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
34using std::max;
35using std::min;
36
37namespace WebCore {
38
39static inline float min4(float a, float b, float c, float d)
40{
41    return min(min(a, b), min(c, d));
42}
43
44static inline float max4(float a, float b, float c, float d)
45{
46    return max(max(a, b), max(c, d));
47}
48
49inline float dot(const FloatSize& a, const FloatSize& b)
50{
51    return a.width() * b.width() + a.height() * b.height();
52}
53
54inline 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
77FloatRect 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
88bool 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
94bool 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.
100bool 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