1 files changed, 163 insertions, 0 deletions
diff --git a/gfx/tests/gtest/PolygonTestUtils.cpp b/gfx/tests/gtest/PolygonTestUtils.cpp
new file mode 100644
index 0000000000..04a2f47498
--- /dev/null
+++ b/gfx/tests/gtest/PolygonTestUtils.cpp
@@ -0,0 +1,163 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "PolygonTestUtils.h"
+
+#include <cmath>
+
+#include "Point.h"
+#include "Triangle.h"
+
+typedef mozilla::gfx::Polygon MozPolygon;
+
+using mozilla::gfx::Point;
+using mozilla::gfx::Point4D;
+using mozilla::gfx::Triangle;
+
+namespace mozilla {
+namespace gfx {
+
+const float kEpsilon = 0.001f;
+
+// Compares two points while allowing some numerical inaccuracy.
+bool FuzzyEquals(const Point4D& lhs, const Point4D& rhs) {
+  const auto d = lhs - rhs;
+
+  return std::abs(d.x) < kEpsilon && std::abs(d.y) < kEpsilon &&
+         std::abs(d.z) < kEpsilon && std::abs(d.w) < kEpsilon;
+}
+
+bool FuzzyEquals(const Point3D& lhs, const Point3D& rhs) {
+  const auto d = lhs - rhs;
+
+  return std::abs(d.x) < kEpsilon && std::abs(d.y) < kEpsilon &&
+         std::abs(d.z) < kEpsilon;
+}
+
+bool FuzzyEquals(const Point& lhs, const Point& rhs) {
+  const auto d = lhs - rhs;
+
+  return std::abs(d.x) < kEpsilon && std::abs(d.y) < kEpsilon;
+}
+
+bool operator==(const Triangle& lhs, const Triangle& rhs) {
+  return FuzzyEquals(lhs.p1, rhs.p1) && FuzzyEquals(lhs.p2, rhs.p2) &&
+         FuzzyEquals(lhs.p3, rhs.p3);
+}
+
+// Compares the points of two polygons and ensures
+// that the points are in the same winding order.
+bool operator==(const MozPolygon& lhs, const MozPolygon& rhs) {
+  const auto& left = lhs.GetPoints();
+  const auto& right = rhs.GetPoints();
+
+  // Polygons do not have the same amount of points.
+  if (left.Length() != right.Length()) {
+    return false;
+  }
+
+  const size_t pointCount = left.Length();
+
+  // Find the first vertex of the first polygon from the second polygon.
+  // This assumes that the polygons do not contain duplicate vertices.
+  int start = -1;
+  for (size_t i = 0; i < pointCount; ++i) {
+    if (FuzzyEquals(left[0], right[i])) {
+      start = i;
+      break;
+    }
+  }
+
+  // Found at least one different vertex.
+  if (start == -1) {
+    return false;
+  }
+
+  // Verify that the polygons have the same points.
+  for (size_t i = 0; i < pointCount; ++i) {
+    size_t j = (start + i) % pointCount;
+
+    if (!FuzzyEquals(left[i], right[j])) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+}  // namespace gfx
+}  // namespace mozilla
+
+TEST(PolygonTestUtils, TestSanity)
+{
+  EXPECT_TRUE(FuzzyEquals(Point4D(0.0f, 0.0f, 0.0f, 1.0f),
+                          Point4D(0.0f, 0.0f, 0.0f, 1.0f)));
+
+  EXPECT_TRUE(FuzzyEquals(Point4D(0.0f, 0.0f, 0.0f, 1.0f),
+                          Point4D(0.00001f, 0.00001f, 0.00001f, 1.0f)));
+
+  EXPECT_TRUE(FuzzyEquals(Point4D(0.00001f, 0.00001f, 0.00001f, 1.0f),
+                          Point4D(0.0f, 0.0f, 0.0f, 1.0f)));
+
+  EXPECT_FALSE(FuzzyEquals(Point4D(0.0f, 0.0f, 0.0f, 1.0f),
+                           Point4D(0.01f, 0.01f, 0.01f, 1.0f)));
+
+  EXPECT_FALSE(FuzzyEquals(Point4D(0.01f, 0.01f, 0.01f, 1.0f),
+                           Point4D(0.0f, 0.0f, 0.0f, 1.0f)));
+
+  MozPolygon p1{
+      Point4D(0.0f, 0.0f, 1.0f, 1.0f), Point4D(1.0f, 0.0f, 1.0f, 1.0f),
+      Point4D(1.0f, 1.0f, 1.0f, 1.0f), Point4D(0.0f, 1.0f, 1.0f, 1.0f)};
+
+  // Same points as above shifted forward by one position.
+  MozPolygon shifted{
+      Point4D(0.0f, 1.0f, 1.0f, 1.0f), Point4D(0.0f, 0.0f, 1.0f, 1.0f),
+      Point4D(1.0f, 0.0f, 1.0f, 1.0f), Point4D(1.0f, 1.0f, 1.0f, 1.0f)};
+
+  MozPolygon p2{Point4D(0.00001f, 0.00001f, 1.00001f, 1.0f),
+                Point4D(1.00001f, 0.00001f, 1.00001f, 1.0f),
+                Point4D(1.00001f, 1.00001f, 1.00001f, 1.0f),
+                Point4D(0.00001f, 1.00001f, 1.00001f, 1.0f)};
+
+  MozPolygon p3{
+      Point4D(0.01f, 0.01f, 1.01f, 1.0f), Point4D(1.01f, 0.01f, 1.01f, 1.0f),
+      Point4D(1.01f, 1.01f, 1.01f, 1.0f), Point4D(0.01f, 1.01f, 1.01f, 1.0f)};
+
+  // Trivial equals
+  EXPECT_TRUE(p1 == p1);
+  EXPECT_TRUE(p2 == p2);
+  EXPECT_TRUE(p3 == p3);
+  EXPECT_TRUE(shifted == shifted);
+
+  // Polygons with the same point order
+  EXPECT_TRUE(p1 == p2);
+  EXPECT_TRUE(p1 == shifted);
+
+  // Polygons containing different points
+  EXPECT_FALSE(p1 == p3);
+  EXPECT_FALSE(p2 == p3);
+  EXPECT_FALSE(shifted == p3);
+
+  const nsTArray<Triangle> t1{
+      Triangle(Point(0.0f, 0.0f), Point(0.0f, 1.0f), Point(1.0f, 1.0f))};
+
+  const nsTArray<Triangle> t2{
+      Triangle(Point(0.0f, 0.0f), Point(1.0f, 1.0f), Point(1.0f, 0.0f))};
+
+  const nsTArray<Triangle> t3{Triangle(Point(0.00001f, 0.00001f),
+                                       Point(0.00001f, 1.00001f),
+                                       Point(1.00001f, 1.00001f))};
+
+  EXPECT_TRUE(t1[0] == t1[0]);
+  EXPECT_TRUE(t2[0] == t2[0]);
+  EXPECT_TRUE(t3[0] == t1[0]);
+
+  EXPECT_FALSE(t1[0] == t2[0]);
+  EXPECT_FALSE(t2[0] == t3[0]);
+
+  AssertArrayEQ(t1, t1);
+  AssertArrayEQ(t2, t2);
+}