DrawPolygon class with Unit Tests

cc/quads/draw_polygon_unittest.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <vector>
+
+#include "cc/output/bsp_compare_result.h"
+#include "cc/quads/draw_polygon.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/gfx/transform.h"
+
+namespace cc {
+namespace {
+
+#define CREATE_NEW_DRAW_POLYGON(name, points_vector, polygon_id) \
+  DrawPolygon name(NULL, points_vector, polygon_id)
+
+#define EXPECT_POINT_EQ(point_a, point_b)    \
+  EXPECT_FLOAT_EQ(point_a.x(), point_b.x()); \
+  EXPECT_FLOAT_EQ(point_a.y(), point_b.y()); \
+  EXPECT_FLOAT_EQ(point_a.z(), point_b.z());
+
+static void ValidatePoints(const DrawPolygon& polygon,
+                           const std::vector<gfx::Point3F>& points) {
+  EXPECT_EQ(polygon.points.size(), points.size());
+  for (unsigned int i = 0; i < points.size(); i++) {
+    EXPECT_POINT_EQ(polygon.points[i], points[i]);
+  }
+}
+
+// Two quads are definitely not touching and so no split should occur.
+TEST(DrawPolygonSplitTest, NotTouchingNoSplit) {
+  std::vector<gfx::Point3F> vertices_a;
+  vertices_a.push_back(gfx::Point3F(0.0f, 10.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(0.0f, 0.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(10.0f, 0.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(10.0f, 10.0f, 0.0f));
+  std::vector<gfx::Point3F> vertices_b;
+  vertices_b.push_back(gfx::Point3F(5.0f, 10.0f, 5.0f));
+  vertices_b.push_back(gfx::Point3F(5.0f, 0.0f, 15.0f));
+  vertices_b.push_back(gfx::Point3F(5.0f, 0.0f, 15.0f));
+  vertices_b.push_back(gfx::Point3F(5.0f, 10.0f, 5.0f));
+
+  CREATE_NEW_DRAW_POLYGON(polygon_a, vertices_a, 0);
+  CREATE_NEW_DRAW_POLYGON(polygon_b, vertices_b, 1);
+
+  EXPECT_EQ(DrawPolygon::SideCompare(polygon_b, polygon_a), BSP_FRONT);
+}
+
+// One quad is resting against another, but doesn't cross its plane so no split
+// should occur.
+TEST(DrawPolygonSplitTest, BarelyTouchingNoSplit) {
+  std::vector<gfx::Point3F> vertices_a;
+  vertices_a.push_back(gfx::Point3F(0.0f, 10.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(0.0f, 0.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(10.0f, 0.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(10.0f, 10.0f, 0.0f));
+  std::vector<gfx::Point3F> vertices_b;
+  vertices_b.push_back(gfx::Point3F(5.0f, 10.0f, 0.0f));
+  vertices_b.push_back(gfx::Point3F(5.0f, 0.0f, -10.0f));
+  vertices_b.push_back(gfx::Point3F(5.0f, 0.0f, -10.0f));
+  vertices_b.push_back(gfx::Point3F(5.0f, 10.0f, 0.0f));
+
+  CREATE_NEW_DRAW_POLYGON(polygon_a, vertices_a, 0);
+  CREATE_NEW_DRAW_POLYGON(polygon_b, vertices_b, 1);
+
+  EXPECT_EQ(DrawPolygon::SideCompare(polygon_b, polygon_a), BSP_BACK);
+}
+
+// One quad intersects another and becomes two pieces.
+TEST(DrawPolygonSplitTest, BasicSplit) {
+  std::vector<gfx::Point3F> vertices_a;
+  vertices_a.push_back(gfx::Point3F(0.0f, 10.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(0.0f, 0.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(10.0f, 0.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(10.0f, 10.0f, 0.0f));
+  std::vector<gfx::Point3F> vertices_b;
+  vertices_b.push_back(gfx::Point3F(5.0f, 10.0f, -5.0f));
+  vertices_b.push_back(gfx::Point3F(5.0f, 0.0f, -5.0f));
+  vertices_b.push_back(gfx::Point3F(5.0f, 0.0f, 5.0f));
+  vertices_b.push_back(gfx::Point3F(5.0f, 10.0f, 5.0f));
+
+  CREATE_NEW_DRAW_POLYGON(polygon_a, vertices_a, 0);
+  CREATE_NEW_DRAW_POLYGON(polygon_b, vertices_b, 1);
+
+  EXPECT_EQ(DrawPolygon::SideCompare(polygon_b, polygon_a), BSP_SPLIT);
+
+  scoped_ptr<DrawPolygon> front_polygon;
+  scoped_ptr<DrawPolygon> back_polygon;
+  polygon_b.Split(polygon_a, &front_polygon, &back_polygon);
+  EXPECT_EQ(DrawPolygon::SideCompare(*front_polygon, polygon_a), BSP_FRONT);
+  EXPECT_EQ(DrawPolygon::SideCompare(*back_polygon, polygon_a), BSP_BACK);
+
+  std::vector<gfx::Point3F> test_points_a;
+  test_points_a.push_back(gfx::Point3F(5.0f, 0.0f, 0.0f));
+  test_points_a.push_back(gfx::Point3F(5.0f, 0.0f, 5.0f));
+  test_points_a.push_back(gfx::Point3F(5.0f, 10.0f, 5.0f));
+  test_points_a.push_back(gfx::Point3F(5.0f, 10.0f, 0.0f));
+  std::vector<gfx::Point3F> test_points_b;
+  test_points_b.push_back(gfx::Point3F(5.0f, 10.0f, 0.0f));
+  test_points_b.push_back(gfx::Point3F(5.0f, 10.0f, -5.0f));
+  test_points_b.push_back(gfx::Point3F(5.0f, 0.0f, -5.0f));
+  test_points_b.push_back(gfx::Point3F(5.0f, 0.0f, 0.0f));
+  ValidatePoints(*(front_polygon.get()), test_points_a);
+  ValidatePoints(*(back_polygon.get()), test_points_b);
+
+  EXPECT_EQ(front_polygon->points.size(), static_cast<unsigned int>(4));
+  EXPECT_EQ(back_polygon->points.size(), static_cast<unsigned int>(4));
+}
+
+// A "wave" shape of points that do not make up those of a convex polygon
+// crossing the boundaries of another polygon. This should not cause a problem
+// and should still result in two different pieces of geometry on either side.
+TEST(DrawPolygonSplitTest, NonConvexSplit) {
+  std::vector<gfx::Point3F> vertices_a;
+  vertices_a.push_back(gfx::Point3F(0.0f, 10.0f, -5.0f));
+  vertices_a.push_back(gfx::Point3F(0.0f, 0.0f, -5.0f));
+  vertices_a.push_back(gfx::Point3F(0.0f, 0.0f, 5.0f));
+  vertices_a.push_back(gfx::Point3F(0.0f, 10.0f, 5.0f));
+  std::vector<gfx::Point3F> vertices_b;
+  vertices_b.push_back(gfx::Point3F(-3.0f, 10.0f, 0.0f));
+  vertices_b.push_back(gfx::Point3F(-1.0f, 7.5f, 0.0f));
+  vertices_b.push_back(gfx::Point3F(1.0f, 5.0f, 0.0f));
+  vertices_b.push_back(gfx::Point3F(3.0f, 7.5f, 0.0f));
+  vertices_b.push_back(gfx::Point3F(5.0f, 10.0f, 0.0f));
+  vertices_b.push_back(gfx::Point3F(7.0f, 7.5f, 0.0f));
+
+  CREATE_NEW_DRAW_POLYGON(polygon_a, vertices_a, 0);
+  CREATE_NEW_DRAW_POLYGON(polygon_b, vertices_b, 1);
+
+  EXPECT_EQ(DrawPolygon::SideCompare(polygon_b, polygon_a), BSP_SPLIT);
+
+  scoped_ptr<DrawPolygon> front_polygon;
+  scoped_ptr<DrawPolygon> back_polygon;
+  polygon_b.Split(polygon_a, &front_polygon, &back_polygon);
+  EXPECT_EQ(DrawPolygon::SideCompare(*front_polygon, polygon_a), BSP_FRONT);
+  EXPECT_EQ(DrawPolygon::SideCompare(*back_polygon, polygon_a), BSP_BACK);
+
+  std::vector<gfx::Point3F> test_points_a;
+  test_points_a.push_back(gfx::Point3F(0.0f, 9.25f, 0.0f));
+  test_points_a.push_back(gfx::Point3F(-3.0f, 10.0f, 0.0f));
+  test_points_a.push_back(gfx::Point3F(-1.0f, 7.5f, 0.0f));
+  test_points_a.push_back(gfx::Point3F(0.0f, 6.25f, 0.0f));
+  std::vector<gfx::Point3F> test_points_b;
+  test_points_b.push_back(gfx::Point3F(0.0f, 6.25f, 0.0f));
+  test_points_b.push_back(gfx::Point3F(1.0f, 5.0f, 0.0f));
+  test_points_b.push_back(gfx::Point3F(3.0f, 7.5f, 0.0f));
+  test_points_b.push_back(gfx::Point3F(5.0f, 10.0f, 0.0f));
+  test_points_b.push_back(gfx::Point3F(7.0f, 7.5f, 0.0f));
+  test_points_b.push_back(gfx::Point3F(0.0f, 9.25f, 0.0f));
+
+  ValidatePoints(*(front_polygon.get()), test_points_a);
+  ValidatePoints(*(back_polygon.get()), test_points_b);
+}
+
+// In this test we cut the corner of a quad so that it creates a triangle and
+// a pentagon as a result.
+TEST(DrawPolygonSplitTest, AngledSplit) {
+  std::vector<gfx::Point3F> vertices_a;
+  vertices_a.push_back(gfx::Point3F(0.0f, 0.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(0.0f, 0.0f, 10.0f));
+  vertices_a.push_back(gfx::Point3F(10.0f, 0.0f, 10.0f));
+  vertices_a.push_back(gfx::Point3F(10.0f, 0.0f, 0.0f));
+  std::vector<gfx::Point3F> vertices_b;
+  vertices_b.push_back(gfx::Point3F(2.0f, 5.0f, 1.0f));
+  vertices_b.push_back(gfx::Point3F(2.0f, -5.0f, 1.0f));
+  vertices_b.push_back(gfx::Point3F(-1.0f, -5.0f, -2.0f));
+  vertices_b.push_back(gfx::Point3F(-1.0f, 5.0f, -2.0f));
+
+  CREATE_NEW_DRAW_POLYGON(polygon_a, vertices_a, 0);
+  CREATE_NEW_DRAW_POLYGON(polygon_b, vertices_b, 1);
+
+  EXPECT_EQ(DrawPolygon::SideCompare(polygon_a, polygon_b), BSP_SPLIT);
+
+  scoped_ptr<DrawPolygon> front_polygon;
+  scoped_ptr<DrawPolygon> back_polygon;
+  polygon_a.Split(polygon_b, &front_polygon, &back_polygon);
+  EXPECT_EQ(DrawPolygon::SideCompare(*front_polygon, polygon_b), BSP_FRONT);
+  EXPECT_EQ(DrawPolygon::SideCompare(*back_polygon, polygon_b), BSP_BACK);
+
+  EXPECT_EQ(front_polygon->points.size(), static_cast<unsigned int>(3));
+  EXPECT_EQ(back_polygon->points.size(), static_cast<unsigned int>(5));
+
+  std::vector<gfx::Point3F> test_points_a;
+  test_points_a.push_back(gfx::Point3F(10.0f, 0.0f, 9.0f));
+  test_points_a.push_back(gfx::Point3F(10.0f, 0.0f, 0.0f));
+  test_points_a.push_back(gfx::Point3F(1.0f, 0.0f, 0.0f));
+  std::vector<gfx::Point3F> test_points_b;
+  test_points_b.push_back(gfx::Point3F(1.0f, 0.0f, 0.0f));
+  test_points_b.push_back(gfx::Point3F(0.0f, 0.0f, 0.0f));
+  test_points_b.push_back(gfx::Point3F(0.0f, 0.0f, 10.0f));
+  test_points_b.push_back(gfx::Point3F(10.0f, 0.0f, 10.0f));
+  test_points_b.push_back(gfx::Point3F(10.0f, 0.0f, 9.0f));
+
+  ValidatePoints(*(front_polygon.get()), test_points_a);
+  ValidatePoints(*(back_polygon.get()), test_points_b);
+}
+
+// Testing the area calculation on a basic flat 10x10 quad.
+TEST(DrawPolygonAreaTest, Basic) {
+  std::vector<gfx::Point3F> vertices_a;
+  vertices_a.push_back(gfx::Point3F(0.0f, 10.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(0.0f, 0.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(10.0f, 0.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(10.0f, 10.0f, 0.0f));
+
+  CREATE_NEW_DRAW_POLYGON(polygon_a, vertices_a, 0);
+
+  EXPECT_EQ(polygon_a.area, 100.0f);
+}
+
+// Test the area of an octagon. It can be seen as a quad with the the corners
+// all chopped off, removing 0.5 of the area at each corner from the previous
+// test.
+TEST(DrawPolygonAreaTest, OctagonArea) {
+  std::vector<gfx::Point3F> vertices_a;
+  vertices_a.push_back(gfx::Point3F(1.0f, 0.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(9.0f, 0.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(10.0f, 0.0f, 1.0f));
+  vertices_a.push_back(gfx::Point3F(10.0f, 0.0f, 9.0f));
+  vertices_a.push_back(gfx::Point3F(9.0f, 0.0f, 10.0f));
+  vertices_a.push_back(gfx::Point3F(1.0f, 0.0f, 10.0f));
+  vertices_a.push_back(gfx::Point3F(0.0f, 0.0f, 9.0f));
+  vertices_a.push_back(gfx::Point3F(0.0f, 0.0f, 1.0f));
+
+  CREATE_NEW_DRAW_POLYGON(polygon_a, vertices_a, 0);
+
+  EXPECT_EQ(polygon_a.area, 98.0f);
+}
+
+// Same quad as before, but with transformations applied to it. This shows that
+// the area calculation works on arbitrarily transformed geometry.
+TEST(DrawPolygonAreaTest, TransformedPolygon) {
+  std::vector<gfx::Point3F> vertices_a;
+  vertices_a.push_back(gfx::Point3F(0.0f, 10.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(0.0f, 0.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(10.0f, 0.0f, 0.0f));
+  vertices_a.push_back(gfx::Point3F(10.0f, 10.0f, 0.0f));
+
+  gfx::Transform transform;
+  transform.RotateAboutXAxis(30.0);
+  transform.RotateAboutYAxis(40.0);
+  transform.RotateAboutZAxis(50.0);
+  for (int i = 0; i < 4; i++) {
+    transform.TransformPoint(&vertices_a[i]);
+  }
+
+  CREATE_NEW_DRAW_POLYGON(polygon_a, vertices_a, 0);
+
+  EXPECT_EQ(polygon_a.area, 100.0f);
+}
+
+}  // namespace
+}  // namespace cc