1// Copyright 2011 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "cc/trees/layer_sorter.h"
6
7#include "cc/base/math_util.h"
8#include "cc/layers/layer_impl.h"
9#include "cc/test/fake_impl_proxy.h"
10#include "cc/test/fake_layer_tree_host_impl.h"
11#include "cc/test/test_shared_bitmap_manager.h"
12#include "cc/trees/single_thread_proxy.h"
13#include "testing/gtest/include/gtest/gtest.h"
14#include "ui/gfx/transform.h"
15
16namespace cc {
17namespace {
18
19// Note: In the following overlap tests, the "camera" is looking down the
20// negative Z axis, meaning that layers with smaller z values (more negative)
21// are further from the camera and therefore must be drawn before layers with
22// higher z values.
23
24TEST(LayerSorterTest, BasicOverlap) {
25  LayerSorter::ABCompareResult overlap_result;
26  const float z_threshold = 0.1f;
27  float weight = 0.f;
28
29  // Trivial test, with one layer directly obscuring the other.
30  gfx::Transform neg4_translate;
31  neg4_translate.Translate3d(0.0, 0.0, -4.0);
32  LayerShape front(2.f, 2.f, neg4_translate);
33
34  gfx::Transform neg5_translate;
35  neg5_translate.Translate3d(0.0, 0.0, -5.0);
36  LayerShape back(2.f, 2.f, neg5_translate);
37
38  overlap_result =
39      LayerSorter::CheckOverlap(&front, &back, z_threshold, &weight);
40  EXPECT_EQ(LayerSorter::BBeforeA, overlap_result);
41  EXPECT_EQ(1.f, weight);
42
43  overlap_result =
44      LayerSorter::CheckOverlap(&back, &front, z_threshold, &weight);
45  EXPECT_EQ(LayerSorter::ABeforeB, overlap_result);
46  EXPECT_EQ(1.f, weight);
47
48  // One layer translated off to the right. No overlap should be detected.
49  gfx::Transform right_translate;
50  right_translate.Translate3d(10.0, 0.0, -5.0);
51  LayerShape back_right(2.f, 2.f, right_translate);
52  overlap_result =
53      LayerSorter::CheckOverlap(&front, &back_right, z_threshold, &weight);
54  EXPECT_EQ(LayerSorter::None, overlap_result);
55
56  // When comparing a layer with itself, z difference is always 0.
57  overlap_result =
58      LayerSorter::CheckOverlap(&front, &front, z_threshold, &weight);
59  EXPECT_EQ(0.f, weight);
60}
61
62TEST(LayerSorterTest, RightAngleOverlap) {
63  LayerSorter::ABCompareResult overlap_result;
64  const float z_threshold = 0.1f;
65  float weight = 0.f;
66
67  gfx::Transform perspective_matrix;
68  perspective_matrix.ApplyPerspectiveDepth(1000.0);
69
70  // Two layers forming a right angle with a perspective viewing transform.
71  gfx::Transform left_face_matrix;
72  left_face_matrix.Translate3d(-1.0, 0.0, -5.0);
73  left_face_matrix.RotateAboutYAxis(-90.0);
74  left_face_matrix.Translate(-1.0, -1.0);
75  LayerShape left_face(2.f, 2.f, perspective_matrix * left_face_matrix);
76  gfx::Transform front_face_matrix;
77  front_face_matrix.Translate3d(0.0, 0.0, -4.0);
78  front_face_matrix.Translate(-1.0, -1.0);
79  LayerShape front_face(2.f, 2.f, perspective_matrix * front_face_matrix);
80
81  overlap_result =
82      LayerSorter::CheckOverlap(&front_face, &left_face, z_threshold, &weight);
83  EXPECT_EQ(LayerSorter::BBeforeA, overlap_result);
84}
85
86TEST(LayerSorterTest, IntersectingLayerOverlap) {
87  LayerSorter::ABCompareResult overlap_result;
88  const float z_threshold = 0.1f;
89  float weight = 0.f;
90
91  gfx::Transform perspective_matrix;
92  perspective_matrix.ApplyPerspectiveDepth(1000.0);
93
94  // Intersecting layers. An explicit order will be returned based on relative z
95  // values at the overlapping features but the weight returned should be zero.
96  gfx::Transform front_face_matrix;
97  front_face_matrix.Translate3d(0.0, 0.0, -4.0);
98  front_face_matrix.Translate(-1.0, -1.0);
99  LayerShape front_face(2.f, 2.f, perspective_matrix * front_face_matrix);
100
101  gfx::Transform through_matrix;
102  through_matrix.Translate3d(0.0, 0.0, -4.0);
103  through_matrix.RotateAboutYAxis(45.0);
104  through_matrix.Translate(-1.0, -1.0);
105  LayerShape rotated_face(2.f, 2.f, perspective_matrix * through_matrix);
106  overlap_result = LayerSorter::CheckOverlap(&front_face,
107                                             &rotated_face,
108                                             z_threshold,
109                                             &weight);
110  EXPECT_NE(LayerSorter::None, overlap_result);
111  EXPECT_EQ(0.f, weight);
112}
113
114TEST(LayerSorterTest, LayersAtAngleOverlap) {
115  LayerSorter::ABCompareResult overlap_result;
116  const float z_threshold = 0.1f;
117  float weight = 0.f;
118
119  // Trickier test with layers at an angle.
120  //
121  //   -x . . . . 0 . . . . +x
122  // -z             /
123  //  :            /----B----
124  //  0           C
125  //  : ----A----/
126  // +z         /
127  //
128  // C is in front of A and behind B (not what you'd expect by comparing
129  // centers). A and B don't overlap, so they're incomparable.
130
131  gfx::Transform transform_a;
132  transform_a.Translate3d(-6.0, 0.0, 1.0);
133  transform_a.Translate(-4.0, -10.0);
134  LayerShape layer_a(8.f, 20.f, transform_a);
135
136  gfx::Transform transform_b;
137  transform_b.Translate3d(6.0, 0.0, -1.0);
138  transform_b.Translate(-4.0, -10.0);
139  LayerShape layer_b(8.f, 20.f, transform_b);
140
141  gfx::Transform transform_c;
142  transform_c.RotateAboutYAxis(40.0);
143  transform_c.Translate(-4.0, -10.0);
144  LayerShape layer_c(8.f, 20.f, transform_c);
145
146  overlap_result =
147      LayerSorter::CheckOverlap(&layer_a, &layer_c, z_threshold, &weight);
148  EXPECT_EQ(LayerSorter::ABeforeB, overlap_result);
149  overlap_result =
150      LayerSorter::CheckOverlap(&layer_c, &layer_b, z_threshold, &weight);
151  EXPECT_EQ(LayerSorter::ABeforeB, overlap_result);
152  overlap_result =
153      LayerSorter::CheckOverlap(&layer_a, &layer_b, z_threshold, &weight);
154  EXPECT_EQ(LayerSorter::None, overlap_result);
155}
156
157TEST(LayerSorterTest, LayersUnderPathologicalPerspectiveTransform) {
158  LayerSorter::ABCompareResult overlap_result;
159  const float z_threshold = 0.1f;
160  float weight = 0.f;
161
162  // On perspective projection, if w becomes negative, the re-projected point
163  // will be invalid and un-usable. Correct code needs to clip away portions of
164  // the geometry where w < 0. If the code uses the invalid value, it will think
165  // that a layer has different bounds than it really does, which can cause
166  // things to sort incorrectly.
167
168  gfx::Transform perspective_matrix;
169  perspective_matrix.ApplyPerspectiveDepth(1);
170
171  gfx::Transform transform_a;
172  transform_a.Translate3d(-15.0, 0.0, -2.0);
173  transform_a.Translate(-5.0, -5.0);
174  LayerShape layer_a(10.f, 10.f, perspective_matrix * transform_a);
175
176  // With this sequence of transforms, when layer B is correctly clipped, it
177  // will be visible on the left half of the projection plane, in front of
178  // layer_a. When it is not clipped, its bounds will actually incorrectly
179  // appear much smaller and the correct sorting dependency will not be found.
180  gfx::Transform transform_b;
181  transform_b.Translate3d(0.f, 0.f, 0.7f);
182  transform_b.RotateAboutYAxis(45.0);
183  transform_b.Translate(-5.0, -5.0);
184  LayerShape layer_b(10.f, 10.f, perspective_matrix * transform_b);
185
186  // Sanity check that the test case actually covers the intended scenario,
187  // where part of layer B go behind the w = 0 plane.
188  gfx::QuadF test_quad = gfx::QuadF(gfx::RectF(-0.5f, -0.5f, 1.f, 1.f));
189  bool clipped = false;
190  MathUtil::MapQuad(perspective_matrix * transform_b, test_quad, &clipped);
191  ASSERT_TRUE(clipped);
192
193  overlap_result =
194      LayerSorter::CheckOverlap(&layer_a, &layer_b, z_threshold, &weight);
195  EXPECT_EQ(LayerSorter::ABeforeB, overlap_result);
196}
197
198TEST(LayerSorterTest, VerifyExistingOrderingPreservedWhenNoZDiff) {
199  // If there is no reason to re-sort the layers (i.e. no 3d z difference), then
200  // the existing ordering provided on input should be retained. This test
201  // covers the fix in https://bugs.webkit.org/show_bug.cgi?id=75046. Before
202  // this fix, ordering was accidentally reversed, causing bugs in z-index
203  // ordering on websites when preserves3D triggered the LayerSorter.
204
205  // Input list of layers: [1, 2, 3, 4, 5].
206  // Expected output: [3, 4, 1, 2, 5].
207  //    - 1, 2, and 5 do not have a 3d z difference, and therefore their
208  //      relative ordering should be retained.
209  //    - 3 and 4 do not have a 3d z difference, and therefore their relative
210  //      ordering should be retained.
211  //    - 3 and 4 should be re-sorted so they are in front of 1, 2, and 5.
212
213  FakeImplProxy proxy;
214  TestSharedBitmapManager shared_bitmap_manager;
215  FakeLayerTreeHostImpl host_impl(&proxy, &shared_bitmap_manager);
216
217  scoped_ptr<LayerImpl> layer1 = LayerImpl::Create(host_impl.active_tree(), 1);
218  scoped_ptr<LayerImpl> layer2 = LayerImpl::Create(host_impl.active_tree(), 2);
219  scoped_ptr<LayerImpl> layer3 = LayerImpl::Create(host_impl.active_tree(), 3);
220  scoped_ptr<LayerImpl> layer4 = LayerImpl::Create(host_impl.active_tree(), 4);
221  scoped_ptr<LayerImpl> layer5 = LayerImpl::Create(host_impl.active_tree(), 5);
222
223  gfx::Transform BehindMatrix;
224  BehindMatrix.Translate3d(0.0, 0.0, 2.0);
225  gfx::Transform FrontMatrix;
226  FrontMatrix.Translate3d(0.0, 0.0, 1.0);
227
228  layer1->SetBounds(gfx::Size(10, 10));
229  layer1->SetContentBounds(gfx::Size(10, 10));
230  layer1->draw_properties().target_space_transform = BehindMatrix;
231  layer1->SetDrawsContent(true);
232
233  layer2->SetBounds(gfx::Size(20, 20));
234  layer2->SetContentBounds(gfx::Size(20, 20));
235  layer2->draw_properties().target_space_transform = BehindMatrix;
236  layer2->SetDrawsContent(true);
237
238  layer3->SetBounds(gfx::Size(30, 30));
239  layer3->SetContentBounds(gfx::Size(30, 30));
240  layer3->draw_properties().target_space_transform = FrontMatrix;
241  layer3->SetDrawsContent(true);
242
243  layer4->SetBounds(gfx::Size(40, 40));
244  layer4->SetContentBounds(gfx::Size(40, 40));
245  layer4->draw_properties().target_space_transform = FrontMatrix;
246  layer4->SetDrawsContent(true);
247
248  layer5->SetBounds(gfx::Size(50, 50));
249  layer5->SetContentBounds(gfx::Size(50, 50));
250  layer5->draw_properties().target_space_transform = BehindMatrix;
251  layer5->SetDrawsContent(true);
252
253  LayerImplList layer_list;
254  layer_list.push_back(layer1.get());
255  layer_list.push_back(layer2.get());
256  layer_list.push_back(layer3.get());
257  layer_list.push_back(layer4.get());
258  layer_list.push_back(layer5.get());
259
260  ASSERT_EQ(5u, layer_list.size());
261  EXPECT_EQ(1, layer_list[0]->id());
262  EXPECT_EQ(2, layer_list[1]->id());
263  EXPECT_EQ(3, layer_list[2]->id());
264  EXPECT_EQ(4, layer_list[3]->id());
265  EXPECT_EQ(5, layer_list[4]->id());
266
267  LayerSorter layer_sorter;
268  layer_sorter.Sort(layer_list.begin(), layer_list.end());
269
270  ASSERT_EQ(5u, layer_list.size());
271  EXPECT_EQ(3, layer_list[0]->id());
272  EXPECT_EQ(4, layer_list[1]->id());
273  EXPECT_EQ(1, layer_list[2]->id());
274  EXPECT_EQ(2, layer_list[3]->id());
275  EXPECT_EQ(5, layer_list[4]->id());
276}
277
278TEST(LayerSorterTest, VerifyConcidentLayerPrecisionLossResultsInDocumentOrder) {
279  FakeImplProxy proxy;
280  TestSharedBitmapManager shared_bitmap_manager;
281  FakeLayerTreeHostImpl host_impl(&proxy, &shared_bitmap_manager);
282
283  scoped_ptr<LayerImpl> layer1 = LayerImpl::Create(host_impl.active_tree(), 1);
284  scoped_ptr<LayerImpl> layer2 = LayerImpl::Create(host_impl.active_tree(), 2);
285
286  // Layer 1 should occur before layer 2 in paint.  However, due to numeric
287  // issues in the sorter, it will put the layers in the wrong order
288  // in some situations.  Here we test a patch that results in  document
289  // order rather than calculated order when numeric percision is suspect
290  // in calculated order.
291
292  gfx::Transform BehindMatrix;
293  BehindMatrix.Translate3d(0.f, 0.f, 0.999999f);
294  BehindMatrix.RotateAboutXAxis(38.5);
295  BehindMatrix.RotateAboutYAxis(77.0);
296  gfx::Transform FrontMatrix;
297  FrontMatrix.Translate3d(0, 0, 1.0);
298  FrontMatrix.RotateAboutXAxis(38.5);
299  FrontMatrix.RotateAboutYAxis(77.0);
300
301  layer1->SetBounds(gfx::Size(10, 10));
302  layer1->SetContentBounds(gfx::Size(10, 10));
303  layer1->draw_properties().target_space_transform = BehindMatrix;
304  layer1->SetDrawsContent(true);
305
306  layer2->SetBounds(gfx::Size(10, 10));
307  layer2->SetContentBounds(gfx::Size(10, 10));
308  layer2->draw_properties().target_space_transform = FrontMatrix;
309  layer2->SetDrawsContent(true);
310
311  LayerImplList layer_list;
312  layer_list.push_back(layer1.get());
313  layer_list.push_back(layer2.get());
314
315  ASSERT_EQ(2u, layer_list.size());
316  EXPECT_EQ(1, layer_list[0]->id());
317  EXPECT_EQ(2, layer_list[1]->id());
318
319  LayerSorter layer_sorter;
320  layer_sorter.Sort(layer_list.begin(), layer_list.end());
321
322  ASSERT_EQ(2u, layer_list.size());
323  EXPECT_EQ(1, layer_list[0]->id());
324  EXPECT_EQ(2, layer_list[1]->id());
325}
326
327}  // namespace
328}  // namespace cc
329
330