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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/resources/layer_quad.h" | |
6 | |
7 #include "base/logging.h" | |
8 #include "ui/gfx/geometry/quad_f.h" | |
9 | |
10 namespace cc { | |
11 | |
12 LayerQuad::Edge::Edge(const gfx::PointF& p, const gfx::PointF& q) { | |
13 if (p == q) { | |
14 degenerate_ = true; | |
15 return; | |
16 } | |
17 degenerate_ = false; | |
18 gfx::Vector2dF tangent(p.y() - q.y(), q.x() - p.x()); | |
19 float cross2 = p.x() * q.y() - q.x() * p.y(); | |
20 | |
21 set(tangent.x(), tangent.y(), cross2); | |
22 scale(1.0f / tangent.Length()); | |
23 } | |
24 | |
25 gfx::PointF LayerQuad::Edge::Intersect(const LayerQuad::Edge& e) const { | |
26 DCHECK(!degenerate()); | |
27 DCHECK(!e.degenerate()); | |
28 | |
29 return gfx::PointF((y() * e.z() - e.y() * z()) / (x() * e.y() - e.x() * y()), | |
30 (x() * e.z() - e.x() * z()) / (e.x() * y() - x() * e.y())); | |
31 } | |
32 | |
33 LayerQuad::LayerQuad(const gfx::QuadF& quad) { | |
34 // Create edges. | |
35 left_ = Edge(quad.p4(), quad.p1()); | |
36 right_ = Edge(quad.p2(), quad.p3()); | |
37 top_ = Edge(quad.p1(), quad.p2()); | |
38 bottom_ = Edge(quad.p3(), quad.p4()); | |
39 | |
40 float sign = quad.IsCounterClockwise() ? -1 : 1; | |
41 left_.scale(sign); | |
42 right_.scale(sign); | |
43 top_.scale(sign); | |
44 bottom_.scale(sign); | |
45 } | |
46 | |
47 LayerQuad::LayerQuad(const Edge& left, | |
48 const Edge& top, | |
49 const Edge& right, | |
50 const Edge& bottom) | |
51 : left_(left), | |
52 top_(top), | |
53 right_(right), | |
54 bottom_(bottom) {} | |
55 | |
56 gfx::QuadF LayerQuad::ToQuadF() const { | |
57 size_t num_degenerate_edges = left_.degenerate() + right_.degenerate() + | |
58 top_.degenerate() + bottom_.degenerate(); | |
59 if (num_degenerate_edges > 1) { | |
60 return gfx::QuadF(); | |
61 } | |
62 | |
63 if (left_.degenerate()) { | |
64 return gfx::QuadF(top_.Intersect(bottom_), top_.Intersect(right_), | |
65 right_.Intersect(bottom_), bottom_.Intersect(top_)); | |
66 } | |
67 if (right_.degenerate()) { | |
68 return gfx::QuadF(left_.Intersect(top_), top_.Intersect(bottom_), | |
69 bottom_.Intersect(top_), bottom_.Intersect(left_)); | |
70 } | |
71 if (top_.degenerate()) { | |
72 return gfx::QuadF(left_.Intersect(right_), right_.Intersect(left_), | |
73 right_.Intersect(bottom_), bottom_.Intersect(left_)); | |
74 } | |
75 if (bottom_.degenerate()) { | |
76 return gfx::QuadF(left_.Intersect(top_), top_.Intersect(right_), | |
77 right_.Intersect(left_), left_.Intersect(right_)); | |
78 } | |
79 return gfx::QuadF(left_.Intersect(top_), | |
80 top_.Intersect(right_), | |
81 right_.Intersect(bottom_), | |
82 bottom_.Intersect(left_)); | |
83 } | |
84 | |
85 void LayerQuad::ToFloatArray(float flattened[12]) const { | |
86 if (left_.degenerate()) { | |
87 flattened[0] = bottom_.x(); | |
88 flattened[1] = bottom_.y(); | |
89 flattened[2] = bottom_.z(); | |
90 } else { | |
91 flattened[0] = left_.x(); | |
92 flattened[1] = left_.y(); | |
93 flattened[2] = left_.z(); | |
94 } | |
95 if (top_.degenerate()) { | |
96 flattened[3] = left_.x(); | |
97 flattened[4] = left_.y(); | |
98 flattened[5] = left_.z(); | |
99 } else { | |
100 flattened[3] = top_.x(); | |
101 flattened[4] = top_.y(); | |
102 flattened[5] = top_.z(); | |
103 } | |
104 if (right_.degenerate()) { | |
105 flattened[6] = top_.x(); | |
106 flattened[7] = top_.y(); | |
107 flattened[8] = top_.z(); | |
108 } else { | |
109 flattened[6] = right_.x(); | |
110 flattened[7] = right_.y(); | |
111 flattened[8] = right_.z(); | |
112 } | |
113 if (bottom_.degenerate()) { | |
114 flattened[9] = right_.x(); | |
115 flattened[10] = right_.y(); | |
116 flattened[11] = right_.z(); | |
117 } else { | |
118 flattened[9] = bottom_.x(); | |
119 flattened[10] = bottom_.y(); | |
120 flattened[11] = bottom_.z(); | |
121 } | |
122 } | |
123 | |
124 } // namespace cc | |
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