need conservative bounds for triangles due to SkFixed drift in SkEdge
Bug: oss-fuzz:8018
Change-Id: I09456f906b7eb89f74ffd2c484bc6e30e029bfbb
Reviewed-on: https://skia-review.googlesource.com/131021
Reviewed-by: Cary Clark <caryclark@google.com>
Auto-Submit: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/tests/PathTest.cpp b/tests/PathTest.cpp
index 45ebd45..6cf5dfb 100644
--- a/tests/PathTest.cpp
+++ b/tests/PathTest.cpp
@@ -5053,6 +5053,20 @@
}
#include "SkVertices.h"
+static void draw_triangle(SkCanvas* canvas, const SkPoint pts[]) {
+ // draw in different ways, looking for an assert
+
+ {
+ SkPath path;
+ path.addPoly(pts, 3, false);
+ canvas->drawPath(path, SkPaint());
+ }
+
+ const SkColor colors[] = { SK_ColorBLACK, SK_ColorBLACK, SK_ColorBLACK };
+ auto v = SkVertices::MakeCopy(SkVertices::kTriangles_VertexMode, 3, pts, nullptr, colors);
+ canvas->drawVertices(v, SkBlendMode::kSrcOver, SkPaint());
+}
+
DEF_TEST(triangle_onehalf, reporter) {
auto surface(SkSurface::MakeRasterN32Premul(100, 100));
@@ -5061,8 +5075,22 @@
{ 0.499402374f, 7.88207579f },
{ 10.2363272f, 0.49999997f }
};
- const SkColor colors[] = { SK_ColorBLACK, SK_ColorBLACK, SK_ColorBLACK };
-
- auto v = SkVertices::MakeCopy(SkVertices::kTriangles_VertexMode, 3, pts, nullptr, colors);
- surface->getCanvas()->drawVertices(v, SkBlendMode::kSrcOver, SkPaint());
+ draw_triangle(surface->getCanvas(), pts);
}
+
+DEF_TEST(triangle_big, reporter) {
+ auto surface(SkSurface::MakeRasterN32Premul(4, 4304));
+
+ // The first two points, when sent through our fixed-point SkEdge, can walk negative beyond
+ // -0.5 due to accumulated += error of the slope. We have since make the bounds calculation
+ // be conservative, so we invoke clipping if we get in this situation.
+ // This test was added to demonstrate the need for this conservative bounds calc.
+ // (found by a fuzzer)
+ const SkPoint pts[] = {
+ { 0.327190518f, -114.945152f },
+ { -0.5f, 1.00003874f },
+ { 0.666425824f, 4304.26172f },
+ };
+ draw_triangle(surface->getCanvas(), pts);
+}
+