1 /*
2 * Copyright (C) 2008 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
14 * its contributors may be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include "config.h"
30 #include "FloatQuad.h"
31
32 #include <algorithm>
33
34 using std::max;
35 using std::min;
36
37 namespace WebCore {
38
min4(float a,float b,float c,float d)39 static inline float min4(float a, float b, float c, float d)
40 {
41 return min(min(a, b), min(c, d));
42 }
43
max4(float a,float b,float c,float d)44 static inline float max4(float a, float b, float c, float d)
45 {
46 return max(max(a, b), max(c, d));
47 }
48
dot(const FloatSize & a,const FloatSize & b)49 inline float dot(const FloatSize& a, const FloatSize& b)
50 {
51 return a.width() * b.width() + a.height() * b.height();
52 }
53
isPointInTriangle(const FloatPoint & p,const FloatPoint & t1,const FloatPoint & t2,const FloatPoint & t3)54 inline bool isPointInTriangle(const FloatPoint& p, const FloatPoint& t1, const FloatPoint& t2, const FloatPoint& t3)
55 {
56 // Compute vectors
57 FloatSize v0 = t3 - t1;
58 FloatSize v1 = t2 - t1;
59 FloatSize v2 = p - t1;
60
61 // Compute dot products
62 float dot00 = dot(v0, v0);
63 float dot01 = dot(v0, v1);
64 float dot02 = dot(v0, v2);
65 float dot11 = dot(v1, v1);
66 float dot12 = dot(v1, v2);
67
68 // Compute barycentric coordinates
69 float invDenom = 1.0f / (dot00 * dot11 - dot01 * dot01);
70 float u = (dot11 * dot02 - dot01 * dot12) * invDenom;
71 float v = (dot00 * dot12 - dot01 * dot02) * invDenom;
72
73 // Check if point is in triangle
74 return (u >= 0) && (v >= 0) && (u + v <= 1);
75 }
76
boundingBox() const77 FloatRect FloatQuad::boundingBox() const
78 {
79 float left = min4(m_p1.x(), m_p2.x(), m_p3.x(), m_p4.x());
80 float top = min4(m_p1.y(), m_p2.y(), m_p3.y(), m_p4.y());
81
82 float right = max4(m_p1.x(), m_p2.x(), m_p3.x(), m_p4.x());
83 float bottom = max4(m_p1.y(), m_p2.y(), m_p3.y(), m_p4.y());
84
85 return FloatRect(left, top, right - left, bottom - top);
86 }
87
isRectilinear() const88 bool FloatQuad::isRectilinear() const
89 {
90 return (m_p1.x() == m_p2.x() && m_p2.y() == m_p3.y() && m_p3.x() == m_p4.x() && m_p4.y() == m_p1.y())
91 || (m_p1.y() == m_p2.y() && m_p2.x() == m_p3.x() && m_p3.y() == m_p4.y() && m_p4.x() == m_p1.x());
92 }
93
containsPoint(const FloatPoint & p) const94 bool FloatQuad::containsPoint(const FloatPoint& p) const
95 {
96 return isPointInTriangle(p, m_p1, m_p2, m_p3) || isPointInTriangle(p, m_p1, m_p3, m_p4);
97 }
98
99 // Note that we only handle convex quads here.
containsQuad(const FloatQuad & other) const100 bool FloatQuad::containsQuad(const FloatQuad& other) const
101 {
102 return containsPoint(other.p1()) && containsPoint(other.p2()) && containsPoint(other.p3()) && containsPoint(other.p4());
103 }
104
105 } // namespace WebCore
106