Add more tests for PolyUtils

* Add fuzzer
* Add bench tests
* Add additional unit test
* Fix some bugs these exposed.

Bug: skia:
Change-Id: I6c587c92cb6cff32ab8300020b78f9f247d2bf64
Reviewed-on: https://skia-review.googlesource.com/139169
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>

1 files changed, 130 insertions, 0 deletions

diff --git a/bench/PolyUtilsBench.cpp b/bench/PolyUtilsBench.cpp
new file mode 100644
index 0000000000..1b987fa038
--- /dev/null
+++ b/bench/PolyUtilsBench.cpp
@@ -0,0 +1,130 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "Benchmark.h"
+#include "SkPolyUtils.h"
+
+class PolyUtilsBench : public Benchmark {
+    // Evaluate SkTriangulateSimplePolygon's performance (via derived classes) on:
+    //   a non-self-intersecting star, a circle of tiny line segments and a self-intersecting star
+
+    SkString           fName;
+public:
+    PolyUtilsBench() {}
+
+    virtual void appendName(SkString*) = 0;
+    virtual void makePoly(SkTDArray<SkPoint>* poly) = 0;
+    virtual int complexity() { return 0; }
+
+protected:
+    const char* onGetName() override {
+        fName = "poly_utils_";
+        this->appendName(&fName);
+        return fName.c_str();
+    }
+
+    void onDraw(int loops, SkCanvas* canvas) override {
+        SkTDArray<SkPoint> poly;
+        this->makePoly(&poly);
+        SkAutoSTMalloc<64, uint16_t> indexMap(poly.count());
+        for (int i = 0; i < poly.count(); ++i) {
+            indexMap[i] = i;
+        }
+        SkTDArray<uint16_t> triangleIndices;
+        for (int i = 0; i < loops; i++) {
+            if (SkIsSimplePolygon(poly.begin(), poly.count())) {
+                SkTriangulateSimplePolygon(poly.begin(), indexMap, poly.count(),
+                                           &triangleIndices);
+            }
+        }
+    }
+
+private:
+    typedef Benchmark INHERITED;
+};
+
+class StarPolyUtilsBench : public PolyUtilsBench {
+public:
+    StarPolyUtilsBench() {}
+
+    void appendName(SkString* name) override {
+        name->append("star");
+    }
+    void makePoly(SkTDArray<SkPoint>* poly) override {
+        // create non-intersecting star
+        const SkScalar c = SkIntToScalar(45);
+        const SkScalar r1 = SkIntToScalar(20);
+        const SkScalar r2 = SkIntToScalar(3);
+        const int n = 500;
+        SkScalar rad = 0;
+        const SkScalar drad = SK_ScalarPI / n;
+        for (int i = 0; i < n; i++) {
+            SkScalar cosV, sinV = SkScalarSinCos(rad, &cosV);
+            *poly->push() = SkPoint::Make(c + cosV * r1, c + sinV * r1);
+            rad += drad;
+            sinV = SkScalarSinCos(rad, &cosV);
+            *poly->push() = SkPoint::Make(c + cosV * r2, c + sinV * r2);
+            rad += drad;
+        }
+    }
+private:
+    typedef PolyUtilsBench INHERITED;
+};
+
+class CirclePolyUtilsBench : public PolyUtilsBench {
+public:
+    CirclePolyUtilsBench() {}
+
+    void appendName(SkString* name) override {
+        name->append("circle");
+    }
+    void makePoly(SkTDArray<SkPoint>* poly) override {
+        // create circle with many vertices
+        const SkScalar c = SkIntToScalar(45);
+        const SkScalar r = SkIntToScalar(20);
+        const int n = 1000;
+        SkScalar rad = 0;
+        const SkScalar drad = 2 * SK_ScalarPI / n;
+        for (int i = 0; i < n; i++) {
+            SkScalar cosV, sinV = SkScalarSinCos(rad, &cosV);
+            *poly->push() = SkPoint::Make(c + cosV * r, c + sinV * r);
+            rad += drad;
+        }
+    }
+private:
+    typedef PolyUtilsBench INHERITED;
+};
+
+class IntersectingPolyUtilsBench : public PolyUtilsBench {
+public:
+    IntersectingPolyUtilsBench() {}
+
+    void appendName(SkString* name) override {
+        name->append("intersecting");
+    }
+    void makePoly(SkTDArray<SkPoint>* poly) override {
+        // create self-intersecting star
+        const SkScalar c = SkIntToScalar(45);
+        const SkScalar r = SkIntToScalar(20);
+        const int n = 1000;
+
+        SkScalar rad = -SK_ScalarPI / 2;
+        const SkScalar drad = (n >> 1) * SK_ScalarPI * 2 / n;
+        *poly->push() = SkPoint::Make(c, c - r);
+        for (int i = 1; i < n; i++) {
+            rad += drad;
+            SkScalar cosV, sinV = SkScalarSinCos(rad, &cosV);
+            *poly->push() = SkPoint::Make(c + cosV * r, c + sinV * r);
+        }
+    }
+private:
+    typedef PolyUtilsBench INHERITED;
+};
+
+DEF_BENCH(return new StarPolyUtilsBench();)
+DEF_BENCH(return new CirclePolyUtilsBench();)
+DEF_BENCH(return new IntersectingPolyUtilsBench();)