11 +208,13 @@
setInsetFan(fan3Pos, vsize, devRect,
rx + GR_ScalarHalf, ry + GR_ScalarHalf);
+ // The outermost rect has 0 coverage
verts += sizeof(GrPoint);
for (int i = 0; i < 4; ++i) {
*reinterpret_cast<GrColor*>(verts + i * vsize) = 0;
}
+ // The inner two rects have full coverage
GrColor innerColor;
if (useVertexCoverage) {
innerColor = 0xffffffff;
@@ -221,8 +226,9 @@
*reinterpret_cast<GrColor*>(verts + i * vsize) = innerColor;
}
+ // The innermost rect has full coverage
verts += 8 * vsize;
- for (int i = 0; i < 8; ++i) {
+ for (int i = 0; i < 4; ++i) {
*reinterpret_cast<GrColor*>(verts + i * vsize) = 0;
}